Cutting a fixture

vhubbard · 2007-09-28 20:42:12

We need to be able to cut a fixture when the CUTTING part of the tool encounters the fixture. This should be a switch to enable the option. Holder/shank collisions can be reported as they are.

Why? When a system reports an error that is not an error, people begin to blow them off and ignore them. When there is a problem it is ignored. We don't need real errors ignored.

Currently in 6.x, if a drill enters the fixture and then is followed by a reamer, they both show an error. When a drill didn't go deep enough and the reamer bottoms out in the fixture, how do we know it is a true problem currently? When a fixture is involved users can not tell if it is really an error. We have "holders" defined on the end of our reamers, taps etc to catch this error.

The same thing when a roughing mill cuts part of a fixture. Following tools may not cut the fixture after the first clearance cut but they all get warnings currently.

It is a common practice to "clearence" cut the fixture when running the first part on a machine. We need collision errors with fixtures more accurate instead of "crying wolf" as they often do now.

JimV · 2007-09-28 21:10:42

vhubbard wrote:

The same thing when a roughing mill cuts part of a fixture. Following tools may not cut the fixture after the first clearance cut but they all get warnings currently.
It is a common practice to "clearence" cut the fixture when running the first part on a machine. We need collision errors with fixtures more accurate instead of "crying wolf" as they often do now.

I agree.
Currently, I have to design my fixtures with "built in clearance cuts" to avoid getting these errors.

DaveF · 2007-09-28 21:53:55

Yes, it was a check box on v5, to allow fixture cutting.
That went away.

with the Vericut you have today, you could load the fixture as stock, and save a VCT after running the program. That would put in the clearance cuts.

Than you could use the VCT as a Fixture model.

Jim's solution will also work, but your should not have to put that extra work into tool design.

This is a issue that needs more thought.

SergeV · 2007-10-02 02:10:03

I prefer Dave's technique. When I needed some clearance on the fixture floor for the cutter, I would make a special NC program cutting the fixture before the first part.

If you have a switch, it could lead to errors not being detected if the switch is not turned back on. The actual method will detect any violation of the fixture by a cutter, removing the material does not allow the detection of subsequent collisions.

It might be OK to contact the bottom plate of a fixture but I have not seen many situations where touching a clamp or a bolt is desirable. How do you discreminate between them?

I remember one of my NC programs came back after cutting 18 months without any problems. Suddenly one of the cutter hit a clamp and broke. I investigated and found out that the first operator had modified the clamp during the tape proofing to avoid a collision. 18 months later, another operator replaced the clamp for whatever reason and scrapped a cutter. And as usual it was the NC program that was wrong :wink:

I don't mean that it is not a valid concern, but a lot of thought must be given to any changes to the error detection.

p-cnc · 2007-10-09 11:35:09

See these Link

http://cgtech.com/forum/viewtopic.php?t=916

http://cgtech.com/forum/viewtopic.php?t=813

Thanks

JimV · 2007-10-25 17:48:16

Hello boys,

SergeV wrote:

I prefer Dave's technique. When I needed some clearance on the fixture floor for the cutter, I would make a special NC program cutting the fixture before the first part.

Ok, I tried this method and yes it is a easy way to clear the fixture, but I'm still getting a collision error.
What I did to fix this was I copied and saved the NC file and tools file adding "fixture" to each name and modified the g-code(depths) and tools (diameters) in each file that pertained to fixture clearance. Reset and ran Vericut using these mod files.
This did the trick, but is this the correct way of going about it?
Is this what you meant by "special NC program"?

SergeV wrote:

It might be OK to contact the bottom plate of a fixture but I have not seen many situations where touching a clamp or a bolt is desirable. How do you discreminate between them?

It appears to me that maybe having a cut tolerance setting for each fixture model as opposed to having just one overall setting, would be more favorable. The user could set a tolerance of say .005" for cutting into the fixture plate. Anything above the tolerance generates an error. Likewise, a setting of .000" for things like clamps, pins, or any hardware would generate an error if touched.
The user would have to import these models separately or in groups, but I think the upside would be well worth it.
This setting could be added to the Model dialog. See picture.
Just a thought.

DaveF · 2007-10-26 20:23:14

How do you discreminate between them?

Seem to me like a new component type is in order.

Fixture cutting allowed
Fixture non cutting allowed

things like clamps, would be non cutting.
sacrifical plates would be cutting.

For cutting, you would probably not want to implement cutting, by adding it to the STOCK component.

Is it possible to have a CUTSTOCK, and have a CUTFIXTURE?
Sounds like a lot of work for developers.

How bout if the idea of Fixture cutting and Fixture non cutting, is feasable, just ignore it. let the cutter pass thru like Dr. Mcoys hand passed thru the table as the ship was dissolving.

Dave out.

VERICUT Users' Forum

#1 2007-09-28 20:42:12

Cutting a fixture

#2 2007-09-28 21:10:42

Re: Cutting a fixture

#3 2007-09-28 21:53:55

Re: Cutting a fixture

#4 2007-10-02 02:10:03

Re: Cutting a fixture

#5 2007-10-09 11:35:09

Re: Cutting a fixture

#6 2007-10-25 17:48:16

Re: Cutting a fixture

#7 2007-10-26 20:23:14

Re: Cutting a fixture

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