Current Help System: PC-DMIS NC (View Core Help)

### PC-DMIS Support for Stacked Rotary Tables

Support for stacked rotary tables running on CNC machines existed in PC-DMIS v42B but, while the addition of kinematic changes in subsequent releases allowed a picture of a stacked rotary machine, it was unusable on CNC machines. For the first time it is possible to run a CNC machine Using a Machine Model, calibrate probe and rotary tables, properly animate and detect collisions with either the machine or part. PC-DMIS NC now includes Using Work Offsets with a Machine Model.

The MathCAD Model used to validate point data in input and output files for Fanuc, Siemens and Heidenhain controller types is included at the end of this document.

Using a Machine Model

A simple PC-DMIS program (NCG3.PRG) using a stacked rotary table is shown below.

Stacked Rotary Table Program

When animated. the probe moves about and there is no visual indication of the machine or rotary tables. Adding a machine model (NC_Vertical_5Axis_2) provides this feedback as shown below.

Stacked Rotary Table Program with Machine Model

The rotary table setup is now automatically updated from the machine model. Select Edit | Preferences | Rotary Table Setup to view the updated values in the Rotary Table Setup dialog screen shown below.

Rotary Table Setup Dialog Screen for Stacked Rotary Tables

Adjusting the values manually in the dialog now updates the machine model held in memory within PC-DMIS and used by the Pathlines generator. The position of the part in some models can be automatically positioned at the center of the rotary table using the Auto Position button in the Setup Options dialog. This is analogous to the other option of transforming the CAD.

Press the F5 key to display the Setup Options dialog screen shown below.

Setup Options Dialog Screen for Stacked Rotary Tables

Now it is possible to see accurate Pathlines after successfully calibrating the rotary table. PC-DMIS now animates the machine moving the rotary tables more realistically.

Updated Stacked Rotary Table with Machine Model Program

Collision Detection with part and machine is also possible.

Lowering the Clearance Plane and adding the Move Point (0,90,-50) is an example of a collision with the rotary table when it is rotated.

Note: Non-zero prehit and retract distance are needed or collisions will be indicated for every hit.

Updated Stacked Rotary Table with Machine Model Program and Collision Detection

Creating a .cnc file now produces the same Pathlines as used when animating.

Run the Journal file (HU801020110321172956.cnj) to produce a perfect report via the Execute function, then navigate to and select the journal file when the dialog screen appears. Click the Ok button to generate the report.

When doing this test, the prehit and retract values should be zeroed prior to generating the .cnc file to avoid adding Overtravel distances to the Journal data.

Stacked Rotary Table Program with Report

Using Work Offsets with a Machine Model

The machine Work Offset needs to be specified by name and value by the user when working with a machine model if Animation and Collision Detection are to work correctly.

Multiple Work Offsets can be specified in this way. Scrolling up and down within the Edit Window produces an effect that can be seen graphically as the part moves when the work offset is updated in the same way as any update to a rotary table angle.

Stacked Rotary Table with Machine Model Program and Work Offset initial line

Scrolling down one line in this case to the Work Offset which is updated from G55 at (-30,-30,-290) to G56 at (30,30,-290), the CAD display shows the part moving (60,60) as follows:

Stacked Rotary Table with Machine Model Program and Work Offset down one line

Moving down two more lines and the rotary table angles are updated from (0,0) to (60,-45) and the display is updated as follows:

Stacked Rotary Table with Machine Model Program and Work Offset down two more lines

Of course, when animating the part program, these steps are also seen in sequence. When generating the .cnc part program, the selected Work Offset is selected by name as usual. In this case G55 is followed later by G56.

This can be tested by pasting the same point data from the generated .cnc file, into the .cnj Journal file and adding the lines for each work offset to generate a good report as shown below. When doing this test, the prehit and retract values should be zeroed prior to generating the .cnc file.

Stacked Rotary Table Program with Report