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Keep Tool Down!

Posted: Wed Jan 25, 2012 8:49 am
by magnus
Can we please get a keep tool down check box/option on visualmill.
Every other machining software I have used has this feature.
When machining deep cavities or profiles in VM the tool will always retract back to clearance plane. It should not retract at all and continue with selected ramp if needed, thus eliminating the dreaded air cut and retract.
Deep pocketing which requires multiple z cuts, as well as profiling benefit from not having a Rapid retract, followed by a slower feed plunge motion. I know you can jack up the feeds on the plunge feed but it is still an unnecessary motion to retract to clearance plane when the software already knows what has been cut.

Re: Keep Tool Down!

Posted: Thu Jan 26, 2012 9:44 am
by MecSoft Support
Try using Skim clearance (in the clearance plane tab) and the tool should not move up to the clearance plane.

Re: Keep Tool Down!

Posted: Fri Jan 27, 2012 9:31 am
by magnus
Works a little bit better but still does a small retract off the part. In order to make this work properly I have to go and tweak the entry exit parameters.

for ex I decided to rough pocket a simple circle, but do a deep cavity of 3 inches.
My rough depth is .070"
Entry Exit Approach motion is Path 10 degree Angle at a height of .07
Retract Motion is 0 everywhere, and apply entry exit at all cut levels is checked.

The tool will still retract .010" not a big deal better than I had it set up before but still unnecessary of a movement, as I don't care If I drag the tool across an area I'm roughing.

For example

N0025G17
N0026G03X-0.092Y0.Z0.43I-0.092J0.F180.
N0027X0.092Y0.Z0.43I0.092J0.
N0028G02X0.216Y0.Z0.43I0.062J0.
N0029X-0.216Y0.Z0.43I-0.216J0.
N0030X0.216Y0.Z0.43I0.216J0.
N0031G03X0.342Y0.Z0.43I0.063J0.
N0032X-0.342Y0.Z0.43I-0.342J0.
N0033X0.342Y0.Z0.43I0.342J0.
N0034G02X0.466Y0.Z0.43I0.062J0.
N0035X-0.466Y0.Z0.43I-0.466J0.
N0036X0.466Y0.Z0.43I0.466J0.
N0037G03X0.592Y0.Z0.43I0.063J0.
N0038X-0.592Y0.Z0.43I-0.592J0.
N0039X0.592Y0.Z0.43I0.592J0.
N0040G0Z0.44
N0041X-0.034Y0.085
N0042G1Z0.43F180.

Want to do very high material feedrate and huge production of this part just trying to tweak the program and eliminate every possible waste available

Although when I profile the outside of the part it works well with the skim plane set to zero.
Thanks!

Re: Keep Tool Down!

Posted: Tue Jan 31, 2012 9:02 pm
by mbr72cnc
I do 3 dimensional wood carvings would like to know why VM will go to clearance every time it will move across instead of staying down when moving the x% amount of step over. Thanks for any input.

Re: Keep Tool Down!

Posted: Mon Mar 19, 2012 7:18 pm
by Andy Birko
This is a pretty ridiculous behavior. I was cutting a bunch of small pockets today but had to use a feed of only .020 per pass (still learning to cut Al with my router). I needed a clearance plane of about .75 to clear some clamps.

I used an entry path that was supposed to ramp down .020 and I set it to use the "Apply entry/exit at every level". Imagine my surprise when it retracted .75" just to go right back down at my plunge feed rate so that it could do the ramp. To put things into perspective, the machining time was more than doubled for this job compared to not having that set.

There should be a way to apply the engage motion at each cut level without retracting all the way to the clearance plane. Perhaps a "retract between cut levels" setting or something like that just to keep from dragging the tool with the possibility to clear islands or something. There must be a better way!

Re: Keep Tool Down!

Posted: Tue Mar 20, 2012 6:05 am
by khalid
You use Mixed Milling technique...

Re: Keep Tool Down!

Posted: Tue Mar 20, 2012 2:55 pm
by Andy Birko
I don't understand what that means. Can you elaborate?