Trimming surfaces

[Randy Maynard]

Hi Jeff and Ocean,

 

Did either of you every use a manual jig borer to put in holes? For the ultimate in precision you would always position holes from the SAME direction to eliminate any error caused by backlash in the screws.

 

One way filtering is built on the same principle. Imagine a grid of points. One way filtering will always start from the same edge and filter in one direction. This eliminates (possible) tiny mismatches in how the points are calculated. Which should, and usually does, result in a better finish. I think it should be the default.

 

I always recommend using the filter. But I only use ARC filter on planar toolpaths. Planar being toolpaths that hold 1 axis stationary and move the other 2 axis. Such as Contour, Rough Pocket and Parallel. And, the new Raster, Waterline and Area Clearance. Arc filtering works well with these toolpaths.

 

Toolpaths that DO NOT conform to planar cuts... In other words, toolpaths that will move 3 axis simultaneous, such as Scallop and Radial are difficult to fit arcs.

 

In non planar toolpaths (like scallop) Mastercam is supposed to filter using points until it finds a planar arc, then put in the arc. But, like everything else, it works on a tolerance and depends on a number of factors, including a post that is setup correctly for a specific machine and deciaml place output. (ALL machines handle arcs differently. AND, machine mfg change their control software from time to time, so it can be a moving target.)

 

Anyway, once in awhile a small arc slips through due to rounding and is interpreted as out of plane (non-planar) and the control will error.

 

Since it is usually occurs 50,000 lines deep, in a hot job... I recommend turning off arc filter in a non planar toolpath.

 

Just my .02

 

Also, many true high speed machines are designed to handle mega amounts of points. On these machines I turn off the filter.

 

The whole premise of filter is that it allows a huge program to be run on a machine that shouldn't really be running it. In other words, that jerky motion and slow feedrates simply means you are trying to shove a big program through a machine that can't handle it. If it were designed to handle it, the motion would be smooth and you would maintain an acceptable feedrate.

 

Filter is a tool, not a magic wand.

 

Again, just my .02