Messages

11

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 09:34:16 AM »

It seems as if I may just need more belt tension. However, it's going to require a fair bit of cross bracing on the machine. Gotta do what you gotta do I guess!

12

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 09:17:39 AM »

Here is a pic of the belt , the left side, the teeth are riding in the grooves as they should, but as you can see, they start riding up onto the teeth in the pulley.

If I pull on the belt VERY tightly, I think it manages to fit, but that kind of tension would rip my machine to shreds.



I'll email the place I got the belts and pulleys from and see what they say.

Cheers,
Dan

13

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 08:52:59 AM »

OK, I think I've found my problem. I set my original shape pattern on F60, and watched the belts move over the pulleys. I notices that sometimes the teeth of the belt actually ride ON the ridges in the pulley, and not the grooves like they are supposed to.

Now, why it's doing this has lost me. The pulleys and belt are the same pitch, so I'm thinking maybe my belts arent tight enough?

EDIT: I just took a pulley off, and wrapped the belt around it. I could get 1 full rev, but after that, the teeth started riding on the ridges. Maybe the machine was very slightly off when these pulleys were machined?

Cheers,
Dan

14

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 08:31:47 AM »

Yes, I still have the steppers as idlers. I'll see if I can remove some of the magnetic structure so they spin freely and see if it makes any difference.

If those gaps were skipped steps, it'd take about 20 skipped steps to make a gap that size.

Multitasking PC: I think that'd be a more random occurrence, and I dont think it'd happen at exactly the same time, every time.

Belt jumping a tooth, possible, though not exactly sure how I can test that. Are my belts better off tight enough that they don't sag much, but not stupid tight, or stupid tight?

Cheers,
Dan

15

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 07:20:48 AM »

Here is how it turned out:



So, it would appear the problem is either in my electronics, or my mechanics.

Does anyone know any guides that could help me narrow down the problem? Or any gcode/tests I can run to help?

Is it possible microstepping could be playing a part in this? I have the controller (Pre-made, generic 4 axis board) set on 1/8 microstepping. I really do like it as it makes everything a lot quieter and smoother, not to mention more accurate, but if its causing me problems I may need to find another solution. But I'm was under the impression almost everyone used mcirostepping without problems?

I built this whole machine myself, and this teeny little glitch is all thats stopping me from finally completing it.

If hi res, detail pictures of the machine will help, I'm ready with the camera.

Cheers,
Dan

16

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 05:16:41 AM »

Well that I'm not exactly sure on. The page before, the g code I was using was proven to be OK, and I can create some text in lazycam and it'll draw it all fine. Maybe mach3 is interpreting the code wrong? Or maybe there is a setting (offset or something) that mach3 doesn't like?

Does anyone have any proper CAD software they know works with their machine, who could create a dxf or some gcode for me to try?

Cheers,
Dan

17

General Mach Discussion / Re: Need help with basic understanding

« on: February 21, 2011, 05:02:58 AM »

OK well. I mounted the laser on the machine nice and steadily, it doesn't move at all now. I also ran the steps per calibration a few times on both axes, and they matched up exactly the same every time.

So not really sure what else could be wrong with it now, apart from software.

Cheers,
Dan

18

General Mach Discussion / Re: Need help with basic understanding

« on: February 20, 2011, 09:40:05 PM »

Yeah, I understand why it could go into the -s now. Originally I didn't have a solid software to test with, so my gcode was all over the place. Now that I know sketchup works OK (Unless the machine isn't the problem), it makes sense that the machine draws it in the exact same spot as you did in sketchup.

I'll mount the laser on it properly when I get home and try it again.

19

General Mach Discussion / Re: Need help with basic understanding

« on: February 20, 2011, 09:39:04 AM »

Well, how would I go about checking if they are skipping steps or the belt is slipping? I've tightened the belts enough that they have minimal sag, maybe it needs to be even tighter? My steppers have a fair bit of torque, it takes a fair bit of effort to stop them, so i'd be surprised if they were the problem.

20

General Mach Discussion / Re: Need help with basic understanding

« on: February 20, 2011, 09:26:11 AM »

Well, it's actually a laser, as its only temporarily setup, it has the potential to move. I did try setting home on the machine to a different position, just to make sure it wasnt a certain section of the machine, but got the same thing. I will secure the laser down better tomorrow and give it another try.

I never said it could have been bad axis setup or an option somewhere in mach3, but there are no pointers that my steppers are skipping or belt is slipping.