Messages

5821

General Mach Discussion / Re: Xylotex to Gecko G540

« on: October 26, 2008, 09:07:40 PM »

Increasing the current can damage the motors, so don't increase the resistor value. The G540 has a current reduction when not moving. If you move the motors, does it then have more torque after it stops?

Something is wrong with your setup. The Xylotex has a max setting of 1/8 microstep mode. The G540 is fixed at 1/10. So if your Xylotex was set to 1/8, with the G540 you should have 10,000 steps per unit. There's no way the steps per unit can be less than the Xylotex with the G540. You might want to call Gecko with your concerns. They should be able to get you set up pretty quickly.

5822

General Mach Discussion / Re: Cutter Compensation

« on: October 26, 2008, 02:20:59 PM »

Expecting it to work on a closed path is asking a lot. I think you're misinterpreting what they mean. If you read farther along, they talk about using an entry move. This is contrary to using a closed shape. Imo, it's probably almost impossible to comp a closed shape without a lead in move.

Looking through the EMC manual, I don't see anything different then it's always been, and have a feeling EMC won't do what you want either. Mach2's comp was based on EMC's, and mach3's advanced comp improved on it. Perhaps EMC has caught up and passed Mach's implementation, but I'll have to see it to believe it.

I don't think anyone's saying you have to code the comped path. You code the exact part, but you also need to code the correct lead-in move(s), and not try to do something that is invalid for comp.

General Method

The general method includes programming an alignment move and two entry moves. The entry moves given above will be used as an example.

5823

General Mach Discussion / Re: Cutter Compensation

« on: October 25, 2008, 11:14:12 PM »

The picture below is an interesting example of how the arc in the profile should have been trimmed to stay within the starting area.
The profile should never cross its self. Although there is times when you may want to cross a profile like in a figure eight it should not be possible to do so using left or right cutter comp.
It should only recreate offset periphery geometries for the first area that can be painted "Flooded" with a brush "Tool" the size of the current active tool.
The specification of the G4* offset word would determine in witch bounds of the area to fill.
A determination of open ended and area type geometries would need to be determined.
Geometry specifying a G4* word and which does not intersect itself would be considered open ended.
Geometry intersecting itself without the G4* word would be a center line tool path no offset needed.
Geometry intersecting itself with the G4* word would need to be "Flooded" like stated above.

If we can get that working in the X Y plane then maybe we can move on two all three. 
 
     

It's cutter comp, not comp / pocketing / magic bad code correction.

It's hard enough to just get it to offset correctly. Comp shouldn't try to decide what I'm trying to do, it should just offset the coded path. That's it.

5824

General Mach Discussion / Re: Cutter Compensation

« on: October 24, 2008, 08:43:51 PM »

You can't change the tool table with g-code. You can however, use P to specify the tool radius used for comp. So, you can use:

G41 P0.165

for roughing, and:

G41 D1

for finishing, and use T1 for both without changing tools.

As for the manual, the comp section was originally copied from the EMC manual. (pictures and all)

And I get the same error as the posted pics as well.

5825

General Mach Discussion / Re: tool and cutter comp issues

« on: October 24, 2008, 11:29:24 AM »

Also, wear offsets have no effect on comp. mach doesn't use them.

This thread might shed some light on using comp.
http://www.machsupport.com/forum/index.php/topic,9030.0.html

5826

General Mach Discussion / Re: tool and cutter comp issues

« on: October 24, 2008, 11:28:20 AM »

G41 - uses the current tool
G41 D1 - uses tool #1
G41 P0.5 - uses a tool diameter of 1.0 (0.5 radius)

now with code i expect the cutter to be at X-.5 and y-.5 am i mistaken?

Depends on the next move. Mach can't determine where to go with comp if it only knows two points.

5827

General Mach Discussion / Re: Cutter Compensation

« on: October 24, 2008, 11:24:23 AM »

Hopefully Brian has a list, that he will be using to fix the issues shortly.

The light went on with your explanation of how this is all supposed to be used.

How it's supposed to be used is very subjective. As long as it works for you (once you understand how it works), you can use it any way you want.

5828

General Mach Discussion / Re: Cutter Compensation

« on: October 24, 2008, 09:12:32 AM »

That's why I'm trying to generate another path only .020 (or even less) around the part. I chose .020 because you don't have to zoom the toopath screen so much to see it and to identify the "problem" which appears. (I'll change it to about 5thou later)

When using comp, you code for the actual part size, with no offsets. If you want to do a rough pass with a 1/8" tool, set up a too in mach3 with .165 diameter, but actually use a .125 tool. This will leave .02 around your part. Then go back and cut your finishing pass, telling mach the tool is .125, and it will cut to size. Same g-code, just use a different tool in the tool table, but they can actually be the same tool.

5829

General Mach Discussion / Re: Cutter Compensation

« on: October 24, 2008, 09:08:49 AM »

To see the problem I'm talking about:
Load your code and then set cutter #1 to .020 (small I know but it should be valid if I want to take just a small extra cut).

Zoom in VERY VERY close on the bottom left corner and run the code.
You will see the cutter come in from the right and stop too soon. It rises up along the vertical line ON THE LINE and slowly tapers out to the left as it rises (as if cutter compensation turned off and back on again).
 This is not a display anomaly as you can also see it in the DRO's as well. The X DRO should be stationary as it rises along the Y axis because it is a square corner. The DRO is constantly counting negative all the way up the left side. It eventually reaches the correct position when it gets to the top .

If you don't see this let me know. I might have to check my default settings.

Sage

As I said yesterday, it appears to be a bug related to the small tool diameter, because it appears to work correctly with a 1/8" tool.

5830

General Mach Discussion / Re: Cutter Compensation

« on: October 23, 2008, 07:41:53 PM »

I've attached the modified file. Try it with 0.0 and then .020 tool #1 compensation. Look in the bottom left corner, left side and top left corner.
I'm sure I'm getting poor old Mach confused somehow. I'd like to know where.
(not sure how to attach a screen shot).

Thanks for you help in getting me to understand this.

Sage

Looks like Mach's having trouble with the very small tool. If you use a 1/8" tool, it looks OK.

Not sure if it's a good idea to use comp in the subroutine like your doing. Although it appearsto be working OK, other than the iissue with the small tool.

If you don't come in from outside the corner like I do, you should enter on an arc like Graham does.