Thanks. What is the cost on new belting?
And Phil said that he still snaps belts when doing carves even with thicker belts.
Also the repeatability and accuracy is amazing.
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Would be interested in hearing if you have any timing issues between the two Y screws. Now that you have a mechanically restricted setup. There is still a possibility of slip within the stepper motors, so it may not be an issue.
None so far. Cutting like a champ.
150ipm .125 doc in oak
that surprises me. Afaik my machine is very similar to yours, and the V wheels are BY FAR the weakest link in my setup. Especially the ones along the X rail are introducing way too much give in the machine. relatively speaking off course.
V wheels do the job.
The next weakest link is the z.
After that new machine.
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From my experience, screw drives are prone to backlash of some sort.
Have read in many places that belts are far better.
Can anyone confirm that or perhaps I am wrong here?
Define backlash!
For screws with anti backlash nuts the is almost no backlash issuesā¦
my design incorporates anti.backlash nuts.
mine are not adjusted yet (aka loose) and i cant even move the gantry by handā¦ even with the system powered down.
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Im running at 150ipm and doc of .125 with a .25 bit and its measuring dead on.
This is awesome. I really want to know when the kit (or parts) are available!
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Backlash is a known issue for many years. I donāt think I need to explain it as I donāt need to explain the sun rising up in the eastā¦
The belts system are known to not have a backlash issue, or perhaps very little.
My question was to see there is a benefit in switching from belts to screw system that I am not aware of.
And, I fail to see how your comment can benrfit the discussion
I have an older cnc machine running on screws, Got anti- backlash gear, and still have some baclash.
I suggest when your machine is up and running with your new mod, give it a backlash test. I will be very intetested in the result.
How do I test? Because when my motors lock I canāt even budge the gantry or carriage.
No movement should should mean no backlash am I wrong?
If I give even the slightest manual turn on the screws the gantry moves exactly along with it. Not even close with belts.
I put my hand on the v wheels during a cut sequence and I felt every tiny shift in direction.
Also when I cut a 2 inch circle pocket itās almost perfect.
Ok. Backlash is when you change direction of an axis. Since when using screw and nuts, you must have some kind of freedom between these two, to allow free movement.
When changing direction say like in cutting a circle, if yoy have backlash the circle,will not be perfect.
Thatās why they invented the anti-backlash nuts.
With belts, this issue,should not happen or at least me minimised to a neglectable error.
To test your backlash you can google: cnc machine dial gauge baclash test - there are few youtubes there for you.
Then my measured backlash is around .0005. Or so my indicator shows.
Define āalmost perfectā. What adjustments do you have available to make it perfect? V-wheel tightness only?
Is your measured backlash in X or Y? Does it vary between sides of the X axis?
Do you have a way to square up the X axis to be perpendicular to the Y axis? Are you seeing any differences in motion between Y1 and Y2? What happens if you get a mismatch between Y1 and Y2?
Iāve measured 0.07~0.08mm (0.0028~0.0031") backlash on my X-Carveās 3GT belts. I have no doubt that a leadscrew with an anti-backlash nut could perform better than this.
However, I am surprised to hear 0.0005" with loose nuts. Are you sure this is not 0.005"? What indicator & base are you using? Now, if you can take THIS on video, youāll have customers knocking on your door.
EDIT: Clarifying āTHISā:
- pick an axis
- jog your gantry to where your indicator preloads
- G1 towards the same direction at relatively low speed for 90% of your indicators range
- G1 back to original position
- read backlash
- reset & repeat 3-4 times to check consistency (and verify that your base & indicator setup is not moving)
wow that is a lot quicker than i can run with GT3 belts. Iād be very interested to see how this progresses.
When it comes to making a ākitā would it not be much more cost effective to have the plates laser cut from Mild steel and powder coated rather than machined from aluminium? We use a lot of laser cut parts at my job and its significantly cheaper and quicker than milling.
Thanks.
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im using a steel plate held down and a magbase with a plunge indicatorā¦ i will double check everything later this evening using your method.
They are waterjet cut. then tumbled to take off the edge. Then im still deciding if i want to have them tap it (extra cost) or if i want to do it myself (extra time) or have the customer do it.