Yes you are right
I may be able to make adapter plate when my cnc machine is running or at worst make new one's when it is finished so not all lost.
at least I have a shell to copy and the plugs are still usable
James
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Yes you are right
I may be able to make adapter plate when my cnc machine is running or at worst make new one's when it is finished so not all lost.
at least I have a shell to copy and the plugs are still usable
James
Yes they do look worth copying for £20 each...Quote:
Originally Posted by luke11cnc
More parts for you:
Attachment 4629
Attachment 4630
Attachment 4631
Attachment 4632
The bore of that last ballnut mount came out very shiny. I used a polished carbide tip in the boring bar from APT:
http://www.shop-apt.co.uk/carbide-in...m-uni-tip.html
I didn't do anything special - it was just cut dry with the auto-feed. Would definitely recommend them for getting a good finish on aluminium...
Now that's looking good Jonathan
Just the gantry side's too do and I've got a long long weekend of work on my cnc
thank you they do look good
James
I have found the 6 pin connectors on ebay but would like advice on there load rating please before I buy as I seem to f-this up quite often
any way here is the link
http://www.ebay.co.uk/itm/10-6-PIN-M...ht_1240wt_1163
Thank you for looking in advance
James
James,
I think you said earlier that you were using Nema 23 motors(I think the Nema 23 peak at around 4.5 amps )so those plugs and sockets should be fine. You could always mount a little junction box next to the motors and connect them up that way like i did. Saves alot of hassle and time.
Ian
Ian
I thought they where nema 23 but they are SY60
James
I think that would be Nema 24 then. Still around 4amps max give or take a tad.
Ian
Yes they are 60mm, which seems to be referred to as Nema 24 though I doubt that's an 'official' size. They are rated for 4.2A per phase in parallel, so those connectors are fine...
I take it they're for the 'control box'?
By the way the CY cable arrived.... so we've got plenty now.
cool Jonathan I will see you Monday
I can't wait to see all the parts you've made for me and Luke
Luke has a short week this week he finishes school on Friday at 12.30 so we will be in the garage all weekend next week working on the CNC machine
Yes they are for the control box
James
Your waiting is over:Quote:
Originally Posted by luke11cnc
Attachment 4639
Attachment 4640
Attachment 4641
My home, gradually filling up with swarf...
Attachment 4638
OMG they look so so cool
thank you Jonathan
Luke is in bed but I will show him before he goes to school
James
Luke's going to love watching the machine for the first time !
Luke has just seen them and said wow are they for my CNC
can't wait until Wednesday,Friday and Saturday to start fitting them.
Luke said "tell Jonathan thank you please dad"
So on that note Jonathan thank you from Luke
James & a big smile on his face Luke
Now I've had my wings clipped
I'm not aloud to do any CNC work without Luke
so you will have to wait until Wednesday and Friday for up dates
sorry but Luke and MUMMY has spoken
but I would like to say
Jonathan you are a god yes god and not good
as Luke said it he is to good and dad can we do that with our CNC
reply
yes son but not just yet, lets get the machine working first ??
Jonathan again a big big thank you
You have made my son very happy and more to the point thirsty for knowledge
At long last some parts have turned up.
post office has gone south in my view
but Jazz one out of two items have arrived and Luke would like to say thank you in his own words and in his own hand writing.
so he has written you a short thank you letter just to prove that it is a father and son project
Attachment 4705:smile::naughty::smile:
James
Thank you Luke for the nice letter. Tomorrow I will remake the missing Jigs and send them first class recorded so they don't go missing again.
James would it be ok to make them from thicker 19mm material so long as the step and hole locations are the same.? I'm struggling with thinner material.
thank you Jazz that's fine
James
Have you mounted the gantry yet? If so why no photos!
What are the Jigs for just out of interest?Quote:
Originally Posted by JAZZCNC
Hello Jonathan
I've not done a lot to the CNC machine over the weekend as we where looking a schools for Luke, plus I have two wedding this weekend so I will try and get some photo's up this week as we did strip out a computer ready for the drivers.
The jig is just a location jig for the Y-axis supported rails as I want to make sure they are true and square on the extrusion I also had to have some m10 T-nuts made as the supplier of the extrusion only go up to m8 plus you had lot's and lot's on your plate and with going back to University I didn't like to ask you to do more before you went back.
How are you doing anyway Jonathan I've not heard for you for ages and ages??
I am waiting for some 10mm round bar to help attach the 50x50 extrusion to the gantry sides I will come over not this weekend but next weekend if that's OK
James and Luke (Luke has a thank you card and gift for you just to say thank you(Bless him)):tup::tup:
Jonathan just looking at your nut mounts you have done, nice job i might add.. but i looks like you could do with a de-buring tool, cleans them edges up a lot nicer then the good old file.
http://www.ebay.co.uk/itm/MONUMENT-3...ht_1217wt_1165
Just a thought ;-)
Those pictures were probably taken before I de-burred them...either that or I forgot to do it! I've never got one of those tools as I didn't know if they were actually good, or just a gimmick, but since you've recommended that one I guess it's worth a try.Quote:
Originally Posted by AdCNC
Generally to de-burr aluminium parts I use the edge of a steel ruler - probably not good practice but it's effective. Similarly if it's a hole de-burr by hand with a drill that's bigger than the hole.
I see.Quote:
Originally Posted by luke11cnc
Ok, that's true. I think I've got some spare M10 T-nuts as I made a load for my rotary table. Migh be M8, bit late now anyway.Quote:
Originally Posted by luke11cnc
Er... fine I suppose. Not so much to do now I'm back at University! I've just started continuing my (quite) high voltage stepper driver design/prototype as that's something I can do here.Quote:
Originally Posted by luke11cnc
That's suits me. By waiting do you mean have ordered or will order soon? If it's the latter then maybe don't bother as I will almost certainly have some.Quote:
Originally Posted by luke11cnc
Well after a long long week
LUKE has broken his foot now
So I have decided to crack on with the CNC machine
Now the frame is true and square (spent all day Friday doing this) fitted ONE side of the gantry side to my ballscrew but I have some binding on the other side (about 5mm out)
My rails are square and parallel but the gantry still refuse's to play. One side hits the end of the table and the other is around 5mm off (I can force the other side to meet the side at a right angel) but this is not right (every fibre of my body says "no, it’s not right") but I am all out of ideas
I am going to look at the bearing today to see if they are mounted correctly (all facing in the same direction) would this throw my gantry out of square??
I am at a loss to where things have gone wrong??
Does it matter if the bearing are pointing in the same way ??
The only two ways I can get the X-axis to run true is to force the right side over by about 5mm or have the table out of square
I’ve just taken some images of the machine and its now only out about 2mm
So I think I was over reacting and it was just crabbing
But I think I would still like a second opinion
any way here we have Luke striping out the old computer (sorry but Luke is in a bad mood :twisted::twisted:(tired me thinks)) not one smile and he told me not to take any more photo's of him
Attachment 4726 Attachment 4727
Attachment 4725 Attachment 4724
Attachment 4722 Attachment 4720
Attachment 4728 Attachment 4723
Attachment 4721 Attachment 4719
do you like my drives two Bosch drills :naughty::naughty:
today I'm going to tap my M10 T-nuts and start mounting the Y-axis
James:tup::tup:
James,
it shoudnt matter which way round you mount the bearings. Keep up the work, your doing well. Can you post a photo of where the parts dont meet so we can get a better idea of whats happening?
How do you manage to synchronize the bosch drills:heehee:
Ian
Thank you Ian I couldn't do it with out help from this web site and it's friendly members
Here is the two images of the x-axis bearings they should be in line but as you can see the right one is not tight to the MDF (about 1.5mm gap) But I can move it by hand.
Attachment 4731 this is the left side
Attachment 4732 this is the right side
Is this just crabbing or should it be in line as It's not under any load ??
James
The joint where the 6" wide plate bolts on to the back of the gantry would have to be perfectly square for the gantry to also be square. The distance is so great that the angle on those joints doesn't have to be out by much at all to get 1.5mm out. Also I'd be amazed if the frame is actually perfectly square, so using it as a reference could be misleading. The other thing is the position of the X bearing mount plates and hole positions - they could be slightly out too. All these tolerances stack up, so it's hardly surprising to me that there's a 1.5mm error ... don't worry about it.
If in the end the machine still wont cut square there's ways round it. If it's not much at all then you can position the X-home switches so that mach3 bends the gantry very slightly to square it when it homes. Clearly that's a bad plan if it's out by a lot as it would put a lot of strain on the structure and motors. You can also compensate in mach3 by using 'formulas' which enable you to make one axis a function of another axis. So you just put X=mY in the X formula box where m is the measured gradient / error. The difficult bit is measuring the error to start with as there's no straightforward reference.
Maybe he's using the steppers as encoders to provide feedback...Quote:
Originally Posted by Web Goblin
Thank you Jonathan
I feel a lot better now did you get my email?
I think the slight whip on the 12mm gantry support rail is not helping, I should be flat when both extrusions are bolted up to it. I was quite surprised when I offered the extrusion up to it and had to G clamp to get it flat.
all going well but I don't have a M10 starter tap, so I will have to get one in the week.
So a change of plan for today's work I'm going to mount the drivers in the old computer case
after I tidy my workshop/garage up (what a mess but not as bad as yours Jonathan:rofl::rofl:)
James
Luke,
did you measure the diagonals of your bed to make sure it was square? Its not out by alot.
If you are interested in taps I have some for sale at the moment. Pm me if you are interested.
Ian
You're welcome to borrow taps from me... but long term you might want your own anyway.
I got your email, thanks.
Thank you for the offer Ian and Jonathan But I have just bought some from ebay
I have a kit tap but it has no starter tap
yes the diagonals are spot on and all the material for the CNC machine has been digitally cut by the supplier
James
James if your only 1.5mm out then thats only 0.75mm across the diagonal. If the machine is not bolted securely to the floor then the frame could very easily bend or move this amount just from moving the gantry back n forth.
If you intend to move it around or it bothers you then put some diagonol adjustable tie rods braces so it can be adjusted and held square. I did this with my machine while building then re-adjusted when I eventually found the place in shop it was going to live then bolted it to the floor . Only then did I tighten and true the gantry/rails etc.
Will it affect the accurecy of cut.? . . Well Yes if your working to high precision then this amount would be considered massive but for oridinery woodworking etc then it's acceptable to some degree.?
I say some degree because there's another issue and IMO better far more important reason to find the inaccurecy and square the frame to near perfect as can be.!
Like jonathan says you can effectively cheat and square the Gantry by forcing it square using the motors.!. . . Problem with this route is that it puts components under constant stress, bearings and even the screws are fractionly twisted this over time leads to premature wear or failing. . . . Much better to find the cause NOW than replace parts or worse still be constantly chasing inaccurecys or even missed steps etc from binding as parts slowly wear away losing performance.!
Taking the time now will pay dividends later down, don't fall into the trap of rushing the machine into service only to pay a big price over the coming months.
Promise you even if it takes a few days to sort this inaccurecy now it will save you weeks of hassle and unneccesary expense months further down the road.
Pulling and holding the frame square with Diagonal tie rods (M12 Threaded rod works good) then bolting the frame down BEFORE finally trueing and bolting the Gantry and rails etc makes the process so much easier and accurate without stressing important expensive components like Ball-screws and linear bearings. This way Only frame is then under tension.!
Edit: I know the T nuts did but have any of those Jigs turned up yet.?
I'd only 'force it' square using the motors if it's not much out at all. Depends on the stiffness of the frame. If it's out by more then bolt the frame down as Jazz says and if it's still not good use the formulas in mach3 to compensate as that will completely eliminate any error.
It's just occurred to be that you could purposefully have the gantry built a little out of square, force it with the motors/ballnuts to reduce or eliminate backlash. The pressure on the ballnuts from squaring the gantry would preload both X-ballnuts rather like if you have double nuts with a spring. Clearly if the cutting force is greater than that preload you will get backlash, but for light work it would work. Disadvantage is clearly extra load on the X rails and I suppose marginally more torque required, so feedrate will be negligibly less. I wonder if this is why I have practically no backlash in my X-axis...I'm not purposefully forcing the frame, but I guess it wouldn't have to be much out.
Yes they have.Quote:
Originally Posted by JAZZCNC
If the bearings are not all the same way it wont affect this. However the force rating of the bearings must be different in each direction as the location of the rows of balls is not symmetrical. I doubt it will make much difference, but you might as well have them aligned so it's even.
That then would just be a bodge to hide poor workman ship.!!. . . . . . . Plus it wouldn't preload the nut it would twist the nut.!. . Yes the affect would appear the same as taking up backlash but what it's actually doing is twisting Nut body onto the balls which in turn apply force against the screw. Both the screw and Ballnut are not designed to run with forces in this direction so again your forcing the screw and nut to run out of design parameters.. . . This cause's premature wear.Quote:
Originally Posted by Jonathan
Much better to build right first time IMO.!!
Aghh Yipee... Thanks for letting me know.!!Quote:
Originally Posted by Jonathan
Or cheap ballscrews - hence why I think my measurement of the backlash might be misleading.Quote:
Originally Posted by JAZZCNC
Maybe, maybe not. It depends what's twisting. If you assume the rails are rigid (not quite true for supported rails as they bend upon the support, but not much) then it must be the gantry in between twisting and any force not parallel to the X-axis is resisted by the X-axis linear bearings leaving only the axial force for the nut. On James' machine, clearly the weakest point on the gantry is the joint between the sides and 6" wide cross piece, so that and the cross piece will bend. The ballnut mount and gantry sides are solid so won't bend noticeably. .. etc it's obvious I don't need to tell you.Quote:
Originally Posted by JAZZCNC
Not suggesting one should actually do this intentionally. The force ratings of the ballnuts is huge, so I think you'd get away with it. I'd be most worried about the linear bearings.
Yes the Gantry will more than likely twist at the point where the sides meet cross brace at one side but the Ballnut is attched to the side so will twist against the screw unless the screw roates the same amount as the gantry twists. Plus like you say the bearings will suffer the worst.Quote:
Originally Posted by Jonathan
Either way it's wrong and not recommended.!!
No, as the gantry sides will not twist at the point where the ballnut is mounted. Looking at the machine facing the Y/Z plane from the top it's cross brace, gantry side, X bearings, X ballnut. The gantry sides will twist between cross brace and X-bearings, but not much at all if any between the X bearings and ballnut as the bearings fix it. The twist will be tiny as the sides are very thick/strong aluminium plate. The same is true for machines configured like ours - the gantry 'ends' have the ballnuts mounted roughly at the same level as the gantry, and the X bearings provide support between so there's nothing to twist the screw. If the X-axis linear rails were not there then yes the screw will definitely be twisted, but that's just silly anyway. Imagine resolving each of the forces, any force not parallel to X that could cause twisting must appear as a contact force on the X-bearings and thus prevent twisting as there should be no clearance in the bearings.Quote:
Originally Posted by JAZZCNC
In either case if there is any twist on the screw it's going to be a tiny negligible amount and the extra force that would apply is surely small compared to say the force from screw whipping.
Don't matter how you try to flog it Jonathan it's simply wrong and not a good way to build a machine. . . Sooner or later the price of inaccurecy and miss alignment of precision components will have to be payed for.!! . . The degree of inaccurecy will be the determining factor to how long it takes . . . . BUT Like Death & Tax's there will be no escaping it.!
I'm not trying to flog it at all. I was just pointing out then that it is wrong to say there is any significant twisting force on the screw, and therefore you're only increasing the axial force on the ball-screw which is the same as what would happen if you did it properly with double nuts and a spring. If it wasn't for the large force it places on the rails I see no reason not to do it. It is obvious that there are far better ways to attain low backlash. I mentioned it originally more to point out how it could lead to a false reading of backlash.Quote:
Originally Posted by JAZZCNC
Well It wouldn't be acceptable to me or a practice I'd employ on any machine with my name to it.!! . . . . So again we'll have to agree to disagree.Quote:
Originally Posted by Jonathan
Oh you might want to checkout how proper double nuts are connected and preloaded.? Dont think you'll find meny springs around.?
SameQuote:
Originally Posted by JAZZCNC
I know, but proper double nuts aren't as good as two nuts and springs / belville washers are they.Quote:
Originally Posted by JAZZCNC
When I referred to 'double nuts and a spring' earlier I was thinking of doing something like this as it's a simple way of implementing it:
http://www.mycncuk.com/forums/showth...ull=1#post8924
Especially with only C7 grade screws where the pitch error limits how far you can go with double nuts.