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Author Topic: Cutter Compensation  (Read 35839 times)

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Offline Sage

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Re: Cutter Compensation
« Reply #20 on: October 22, 2008, 10:43:36 PM »
ger21:

Thanks for that. I see it's a lot more complicated than I thought and that a lot of planning went into your code. This perplexes me quite a bit because, being that I'm just learning, I'm reading a lot of different books, and so far, I gathered that the tool compensation is something that is used to quickly make changes to a program to accommodate, for, say the fact that you may only have a 3/8 cutter instead of a 1/4 cutter or maybe something as small as a worn tool. I imply from this that cutter compensation should work (with obvious limits) on almost anything. Far cry from the tedious planning you have applied in making a complete program around tool compensation.
 I can see that the compensation works on your program but what of the real life situation such as mine where I take an otherwise properly functioning program and add cutter compensation for a perfectly good reason i.e. to add some roughing cuts to the path??
This is why I am more interested in figuring what is wrong with my simple program rather than generating something new that actually works.

BTW
Using your ideas and to see what could be done with my code, I added some simple code to take the tool on a little tour well outside the part and back again. I added only .020 compensation to tool #1 and I can see that it goes around the touring lines with the offset visible just fine. SO there is something in your "rule" about moving more than the cutter diameter. Lesson learned there.
BUT the path is still screwed up in the bottom left corner where it does not seem to go far enough in -X to clear the original path. This screwup is far remote from any of the lead in/out code. I can't figure out why it messes that up.

Still perplexed about the usability of the cutter compensation function for what (I thought) it was intended.

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
« Last Edit: October 23, 2008, 06:46:52 AM by Sage »

Offline Graham Waterworth

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Re: Cutter Compensation
« Reply #21 on: October 23, 2008, 03:49:26 AM »
Go to additional options below left of the reply box and use the attach box.

Graham
« Last Edit: October 23, 2008, 03:51:32 AM by Graham Waterworth »
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Offline Sage

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Re: Cutter Compensation
« Reply #22 on: October 23, 2008, 06:40:52 AM »
Graham:

Reply / additional options / attach    is how I attached the file. What I don't know how to do is attach a screen shot. My problem was getting the print screen into a jpg (or the many other acceptable forms listed) to attach. I don't see a tool to insert a screen shot. The usual Paste didn't work after doing a shift-prntscrn.
Please enlighten me.
Sage
« Last Edit: October 23, 2008, 06:48:04 AM by Sage »

Offline ger21

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Re: Cutter Compensation
« Reply #23 on: October 23, 2008, 09:11:44 AM »
Paste into paint and save as .jpg.

There's no tedious planning at all with my method. Pick a corner of your part, extend the lines by the tool radius (for the biggest tool you might use), and add a lead-in line. I wrote an AutoCAD macro that automatically writes the code from within AutoCAD. Only took about a minute to open your .dxf, add the lead in, and export the code. :)

It's a littly tricker if you don't have a corner, but I can give you an example of that too if you'd like. But it'll have to wait until tonight.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

Offline Graham Waterworth

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Re: Cutter Compensation
« Reply #24 on: October 23, 2008, 10:00:52 AM »
Or go and download Screen Hunter, its free and works great, many here use it.

http://www.wisdom-soft.com/sh/sh_free.htm

Graham
Without engineers the world stops

Offline Sage

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Re: Cutter Compensation
« Reply #25 on: October 23, 2008, 11:37:23 AM »
Ok guys. Give me some time to absorb this. I'm still perplexed by the actions of Gerry's code.

Any further thoughts on why Mach is screwing up on my code as described and posted a couple of messages back?(Sage_comp2).

I can learn more about what I should and should not do by understanding why something doesn't work i.e. my code.

Maybe I'm wrong?

Sage

Offline ger21

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Re: Cutter Compensation
« Reply #26 on: October 23, 2008, 01:40:00 PM »
I won't have time to look at yours for about another 6 hours, when I get home from work.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

Offline Graham Waterworth

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Re: Cutter Compensation
« Reply #27 on: October 23, 2008, 02:32:15 PM »
This is how I would do your job :-

The green is the job, the blue is the cutter path.
« Last Edit: October 23, 2008, 02:36:50 PM by Graham Waterworth »
Without engineers the world stops

Offline ger21

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Re: Cutter Compensation
« Reply #28 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.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Cutter Compensation
« Reply #29 on: October 23, 2008, 08:45:29 PM »