crash - tool rubbing on work

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dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

crash - tool rubbing on work

Post by dgolber »

Problem: Tool shank rubbing on workpiece.

Rhino 4.0 SR9 9 Mar 2011 Commercial
RhinoCAM 2012 3,0,0,48
Running on Windows 7

Files attached:
test.3dm
my tool library.csv I TRIED TO UPLOAD THIS, BUT YOUR SUPPORT SOFTWARE WONT LET ME. WHY IS IT SET UP THIS WAY?
picture.jpg
test.nc I TRIED TO UPLOAD THIS, BUT YOUR SUPPORT SOFTWARE WONT LET ME. WHY IS IT SET UP THIS WAY?
THEN I RENAMED IT TEST.NC.TXT BUT IT STILL WON'T LET ME UPLOAD IT.


All my own stuff is in mm.

The cutter is a 1/32" = .7938 mm flat end, with length of cut 3/32" = 2.381 mm.
The shank is 1/8" = 3.175 mm.
(The tool actually expands out from the cutting portion to the shank, but I've just described it as having the shank diameter right above the cutting portion.)

Doing some testing, I saw rubbing. The attached files show that the problem is coming out of RhinoCAM.

picture.jpg is a screen shot of the RhinoCAM simulation, showing that when the cutter touches the floor, it is rubbing on the wall.

If we look at the "Toolpath" within RhinoCam, we see that tool touches the floor at

184 GOTO 4.598649,253.400001,31.692927

Since the wall is at 252.4007, this means that the axis of the tool is 1 mm from the wall. But the radius of the tool is 1.5875 mm, so the tool is rubbing on the wall. This agrees with what picture.jpg shows.

The posted file test.nc has

N0108 X4.5998 Z38.7570
N0109 Z39.3148
N0110 X4.5986 Y253.4000 Z39.1382
N0111 Z31.6929
N0112 X-4.6186

showing that when Z hits the floor at N0111, Y is indeed 253.400.

So that's where the rubbing is coming from.

If you look at the toolpath in RhinoCAM, you see a lot of other weird motions.

I look forward to a quick resolution of this problem.
Attachments
picture.jpg
picture.jpg (235.13 KiB) Viewed 20644 times
test.3dm
(495.32 KiB) Downloaded 1113 times
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

Your software cropped the original jpg, as far as I can see, cutting off the significant part. Here is the significant part.
Attachments
picture cropped.jpg
picture cropped.jpg (7.11 KiB) Viewed 20643 times
MecSoft Support
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Joined: Wed Aug 01, 2007 4:15 pm
Location: Irvine, CA, USA
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Re: crash - tool rubbing on work

Post by MecSoft Support »

You could compress the files to a .zip format and upload it to the forum.
It looks like the shank diameter is set larger than the tool diameter just for this specific tool. If you set the shank diameter the same as tool diameter and generate the toolpath, this should take care of the issue.
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

I'm afraid I don't understand your reply. The shank diameter of this tool IS bigger thank the cutting end. I set the rhinoCAM parameters to describe the tool, using the facilities that rhinoCAM provides. Are you telling me that rhinoCAM is unable to correctly provide a tool path if the shank diameter and the cutting diameter are not the same?
MecSoft Support
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Joined: Wed Aug 01, 2007 4:15 pm
Location: Irvine, CA, USA
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Re: crash - tool rubbing on work

Post by MecSoft Support »

I am providing you with a work around. This seems to be a bug that manifests in this behavior under this particular geometrical condition.
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

Thank you. Hoping to see the workaround soon.

Note that what I sent you was grossly simplified from my real situation. I only saw it because I saw burn marks in the workpiece. Lucky (for both you and me) that I'm working in wood and not metal. Just burn marks, no pieces of metal flying around the room at high speed.

How long has this bug been known? Is it in all versons of RhinoCAM? Exactly when does it appear? Does MecSoft have a list of all bugs?

The point is this: Just in case you haven't been reading the newspapers, General Motors is in big trouble because of a bug in their product that they were slow in notifying people about. In their case, more than 50 people have died.

I will guess that no machinist has died because of metal flying around from MecSoft tool-workpiece crashes. Not yet. MecSoft has the opportunity to do the right thing now: send a message to every user of their product not to model tools with shank diameter different from the cutting edge diameter. Or whatever the best fix is.

More generally, I suggest that MecSoft immediately publish their current list of problems, annotated with "what it means for the user", with an emphasis on safety. Get it to all known users. Remember: 18000 RPM. Lots of horsepower. Lots of danger.

Better get this over to your legal department.
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

Any news on that work-around?
MecSoft Support
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Location: Irvine, CA, USA
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Re: crash - tool rubbing on work

Post by MecSoft Support »

Development is looking into it. Will only be in the next service pack. The workaround for you now is to use a tool with the shank size the same as the tool size.
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

Has this been fixed in RhinoCAM 2016?
dgolber
Posts: 36
Joined: Wed Mar 26, 2014 7:22 pm

Re: crash - tool rubbing on work

Post by dgolber »

I asked: The answer is no. This bug has not been fixed yet.
MecSoft Support
Posts: 2405
Joined: Wed Aug 01, 2007 4:15 pm
Location: Irvine, CA, USA
Contact:

Re: crash - tool rubbing on work

Post by MecSoft Support »

Development is looking into this and will be fixed in service release for 2016 version of the product.
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