Redistributing points for multi-axis machine tools

Gimbal lock explanation

A gimbal lock is a specific configuration of a multi-axis machine tool that occurs when the tool axis aligns with at least one rotary axis due to the position of one or more toolpath points. This configuration results in undesirable movements because, when close to the gimbal lock, small adjustments in the tool axis can require large changes in a rotary axis.

The graphic below shows the rotary axis of table-table machine tool (undesirably) rotating almost 180 in one second. This is because the machine tool machines a toolpath point at the bottom of the bottle cavity that coincides with the machine tool's gimbal lock.

Redistributing points

When redistributing points to prevent the undesirable movement of a machine tool's rotary axes, consider the following:

• If you do not specify a coordinate system, PowerMill assumes the position of the machine tool's gimbal lock is on the Z axis of the toolpath workplane.
• When redistributing toolpath points, PowerMill maintains machining tolerance. Therefore, PowerMill cannot prevent all undesirable movements of the machine tool's rotary axes. As a work around, you can move the tool axis far away from vertical, or use a vice to clamp the part at 45 to the machine table.

  

• You can identify undesirable movements of rotary axes visually and by using the Machine Tool Position dialog or the Simulation Analysis plugin for even more detailed feedback.

  The Simulation Analysis plugin is an effective tool for identifying undesirable movements of the rotary axes because it represents the movements of a machine tool's axes in a line graph. In the graphic below, the C (rotary) axis (drawn in purple) swings from approximately 85 to -85 in one second

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