We have a 6 axis horizontal mill with a A-C head and a B axis table. I have 2 linked posts which drive it in a A-C, or a A-B configuration. In the A-B configuration, the C axis is locked. I'm trying to profile a cylinder on the B axis centerline (which has a cylindrical floor) by tilting A to -90 and using the B axis and Y axis to contour with the x axis locked at 0, but I haven't figured out how to get a post to output X0 with Y, Z and B coutouring. Any ideas?
Once trying to use B instead of C in kind of an XZC mode - I think this kinematic situation will not be handled by lock axis or XZC kinematic settings - and is a custom situation that will have to be accomodated in the post code. My guess is that you will have to use PB_CMD_before_motion command and set up the mom_pos and mom_out_angle_pos's yourself (using mom_mcs_goto and mom_tool_axis and kinematic situation.) This can be done with matrix math or if after version NX9 - there is a new command "MOM_convert_point" that may help. Another option is to flip the mcs so it is XZC for this motion - and put the result in appropriate block template axis positions for XYB - I wish there was a way to do this dynamically with post.
I think I'll attempt this later. I found a work-around to get through temporarily. By tilting the tool axis .0025 degree and cutting a cone, the post was forced to use the b axis to resolve the axis locations. Truncating the output to 4 decimal places puts the A axis back at -90.
I've been trying this, but if the tool axis is parallel to the centerline of the cylinder (Y axis), it wants to use the X and Z to profile the cylinder rather than the B axis. The X seems to take precendence over rotary axes