G41/G42 discussion.

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Re: G41/G42 discussion.

Postby ger21 » Fri Jan 26, 2018 6:48 pm

1/4" tool = 2 passes at 300ipm
1/2" tool = 1 pass at 800ipm.

What I showed was not a leadin along an arc, but a leadin prior to the arc. Any control can do that move.
We don't use leadins like that, because we are cutting parts out of a nested sheet, and there is no room to enter at 90°. So we ramp in at a 3°-5° angle in between parts, to maximize material usage.
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Re: G41/G42 discussion.

Postby Battwell » Fri Jan 26, 2018 6:52 pm

an example of an old hand coded parametric part- using tool offset for everything (which was the norm using this control)
just a simple part- but you can see how easy it is to get short segments
https://youtu.be/SYUme8WaiXg
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Re: G41/G42 discussion.

Postby ger21 » Fri Jan 26, 2018 7:09 pm

I can work around the gouge in a variety of ways if I have to. We'll just see how it all shakes out.
A mostly working comp is much better than no comp. ;)

Just need to fix the leadins.
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Re: G41/G42 discussion.

Postby Battwell » Fri Jan 26, 2018 7:33 pm

Vmax549 wrote:Hi Battwell , How did it handle an outside circle profile as far as eliminating teh undercutting from teh leadin comp? Did you have to overcut teh circle by teh tool radius or did teh control handle it ?

(;-) TP

id just lead into a circle with an arc. - control handled it- exiting at the same as entry point nothing was left uncut.

but the gouging is what stopped me programming like that- i now use vectric cad/cam - so no need for comp for me now .
my biesse control has long gone!- everything had to be typed into control- no dnc facility etc on it
was made by fred flintstone... but he made comp work lol
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Re: G41/G42 discussion.

Postby ger21 » Sat Jan 27, 2018 1:09 am

ger21 wrote:I can work around the gouge in a variety of ways if I have to.

Something like this seems to work well.

comp 4.JPG
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Re: G41/G42 discussion.

Postby cncdrive » Sat Jan 27, 2018 5:22 am

I agree 1000 % :P IF UCCNC will warn me of a gouge I can fix.


This is good statement, because it points out the fact that if the software would know when a gouging happens then action could be taken, but for that it has to know when it happens.
So, if the software could detect these cases then it is likely that we could figue out an extension algorithm to the basic algorithm to not let the gouging to happen.
But for this the task is to determinate the condition when gouging happens.
The condition should be very precisely defined, because if the condition is not precise then the extension code which would fix the gouging will hurt other cases when gouging not happens, the wrong condition will make the software think it happens and so it will hurt other cases when it would try to correct when there is nothing to correct.
So, the first task is to determinate very precisely when exactly the gouging happens, and then that could be used as a condition check which if mets then correction code could run to avoid creating it.
I'm not saying yet if it is possible or not, because it may be not possible to do this is the condition can't be distiungish from other cases, but if the cases can be determinated clearly then I see a chance that additional correction code could be used to fix it.
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Re: G41/G42 discussion.

Postby cncdrive » Sat Jan 27, 2018 6:16 am

To give a warning you have to define a condition check which can clearly explore cases when gouging happens, and only those cases.
If you have that condition defined correctly only then could the software give warnings, however then there is only one step to even run corrective action.
Again, I'm not saying if defining that condition is possible and I'm also not saying that running corrective action is possible, because I did not investigate it deep enough yet.
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Re: G41/G42 discussion.

Postby jazzcnc » Sat Jan 27, 2018 3:09 pm

Ok Battwell tempted me to join in the party so here I am.!! (Hi Gerry)

Nothing much to add other than to show another software/controller which is well established and tested that does the same with comp. Centroid CNC12 on Acorn controller.
Bren sent me his example and asked to check G42 the result is the same see pic.

20180126_210022.jpg
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Re: G41/G42 discussion.

Postby cncdrive » Sat Jan 27, 2018 4:31 pm

Terry,

To warn you have to detect gouges which does not sounds and easy task, and I don't know yet if it is possible to do it.
Adjustable lookahead would not fix this problem at all.
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Re: G41/G42 discussion.

Postby ger21 » Sat Jan 27, 2018 7:45 pm

cncdrive wrote:Terry,

To warn you have to detect gouges which does not sounds and easy task, and I don't know yet if it is possible to do it.
Adjustable lookahead would not fix this problem at all.



Can't you scan the file while loading? If it takes longer, make it optional?
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