SmartCAM Technical Bulletin: 98

Topic: Guidelines for Rotary Axis Work

Technote 98
Product: Advanced Milling, FreeForm Machining
Date: 03/95
Version: All

Positioning a Rotary Axis ( Part with need for 4th or 5th axis positioning or Tombstone )

All positioning moves are output through the @TPINDX template section. SmartCAM knows to go to the @TPINDX section when the element being processed for code belongs to a different TOOL PLANE than the last element processed. When you define Workplanes that will require some A or B axis positioning move, be sure you turn on the "Match Plane" switch before you give the new plane a name. The Tool Plane MUST match the Work Plane.

The @TPINDX section should contain system Template Words to get the information out to the code. For an A axis move, this would be A#INDXA. For a B axis move, this would be B#INDXB. In these cases, the first letter is the output literally, and is followed immediately by the system variable that will contain the angular value.

Example code generators for A and B axis positioning are those in the MSMF directory that have names ending with a B or an A. For example, M_FDL_A.TMP and M_FAN_A.TMP. There are others, and some have special logic to do special things. It is worth reviewing them as you may get a good idea. Look at how SMF questions are answered in .smf files with the same names. SMF questions that relate to Rotary Positioning are Q289 through Q304.

Wrapped Geometry in Advanced Milling

Geometry that has been Wrapped is output through the @LINE template section. If the Wrapped geometry contains Arcs, they are exploded to lines as they are processed. If there are holes drilled in the Wrapped geometry, they get output through the @OP_section (@FXD for older versions) template sections.

This means that both of these sections need to contain either A#INDXA or B#INDXB along with the X, Y, and Z position variables they would normally contain. Depending on what is going on, any three of these may change and be output.

You do not get ramped moves in Wrapped geometry, but rather a series of short linear moves combined with short plunges.

Example code generators for Wrapped geometry are MW_DYP_A.TMP, others that begin with MW_ . Others are some of those listed above whose names end in B or A. Look at these, and if they have A#INDXA or B#INDXB in their @LINE sections, they will code Wrapped geometry. Look at how SMF questions are answered in SMF files with the same names. SMF questions that relate to Rotary Contouring are Q430 through Q453.

Rules for Wrapped geometry are:

  • Geometry must belong to a plane that has the wrapped axis coincident to the world X or Y axis.
  • Geometry must be wrapped about the X or Y axis. Not an axis parallel to X or Y.
  • The Level for the Seam Axis Start and End Points, and the level of the geometry, should be the same as the Radius input. While SmartCAM will Wrap the geometry if they are not the same, the output will not be what is expected.