Cutting a circle with a lead in perpendicular.

[Vmax549]

Can someone post a simple Gcode file that this happens in . I guess I have been lucky as I have never heard of this problem in anything other than UCCNC and I have used MANY comercial and DIY jet type controllers over teh last 20 years.

I have tried to create this condition in a Gcode file but so far have failed to do so in V2109.

(;-) TP

[stivemaster]

Well, your version may not have this bug. I have 1.2048 and it happens. I asked what would happen with the key, if I changed the version of 1.2049 I did not get the answer.

[cncdrive]

Again: It is not a bug.
The same problem happens in Mach3 also and because it is a mathematical and numbers representation problem it exists on all controls.
And the issue is that the coordinates are syncronised (updated to real value) and with a fractions steps per units value there will be error in value because the 1/steps per value will not always give the exact coordinate of the arc start point which was calculated by the CAM program and which was in the previous movement. But the syncronisation is a must when there is a macro or some other commands, otherwise the coordinate was not correct for the macro etc.
I have explained it in more details earlier with drawings too, but I can't find that post now...

Terry: You can't reproduce it because the chances for this to happen is low. It requires a certain steps per value (axis resolution) and a certain situation of coordinates and a certain coordintes of the arc end point to happen. It only happens with full circles or with very very close to null circles. Full circles can mathematically become null circles and null circles can become full circles. (about null and about full ofcourse)

[Robertspark]

Sheetcam, split circles into quadrants:

For sheetcam, the solution may be (not tried it yet) to edit the post processor

Code: Select all

 Options->machine->post processor. Click on the 'edit post' button.
Add this as the first line of the post:
post.SetOptions(post.ARC_SEGMENTS)

I'd suggest looking at sheetcam and customize the post processor to get it to do what you want it to do.

[stivemaster]

In post 12 I wrote what I want. What you offer is not a solution at all. You have not seen what the difference between an arc and a series of 500 straight lines is it?

[Vmax549]

Balazs, I think this is your example you were looking for ??

http://www.forum.cncdrive.com/viewtopic ... 1195#p9086

(;-) TP

[cncdrive]

Yes Terry, thanks that is the post what I was trying to find.

[Vmax549]

So just to be clear can we assume that this issue was fixed in UCCNC as per V2103 ?

V2103
- An issue with full circles execution was fixed, that if the software was forced to syncronise with the motion controller after a motion which movement gave the startpoint of the arc and then the full (360°) circle was executed after the code which caused the syncronisation and if the 1/steps per value was not an integer divisor of the endpoint then the circle was in some cases no more understood as a full circle by the motion software, because the syncronisation caused the start coordinates and the end coordinates to become different points, because the steps per value did not allow the programmed coordinate by resolution and so then the circle might not be executed depending on which side the start coordinate offset. The issue was fixed with the controller is now not syncronising the coordinates while in cycle except for certain operations which require the syncronisation.
- Rigid tapping and Thread cutting possibly missed to make the syncronous motion in some case (~1 out of few hundreds usually). This was fixed for the ethernet controllers only in the previous release and now the same was fixed for the USB controllers.

Just to confirm, (;-) TP

[beefy]

What you have never thought about is that plasma cutting - obviously, a large number of customers need you and other than synchro-acting codes that you started to create for everybody.
There should be only M10 and M11 that are quite sufficient.

Quite sufficient for you perhaps, but myself and other use other synchro codes, and they are very valuable. After all they were created because someone needed them.

[stivemaster]

Hope you read carefully? Which code you use and is so valuable to you.
And let's say this - if company X has a THC controller and needs M555 to operate this controller, does that mean it was needed?