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motoxy
03-01-2012, 09:46 PM
Hi guys. This is my first attempt at building anything like this myself. I have a history in motorcycles for 45 years and used to be a mech eng designer. Its a bit diferant without a full blown workshop doing your bidding. This project has a limitation on funds but I will not skimp if possible.

As it is the first I have decided to make a torsion box base. If this all works then I can upgade to a metal frame later. I also thought that linear rail bearings would be better than bearings on angles.

I realise that regidity is essential so the y gantry has been constructed from 10mm Ally. Although it came cheap the angle was not exactly 90deg :rolleyes:. Bit of patience and it appears to be fairly accurate. When the rails arrive for it the will be measured off the x rails to locate. If it ends up being too heavy then I can cut sections out to lighten the load. It rolls well but inertia maybe a problem.

I have ordered ballscrew, 2 for the x and 1 for the y. My next decision is stepper size (3nm maybe) and whether to build or buy the z.

Comments are always welcome. Already had great advice on spindle choice.

Bruce

Jonathan
04-01-2012, 11:40 AM
I too started with my X-axis rails mounted to a torsion box made from MDF/pine with a gap left either side to hide the 2 leadscrews. I'm still using the torsion box as the machine bed. Making the steel frame for mine made a huge difference. What size are your X-axis rails, they look like only SBR16 or 20mm?

Plate is weak for the gantry since when the machine is cutting parallel to X the cutting force will try and bend the gantry, and that's in the direction that's worst for a rectangular cross section. It's also the worst cross section to choose for twisting. Adding extrusion, or more plate perpendicular to it to the back would help, but you could try it and see and make sure you leave space to add it at a later date if required. What is the width of the plate, so I can calculate the deflection (roughly)?

I'd be inclined to add some triangular pieces to the aluminium angle to stop that flexing.

3nm is a good choice for the stepper motors. Lots of people, including me, use them. If you can afford 70 volt drivers (like MDS752) then you will get a higher feedrate than 50V (like MDS542), but it's more difficult/expensive to find/make a suitable power supply. The mass/inertia of the gantry is not a problem with these motors. Chip's and mine (and many others) using the same motors weigh a lot more.

Have you bought the ballscrews yet? If not then get 10mm pitch (RM1610) for X/Y to get a higher feedrate and use HTD timing pulleys (although 1:1 ratio is about right for those motors and 10mm pitch screws adding the pulleys still helps as it reduces resonance). 5mm pitch screws (RM1605) will work but it wont go anywhere near as fast, or more importantly the acceleration will be less and possibly vibrate more as the screw is spinning twice as fast.

motoxy
04-01-2012, 01:28 PM
Thanks for the heads up guys. All the material is 10 mm thick and 150mm wide. I had wondered about the the plate for the gantry but thought I could add box/angle to the back if required. the rails are 16mm

Unfortunately I have already ordered the lead screws and they are rm1605. I really should ask first DOH!. I am going to look into ordering the motors controllers this week sometime.

The angles on the rails were left hanging for, just as you say, the support for the nut on each side. I also thought that this allowed for the Y screw supports to be further apart and thus allowing me to use more of the bed width.

I really appreciate all your help guys
Bruce

motoxy
04-01-2012, 06:25 PM
x and y screws plus the y rails arrived today. Had a thought about the gantry design and have to agre especially with the angle on the rails. Looks like a bit of a rebuild required. I will also have to think about the z gantry.

Swarfing
04-01-2012, 07:28 PM
Jonathan


Have you bought the ballscrews yet? If not then get 10mm pitch (RM1610) for X/Y to get a higher feedrate and use HTD timing pulleys (although 1:1 ratio is about right for those motors and 10mm pitch screws adding the pulleys still helps as it reduces resonance). 5mm pitch screws (RM1605) will work but it wont go anywhere near as fast, or more importantly the acceleration will be less and possibly vibrate more as the screw is spinning twice as fast.

He is using an MDF box and i think the screws he has ordered are much more suitable, you need to stop pressing everyone with the need for speed? shake rattle and role will not bode well here.

Bruce your screws will be just fine for the application you have there.

Jonathan
04-01-2012, 07:34 PM
He is using an MDF box

So was I, and I am now though it's no longer there for strength. To start with that will be a limiting factor, but there's always the option to add a steel frame ... or even a simple rectangle on the bed made from steel box would help a lot.


you need to stop pressing everyone with the need for speed? shake rattle and role will not bode well here.

That's why I mentioned you'll get better *acceleration* with 10mm pitch screws, and less vibration from the screw as it's not spinning so fast. I agree high rapid speeds are pretty much useless, but good acceleration is important. When I cut the mayan calender using lower aceleration values (as I was limited by the computer) than Jazz did added over an hour to the time it took. That's quite an extreme example admittedly, but the general trend is true.

Yes they will work fine, but not as well as could have been.

Swarfing
04-01-2012, 07:39 PM
The problem is every time you mention 1610 screws it makes it sound like everybody has to rush out and buy them?????? just remember to when you first started mister and how difficult it was. I use 1605 screws and belts on mine and it is more than enough for it's job, i could have my X axis twice as fast as yours with the belt but it would be pointless.

Thats it my rant is over and i'm stepping back from the computer for a cup of tea.

motoxy
04-01-2012, 08:06 PM
I can appreciate both sides of the argument. My mistake was getting confused on some of the other sites and deciding to go it alone.....and then finding you guys. This is not a quick project and will take some time. I have many commitments between my work as a landscaper and my wood turning as well as other Things. Need to decide on the z so I can order parts for it. Probably just use a plate with 2 rails I still have some of the 10mm plate left. I will have to order some rails and a short ball screw.

Jonathan
04-01-2012, 08:21 PM
The problem is every time you mention 1610 screws it makes it sound like everybody has to rush out and buy them??????


In my opinion 1605 has very few advantages over 1610 for a router, which is why I recommend it so often.


just remember to when you first started mister and how difficult it was.

When I was designing my router, the rotating ballnut design was far more difficult that picking the ballscrew, but that's just my opinion.


I use 1605 screws and belts on mine and it is more than enough for it's job, i could have my X axis twice as fast as yours with the belt but it would be pointless.

Even if you manage to get 60m/min, it will only be for a short time before failure. Realistically it's impossible. In terms of speed and acceleration 1610 screws outperform 1605 by a large margin. Even hypothetically running a 1605 at 2:1 is still inferior in performance to a 1610 at 1:1 due to higher K.E.

I started with a 2mm pitch screw on Y and 2.5mm on X since that was the biggest I could afford at the time (not ballscrews), and I made a rotating nut for X to compensate and that funny wonky bearing drive, that I wish there was a simple name for, on Y to lower the friction.

Swarfing
04-01-2012, 08:28 PM
Bruce i apologies for tramping your thread but things like this puts doubt in new comers minds and they then abandon their projects because it gets too expensive. Advice on your Z though is definitely not go for 1610 screw enless you are using high powered steppers. The greater the thread angle the easier it is for the stepper to not be able take the weight. Please do not ignore Jonathan's advice as he has a lot of experience learned first hand. Just stick to your budget and if it is not enough for what you really need then save rather than waste it on buying the first thing that comes along.

A great effort on your build so far

motoxy
04-01-2012, 08:48 PM
Hey I enjoy seeing people put their theorise to the test. I have a budget but I also like do the best I can. As I already have the screws then thats fine. The upgrade to a water cooled spindle was good advice and still stays , just, in budget. If I cannot afford it then as you say I will save. Biggest problem is deciding in what order to buy stuff.

I will do a sketchup of my gantry redesign and get some coments. probably at the weekend.

Thanks again
Bruce

motoxy
05-01-2012, 12:17 AM
Right...cough... remember when you were a young engineer you always had to know how things worked. I remember taking a clock apart, and my electric train, my mums iron. Then I got into motorcycles and that was great fun. been doing it for 45 years with varying degrees of success. Always have to find out how they work and maybe put them back together. Well.. oh dear I am not sure how to say this....I was very interested in exactly how the ball screw worked. You guessed it. I unscrewed it and the balls fell out. After spending the last hour trying to rebuild it I realised that the plastic bungs are where they put the balls in and then press hot plastic in to close it off. Is this now an ex ballscrew system or is it fixable? Thankfully it was the shorter one if it has to be replaced.
On that high note of failure goodnight

Bruce (yes i am going to spend the night standing in the corner)

Jonathan
05-01-2012, 12:32 AM
Just to be clear, all my previous comments about 10mm over 5mm pitch were referring only to X and Y. Also a 5mm pitch screw can still backdrive on Z (mine does) if it's aligned well.

I took the ballnut off once just to see what all the fuss was about. I spend a while trying various methods of poking the balls back it which didn't really work. The easiest way (other than buying just a new ballnut) is to get a very strong magnet and stick it to the side of the ballnut. then you can carefully place the balls back in one after the other as they'll stick to the nut inside. Then you machine/find a bar that's just under the pitch diameter of the ballscrew minus the diameter of one ball so it just slides in (doesn't have to be accurate as long as the balls can't fall out). Introduce the ballscrew into the nut allowing it to push out the bar as you turn it on. Only took about 10 mins once I'd found the magnet (2"x1"x0.5" neodymium).

You can also try putting grease on the balls so they stick to the nut inside, but that's not as effective as the magnet. I think you should demagnetise the nut afterwards.

motoxy
05-01-2012, 12:48 AM
You university boys so darn clever. This is definatly something to tackle at the weekend.

Good night all

bruce

JAZZCNC
05-01-2012, 10:30 PM
In terms of speed and acceleration 1610 screws outperform 1605 by a large margin. Even hypothetically running a 1605 at 2:1 is still inferior in performance to a 1610 at 1:1 due to higher K.E.


Ok can't resist got to jump in.!!!:twisted: . . . Don't need to worry about 5mm pitch being inferior because of K:E bull shit etc because it don't mean jack shit for a DIY machine, it will still perform more than good enough.! . . ( If built good enough.!!)

Yes jonathan's correct when he points out that the calculated physics way of looking at it that 10mm pitch wins for a router!. . . BUT. . . I can tell you because my machine use's 5mm pitch geared 2:1 it's absolutly no problem and in no way limits the performance. Actually IMO it's a bennifit because it's just a simple belt/pulley change to gain resolution.

That said I agree that 10mm pitch (except Z axis then 5mm) would be better choice for a router which mainly cuts wood or plastics. Anything harder IE Ali etc and then extra speed 10mm pitch gains is wasted as the feed rates dictate. 99.9% of the time you'll be lucky to cut any where near quarter the speed 10mm pitch allows.!

An often over looked and misunderstood area which Jonathan touched upon earlier is acceleration.!! . . . IMO and experience for most jobs (Esp 3D) that don't need high feeds (2mtr/min or less) then your much better off tuning your motors to give higher accel than velocity. . . Often less is more.. . Like in the Aztec case where there are lots of short moves it can and does often make job's faster. 3D and v-carving really see the most increase's from high accelleration.

I use Mach3 and it's such a simple job to create profiles that you can easily tailor for specific job types or conditions. IE I have 3D profile tuned for Accelleration. 5mm pitch profile (pulley/belt change)for when resolution needed. I also have profiles for Inch units for each so when I get given code that use's imperial measurements I don't have to fanny about changing settings or code.
Doing it this way makes it very simple and quick to change from one to the other.

So Like 2eOpoz I 100% agree 5mm pitch will be fine in your case.!. . . . BUT . . . 100% Agree with jonathan 10mm pitch rules for a wood/plastic router.

Anyway the screw pitch or speed will be the least of your troubles if you don't beef that gantry up.!!

motoxy
05-01-2012, 10:57 PM
Ok Ok I promise to do a redesign on the gantry:rolleyes:. I have learnt more in a few days here, mainly how little I know but I am so grateful for all your help.

Jonathan
06-01-2012, 12:10 AM
Don't need to worry about being inferior because of K:E bull shit

I think you'll find just about everyone apart from you agrees kinetic energy isn't 'bull shit' and is very important, I'm not even going to argue this point because it's so widely accepted. No matter if a machine is made in a home workshop or professionally, it can't escape the laws of physics. A 3nm Nema 34 motor wont go as fast as a 3nm Nema 23, it's due to exactly the same calculation!


my machine use's 5mm pitch geared 2:1 it's absolutly no problem and in no way limits the performance. Actually IMO it's a bennifit because it's just a simple belt/pulley change to gain resolution.

As far as I'm aware you've not tried 10mm pitch rails on your router, so I can't see how you could possibly know that. I'm well aware that you don't respect calculation, and that might well be true for you, but for just about everyone else, calculation plays a hugely important role, and if it didn't work like you say, the theory simply wouldn't be there.


it's just a simple belt/pulley change to gain resolution

That clearly also applies to 1610 so it's not a benefit. Since you only recognise empirical evidence, your version of the Mayan calender I cut on 1:1 looks amazing.


99.9% of the time you'll be lucky to cut any where near quarter the speed 10mm pitch allows.!

It's not about cutting faster, it's the acceleration gain from using 10mm pitch that's most important. You told me your acceleration on the Y-axis is 900mm/s/s, with 5mm pitch. I now have mine set to 2000mm/s/s with 10mm pitch (more shakes the machine too much).

I get the impression you think I'm saying 5mm pitch won't work, seeing as you say "it will work fine". I agree with that, but when designing a machine I think it's foolish to aim for it working fine, you should aim for it to work as well as possible, not just well enough and 5mm pitch screws will simply limit the potential of your machine.

I'm not going to say anything more on the subject since apparently it provokes a particularly strong reaction, I think motoxy has all the info to make an educated decision. Good luck.

Motoxy: There's a quote for that - The more I know, I know, I know the less. (John Owen)

Swarfing
06-01-2012, 12:38 AM
Dog with Bone? :rofl:

JAZZCNC
06-01-2012, 01:27 AM
Jonathan . . .My point was that 5mm pitch geared 2:1 works fine because I use it.!. So all your bullshit spouting about K:E means sweet F:A whether nema 23 or 34 because for 99% of DIY use both are far more than good enough.

Also If you look again ya touchy lickle git you'll see I agreed with you on the 10mm pitch.!!


Presumption is the mother of all F:U.!! . . . SO NOW. . How the F~@K do you know what I've done or not done with my machine.? Or any other machine for that matter.:exclaim: . . . . . reading a few old post's don't make you Physic Sally.:mad:

If you want to get into machine design and foolish ness. My approach is that you build a machine to be strong and accurate as possible to do the best it can at it's intended purpose.! .. . To build with just speed in mind at the sacrifice of accurecy, repeatabilty resulting in poor quality in-accurate work.!!. . . is plane stupidity IMO.

Now wasn't having a go at you or saying what you said was wrong or wouldn't work so suck your petty lip back in and drop it.!:tup:

Swarfing
06-01-2012, 01:43 PM
ok but no kissing please:heehee:

wiatroda
06-01-2012, 03:13 PM
I wonder what would happen to lock in Jazz and Jonathan in a big brother house. Make them to make ONE cnc machine.
That would be most interesting BB ever. For a first time I would watch it.

JAZZCNC
06-01-2012, 03:53 PM
I wonder what would happen to lock in Jazz and Jonathan in a big brother house. Make them to make ONE cnc machine.
That would be most interesting BB ever. For a first time I would watch it.

Easy question to answer.!!. . . My bezzy mate and I would agree to disagree then have it built in record time both hopefully learning something new in the process:tup:

wiatroda
06-01-2012, 04:09 PM
For me and I bet for many others both of you are great source of knowledge and experience. You just have totally different approach hence you are great contributions to this forum complementing one another.
Both of you developing one project would create perfect WHOLE :tup:

JAZZCNC
06-01-2012, 04:14 PM
LMFAO. . . I've got to tell you my son's response to seeing me smiling to my self while writing that.!

" No you wouldn't, You'd test the Moment of inertia of his head with the ballscrews to see if they produced enough Kenetic energy to clear the Big Wall"

Personally I don't know why he'd think that.?? . . . . I didn't know there was Big wall:naughty:

wiatroda
06-01-2012, 04:38 PM
LMFAO. . .

" No you wouldn't, You'd test the Moment of inertia of his head with the ballscrews to see if they produced enough Kenetic energy to clear the Big Wall"

Personally I don't know why he'd think that.?? . . . . I didn't know there was Big wall:naughty:
:rofl::rofl::rofl: Did he mean Big Wall around Big Brother' house?:rofl:
So you would do empiric aspect of the job , leaving formulas and calculation for Jonathan ??:naughty:

motoxy
06-01-2012, 05:59 PM
Jonathan - i am having that quote as my signature. Thanks.

As for all the spat Your both absolutely right. Without calculations we would have no idea what could be achieved. But suck it and see can be so much fun. Somewhere in the middle would be where you find success.

Now if its alright with you guys I would like to have my thread back. :wave:

I have thought about my gantry today. Repairing fences can be boring. How about 80 x 40 Al profile as the cross rail with the 10mm thick ally side fixed to cut down version of the 10mm thick angle? I will draw over the weekend.

Bruce
Value frame are cheaper than marchant and dice.

motoxy
07-01-2012, 09:33 PM
Just been given an old computer for the project. Checked it out....chucked it out. Boy some comps are really old.

Got the balls back in the screw but i will have to make up a guide tomorrow as they push out when you try to screw it together.
I am going to check out my supplier to see what ally box he as available and will then decide what to do about the gantry.

Bruce

Swarfing
07-01-2012, 09:40 PM
Bruce roll up some cereal packet cardboard for now and find something to pack the middle out once inside.

motoxy
07-01-2012, 09:55 PM
2e0poz you are yet another genius on this site....I have a functioning ball screw. Thanks everyone for your help. Nice to realise I am not the only curious one on this site that justhad to look inside:wink:

Bruce

Jonathan
07-01-2012, 10:12 PM
The main problem with the 150x10mm plate is that that cross section has very poor torsional stiffness. The deflection neglecting twisting is not too bad, though it can easily be improved. Torsional stiffness is very important since the Z-axis acts as a lever applying a large moment to the gantry, so poor torsional stiffness leads to high tool deflection = chatter, poor finish, lower loot life and not being able to cut aluminium well.

The best cross section for torsional stiffness is one where as much material as possible if far from the centroid, that's clearly a tube, and since the stiffness constant is proportional to the radius to the power 4, a small increase in wall thickness or diameter has a big effect. Unfortunately it's rather difficult to attach rails to a curved surface! So the next best thing is to use box section. As a reference, the torsional stiffness of 80x80mm aluminium box section, with just 3mm wall thickness, which is what I use on my machine is almost 40 times greater than 150x10 plate. For forces parallel to X (i.e. orthogonal to the gantry) the stiffness is also significantly greater for that size box section.

If you add two pieces of 50x10mm aluminium to the plate, attaching 10mm surface to the top and bottom of the 150mm surface, the deflection parallel to X is massively reduced (to the point where it's about equal to that for the box section) however the torsional stiffness is still 16 times less than my box section. Add a thin plate on the back (3mm or whatever) and it's a whole lot better. But then you've effectively just make a box section! Adding aluminium profile could work to, but bear in mind the same rules as in this little example apply (look at the cross section of the aluminium profile).

Perhaps you could instead use the 150x10 for the Z-axis (as torsional stiffness there is irrelevant) and add the plates as above to the Z-axis as 10mm is probably not enough on its own.

Hope that helps / gives you some ideas.

Another important factor is the rigidity of the joints between the piece(s) between the gantry, so bolt it well. Doesn't matter how rigid the beam is, if the ends are not connected firmly it will bend and the joints. At the moment you want some more bolts nearer the edge of the aluminium angle, but I guess you've just not got round to putting those in yet.

(Note in the calculations above I didn't take into account the rails themselves. These will add to the strength, but I think relying on the strength of the rails to make the gantry sufficiently rigid is going about it the wrong way. You should get it rigid enough to start with.)

What's the width of the gantry between the supports?

motoxy
07-01-2012, 10:22 PM
Hi Jonathan

I am beginning to see where your coming from. I have taken on board previous comment about the over hang over the x rails. At the moment their 700mm but I could reduce this to 600. I am going in on monday to see what box is available.I thought about 80 x 40 with the rails top and bottom.

Bruce

Jonathan
07-01-2012, 10:27 PM
I thought about 80 x 40 with the rails top and bottom.

80x40x3 box section is less than a third as torsionally stiff as an 80x80x3 box section. Same reason as before - material is distributed further from the centroid with a square compared to a rectangle.

These photos show mine (old pictures!) with the size I mentioned. I put 20mm thick plate in the ends of the box section to make as strong joint.

51765177

motoxy
08-01-2012, 12:04 AM
emmm. okay. I have looked on line and 3" x 3" x 10 swg (3.2mm) is easily available. My limitation is no access to a mill. All my work is bench work. But I am sure I can come up with something.
I feel I have come a long way since i started reading the site where someone was building a plywood cnc on his kitchen table. I have t admit that I am glad to be getting so much advice that does make sense.....so far

BTW I have made an offer on the spindle. See if he bites???

Jonathan may I ask what you are studying at uni?

Bruce

closing off see you all tomorrow some time.

Swarfing
08-01-2012, 12:44 AM
See your mum was right? there was reason why she said to eat up your weetabix in the morning:whistling:

Jonathan
08-01-2012, 12:58 AM
Jonathan may I ask what you are studying at uni?


Electrical engineering.


See your mum was right? there was reason why she said to eat up your weetabix in the morning:whistling:

Er, who was that aimed at - I don't follow?

Swarfing
08-01-2012, 01:27 AM
Cereal packet - Weetabix........Bruce

motoxy
08-01-2012, 08:24 AM
Dear mum, bless her

motoxy
08-01-2012, 05:09 PM
Just ordered my spindle and inverter. Made an offer of 140 instead of 172 and it was accepted:dance: Other than postage that makes it the same price as a Kress. Bargain.

Now off to redesign the gantry.
Bruce

motoxy
08-01-2012, 06:51 PM
Yup
Here is the item no. 190618666009

There are more to be had

Bruce

motoxy
08-01-2012, 09:07 PM
OK Here is a thought on redesigning the gantry. Any similarity to Jonathan's machine is purely down to plagerism. I have looked at a construction that I can do myself. I will make some enquiries tomorrow about acccess to a m/c shop.
518051815182

Jonathan
08-01-2012, 11:12 PM
Any similarity to Jonathan's machine is purely down to plagiarism.

Problem with plagiarism is, as they always tell you at school, you copy other people's mistakes! I've put the ballscrew on the Y-axis of my machine in a sub-optimal position, which you've copied! It needs to be closer to cutter / between the rails. The problem is everything between the cutter and ballscrew can deflect, as the linear bearings don't offer much support in that direction. I posted more about it here:

http://www.mycncuk.com/forums/showthread.php/3700-Two-ballscrews-on-both-X-and-Y-axis

(But don't start thinking of two ballscrews like I suggest there - it's excessive! Just put the ballnut on the other side.)

motoxy
09-01-2012, 06:29 PM
Had to sit in a hospital waiting room today so plenty of time to think about this. I will try to get a sketch up later with a smidgin less plagarism.

Bruce

motoxy
09-01-2012, 09:37 PM
YEAH!! Just sold my old street fighter so i have the dosherooney for the motors etc.

motoxy
09-01-2012, 10:09 PM
Right. Here is another thought about the gantry.

Jonathan
10-01-2012, 12:05 PM
neh lad for future reference 146 or make and offer,thats where mines from


Same here (wonder why!), but the postage on 190618666009 is cheaper so Bruce did well. I chose solar.jean at the time as I read that his were better quality, but then he changed the model between us getting it so who knows.
If anyone else can be bothered to read it all, before buying a spindle there's lots of discussion on which is best (4 bearings versus 3, and better bearings versus fake) here:

http://www.cnczone.com/forums/diy-cnc_router_table_machines/101803-so_you_want_chinese_spindle-8.html#post775132

It seems the consensus is the spindles from linearmotionbearings2008 (i.e. same place we get the ballscrews) are the best at the moment.

JAZZCNC
10-01-2012, 06:11 PM
It seems the consensus is the spindles from linearmotionbearings2008 (i.e. same place we get the ballscrews) are the best at the moment.

I can back this up as well. I have bought spindles for machines I've built for people from several places and Chai's(Linearmotionbearings2008) are much nicer and seem to be consistant every time I get one, they only seem to change when there's an upgrade. He tends to be slightly more expensive but I think they are worth the extra.

The last one was for my own machine and it was upgraded from the previous one's. The water conections where larger bore and the Wire connector was much better with a dedicated earth, the Amps where also higher 8.5A from 7.5A which helps torque at lower speeds this is much welcomed.!

It's been a few months since last bought one but I will be getting one for a machine soon so will see what the next one's like.!!

On another note.!! . . . I made the same offer you did bruce to the same guy and he declined.?? . . . . Don't figure.! . . Guess you caught him in a good mood Bruce. . Lucky bugger.:toot:

motoxy
10-01-2012, 10:45 PM
Guess you caught him in a good mood Bruce. . Lucky bugger

Guess we talk the same language (chai chai)

motoxy
11-01-2012, 10:47 PM
I did not realise when I started this that it would occupy my every waking moment. This is the latest design, Strange thing is I seem to have gone full circle but added strength to the gantry. What do you think, could this be a go?

Bruce

motoxy
12-01-2012, 03:53 PM
Just had a knock at the door. Nice man had a package for me. One spindle and controller.:yahoo:
Just like to say that that spindle is really heavy?? Now have to trawl web for wiring info.

Bruce (with a big smile)

JAZZCNC
12-01-2012, 04:42 PM
Now have to trawl web for wiring info.


Wiring is the easy part, if you struggle it will more likely be the VFD settings you'll want help with.? . . . It's not hard thou and it's all out there. It's been a while since I setup huanyang VFD but if your stuck just ask. . . . Jonathan will probably know them straight off the top of his head.!

Jonathan
12-01-2012, 04:57 PM
You've got the newer VFD. You'll find the 4mm collet that came with the spindle is not brilliant as it only has 6 slots. That causes it to not grip the cutter as firmly or concentrically as collets with more slots. Get a set of the collets on eBay which have more than 6...


Jonathan will probably know them straight off the top of his head.!

I do actually, since before I got the second one I used to change them a lot...this is what I use:

PD004 and 5 are 400 (frequency)
PD009 = 15 (intermediate voltage)
PD011 = 120
PD014 = 2.5 (acceleration time)
PD015 = 2.5 (deceleration time)
PD025 = 1
PD072 = 400
PD141 = 220 (motor rated voltage)
PD142 = 8 (max current, amps)
PD143 = 2 (motor poles)
PD144 = 3000 (rpm display scaling - had to look that one up)

You'll probably find some, or even most of them are already set. PD003 is just the frequency it starts with on the display, so before you press run I'd set it to something low (say 50Hz) to check everything is ok then work up to 400Hz. Needn't worry about setting up the water cooling to start with as it'll easily survive the couple of minutes it takes to test without cooling.

For wiring ... 4-core shielded from VFD to motor, connect earth at machine (spindle mount is probably easiest) and frame and the other end to the earth connection in the VFD. 3 power wires from motor go to UVW in no particular order. If they're the 'wrong' way the spindle will start spinning the wrong way, so to avoid pressing reverse every time just swap any two of UVW wires (like you could on a stepper motor phase). Mains input to RST, pick any 2 any way round as it makes absolutely no difference (since it's just got a 3-phase rectifier in there) and remember the earth, otherwise you'll get a mains shock off the machine frame which gets less amusing after the first few times!

Also make sure the wire close to the spindle connector is clipped to the Z-axis so that there's no tension on the cable. The constant bending otherwise can cause various problems as the wire degrades (took me a while to find what was causing that one), or if you're unlucky it could snap/short and destroy the VFD and spindle. Not mentioning any names :wink:

This picture shows what I mean, though actually I took it to show the air cooling:

5216

motoxy
12-01-2012, 05:43 PM
Thanks guys. I will probably get a chance at the weekend to wire it up just to test. I have to order the ally now for the new gantry.

Bruce

Thats it ordered.

Jonathan
12-01-2012, 06:12 PM
they wasnt off the top of his head when he blew up my inverter and tripped the house:wave:

That was some time ago / first one I'd done except my own, :redface::redface: sorry! Connected the output wires to the mains and the spindle to the input, it switched on as normal (as the protection diodes on the IGBTs will have rectified the mains to power it) and let me put all the settings in. When I pressed run it went bang and lots of smoke... got it to work again after replacing the IGBTs, but something else died after about 30 seconds and I couldn't work out what it was.

JAZZCNC
13-01-2012, 01:42 AM
Not mentioning any names :wink:



What silly bugger would do something like that.!!. . :wave: . . . . . . . Thou I'm pritty sure this beats my expensive cock up.!:clap:


That was some time ago / first one I'd done except my own, :redface::redface: sorry! Connected the output wires to the mains and the spindle to the input, it switched on as normal (as the protection diodes on the IGBTs will have rectified the mains to power it) and let me put all the settings in. When I pressed run it went bang and lots of smoke... got it to work again after replacing the IGBTs, but something else died after about 30 seconds and I couldn't work out what it was.

motoxy
13-01-2012, 09:09 AM
and i was worried about dropping the balls out of the screw nut...........

jcb121
13-01-2012, 04:53 PM
If you are using Sketchup and Using SBr20 rails and rm2005 rails and screw from linearmotionbearings2008, then you can download my models into your models from the warehouse.

motoxy
13-01-2012, 06:02 PM
jcb121 thanks for that. I had already got 16mm rails before finding this warm and pleasent home they call mycncuk. Would still be interested in seeing your model. Iwill try and put mine up sometime.

Bruce

Jonathan
13-01-2012, 06:55 PM
SBR16 is a bit small ... not the end of the world but 20 or 25 would have been nicer. Did you get 16 for X/Y/Z or just some?

motoxy
13-01-2012, 07:46 PM
:redface:Just the x and y. I still have to get some for the z and the screw.

Bruce

m.marino
13-01-2012, 08:52 PM
Yeah Bruce I know that feeling better then I want to trust me. Much better then I want to.

Michael

motoxy
15-01-2012, 06:39 PM
I have spent an enjoyable afternoon staring at the screen. My problem was enough strength to overcome rorational deflection and keeping everything close. I think I may have cracked it using 100 x 50 x 6.35 al channel. Although I have shown a single section it would be no problem to bolt another piece back to back if it was required on building. The rails are close and the leadscrew is also very close. Tidy.Okay comments please.Bruce

I changed the design slightly for the assy and put channel at the top to support the motor mount.

Jonathan
15-01-2012, 09:03 PM
C section also does not have very good rotational stiffness. If you added another bit on the back that would make an I, better but still adding some rectangular on the back (100*50, or over 100) would make a big difference. 1/4" looks a bit thin to be mounting the rails on.

Two pieces of box section wide enough for the rails on a flat aluminium plate with the rails facing outwards is probably the simplest.

m.marino
15-01-2012, 10:10 PM
Bruce,

Another option you could look at with that build is two section of rectangular box section and bolt a backing plate or wings to them and bolt that to the gantry uprights as well as the box sections themselves. This will give a good bit more rigidity and either the wings or the backing plate could be indexed to help keep it all true and proper. Drop me a message and I can send you a few files in a format that you can use of ideas Jazz and I worked on that will work. Also take a look at my build log as there are some ideas in there you might be able to use. The following might help:

http://www.mycncuk.com/forums/showthread.php/3661-1st-Build-Second-machine/page6

If you scroll down you will see one model with sections lifted off to show an idea for the Y axis. That might be a good place to start from and change the solid rail to box or rectangular section extruded aluminium or steel and you would have something that would be a good bit more rigid then the channel. Just trying to help and hope not to offend.

Michael

motoxy
15-01-2012, 11:27 PM
I may be sulking but I am not offended.
.
.
.
Just kidding. I know that you guys just want me to be succesful and I really am happy to be guided. I am enjoying this part of the work and I know that I have to get this right now or spend more later.

Big Thanks
Bruce

JAZZCNC
16-01-2012, 02:38 AM
I may be sulking but I am not offended.
Well let me have ago.!!. . . It's my special talent offending!!. . . . Ask my parole officer:whistling:. . . . . Only :joker:on both accounts.:smile:

Bruce I'd be very weary with both the Channel and the angle they could both give you more trouble than they are worth.?
Angle and channel are very rarely 90deg or very flat.! If the angle for the bearings hisn't perfectly 90deg and flat it will cause binding in the bearings. If compounded with the channel the rails are sat on not being square or flat then you'll have a bear of a time with sticking.!
Both the Angle and channel will need bracing to fight flex and resonance, esp where the angle meets the channel used for gantry sides.

Can I just ask why you are using channel,angle and 10mm plate in all your designs.? Do you have the material or a cheap source.?

If you have the 10mm plate then why not build using a bolted and braced design which incorparates the gantry sides to increase strength and ridgidty. If braced enough even 9.5mm plate can make a very stiff gantry and Z axis.

routercnc
16-01-2012, 01:32 PM
If it's any help here is a link to the stiffness calculation spreadsheet I posted some time ago.

http://www.mycncuk.com/forums/showthread.php/2214-cnc-machine-stiffness-calculator

Thanks

motoxy
16-01-2012, 06:23 PM
Mr Routercnc That is an amazing spread sheet. okay I can now see box rules!! This was a previous design. I had the plate on which i mounted the rails and this was bolted to the box. The angle at the top and bottom get bolted to the plate and box as strengtheners. Is the angle more trouble that its worth? I cannot find where this was slated before so here is your opportunity. Piccy below.

Jazz i have a limited supply of 10mm plate, 50mm x 6mm angle and a length of 75 x 3.2 box. When i started I was going to make one of those plywood cnc m/c's. Wood I have plenty of. Trouble is you guys have shown me the error of my ways and I know that you are all prodding me in the right direction. Also As I said before this is a bench construction as I do not have access to a mill or c/lathe at the moment.

I can only ask you all to be patient. when you get close to 60 the old marbles fall away a bit.


Edit - Talked about in a pm but not actually slated..

Bruce

motoxy
16-01-2012, 06:52 PM
Just got another computer. Has seperate video card and plenty of memory. Came without a drive so I am just doing a clean install with xp. I will need to study the board and cards and get some drivers.

Ever noticed how confusing it is to be using 2 computers at the same time. Keep using the wrong keyboard and wondering why nothings happening. Oh well.

Bruce

Jonathan
16-01-2012, 07:28 PM
The last drawing looks good to me so long as you bolt both the plate and box section to the gantry sides.
That spreadsheet is rather good. Same formulas I used earlier in this thread.

motoxy
16-01-2012, 09:13 PM
Thanks Jonathan. I feel that at last I am getting close to re-starting this project. How heavy 4 core do you recommend for the spindle?

Bruce

Jonathan
17-01-2012, 12:15 AM
How heavy 4 core do you recommend for the spindle?

1mm^2 is fine, but I used 1.5mm^2 CY since that's what I have for the stepper motors and it's more efficient to buy the same for all. It's important to use shielded here and earth it well.

Edit: Forgot to mention the reason you don't need so thick cable even though the current to the spindle is higher is it's mains voltage.

motoxy
17-01-2012, 09:19 AM
Thanks for that Jonathan.

routercnc
17-01-2012, 01:37 PM
Hi Bruce,

In reply to post #73 I would delete the box section and the 2 angle sections. I would then replace them with either an RHS (rectangular hollow section) of similar depth to the plate, or stack one box section on top of the another and bolt the rails&plate to that. Looks like it would be a reasonable fit based on your drawing.

With the RHS option you could potentially delete the plate, but I think on balance I'd still leave it in.

Hope this helps,
Barry

Jonathan
17-01-2012, 02:10 PM
Like this?

5239

(not to scale, 3D cad program stopped working otherwise I'd post a proper drawing)

motoxy
17-01-2012, 03:47 PM
Jonathan do you ever stop thinking? Between you and mocha I have a pretty good idea about how to progress. I will do a quick sketch and get comments.
Thanks for your help
Bruce

motoxy
17-01-2012, 05:10 PM
Right, here is redesign 5-1.

Obviously I will need to figure out the best side pieces for the gantry. Am I, sorry, are we heading in the right direction?

Bruce

Jonathan
18-01-2012, 12:02 AM
are we heading in the right direction?

You've gone for a pretty generic arrangement now, which is fine.
It will be stronger to put the bearing blocks for the Z-axis on the Y-axis and the rails on the spindle plate. This sort of thing (mine):

5249


Between you and mocha I have a pretty good idea about how to progress.

Time spent discussing his machine was well spent then.

routercnc
18-01-2012, 01:25 PM
Hi Bruce,

I meant one of these to keep your re-design work to a minimum. But what you've since drawn is also good.

52505251

motoxy
18-01-2012, 06:27 PM
Routercnc - Thanks for that. The latest soluton allows for the screw nut to travel between the rails which keeps the overhang to a minimum. Apparently I still have a bit more work to do on that.:whistling:

Chip - I realise it may be a bit belt and braces but what I have learnt so far is that strength is paramount. The back plate will assit in the end supports and reduce any rotaional force on the boxes....maybe

Thanks for the comments guys

Bruce

Forgot to mention i order the cabling. I dare not order any other materials as there is still time for a few more designs. :wink:

motoxy
18-01-2012, 10:22 PM
Cleaned up the drawing a bit and corrected the plate thickness on the spindle mount. I have placed the rails on the spindle plate. I am not sure that I understand why as the increase in plate dimension and the rails being further from the center of the gantry would surely put more pressure on the gantry rails. I am obviously missing something here.

Bruce

motoxy
18-01-2012, 11:28 PM
Just a final thought before nurse tucks me in. When i started this project I was going to use mahogany and pitch pine. Now its box, plate and tough stuff. The base I built was a mdf torsion box. That is going to have to change. A steel frame is, I can see, inevitable. Thankfully my ex racing buddy is a great welder so i think that a cream bun in his direction may be required. Thats for the future so good night and thanks.
Bruce

Jonathan
19-01-2012, 12:03 AM
If you use the MDF torsion box mounted between a steel frame like I do now you'll have a very rigid machine:

52535254

Mine is 18mm MDF on top, 9mm MDF underneath with 3x1 PAR pine in between ... convenient sizes at the time to fit the leadscrews inside.

Part of the reason why is you can make it so the height of the bed is adjustible, so you can still machine tall parts without compromising the rigidity (due to large overhang) when machining sheet material. That is also where the Z-axis design you have now drawn with the rails on the spindle plate is significantly stronger - compare the distance from tool to linear bearing blocks.

motoxy
19-01-2012, 10:55 PM
While trying to adjust the position of the z motor I realised that it would get in the way of the spindle mounting plate. Solution is obviously to mount the motor on the back of the gantry and use a small belt drive to run the z screw. This probably explains why i see it on many m/c's. Gosh max and jonathan i worked that out all on my own......guess it must be wrong then.

Bruce

Jonathan
19-01-2012, 11:19 PM
Using a timing belt is a great idea for a number of other reasons. It enables the ratio between the stepper motor and ballscrew to be changed. This alters the region which the motor operates in within the speed/torque curve, which with careful selection will get better acceleration and or feedrate. For instance I found with my Z-axis by calculating to get an estimate and then trying various pulleys that 42:22 ratio was best, with the larger pulley on the motor. The other big gain is the timing belt 'seperates' the ballscrew and motor so the vibrations do not transmit so easily - in other words it damps the system reducing resonance. Again this improves the feedrate, so it's a good thing to do on the X and Y-axis too. If you put a 2:1 ratio on the X and Y ballscrews it should get better acceleration and less importantly top speed, but you sacrifice resolution slightly (in most cases negligibly) plus you've always got the option of swapping the pulleys round to get better resolution...
<br>

motoxy
20-01-2012, 07:36 PM
got the cable today so i will try and blowup the spindle over the weekend:eek:

motoxy
21-01-2012, 08:12 PM
Wired up the spindle and did not blow it up. I have a link to youtube to prove it.:smile:

http://www.youtube.com/watch?v=C8bMGFps0Q4&feature=youtu.be

Bruce

Jonathan
21-01-2012, 08:23 PM
Nice

It does always flash. Bear in mind if you run it in reverse without a cutter in but the collet nut on the nut has a tendency to fly off :naughty:

motoxy
21-01-2012, 09:58 PM
Nice

It does always flash. Bear in mind if you run it in reverse without a cutter in but the collet nut on the nut has a tendency to fly off :naughty:

oops:redface:

How can you get the readout to give rpm?

Just doing a redraw to get some accurate drawings after all the sketching.
Bruce

Jonathan
22-01-2012, 12:07 PM
How can you get the readout to give rpm?

Assuming you've set PD144 to 3000 you just keep pressing the >> button until you get to RPM.

I generally leave it set on current - much more interesting as you can see if the cut is drawing too much power.

motoxy
22-01-2012, 02:25 PM
Thanks Jonathan. So glad I did not go down the kress route.

motoxy
22-01-2012, 05:18 PM
Okay its sunday afternoon and I have spent an hour chopping wood. You know when you get what you think is a great idea. You rush in and draw it up and think...eerr i'm not so sure.

I was concerned about getting good fixings in the box even though it is 6mm. Rather then pushing tubes through I came up with the idea of prespacing blocks along a threaded rod and pushing it into the box. Drill through and fix everything. You then have 4 end bolts to clamp up the sides.

Your thoughts???

Bruce

Just decided that that idea is pants. Think I may have a better one.

motoxy
22-01-2012, 08:07 PM
Probably just have a block fixed each end for location and fixing. Drill the opposite side of the box where the rail mounting screws are along the centre line just big enough to hold the nuts to lock the screws through the box. This should not have a detrimental affect on the overall strenght of the box.
I should probably now be thinking about buying some more parts. z rails and screw, motors and couplings. Then start getting some materials.

motoxy
24-01-2012, 05:56 PM
Well I think its about time to get my motors, drives etc. and couplers. I have looked at diycnc, zapp, cncrouterparts and cnc4you. Any others I should check out or any advice to be had? Probably have to buy the power supply in uk to avoid 110v.

Bruce

Jonathan
25-01-2012, 11:26 AM
Last time I checked cnc4you was cheapest for steppers including postage (though it looks like that may have changed now) and eBay for the drivers. I'm not aware of any other places.

The drawing in post #98 - You should make the joint between the X-axis linear bearings and gantry sides stronger. Currently it's only aluminium angle which will bend at the corner relatively easily, and since the bearings are free to rotate upon the rails that will cause deflection. Perhaps you could use box section there, or better just add some triangular pieces to stiffen it.

Power supply - 500VA toroidal transformer plus bridge rectifier and capacitors is all you need. www.rapidonline.com are reasonably priced.

motoxy
25-01-2012, 09:48 PM
Hi Jonathan, thanks for the heads up on the angle. hard to think I used to be a designer.:redface:. Currently being checked over for memory loss problems which probably explains a lot.
I am going to start my build now. I am ordering material tonight as I think I can start moving forward now.

How easy is a self built power supply???

zapp have this as a kit http://www.zappautomation.co.uk/product_info.php?products_id=365&osCsid=1cc466ad4b69e16a34547704f50af02c 316

Do you think these are to cheap or worth a punt http://www.ebay.co.uk/itm/250862492828?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_3191wt_1110

Bruce

motoxy
25-01-2012, 10:18 PM
Thats it. Ally ordered.

Jonathan
27-01-2012, 04:12 PM
How easy is a self built power supply???

zapp have this as a kit http://www.zappautomation.co.uk/product_info.php?products_id=365&osCsid=1cc466ad4b69e16a34547704f50af02c 316

Do you think these are too cheap or worth a punt http://www.ebay.co.uk/itm/250862492828?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_3191wt_1110


Very easy to make a power supply. Connect primary of transformer to mains via a fuse, secondary to bridge rectifier (e.g. bit excessive but you can't go wrong with http://www.rapidonline.com/Electronic-Components/35A-Bridge-rectifiers-29671) and output of rectifier to smoothing capacitors. Minimum about 10,000uF, 80V or greater. Switch on and check the output voltage and polarity is correct with multimeter just to be sure then connect it to the stepper drivers.

I tested a driver that looked identical to the ones you've linked to on eBay. I'd happily buy them if I needed some 50V drivers.

Edit to add:
Apparently it's not blatantly obvious this 4 line post isn't a substitute for proper research, so please note that this isn't a set of complete instructions but a general guideline.

motoxy
27-01-2012, 08:41 PM
Okay I have purchased most of my main electrics. Jonathan was trying so hard to save me money but to be honest I was not happy building my own psu. I decided that I would get all my parts from one source in the UK so I could have a warranty and tel support. cnc4you are the lucky recipients of my dosh. I had a long talk with Brian and feel very confident.

I have some parts being made by a very kind young gentleman, I wont mention that its Jonathan as I do not want to embarrass him.

So by the end of this week I should have enough parts to begin the build, again. Hopefully this time, after all your good advice, properly.

Ooo i'm so excited.:yahoo:

Bruce

JAZZCNC
27-01-2012, 08:54 PM
Very easy to make a power supply. Connect primary of transformer to mains via a fuse, secondary to bridge rectifier (e.g. bit excessive but you can't go wrong with http://www.rapidonline.com/Electronic-Components/35A-Bridge-rectifiers-29671) and output of rectifier to smoothing capacitors. Minimum about 10,000uF, 80V or greater. Switch on and check the output voltage and polarity is correct with multimeter just to be sure then connect it to the stepper drivers.

Jonathan I,m sorry but I'm not happy with your reply and I've got to say something.:thumbdown:

Your flippant answer regards transformer and capacitors/rectifier is very dangerous in the wrong hands and your putting folks in danger of either blowing up there drives and worse still potential to KILL them selfs.:surprised:

They need to know that yes while it's not difficult to build a transformer supply it does have to be done correctly and components correctly sized to give the correct output they require.
They need to know that the transformer seconderys need to calculated and sized correctly so when rectified from AC to DC they get the correct output so doesn't fry there drives.!

They need to know for stable performance the capacitence should be calculated in relation to V & A required, to say just use anything bigger than 10,000uF is far from ideal.!!
They also need to be aware of the very big potential to KILL them selfs if they dont treat Big capacitors with respect.
They should also be made aware of the need to build in a capacitor drain to be absolutly safe when working on the control box, and that regardless of whether the box is plug in the wall or not that with out a drain system built in then there at risk of being fately electricuted if touched in the wrong place.!!

They need to be made aware of other factors regards rectifiers, like they should really be mounted on heat sinks also how they are wired and they have positive and negative output.

Folks It's not difficult but it's not just simply grab any old transfromer and capacitors and stick it together with a recitfier like Jonathan makes it appear.!!
It needs to be calculated correctly for correct output and as always when working with electricty treated with utmost respect.

While I know how to size and build one I won't post the information in thread like this because of the potential for error then blame.!!
I will gladly help folks on a one to one basis via email or preferably on the phone/skpe because I can explain and control better that it's done correctly. Just won't do it in public.!!

The information regards sizing components correctly is available on the net if you search. But please be sure you fully understand before attempting other wise you risk the BIG possibilty of destroying your drives or Worse your self if you get it badly wrong.:confused:

EDIT: Jonathan dont bother coming back at me because you can't really and I'm not getting into another thread hi-jacking slanging match just needed to be made clear for the sake of others.

Bruce I'm sorry for wasting more of your thread space.:redface:

Jonathan
27-01-2012, 11:46 PM
I'm allowed to have an opinion as well. Any DIY project like this involves an element of risk. I assumed that taking elementary safety precautions was contextually implied, and if I was wrong to assume that on a forum like this I apologise. I have added some wording to make this clear now.

Just for the record, the mains part clearly is dangerous, but for the rest of the PSU wikipedia sums it up nicely:


Voltages of greater than 50V applied across dry unbroken human skin are capable of producing heart fibrillation if they produce electric currents in body tissues that happen to pass through the chest area.

10,000uF capacitors are perfectly fine for motoxy, as I said before more would be nice. I can only put my hands up and laugh that you would argue about something this elementary with someone who studies electrical engineering and has the same capacitance in both of his PSUs working fine without problems.

If motoxy hadn't bought the parts already I would have happily soldered them together for free and sourced the parts, it would have taken at most 15 minutes.

So after that completely unnecessary attack on my post, you know what? I think I will bother.

JAZZCNC
28-01-2012, 01:56 AM
I can only put my hands up and laugh that you would argue about something this elementary with someone who studies electrical engineering and has the same capacitance in both of his PSUs working fine without problems.

No Jonathan shame on you because for this very reason you should know better.!

I'll say it AGAIN BECAUSE YOUR A STUDENT AND OBVIOUSLY THICK AS SHIT. . . People read your posts and take your word as gospel.

If your going to post on serious stuff like electricty then please have some concideration for those that don't have much if any experience but a massive desire to try, which is great and I for one fully encourage in 99% of cases but with electrical issues then caution needs to exercised and advised.!!

Now go stick your tongue across them 10,000uF Caps if your so sure it will only tickle.. .:wave:

motoxy
01-02-2012, 05:41 PM
Thats the drivers, motors, bob and psu arrived. I guess I am going to have to tidy the workshop and get started.

Bruce

motoxy
10-02-2012, 08:39 PM
I know what your thinking, here's another of those that start a build log but do not build.

SURPRISE:yahoo:

I have started the rebuild. I have put registers into the top and bottom plates of the z gantry and started drilling and tapping to connect. The I used my home made
under the bench router table. I know it will not be with a tight tolerance but I kind of got the urge to do as much as I can on my own. That said its thank you to Jonathan for a fine pair of ball nut brackets and spindle mounts.
Do not expect this to be a speedy build. As you can see I have done 3 bolts so far.:whistling:

m.marino
10-02-2012, 09:08 PM
Well done Bruce.

Jonathan
11-02-2012, 12:00 PM
Sorry to bring bad news, but you've put the joints on the plates the wrong way round. Normally people do it such that the top and bottom plates, to which the Y-axis bearings are mounted can move up/down a little then be bolted down to accommodate variation in the Y-axis rail spacing. You had it right in the drawing in post #87.
There shouldn't be any need to start changing things as long as the top and bottom sides of the plates are square to make the bearing plates parallel. If so then you just need to make the gantry such that there's a little bit of adjustment in at least one of the Y-axis rails. The other solution is leave the bigger plate on the Z-axis as it is and cut the smaller one to fit between and make that joint adjustable.

motoxy
11-02-2012, 12:08 PM
I know what your saying jonathan. I made an error in the design and only realised after I had ordered the material. I have given it a lot of thought and have a system to adjust the y axis. If it becomes a problem then i will order some more material. Budgets a bit tight at the moment so I will have to see how it goes. Thanks for keeping an eye on me.

JAZZCNC
11-02-2012, 12:13 PM
Sorry to bring bad news

Your worse than the Grim Reaper boy. . :naughty:

Bruce he's correct but just shim if it's tight.!!

motoxy
11-02-2012, 12:23 PM
Shim (spacer) (http://en.wikipedia.org/wiki/Shim_(spacer)), a thin and often tapered or wedged piece of material

That sums up most of my metalwork

motoxy
12-02-2012, 06:49 PM
Next step is the y rails. I routered out a register and then did it again. The rails edges are rounded and I did not go deep enough. Hopefully not to much wrong this time. Next will be drill and tap the rails in place.

Bruce

JAZZCNC
12-02-2012, 07:12 PM
Bruce Having a register to work from is good idea BUT Becareful it can bite you with round rail.!!. . . . The base edge of round rail is often not very straight (Or Flat) so carefully check that
1: It's straight
2: The distance from rail to Edge is consistant along it's length.

If it is straight and consistant then you can work from the register when setting rails parallel if not then work direct from the round rail.

motoxy
12-02-2012, 08:06 PM
Thanks for the warning. My intention is to get as much straight and parallel as possible but when setting out the various components I will use a dti on the important surfaces.

Cor if i new what i was doing i would be dangerous:naughty:

motoxy
14-02-2012, 07:47 PM
quick update. Y bearings are in and the rails screwed into the box. I clamped the ends just to push it back and forth and thankfully there is no hint of binding. Mind you I am sure you will tell me what I have done wrong....:joker:

Bruce

motoxy
28-02-2012, 06:52 PM
Just thought you might like to be updated. Thankfully shimming will be at a minimum as most of the crucial measurements seem to be reasonably close less than 0.1 degree.
Still got to add pads to the base of the sides and bracing on the back.

Bruce

In case your wondering I have made sliding fit pads for inside the box. These have been threaded so the tie bars although going right through will not stress the box. Once I am happy with the build these pads will be locked in place with bolts.

m.marino
28-02-2012, 08:30 PM
Well Done Bruce,

Coming along well and looking good. Keep it up and it will be running in no time flat.

Michael

motoxy
10-03-2012, 10:14 PM
Just a quick update. Been busy and work is about to kick in. The y gantry is almost finished, probably another 6 hours should see it done. The z is waiting on Michael Marino's machine becoming available and then we can machine the recesses in the plates.
Going to see if i can coax my mate to do the welding of the frame for me. So it is progress just a bit slow. Would be quicker if i made less mistakes!:redface:

Bruce

motoxy
19-03-2012, 09:21 PM
Next update. Its now a rolling y chassis. The mounting plates above the x bearings will be cut down to size after i know where the ballnut bracket will be located. It does not look much since last time but I must have drilled and tapped 50 or so holes.
If all the limit switches are connected in series would it make sense to mount them all on this gantry as this would mean only one cable going from the gantry to the control box?

JAZZCNC
19-03-2012, 09:43 PM
If all the limit switches are connected in series would it make sense to mount them all on this gantry as this would mean only one cable going from the gantry to the control box?

Yes With a bit of care and planning it's possible to use just 1 switch for each axis all wired in series. Doing it this way then yes it's possible to mount them all on the gantry.
Basicly you need some kind of ramp or bracket either end of each axis to trip the switches.

Confession time now bruce I forgot to do what I've got to do.!!! . . . Will do it ASAP promise. .:redface:

motoxy
19-03-2012, 10:53 PM
Jazz there is no rush.

I take it that these switches are homing at one end and limit at the other? Or are homing switches separate?

You will notice that i am entering another area of simple and possibly obvious questions. YOU HAVE BEEN WARNED!:smile:

Looks like Michael is nearly ready to start on my z plate. Once that happens then hopefully there will be another lurch forward.

Hugs and kisses

Bruce

JAZZCNC
19-03-2012, 11:57 PM
I take it that these switches are homing at one end and limit at the other? Or are homing switches separate?

NO for limit switch's to be any use then you need the switch to be tripped either end. Often 2 switch's are used per axis mounted static at either end but a single switch per axis can be used if fastened and travels on each axis then triggered by use of a ramp or bracket if mechanical. Optical or proximity type switch's are also good for this type of application as the can be triggered by static magnets etc.

Home switch's can be either separate or the limit switchs can be used as double duty. Mach3 knows the difference between when the switch is triggered as limit or home.!
Basicly the switch is always treated as a limit while the machine is working but then when told to home temporely disables the switch as a limit and treats the switch as a home switch then when finished homing goes back to being a limit switch.

motoxy
31-03-2012, 10:15 PM
Just to let you know that this build is not dead I am thinking about the base. Steel box is 50 x 30 and 100 x 50. I intend to fix 10mm ally plate on top with an overhang that will support the screw/ motor. and give it some protection from debris. Therefore the rail and screw are fixed together and the critical factor should be lining up the left and right plates. Fillets will be added on the build.I really ought to start setting up the electrics now but this part does make me a little nervous so listen out for some stupid questions soon. :confused:Bruce

motoxy
20-04-2012, 06:04 PM
Okay base is on the way and looks more like a jazz base then the previously drawn tea trolley. So I am starting on the electrics. Laid out a few components and will hopefully get some wire, plugs, connectors etc tomorrow.

Fillets and bracing added by the blacksmith.

JAZZCNC
20-04-2012, 08:29 PM
Okay base is on the way and looks more like a jazz base

Don't blame me and anyway it looks nowt mine.!!. . .5807

motoxy
20-04-2012, 08:53 PM
Oh come on jazz, Lick of paint and its done......................

motoxy
22-04-2012, 09:36 PM
Looking to get the limit switches now and was wondering if the chinese 10 for a bowl of rice are worth the effort.
I presume that I will need to get some 0.2 2 core shielded cable.

Bruce

motoxy
28-04-2012, 09:13 PM
Today it took its first breath of life. The control box is almost complete. I just have to get some 5 pin plugs and sockets for the motors. I decided to make a temporary connection to a motor and try it out. Ya beauty! :yahoo:Worked a treat. Got some good advice from Michael and I am well pleased.

Some more ally arrived yesterday so as soon as possible I can continue the build.

In the photo of the control box the wires hanging out the side are the temp connection to the motor.

Bruce

Chris J
28-04-2012, 10:46 PM
Looks like you have made a good job of that control box.

motoxy
08-05-2012, 09:40 PM
A great big thanks to Michael for machining my z plate registers for me. There has been some progress recently. I have started making the x rails and will get some piccies as soon as I can.
Hows this for an interesting way of losing business. I went to my blacksmith with whom I have concluded about 10,000 of busines this year to make me my base. He wanted 200 which was reasonable. Then I went in after a couple of weeks to check on progress he had not started it but thought that it would not matter as it was just for my 'hobby'. Grrr

Bruce

motoxy
11-05-2012, 07:45 PM
X runners almost completed.

m.marino
12-05-2012, 12:01 AM
Looking good Bruce, looking very good indeed.

Michael

motoxy
15-05-2012, 09:21 PM
had to baby sit an 8 year old tonight. Brilliant someone with the same engineering awareness as myself. So we set up the rig as a temp and checked a few things out. Definitely going to have to do a bit of light shimming but all in all........who am i kidding there is quite a bit to do but it is all doable. One of the bearings is loosing its balls so that will eventually have to be replaced. But I have to say it is all very exciting.

motoxy
05-06-2012, 09:52 PM
Thats most of the metal bashing completed know. All thats left is brackets to connect the x screwnuts to the gantry and mounts for limit switches. Gues I will have to start on connecting the electrics now. This is the bit that I am not confident about so a bit more reading of old threads and a few stupid questions, as usual.
The y motor has had its mounting made after this picture was taken.

Bruce

JAZZCNC
05-06-2012, 10:25 PM
Just looking at them X brackets Bruce how are you going to mount them to the bearing plates with that big overhang from the plate which the rails sit on.?

It's looking good thou getting very close to fire up time.!!!

motoxy
05-06-2012, 11:16 PM
I will send you a dwg and you can tell me if it will work.

Bruce

motoxy
21-07-2012, 03:15 PM
It Lives!!!! Well z and y are working. I have the material at last for the x ballscrew brackets and the limit switches are on their way. The e stop is connected through the breakout board but I think that the external relay for the power to the spindle may be in order. Pictures when the brackets are finished.
Its not pretty but I love it...said the same about the kids

Bruce

motoxy
01-08-2012, 09:38 PM
We x y z all working and tolerances not bad. Tied a pen on and drew a line on x and y and seems good using a square.

But I have a bit of a problem with one side of the x axis. As it moves across one side starts to make a noise as though it was starting to bind up. Does not do it in the reverse direction. I have loosened the rails to allow them to move but makes no different. could be the bearings may have been knackered being put of and on the rails as it was built. I have a spare set to try. Disconected and pushing it there is no problem. It probably is the rail/ballscrew tightening.

Have to wait till the weekend now but promise some pictures or maybe video soon.

Bruce

motoxy
24-08-2012, 05:53 PM
Cannot believe its been 3 weeks!! Today I decided to swap over the ballscrews but leave everything else as is. The binding sound now comes from the other side and yes I think I know the problem. You may remember that I thought it was a good idea to take a ballscrew apart and see how they worked. I think that I may have not found all the balls and that this is the cause of the problem. So I shall have to get another ballnut and try again.

Water pipes are connected and basically just limit switches to fit.

I have fitted a drag chain on the x axis and I am getting another for the y axis. Some bracketry for that and we are almost ready.

Bruce

motoxy
31-08-2012, 01:18 PM
AAARRGGHHHH I HATE COMPUTERS. All ready to do some alignment checking and the computer decided to crash and reboot. Thats all it does now is reboot, crash, reboot, crash...... Tried a linux disc but that would not load either. It has always been a bit suspect as it would happily run mach but not cambam. Here are a couple of pics. Wiring still waiting to for a tidy up.

Thought you might like to meet my assistant. He seems to have moved into the workshop. I have evicted him but he comes back. I am hoping to train him to weld.

bruce

Jonathan
31-08-2012, 01:28 PM
Looking good. Did you solve the suspected problem with the ballnut? If you've not already, try turning the ballscrews by hand to see if they feel smooth with no cyclical torque variation.


Thought you might like to meet my assistant. He seems to have moved into the workshop. I have evicted him but he comes back. I am hoping to train him to weld.

I think he'd be more suited to pop-ribbeting?

motoxy
31-08-2012, 01:38 PM
I think he'd be more suited to pop-ribbeting?[/QUOTE]

HA! Told him that and he laughed.

Got a new ballnut from cnc4you and all the horrible noises have gone. I am so close to finishing but there is always just one more little thing....
The tray on the back is for the drag chain. Then the cables and tubes will be sorted.

m.marino
31-08-2012, 09:20 PM
Well done keep up the good work.

Michael

motoxy
07-09-2012, 08:06 PM
Limit, homing switches in place and both drag chains. Trying to connect the touch off plate but so far to no avail. All thats really left to do is connect the spindle. Tried the water pump I had and it was useless so its off to ebay. Promise a picture next time I am in the workshop.

Runs beautifully at 2000 mm/min on the x but any more and it sounds yuck and at 2500 it seizes. Tweaked alot so just have to keep looking. I suspect that the old drill press, chopsaw, handtools build suffers a bit from lack of precision so when I am cutting I will try to fabricate the more essential parts to a higher standard.


Nearly there!!

Bruce

JAZZCNC
07-09-2012, 08:22 PM
Bruce 2mtr/min is more than enough for cutting Ali to upgrade so don't fret mate.

You'll be amazed how much more you'll eck out the thing with a bit of shimming and tweaking.

What's with the plate.? What's it doing or not doing.? How you connecting it.?

motoxy
07-09-2012, 08:28 PM
connected it to input pin 13 (i think ) and then thought how does this work. Chatted to Michael and it acts by earthing. Touched it to earth nothing. Somehow I think I have it a bit screwed up. So I stopped until I could find an article or post to clarify.

Bruce

JAZZCNC
07-09-2012, 08:51 PM
First have you enabled and set the Probe Inputs in Mach to pin 13.?
If so then just take a wire from any of the Negative pins of the BOB and touch to wire coming from pin 13 then it should work. Check the diagnostics screen input signals state ad the digitize pin should light.

If on all time without wires touched then flip pin 13's active low setting. Then it should work has expected.?

motoxy
19-09-2012, 11:24 PM
Still not managed to get the probe working but BIG news. I have a video of the first proper cuts.

movie first cnc cuts - YouTube (http://www.youtube.com/watch?v=Rd3YB4IsICs&feature=plcp)

Thanks guys for all your help....and the help that is still to come.

The m/c is a bit wobbly because I have it up on castors to move it about as I work onit. Once finished it will be wedged up.

A very happy Bruce:triumphant:

WandrinAndy
19-09-2012, 11:57 PM
Nice one! I can see myself wasting stacks of material once my CNC is ready to cut... It's almost as mesmerising as watching a fire!

JAZZCNC
20-09-2012, 12:20 AM
Nice one! I can see myself wasting stacks of material once my CNC is ready to cut... It's almost as mesmerising as watching a fire!

Yep and there'll be times you want to set it on fire . . Lol

Nice one bruce looking good . . .:applouse:

Jonathan
20-09-2012, 01:23 AM
Yep and there'll be times you want to set it on fire . . Lol

So long as there's not times he wants to extinguish the fire...

How long until we see an Aztec calender?

motoxy
20-09-2012, 08:54 AM
So long as there's not times he wants to extinguish the fire...

How long until we see an Aztec calender?

Me..Aztec...never...maybe...soon as possible:witless:

Bruce

TrickyCNC
20-09-2012, 09:03 AM
great news Bruce :)

Well done .

motoxy
29-09-2012, 10:58 PM
Well counted my chickens that time. When i looked closley at the first cutting it seemed to be alright but not perfect. When I tried to use the machine again it kept locking up. I assumed it was ball nut, bearing housings, bent screws. So I have spent hours moving, drilling stripping and rebuilding with varing amounts of success but never really solving the probleml. At one time I thought i had it beat but when trying to cut a design whole sections were out of alignment. I had Michael round to help plus a retired cnc fitter all to no avail.
Today I decided to go back to basics and put up the dti and found I was losing steps on just one of my x drives. Chatting to dean I checked all the wiring and swapped the step settings from 1/8 to 1/4. The problem got worse and it would jam after 150mm. if I loosened the motor mounting nuts it worked. I could hear a ringing and thought nothing of it. Swapped the two motors and then neither would work properly. Finally I thought I would take note of deans advice and looked at the steps again. I changed it to 1/5 and instantly everything was just dandy.

I have put the machine back together and cut a new sign. It is so much better in quality and cleanness of cut.

All thats left to do is get the probe plate working but that will have to wait until another day.

Bruce

martin54
29-09-2012, 11:11 PM
Well done Bruce, well that's 2 machines in Edinburgh I need to go & look at now lol.

JAZZCNC
29-09-2012, 11:58 PM
Bruce you've met me and seen how little hair I have left.? . . . .Know your learning how it happened. . . Lol

Looks good and pleased could help.!! Resonance can be a right bitch if it gets you, thou must admit I'm surprised it did with using modern drives.! Thou from everything you had done and told me on the phone it was little else could really be.?

m.marino
30-09-2012, 10:59 PM
That is great to hear and really need to get some video up from some cutting I have done lately but between making models, feeding the machine and other work have not got it done. Great to see Bruce and keep on trucking.

Michael

kingcreaky
03-10-2012, 12:25 PM
fantastic build thread. fantastic ending. well done outstanding work. what an inspiration

motoxy
08-10-2012, 10:07 PM
Built my self a dust shoe over the weekend as I am at last fed up with holding the hose next to the work. I wanted one that 'floated' so that its height was not governed by the spindle. Mark 1 used screws to guide it and was a failure. So I decided to use bearings. These are inline skate bearings from another project. The brush is from a letter box draught excluder.
I have a video which shows that it works really well.

Still cannot get the touch plate to work!!!

dust shoe - YouTube (http://www.youtube.com/watch?v=XN3284QsyWE&feature=youtu.be)

The sign at the end is my first attempt at something a little more complicated.

Bruce

motoxy
28-10-2012, 09:53 PM
Well that about it. I now have the touch plate working and from here on in its just tidying and tweaking. I have cut some signs and other test pieces and I am very happy with the final product. This probably is the end of the build log so a big thanks to all of you who helped me complete this project. :thumsup:
Any further updates or info I will just make separate posts.

Bruce

jonbabbz
29-10-2012, 12:49 PM
Congrats. Looks awesome and I love that floating dust shoe.

JoeHarris
29-10-2012, 10:12 PM
Awesome...