Pocket Machining Tips

Technote 143
Product: Milling Applications
Date: 12/96
Version: All

Problem:
My tool is gouging. Pocketing is not recognizing my island and/or wall geometry.

Solution:

NOTE: This information is supplemental to the information in your application's reference manual. Be sure to review the instructions contained in it related to roughing and pocketing before using the tips shown below.

Four Common Problems and their Solutions:

1. Preventing gouging when transitioning to/from multiple pockets.

   Often the outside profile of your pockets has been drawn on a layer rather than with a step. In this case the pocket boundary has no clearance value associated with it, and the tool may not retract to avoid the boundary wall. You can assign a clearance value to your pocket boundary by doing the following:

   1. Group the pocket boundaries.
   2. Do a property change on the pocket boundaries. Choose Edit - Property Chg - Toolpath.
   3. Change the Clearance Value setting to "ON", and type in the needed clearance. You do not need to choose a step number or fill in any other values.
   4. Choose "Accept."
   5. Create your pocketing tool path as usual.
   6. You may change the Clearance Value settings of your geometry back if needed.
2. Preventing gouging of island geometry.

   If you have created your island geometry on a layer it has no Clearance Value assigned to it. Follow the steps outlined above in #1, first grouping your islands instead of the pocket profile.

3. Why does SmartCAM seem to disregard my profile top and clearance values, for my tool path and island geometry, when generating tool path?

   In some cases SmartCAM assigns the Clearance value of the Material Boundary (usually "OFF") to the pocketing tool path and grouped islands when generating pocketing passes. Check this by doing an Element Data on both the tool path and island geometry. If the Clearance Value has been set to "OFF" on either of these it can be changed back by:

   1. Group tool path and/or islands.
   2. Choose Edit - Property Chg - Toolpath.
   3. Change the Clearance Value setting to "ON" and type in the needed clearance. You do not need to choose a step number or fill in any other values.
   4. Choose "Accept."
   5. View Show Cut or Show Path to verify changes.
4. Pocketing around a large number of islands.

   When trying to create tool path around a large number of islands SmartCAM may not complete the process. The more island profiles grouped the more taxing the calculation of tool path will be on your system. If your system's resources cannot meet the need for the tool path calculation try splitting the roughing routine up by roughing only one portion of the cavity at any given time and connecting all the portions of tool path later by hand.