a Steel Box Section Build with SBR20 & Ballscrews Plus a few questions

How do you propose to get the main axis shafts level and parallel with each other? Commercial companies using this style of frame will have accurate jigs to hold the frame in position while they weld it. Special purpose machine makers mount rails onto a flat ground plate, which is mounted onto the frame, to ensure flatness. With the flat plate and one shaft mounted you could check parallelism using a dial indicator to locate the position of the other shaft.

Hey colin

Sorry for the Delay in replying. I have given myself room to move components for small adjusting of plates which is lucky too because as previously said I just cant get the holes as close as I would like. although I centre punch and then centre drill and then go larger but I think with my newer drill press it has got better. But i have made 6mm holes in the plates that bolt to the m5 tapped holes so that will give me a small amount of movement.

I have a dial indicator to get as close as I can although I need to find a long enough straight edge to trust and then using the Vernier caliper too.

I will then be able to then flatten the spoil board once everything is running so it won't matter if the machine is a small part of a mm out because it will al be parallel with itself and also the work piece.

Well that's the plan anyway. I will be using Epoxy for the rails to get the top rails flat running a channel between the rails and this will then self level.

i think then it will be a lot of fiddling about to chase every last 0.0 of mm

I would be great to have those known flat and precise equipment of the manufacturers have but money would never allow for it sadly.

thanks

Rob

What about using a laser level and laser distance measure. If you are careful you could use a sheet of glass to check for level.

Great idea I didnt even think about glass I will be keeping my eyes open when I pass any skips from now on.

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Originally Posted by Colin Barron

What about using a laser level and laser distance measure. If you are careful you could use a sheet of glass to check for level.

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Best look for old double glased unit the edges are taped and safer, wear gloves and glasses.

Well still building the frame but also learning as I go about the electronics and everything else.

I am looking at the pulley's to use dean said that a 2:1 gearing ratio is good for a 1605 Ballscrew but does it matter how many teeth are on the pulley as long as it is 2:1 on the otherside of the motor I can't find any threads that show how to work it out.

I am looking at using Nema23 4nm from CNC4You which look to be low inductance and high torque also nothing really shows the torque curves to show if it is usable power through the range.

Has anyone used these motors at all ?

I know that it is best to wait for buying things but my year end accounts are up so trying to make sure I can buy the bits before then.
I have now ordered the 4 Leadshine AM882s because I will be using duel screws on the X.

I'm now ordering the Hiwin rails from Fred because its taking forever to build if I use the supported rails I don't think it would ever get upgraded so do it one do it right.

So its back to cad and make the changes.

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I am looking at using Nema23 4nm from CNC4You which look to be low inductance and high torque also nothing really shows the torque curves to show if it is usable power through the range.

Has anyone used these motors at all ?

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These are the one's to go for, good choice and the AM882's are also good.

In general 1605 screw on Z and 1610 on X and Y . I have used 1:1 on X and 2:1 on X & Y (router twin screw)

Hey Clive

Brilliant thank you very much for that I will get them on order.

I have looked on the cnc4you and the grubscrew pulleys but i'm not sure if there is a formula to stick to or is it not the teeth but the ratio that is important. I'm sorry I have never got to grips with pulleys.

I think the original 1605 ballscrews because now I'm going with Hiwin rails i'm going to maximise the space.

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Originally Posted by grain_r

Hey Clive

Brilliant thank you very much for that I will get them on order.

I have looked on the cnc4you and the grubscrew pulleys but i'm not sure if there is a formula to stick to or is it not the teeth but the ratio that is important. I'm sorry I have never got to grips with pulleys.

I think the original 1605 ballscrews because now I'm going with Hiwin rails i'm going to maximise the space.

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I have just noticed that you posted 4Nm I generally use 3.1Nm motors. re the pulleys I will check tomorrow but have a look at 30 teeth for the small one you could also use 1:1.5

Thanks Clive I will have a look at the 30 Teeth. Like all things I went on the theory the More power the better :)

I'm using two 3Nm motors to drive my X axis. 68V PSU.Steel gantry, with spindle, etc, probably weighs around 50kg. 2005 ballscrews, driven 1-1 through (from memory) 20T pulleys. Gives me about 5m/min rapids. That corresponds to about critical speed of ballscrews and corner speed of motors. 2010 might give me a bit more speed but probably at the cost of acceleration which is more useful if you are doing fiddly detail cutting.

So I still haven't finished my Frame still after a long long delay in making the CNC after house moves work and another daughter it's time to get this thing back on track again, when I started this I never in a million years thought I would still be making it.

Although I haven't been making any progress on my machine I read through the amazing posts on here most days still.

Attachment 29526

So I have been redesigning my original again and I have found that Item does a 45x90x90 10mm Profile

https://www.aluminium-profile.co.uk/...file-kjn992387

The plan would be to put the two together with bolting through one and then into 'T nuts on the second profile.

It will then be wider than the width of the frame to allow the full width of the cut (Which I didn't have previously)

Attachment 29527

I need to change the bracket so that it doesn't get in the way of the Z

It will have a movable shelf which I haven't added to the design in fusion 360 as yet so the spindle won't need to go right down to the bottom shelf.

It is roughly the same pricing as a 200x100 cold-rolled box section but I think it will be easier for me to complete the gantry with this instead of the steel and not have the resin to be put on to get the accuracy on the rails as time in the workshop is still limited these days.

Looking at the profile it seems pretty sturdy and it would have 5mm on each side of the rail to attach on the slots. But before I get too carried away with the design I thought I would check if this is a good possible profile to use.

Any thoughts would be most welcome.

Thank you

Have a look at John Ward's site.
https://www.youtube.com/watch?v=Xbiipb6nnZg
You will achieve greater accuracy using flat plate fitted on top of your frame and shim at mounting positions.

Pointless using such a heavily built gantry on such a weak flimsy frame.! You seriously need to brace that frame-up.

Good Morning

Thank you for the replies, Thanks Colin I will look through the link very appreciated, Thank you Jazz yes the actual frame that I have pretty much built most up and has more bracing of each corner and I'm adding diagonal pieces on the Horizontals of the bed and then the second top shelf (not shown) will also be bolted to the mainframe to add more rigidity.

Because I had that part built its more of the Gantry design I'm changing from the 50x50 box Gantry I originally had as my design to the Aluminium Gantry, but I wasn't sure if the Gantry would be as good and as strong as the 50x50 Box design I had previously,


Attachment 29546

The profile I'm thinking I using is this but I couldn't find too much about the strength of it in terms that I understood (Me not clever enough not Bosch's information)

Attachment 29547

I will use the Profile to create a stable base to connect it to the Plate. the Screw and mounts will be put on ali plates because of the room available on the 45mm and I need 60mm width for the screen bk12 fittings.


But I like the words from Jazzcnc used Heavily then I will continue along that route with my design I haven't ordered the profile as yet and I'm trying to get the rails on order soon.


I see Aliexpress and ebay don't seem to all say Hiwin rails now although the part numbers they use are still the same.

Fred shows that he sells original Hiwin still and also a 3rd party range which seems to be a lower cost but has anyone used these instead of Hiwin or is it just false economy and just go for the Hiwin rails?


Thank you

Rob

You can also skin the frame with sheet material (rather than diagonal beams) for bracing

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Originally Posted by pippin88

You can also skin the frame with sheet material (rather than diagonal beams) for bracing

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Sheet material will do very little for it other than turn it into a Big Drum. It needs proper and substantial bracing to handle the forces a heavy gantry will put on it. If done properly it will also reduce resonance/vibrations.

Thank you very much for the replies, I have been adding to the design of how I have made the frame, although I still have the horizontal cross members to put together.

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Also wondering if anyone has used Fred from BST Automations own Linear rails ? or is Hiwin the way to go,

Thank you

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Originally Posted by grain_r

Also wondering if anyone has used Fred from BST Automations own Linear rails ? or is Hiwin the way to go,

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Yes, I use lots of them and they are good for the money, but they are not as good as Hi-win so don't expect Hi-win quality. That said they more than good enough for a serious Hobby level Router and if maintained properly will last for years and they are nearly half the price of Hi-wins so no one should expect them to match Hi-wins really.

If you're wanting the best Stiffness and working the machine hard in a production environment 10-12hrs per day 6 days a week then you should go with the Hi-wins.

Re the frames It's still a little weak on the bracing IMO, because the sides are so tall the short end diagonals don't extend far enough across the beam, same down the sides, this will allow the cross beams to flex as the sides apply a bending motion to them. You would be better with another lower cross beam with diagonal braces between them.
My first machine was built similar to this design but with short sides and it flexed at this point, I later braced it up as mentioned above and it was much stiffer.

If you don't need to pass material thru the machine I would also fit triangle plates to the ends to brace the sides. Those tall sides with spindly tubes are a massive weak link in this design, why such tall sides with such a short Z-axis.?

Hey dean great thank you very much for the information on the Rails I have been looking and will be most likely going for those OEM rails, It will be purely a home Cnc just for hobby work so sounds good enough for me.

I will add some more bracing to the design higher up too.

The original plan was to make foam moulds for fibreglass parts for a car I was building so I could then keep layering up the foam and moving the shelf down to create the arches and other large parts, But that has changed now :(maybe one day) but its going to have a movable shelf for sheet woodwork so once the shelf is in that should also add to the strength too.

I originally left the ends open for end-grain cutting but I will add the end bracing too and I can always take them off when I'm doing normal sheet work.

thank you

I have been Emailing Fred to get a quote for the rails

I have my 1605 ball Screws from my original design and order but I see everyone seems to use the 1610 ball screws on a 1:1 pulley instead of the 2:1 Ratio but would it be okay to use the existing 1605's or is it worth buying the 1610's from Fred whilst I'm getting the rest shipped over.

I wasn't sure if I make any gains of Torque and speed this way?

I also have a pricing of the 2.2 Spindle and VFD I thought again just one shipping might be good but I haven't really heard of anyone having the spindle from Fred. I know the old adage of the finish the other things before they are needed but I am buying some of this to use in my business and trying to save a little from my Tax bill :eagerness:

any help would be most appreciated.

Thank you

Rob

If you are ordering anyway then I would get 1610's if it's being used mostly as a wood router because you'll want the extra speed they offer. Don't worry about torque because if you use correct size steppers with a decent amount of volts you'll have more than enough torque. If your just cutting aluminium with it then 1605 will be fine with a 1:1 ratio as you won't cut much above 3mtr/min and you'll get around 5-6mtr/min rapid speeds which is more than enough for smaller machines.

Fred's spindles are fine, I have fit dozens and not had any troubles yet, they are pretty much all the same and in general, I have fit 100's over the years, and less than 6 have gone faulty on me.

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Originally Posted by JAZZCNC

If you are ordering anyway then I would get 1610's if it's being used mostly as a wood router because you'll want the extra speed they offer. Don't worry about torque because if you use correct size steppers with a decent amount of volts you'll have more than enough torque. If your just cutting aluminum with it then 1605 will be fine with a 1:1 ratio as you won't cut much above 3mtr/min and you'll get around 5-6mtr/min rapid speeds which is more than enough for smaller machines.

Fred's spindles are fine, I have fit dozens and not had any troubles yet, they are pretty much all the same and in general, I have fit 100's over the years, and less than 6 have gone faulty on me.

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Hey Jazz Thank you very much for that, Righty Oh I will add them to the order it won't be a bad thing because the originals I have don't have much room for a pulley. I'm sure they will get used for something else one day.

I will add the spindle too and then just hope that the customs people don't think it looks interesting enough to open :)

I'm still undecided to go with the oem or Hiwin Rails the difference is $325 dollars and because I want to do it right I'm leaning to the Hiwin.

Thanks

Rob

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Originally Posted by grain_r

I will add the spindle too and then just hope that the customs people don't think it looks interesting enough to open :)

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They won't probably open it but that doesn't mean anything really, they will always charge you VAT and duty based on the invoice amount.

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Originally Posted by grain_r

I'm still undecided to go with the oem or Hiwin Rails the difference is $325 dollars and because I want to do it right I'm leaning to the Hiwin.

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Well in that case then I'd go with Hi-wins.

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I have don't have much room for a pulley.

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Fred will machine what ever length you want for the pulley, tell him what length you want the F length to be.

That is where the pully fits.if you make it too long you can always cut it off.25-30mm is fine

Good Morning

Thanks, Jazz I will go for the Hiwins at least I know it will be right then, Thank you, Clive, I will go for 30mm for the Pulley.

thank you very much for your help.

Thanks

Rob

Quote:

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Originally Posted by grain_r

Good Morning

Thanks, Jazz I will go for the Hiwins at least I know it will be right then, Thank you, Clive, I will go for 30mm for the Pulley.

thank you very much for your help.

Thanks

Rob

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Not sure but I think the F length is included in the overall length of the screw so check with Fred or send him a sketch

Hello Clive thank you for that I wasn't sure on that part,

I have a 300mm ballscrew which is the 1605 from when it was going to be a round rail system would it be a 1610 for this too or will I be able to get away with the 1605 for that?

thank you

Rob

Quote:

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Originally Posted by grain_r

Hello Clive thank you for that I wasn't sure on that part,

I have a 300mm ballscrew which is the 1605 from when it was going to be a round rail system would it be a 1610 for this too or will I be able to get away with the 1605 for that?

thank you

Rob

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1605 will be fine for Z-axis, if connecting to motor with timing belt use a 1:1ratio.

Hey Jazz

Perfect That's Great News, Yes the plan is to use a belt to the screw, it doesn't have much of the end on it but I thought I can open up the pulley to go over the thread slightly or use a coupler and a short length to the pulley although I thought that might get some backlash so hoping to go with the first option.
Thank you very much for your help.

Quote:

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Originally Posted by grain_r

Yes the plan is to use a belt to the screw, it doesn't have much of the end on it but I thought I can open up the pulley to go over the thread slightly

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My old mate John S whos no longer with us, bless him, used to tap the pulley halfway and use this as the nut.! . . . It worked good and easy to do.

That's a great idea I wouldn't have thought of that,
He sounds like a very clever and resourceful man, I am very sorry that he is no longer here, He lives on with his ideas being used and friends' & Families memories.

Hey Everyone
Well it's been a while since I have posted anything but I have been slowly doing a little when I can sneak off to the garage for a short while.

I have still been lurking furtively in the shadows though :)

I have noticed that since I started the Make "a quickie CNC project" that my quality of work has gone up and so things that I must have been happy(ish) with originally I have then re-done to a better standard. I would have never thought I would still be making this thing when I first started designing. but I am also grateful that I am.
It has been in my thoughts at least once a day of solving different things and I am learning new skills all of the time. So instead of the CNC creating items it really is turning out to be my actual hobby to create this thing.

Sometimes when I have had a rough day I go to the design space in my mind and build it. Okay, some might say actually physically building stuff is the way to go through.

My Hole drilling was always an issue of getting it accurate enough to be happy with but with so many possible ways it could wander slightly even using centre drills i still wasn't happy, So I have been using a little sieg x2 mini mill and that has made the job much better but it doesn't have a DRO on it as yet and so even though the mill can get to the correct place a drill can (And does) move around.

I have always stayed away from 3d printing thinking that it wasn't for me and that the quality of parts that I had seen from other people's tries just wasn't something that I would use. Well, how wrong was I.
I have purchased the Ender Creality 3 and it is amazing. sure it can create stuff that will sit collecting dust on the shelf but also it can create useful parts.
it is supposed to go to 0.01 of an mm

Attachment 31255

So I created a drill template so that even if it is wrong they would all be the same so they would be right (My Logic anyway).

Attachment 31256

I have had issues with getting the drill marks as accurate as I wanted so I made some centre drill markers and some Centre drill markers with very small centres so that I could mark the masking tape and then use a punch to get it pretty close.

Attachment 31257

Attachment 31261


So then onwards to fix my errors from my previous times. JazzCnc mentioned a long time ago about welding nuts into a hole and especially because I am using 3mm it would help. I haven't done this on all of the holes but on the not-so-accurate holes, it has worked really well.

I took the coating off with the Brick cleaning acid as suggested (I do listen :eagerness:)

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I have been working on a mockup for the Gantry at the moment too, The frame is pretty much there

I am working on a movable shelf at the moment so the material will be much higher than the bottom is at the moment but this is if I wanted to create fibreglass moulds for the full height work.


Stemming from my original design I didn't think enough about losing the width of the cut when the gantry plates go to the end.
I originally planned on the Hiwin carriages further forwards and giving a larger gap between the carriages. but not I am thinking the the base plate will then be flush with the front of the Ali Profile and then the x will be allowed to slide further across giving me the maximum cutting size that I can.

the downside of this is that the main load will be on the front carriage but I'm also thinking this will be a plus point, not a negative point the Carriages will be an 80mm gap between each other and I think it looks right.

the Base plate won't be like the block it will be 2 plates of 10mm Tooling plate to make it 20mm thick and it will go across and hold the ballscrew block too.


Originally it was designed to make a plate that goes further forwards to make the spacing larger and the load sit between the 2 carriages better.

I can always change it in the future if I get any issues.

Because everything is so expensive at the moment instead of using epoxy to level the rails I am going to use some Ali profile that I already had for a job that I didn't use to save a few pennies. I can always use Epoxy in the future if it isn't as level as I hope but I will be able to check that.

thanks

Rob

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Since it is a little chilly out there and the garage is cold at the moment I have started to look at making the Electronics side of things whilst I wait for the heat to come back. Cold fingers and screws are always an experience :tennis:

Attachment 31567

I have been looking at using a PC tower case because the wall enclosures just seem so much money at the moment but I also like the size of the case, then the expansion ports will be to connect the motors and Sensors and various items.
The Powersupply will be out of the way underneath the main section and so will help with the separation. then I will run the fuse and MCB in the same place as the Toroidal power.

So I have been looking at using a 240 Volt VET Toroidal Power unit which has x2 25v outputs 625 VA.
I am using the lead shine AM882 drivers with the four cnc4you 4nm motors. which show they take around 2 Amps so need 70v to run the lead shines.

but I wasn't really sure if this is the correct unit I will need in all honesty.

https://www.rapidonline.com/vigortro...-x-25v-88-0012

the bridge rectifier I have been looking at is a 35 Amp rectifier https://www.rapidonline.com/dc-compo...mb356--47-3228

but that is then when I have become unstuck on the Capacitor choice and I'm not sure how to work this out so I wondered if anyone could possibly point me in the correct direction.


Thank you very much.

Rob

Rob

The attached is all you need though the price will be wrong. The toroidal you have is ok

This vid from Joe will help https://www.youtube.com/watch?v=4OoQ...zD30sZjtp_VyqY




Attachment 31568

Hey Clive

Thank you very much for that, that is a great help, I haven't made a power supply like this before so I'm not sure if these create much heat when in use. The space will be a little limited so the components will be quite close to each other and planning to put the incoming MCB for the power supply Horizontally above the toroidal doughnut the plan is roughly to keep it a similar size to a PC power supply in height but in a longer package.

thank you very much.

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Originally Posted by Clive S

Rob

The attached is all you need though the price will be wrong. The toroidal you have is ok

This vid from Joe will help https://www.youtube.com/watch?v=4OoQ...zD30sZjtp_VyqY




Attachment 31568

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Good Morning Clive

I have been onto Rapid to place the order but unfortunately, the Capacitors are out of stock until February. I have looked through but couldn't find any others with the same rating is the 4700 Uf 100v the only capacitor's that will work? I'm sorry to be a pain.

thanks


Rob

Quote:

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Originally Posted by grain_r

Good Morning Clive

I have been onto Rapid to place the order but unfortunately, the Capacitors are out of stock until February. I have looked through but couldn't find any others with the same rating is the 4700 Uf 100v the only capacitor's that will work? I'm sorry to be a pain.

thanks


Rob

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https://uk.rs-online.com/web/p/alumi...citors/8467133

https://www.ebay.co.uk/itm/393492725...Bk9SR9SekPWlYQ

Quote:

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Originally Posted by Clive S

https://uk.rs-online.com/web/p/alumi...citors/8467133

https://www.ebay.co.uk/itm/393492725...Bk9SR9SekPWlYQ

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Thank you very much clive