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PB/CSE - Force alternate solutions with direction cosines (A3 B3 C3)


Hello all,


I have a situation that I'm wondering how to handle with the 840D control, and then subsequently in the post and simulation.


I have a dual head 5 axis machine. We're currently posting 5 axis operations with direction cosines/vectors (A3 B3 C3) because the machine can have multiple kinematic configurations. As you are aware, this defined tool vector can be achieved usually with 2 rotary axis positions, and since the head may not be symmetric, sometimes we would like to force the alternate solution with a UDE for clearance. We are doing this successfully on other machines where we calculate rotary axis values, but are wondering how this could be handles in direction vectors mode. I looked into the Siemens command "THETA", but it looks like perhaps it is only used in 6 axis machines, and additionally the sinumerik CSE parser doesn't accept it. My only other thought is to pre-position the rotary axes to position close to the solution we want it to adopt, but in that case it kind of defeats the purpose of using direction cosines in the first place. Any suggestions?

Thanks and regards,



Re: PB/CSE - Force alternate solutions with direction cosines (A3 B3 C3)

Gears Esteemed Contributor Gears Esteemed Contributor
Gears Esteemed Contributor

You might want to test the "pre-position" option before doing anything in the post.

At least once I pre-positioned "close" and the machine went ahead & used the "other" solution anyhow once I switched to A3/B3/C3.

For a variety of reasons we just switched to outputting rotary axes directly, I never had a chance to figure out why (probably something I did, but I don't know).

Ken Akerboom Sr CAx Systems Engr, Moog, Inc.
Production: NX10.0.3.5 MP16/TC11.2
I'd rather be e-steamed than e-diseaseled

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