Form Cutting using Motoman Robot

[WiBa]

Hello, I currently program and use a ES200N robot with NX100 controller and am trying to use the form cutting function. Whilst I have some Motoman manuals, I cannot find anything detailing form cutting, specifically the various parameters within the function. Can anyone help me?

-----------------------------------

I now have a copy of the Motoman Form Cutting Manual, but if anyone has experience of successfully using this function, particularly for milling cutting, I'd be interested to hear.

[Stormtrooper]

Can you please send me a copy of the manual.

Regards
Stormtrooper

[WiBa]

sent via email.

[Stormtrooper]

Thankyou for the e-mail
Let me know what manuals you need and I will get them sent to you.
For starters I have attached some NX Controller manuals

[95devils]

What specifically to you want to know?  I use form cutting quite often.  The applications I use it for are laser cutting, laser welding, plasma cutting, and deburring.  I have never and don't know why you would ever use it with a spot robot.  If you have specifics, let me know.

[WiBa]

Trying to cut/ mill circular holes in carbon fibre panels. Have tried both circular interpolation and form cutting, with form cutting giving the best results. The holes still end up slightly oval. With the circular interpolation, there were always two points diagonally opposite each other, a bit like the "punch- thru" points you see when laser cutting. This is my first time using a Motoman Robot so I'm interested to know why you mention "spot robot"?!

[95devils]

The reason I mentioned spot robot is that's what a ES-200N is.  Expert Spot.  The arm is designed to integrate the weld, air, and water cables through the arm so that it is protected with a spot gun attached. 

What diameter are the holes that you are cutting?  Where is the robot in it's envelope when it is cutting the holes you are having problems with?  I'm asking these questions because the robot was not intended to cut. 

The bigger the robot, the less accurate it is, cutting requires accuracy.  A ES-200N is 4 times lousier with repeatability than a robot intended for cutting.  Stretching the robot out will introduce bounce and even backlash in the RV drives will introduce repeatability problems.  It's a matter of selecting the right robot for the job.  Motoman makes an EC series robot that is designed for cutting.

When I use Formcut for laser (worst case scenario), I select the right arm and even then it takes 2 of us about 8 hours to set it up properly.  This isn't even starting to program.  It's calibrating the tool, weighing the components and telling the controller the weight and location of these components, and reinstalling the components.  Many parameters then get adjusted to get a perfect path.

Is the tool normal to the surface when you are cutting?  Is the bit chattering and/or is the part chattering as you cut it?  I have had to take high speed videos before to analyze the application before.  I can run the application through MotoSim EG if you need help, I could see the robot side of things but not the actual operation.

[WiBa]

Hole sizes range between 10mm and 30mm diameter.

Robots position in its envelope varies due to the size and shape of the components being machined. Mostly at 800mm - 10000mm above floor level (robot is floor mounted), sometimes at a location requiring quite a stretch from the Robot.   

Travel and cutting speeds have been minimised to try to reduce the effects of bounce. Repeatability doesn’t appear to be a problem, as the holes profiles are repeatedly not good circles!

The tool is usually normal to the surface being cut. The parts are vacuum held pretty good so there is normally no chattering.

What would you need from me to run a MotoSim trial, a copy of the form cut program JBI?

[DanH]

You can also check out a robot calibration system (see www.dynalog-us.com, look for DynaCal) to improve the accuracy. Works with Motoman robots.