Pocket issues

[somename75]

Is anyone having issues with pockiting passes leaving little islands where it shouldn't. I have been playing around with the stepover percentage with little luck trying to get it to clean up the floor. If I tell it 60 percent stepover and the tool is a flat endmill it seems to me that there should never be a part of the floor that doesn't get cut.

[Rick Henrickson 65]

what pattern of pocket are you using?

[somename75]

Parallel spiral, which sometimes will clean up the floor, but not very reliably.

[Midwest]

Parallel Spiral - Roughs the pocket in a spiral that offsets the outer boundary by the stepover amount each time. This option does not guarantee cleanout

[Midwest]

Some have this......"does not guarantee cleanout"

 

 

Cutting methods for pocket roughing

Choose from the following cutting methods to rough your pocket. Click on the Example link for each entry to see a picture of the tool motion.

 

Zigzag - Roughs the pocket in a linear motion according to the roughing angle. Example

 

Constant Overlap Spiral - Creates one roughing pass, determines the remaining stock, and recalculates based on the new stock amount. This process repeats until Mastercam clears the pocket. This option creates more small linear moves but cleans out more stock than parallel spiral. Use the Advanced dialog box to configure the overlap tolerance. Example

 

Parallel Spiral - Roughs the pocket in a spiral that offsets the outer boundary by the stepover amount each time. This option does not guarantee cleanout. Example

 

Parallel Spiral, Clean Corners - Roughs the pocket in a similar method to parallel spiral, but adds small cleanout moves in the corners of the pocket to remove more stock. This option increases the possibility of but does not guarantee cleanout. Example

 

Morph Spiral - Roughs the pocket by gradually interpolating between the outer boundary and the island. Example

 

True Spiral - Creates roughing passes of all tangent arcs. The result provides a smooth motion for the tool, a short NC program, and good cleanout. Example

 

One Way - Roughs the pocket in one direction. Example

 

High Speed – Provides smooth arc movements and can help you eliminate tool burial. Choose the High speed button to set additional parameters. Example

 

 

HTH

[Todd Tracey from Fastech]

Paralel Clean Corners will usuall fix a stubborn pocket, BUT, will run longer because of the little out moves at each change of direction.

[somename75]

Ok, is there an option that will guarantee cleanout?

[Michael Sullivan]

I've always had trouble with that. I've come to accept it as a fact of life at this point. especially if the pocket shape is very irregular and/ or it has bosses all over. Usually playing with the step over and or pattern fixes it. sometimes I end up using (back to the basics)2-d contours with multi-passes and depth-cuts out of frustration as a quicker more predictable and flexible solution.(with construction geometry of course)

However I can recommend the Freehand contour c-hook to clean up any little bits tool path left behind though.

that works great too.

[Colin Gilchrist]

"Is there an option that will guarantee cleanout?"

 

The short answer is to change your programming technique. I usually pocket with a 35% stepover, High Speed method. I turn trochodial cutting "Off" and use a Corner rounding radius of 35% of my tool diameter. Then I setup my Helix/ramp entry option to cleanout an entry area for my tool. Setting up a pocket in this manner reduces the percentage of radial engagement of the cutter throughout the whole pocket. By maintaining a more constant angle of engagement, you can increase your depth of cut and DOUBLE your feed rates (At least!). This should reduce tool breakage, increase cutter life, and make pocketing much easier. The only drawback is that you will have to program a re-machining toolpath to clean out the pocket's corners. Its a small price to pay for the productivity you gain.

 

HTH,

[MLS]

I use constant overlap spiral for finishing typically with 35-40% radial stepover.

 

Constant overlap spiral or zig-zag with up to 80% radial stepover for roughing.

 

My preference.

[Rick Henrickson 65]

I like constant overlap spiral with 65% stepover, faster and cleans floor. Or like colin said high speed!

overlap doesnt require adding an extra pass.

[somename75]

Thanks for the input all. I am familiar with your method Colin, but it doesn't suit this case. I am only pocketing .03 deep so the a higher radial engagement is prefered, plus high speed techniques dont lend themselves to the POS that I have to code for. So it sounds like pocket doesnt work properly, or is this more of an enhancement request ?

[Matt Berube at Ferron Mold]

 

 

What do you have for the "toolpath support" setting in the Mastercam section of your "Control Panel" ?

 

I wonder if it would make a difference for you ?

[somename75]

I get an upload page when I try your link Matt.

[somename75]

sorry bout that i hit it too quick I think. I have it set to use new offset.

[Matt Berube at Ferron Mold]

Yeah, sorry. I was tweaking it and it got messed up for a moment. Click the thumbnail...

[Midwest]

 

X2MR2???????

 

 

 

[Cuda84]

Try the high speed toolpath, Finish horizontal, if you have surfaces this will work very well. The finish horizontal finishes all flat surfaces.

[cadcam]

now look at what you done Matt.

[somename75]

I did try to surface finish horizontal toolpath, but like every time before that I have tried to use the new tool paths it pukes on my model for some reason. I consistantly get an error " Unable to extract (at least) one solid face" I sent it off to my dealer yesterday, but have not heard anything back yet. I guess this is why I am frustrated

[Midwest]

quote:

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now look at what you done Matt.

---

 

 

[Matt Berube at Ferron Mold]

quote:

---

X2MR2???????

---

Somebody has to test this stuff out for you guys !

[Midwest]

 

 

Thanks Matt

 

 

[gms1]

Ive always had issues with the pocket routines mcam has. Even on simple half rectangle with corner rad geometry pockets open pocket toolpaths leave islands. I too have just grown used to making more work to get something simple done.

Its not about toolpath strategy either. If I need something to cut from A to B I shouldn't need to add C and D to get to B. I have to try and make my programs as efficient as possible so we can compete so it starts to add up over time when I have to make/add geometry or make a different toolpath.

Sorry for the rant, but im not interested in sugar coating anything atm.

[3R!< W3NG3R]

I have only ever had a problem with parallel and high speed. Every other strategy has naver let me down. Just lucky, maybe? (that would be a first!)