DMG Mori Siemens Cycle 800 5-axis Tracking Issues

For over 2 years we had been struggling to get consistent accuracy out of our DMU 50 machines when the table swiveled to extreme angles in Cycle 800 ie. B90 C90. Turns out we had been setting the offsets incorrectly. When using the "Align Edge" probing cycle, there are 2 different options on how to store your offset: "Rot B/C axis" and "Coordinate Rot." If your program is using Cycle 800 to swivel, YOU MUST STORE YOUR ANGLES IN COORDINATE ROT and leave the numerical B and C work offset at 0. You must go to the "details" page under work offsets to see the rotational values. After you have set the rotational offsets you must call up a cycle 800 with 0s in the rotation and transformation values for the machine to level the part. Then you can correctly probe X, Y, and Z while the cycle is still active.

We had been setting the offsets in the regular B and C work offsets, causing mass confusion and headache on why our machine couldn't position correctly. Hope this helps out anyone else with accuracy issues on Siemens DMU machines! If you use them right they're pretty accurate!

I've run a 125 FD for years and I never had any problems with cycle 800. I do run 3D quick set a few times a year. Or if I have a accident.

My 125 horizontal don't have quick set but I do it manualy and never had any major errors when using cyle 800

Don't you have 3D quick set ?

When I rotate I rotate origin and machine in the same cycle800 command.

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Thomas, I think what you are suggesting depends largely on your workflow. The situation you describe makes sense if you are trying to align something that is not planar to X/Y. Since the DMU50 can only rotate the X/Y plane one direction, it has to use a coordinate rotation to "flatten" that plane when attempting to probe and adjust. However, for parts that simply need a rotation of the C axis (or even the B axis) to align, the "Rot B/C axis" option should be perfectly acceptable.

We do use 3D Quickset

Yes you are correct, the parts we machine are mostly castings and have datum points that are not aligned with the machine axis. If you're just doing 3 axis work you can align with Rot B and C

Thomas.Sears said:

Yes you are correct, the parts we machine are mostly castings and have datum points that are not aligned with the machine axis. If you're just doing 3 axis work you can align with Rot B and C

Click to expand...

It is also okay to use "rot B/C axis" for 5 axis work. The issue is that the machine must be able to physically rotate to straighten the plane. If it cannot drive to position, then the machine must use a coordinate rotation.

boosted said:

It is also okay to use "rot B/C axis" for 5 axis work. The issue is that the machine must be able to physically rotate to straighten the plane. If it cannot drive to position, then the machine must use a coordinate rotation.

Click to expand...

Something must be different either in our machines or program post. We tried to cut a square test block, facing the top and then rotating to B90 C90 to cut a slot parallel to the top. Came up with .003 misalignment between the slot and the face with offsets in B and C but perfect when using the Coordinate Rotations. Are you using UG NX?

Hey! Thanks for this. Hardmilling detail on some small parts that need to be dead on. Decided to probe/rotate instead of indicating. Leveling part w/cycle800 and then setting coordinate rotation align edge.