840D Tool Axis Output

[hollenbeck]

I am working on a post for a Sinumerik 840D (5axis) and have found some issues with the tool axis. My machine coordinate system is defined in the center of the part (center of rotation in A,B)

When I post the code, if I am cutting on the "top" of the part (where the tool axis is originally facing), there is no rotation and the output z values are positive. This is expected because the tool is cutting the top of the part.

However, when the part indexes 180degrees about A, the z values are negative. It is as if the post does not recognize that the tool is now facing the bottom of the part.

When I output code using a fanuc post, for example, the z values are positive because the part has already rotated around in A to face the tool.

Does anyone have any ideas how I can get the Sinumerik post to output correctly? In other words, I would like to prevent the tool from trying to go through the part.

Thanks

 

[SevanD]

Have you received a answer yet? there are several possibilities, many new controls using a tool center point management feature actually want this type of outup, as the actual position of the tool relative to the coordinate system is correct (I am envisioning head table config, A table B head) For example with a ITNC 530 control running their TCPM or M128 the position is always that which it would be in your cad system, the tool axis changes.