[CROSSHATCH]

I'm running cut 3d and cutting a prototype product. My work areas is 7 by 4.50 by .375 (Cut in half because it's two sided) so i'm only giving half the depth.

Anyway, my roughing pass went fine, cut from each of it's starting points etc.

I am now dealing with really really frustrating annoying stuff using my final pass! I am ever ruining my prototype piece with cut3d it seems.


When I run the final pass, everything starts out fine. I initially set it for a .016 DOC and things were turning out good. Until I came back to the part after letting it run for over an hour and found that part of my piece was cut on the final pass. I ran the program a second time to see if it would cut the areas it missed the first time. On the 2nd try, I ended up seeing that where it did not cut, the x and y were working in good order over the area but the Z-axis was off. It was above the piece but doing the finish pass but obviously not cutting.

So I re-did the file and did a 135 degree angle cut, it cut the area it missed last night but did the same thing over one of the sections. It was working the entire piece with x and y but over this missed spot, again it was over the the pieces by a few millimeters.


I am not trying for a fourth time, running an inefficient X- finish pass.


I checked the 3d render and viewer and it shows it cutting right.



I don't have a feeling that it's the machine because it keeps happening over the same areas. So if the machine/electronics were to skip steps, the whole piece would eventually get messed up.





Anyone have this problem



-Jason

[DonFrambach]

Hello Jason, I'm new to Cut3D (only done a few models that have turned out well)

From my ignorance, I do have a thought.

Would it be possible for you to find where in the G-code your system is not cutting? If you can do that, you will be able to tell if the Z axis is too high because the instructions are incorrect or if your mill is not properly following the G-code instructions.

Don

[Khalid]

may be not the electronic fault..but it may be the cause of some mechanical faults..check ur lead screw at those locations...

[CROSSHATCH]

It only happens when it rapids to a new spot. I just sat in front of the mill for 50 mins watching it cut.

I think there may be to much weight on the z-axis so when it rapids, and gets that burst to rapid it loses steps on the z-axis axis. But that makes me wonder because if it loses steps going up, in theory it should be lower then it is.


In any case, I just changed all rapids to 18 Ipm instead of 24 Ipm.


One last test tonight


There goes my aluminum stock!


-Jason

[CROSSHATCH]

This very well can be a problem with the Z-axis. I'm simply going to take off the z-axis tomorrow and tighten the leadscrew nut for any backlash. This is the only one I have not done.

Other then that, I don't see what would be wrong with my system.


-Jason

[ger21]

Slow down the acceleration instead of the rapids. It's during the acceleration that you're probably losing steps.

[CROSSHATCH]

Ahhhhh truee!!


That makes sense. I have a feeling right at the initial state of the rapid, more amps are trying to be drawn and then it loses steps.

And throughout the maching, the z-axis is always moving up and down. The first area always seems to machine just fine. Whenever it gets to the 2nd, 3rd areas it starts messing up on the z-axis, NOT on the x or y.


Other then that, everything looks decent and ok. But this is completely ruining my part.



-Jason

[CROSSHATCH]

I had my acceleration at 10 m/s (In emc) which may not be that fast, but hopefully now that I changed it to 2.0 M/S and put the Velocity at .35 I will be able to z-axis better.

I'm looking at my part and I can see where it all messed up and blah!

Would be so much better if this never happened



-Jason

[CROSSHATCH]

Ger21- Just to clarify, I went from on the acceleration 10 m/s^2 which gave me an instant reaction. To 2m/s^2 which at the start the motor starts slowly and then picks up and then slows down the same way, it's not instant start and instant stop. Is this what I should be looking for at least for the z-axis?


I hope to god this works!


-Jason

[ger21]

Yes, but you shouldn't have to lower it 80%. Try it at 5-7 and see if it works. If not, back it off some more.

[CROSSHATCH]

Well I decided to start cutting it at 2, oops. I cross my fingers and hope it works.

I left the intial Rapid at 24 ipm instead of back it off, I only did the acceleration.



I hope this works! Omg I hope!



-Jason

[CROSSHATCH]

No prevail!

God!!! Maybe I need to slow down the rapids on the z-axis? As odd as i may seem, maybe thats it. It's not backlash because the entire part would be messed up. It's only certain areas that are repeatedly not cut


-Jason

[CROSSHATCH]

Part failed again even when I drop all axis to a MAX 15 Ipm rapid. Maybe I need to drop it less then the actual cutting speed which has gone from 17-now 9 IPM.


I'm lost


-Jason

[tahustvedt]

The toolpath code for miling the finishing pass on 3D shapes is very big, often several MB. Sometimes My memory card is full and an incomplete toolpath is saved on the memory card. When I import it into Mach3 only part of the toolpath is visible.

Is there a max limit to how big the toolpath can be with Emc perhaps?

[greenb_60097]

Jason,

I had a very similar problem on my router. Everything was working great until I tried one of the dished out 3d freebies from vectric in cut 3d. Mine would taper and leave the profile sort of on an angle, ie if I started the dish say at -0.25" it would finish with my zero say +0.25 above my zero. It didn't mater if I rastered in x or at a 45 degree. I spent hours trying to troubleshoot this. Changed out lead screws on my z, change motors, change controllers, put z on a separate power supply and nothing seem to help....so I feel your pain....BTDT..have the tee-shirt, etc. It never made sense to me that I would only lose steps in the +z direction and they seemed to accumulate..

Finally, at wits end and not wanting to pull out any more hair, I bought a much bigger nema 34 stepper. Since I'm running the keling kit with nema 23 495inoz motors and the motor controllers wouldn't handle the amps I also bought a gecko 203v drive. Since I needed to make an adapter for the larger frame motor, I thought what the heck and added the gecko drive to the z-axis expecting the same result. I went ahead and started the 3d toolpath that was giving me difficulty and well, son of a beach it worked like it was supposed to. In fact I haven't had the problem since and I didn't need the big honkin stepper for the z

Hope this helps, I feel your pain
Brian

[CROSSHATCH]

Good information. But tahust is right. The finish passes are very large. Mine are 1.11mb + When EMC cuts it, the computer lags really bad later in the end of the cut. I am buying a new computer as I feel it's all on that end of the problem.

-Jason

[greenb_60097]

I remember back awhile ago >1year someone posted a problem like that as well and he finally traced it down to getting a new confusor....it was one of the RC guys, but I cant remember his screen name....

I have good luck with ebay used dell p4 3g machines, I've picked up 2 back ups for around $75-100/ea shipped when the power supply on my office pc took a dump....but I fixed the power supply but bought a back up just in case I feel better with the backups, if nothing else I can swap out instantly and be up and running in minutes if my control confusor takes a dump.

Brian