Pocket milling

[Thad]

What should my settings be in order to ramp off the wall when milling a pocket. Currently, it's only a problem (a) when on the last pass and ( when milling a closed pocket. When cutting an open ended pocket, I select a start point that is off the part.

 

At the end of each pass, it moves to the start point and starts the next pass. But on the last pass, the pocket finishes against the wall, and then drags along the wall on the up feed. If I use the finish pass option in the roughing/finishing parameters page, I see there are options for lead in and lead outs. What should my "finish pass spacing" be in relation to the "number of finish cuts" and "finish step" values in the depth cuts dialog box? Should they be the same? If I'm using the finish pass option, should I NOT be using the finish pass in the depth cuts dialog box? The only reason I'm looking at the depth cuts dialog box, is because of the lead in and out options. I don't need it for the finish pass part of it. Using v7.2c

 

Thad

[P_Scott]

Thad,

 

There are many things that you could do with the closed pocket geometry. Use the Lead In/Out parameter button on the finish pass of the pocket. The Finish pass spacing of the Finish section is an XY stepover value. The Depth Cuts finish step is a DEPTH, or Z, stepdown value. In the Lead In/Out button you can "Use Entry Point" and "Use Exit Point" as long as you include a point in your chain geometry of the operation. Another option is to "Start Finish pass at closest entity". This switch will start the finish pass of the pocket where the roughing passes end, not retracting between the roughing and finish passes. You can also break the first entity of your pocket chain at it's midpoint so the Chain start point can be selected in the middle. The Pocket operation can be used as a simple roughing only toolpath, leaving a slight amount of material on the walls, and finish the pocket geometry with a Contour op. HTH

[Thad]

Thanks for your reply Peter, but I still couldn't get it to work. Here is how I have my settings:

 

In pocket parameters/depth cuts:

Max cut .05

# of fin cuts 1

finish step .05

stock to leave .01

 

Rough and finish parameters/finish:

# of passes 1

I have checked "machine finish passes only at final depth.

I have checked lead in/lead out and am using a rad only. I also tried using a start and end point with no luck. Does the point have to be on the geometry (pocket wall)? When I did this, it made it impossible to select it to chain it. MC always wanted to select the line, not the point.

 

The only reason I need the finish pass is to ramp off the walls at the end of the cut. What am I doing wrong?

 

Thanks.

Thad

[kccadcam]

thad, I put a sample pocket on the ftp under mc7 files called: finish pocket walls.mc7

 

Look at the settings under lead in/out.

Is this what you want??

[Thad]

Kevin, thank you for your time.

 

This is the closest thing that I have seen to what I'm looking for. I don't need the tool to contour the entire pocket boundary when done with each pass, or when done with the pocket. I changed the settings to do what I thought would do that and I ended up with my results from yesterday...no ramp on the pocket. What I want it to do is, ramp off the wall when the pass is complete, just like ramping off the wall when a contour finish cut is used. I don't care if it does it on every pass or only the last pass, I only *need* it on the last pass. GibbsCam will allow you to define how it approaches the wall of a pocket. It will go through the normal pocketing cycle, milling from the inside out, but then when it contours the boundary of the pocket, you can choose a 90 degree, radius ramp on, or both as an entry/exit to the pocket. That is what I'm looking for. BTW, with MC, I always use "parallel spiral" option.

 

Thad

[kccadcam]

Thad,

Try leaving stock on the walls with your pocket routine and then go back and finish the walls with a contour for the ramping off of the walls.

[Thad]

"Try leaving stock on the walls with your pocket routine and then go back and finish the walls with a contour for the ramping off of the walls."

 

That's exactly what I do. I just don't want the cutter dragging up the wall on the retract of the roughing pocket cycle. Can MC ramp off the wall on a pocketing cycle without contouring the entire pocket boundry? It's not *that* big of a deal. I simply asked if there was a way to avoid it.

 

Thad

[Thad]

Kevin,

 

I thought about it last night and I realized that you gave me exactly what I was looking for. My concern was milling the boundary of the pocket taking .010 off with each pass. We do some decent size pockets and adding the extra pass that only cuts .010, just to get a ramp off, didn't seem like it was worth it. I didn't think of changing the "finish pass spacing" value to something larger to resemble a typical cut. When I did, it worked great! Thank you for your help.

Thad