We encountered a similar problem. In our scenario, the Z axis was being driven at speeds that exceeded the values set in the Trajectory Planner, which caused faults in the SnapAmp.

Tom K provided a version that wasn't supposed to do this, version 431n or 431o. I can't find the email in which he mentioned which version it was, and we didn't get it, and now it's no longer available.

We are currently using version 431s. I believe it still has problems with our trochoidal milling operations. We tried cutting an aluminum bar, and took video of the operation. After 15 minutes, it appears that the machine was commanded to move into the uncut material at a bit depth of approx. 6 mm. The operation that should have been done was a circular motion with a stepover of .11 mm. Instead, it suddenly moved 1 - 1.5 mm in the -X direction, from what we can see in the video. For a 2 mm bit, that was the end.

Tom, does version 431s have the changes that you made to address the sudden Z-axis movements? I assumed it does.

Here's a frame-by-frame video of the bit breaking:

http://www.qdea.com/andy/2_mm_Bit_Breaking.mp4

Hugh Sontag

---------- Forwarded message ----------
From: <todmorg@...>
Date: Mon, Feb 10, 2014 at 8:41 AM
Subject: [DynoMotion] Trajectory planner questions
To: DynoMotion@yahoogroups.com

I am having problems with slamming deceleration/acceleration between g1's g2's and g3's. I am using KmotionCNC version 4.31e. This version does not have the "Arcs to Segments" check box

I have set the Acceleration values in the tool setup screen AND the init.c file to extremely low values to try to eliminate the slamming between segments, but it will not go away unless I set the Collinear tolerance to a large value, like .2, then it runs smooth on most of the segments, but still slams on some of the segments and breaks the arcs into coarse line segments ( A .8" circle will have about 12 flat sides instead of being a smoth arc ).

It feels like the Acceleration/Deceleration curves are being skipped and the machine is slamming to start and stop instantly between moves. I have attached a random clip from a file that seems worse than some others

Kflop/Kanalog AMC 30 amp DC servo drives, 127,000 steps per inch X,Y&Z.

Thanks, Todd

N195

N200 G00 X-2.6291 Y-1.8023

N205 G00 Z0.1

N210 G01 Z-0.51 F35.0

N215 G01 X-2.6008 Y-1.5288 F70.0

N220 G02 X-2.75 Y-0.9709 I1.6662 J0.7446

N225 G01 X-2.9111 Y-0.7481

N230 G01 X-2.4678 Y-1.8246

N235 G01 X-2.4523 Y-1.55

N240 G02 X-2.6346 Y-0.7842 I1.5177 J0.7658

N245 G02 X-2.4974 Y-0.1151 I1.7 J0.

N250 G02 X-2.5 Y0. I2.4974 J0.1151

N255 G02 X-1.9615 Y1.55 I2.5 J0.

N260 G01 X-1.9217 Y1.8221

N265 G01 X-1.7482 Y1.8202

N270 G01 X-1.7995 Y1.55

N275 G03 X-2.375 Y0. I1.7995 J-1.55

N280 G03 X-2.371 Y-0.1381 I2.375 J0.

N285 G03 X-2.5096 Y-0.7842 I1.4364 J-0.6461

N290 G03 X-2.3109 Y-1.55 I1.575 J0.

Group: DynoMotion	Message: 9172	From: Hugh Sontag	Date: 2/10/2014
Subject: Fwd: [DynoMotion] Trajectory planner questions

Group: DynoMotion	Message: 9175	From: Tom Kerekes	Date: 2/10/2014
Subject: Re: Fwd: [DynoMotion] Trajectory planner questions