Need Suggestions for a More Efficient Way...

[Reko]

I have to machine away material in between the blue and red contours. The red is actually a deeper pocket so there is no stock there.

 

I usually use "area mill" but it cuts air when it's inside the red area.

 

Seems like there would be a better way to attack this. Any suggestion?

 

[DavidB]

Trim the blue line at the bottom at the the two vertical Red lines and pocket machine it.

[Reko]

David,

 

Problem is, I need to finish the blue contour, but I need to overlap the red by about .100" because it is a deeper pocket.

 

Also, there is only about 1/4" between the blue and red contours at red's widest area. I'm using a 3/4" EM, so chaining both contours would avoid that area.

 

See my dilemma?

[SydwazShawn]

I would split into 2 operations. Do the top blue first, then set top of stock at lower red level than do that pocket.

[SydwazShawn]

Somtimes I will offset the red border half the tool dia, then chain the blue and then red. The red would be the island that it doesnt cut.

 

I dont waste my time unless its a repeat job.

[Reko]

quote:

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I would split into 2 operations. Do the top blue first, then set top of stock at lower red level than do that pocket.

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That may be the way to go.

 

I guess short of writing a manual path, there probably isn't a way to make it do what I want it to do.

 

Thanks.

[DavidB]

quote:

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Problem is, I need to finish the blue contour, but I need to overlap the red by about .100" because it is a deeper pocket.

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Xform offset contour Red .1 then use pocket.

[Reko]

I've thought of that, but again, the EM (3/4") won't go through the thin area here:

 

 

Even when I offset it enough for the EM to go through, it takes two passes instead of one, which, again, is like cutting air and wastes time.

 

I know I'm being too picky here, but when my boss sees a toolpath that isn't cutting anything, he's not pleased. He's not a machinist so the only thing he can relate to is seeing chips flying everywhere... that makes him happy. Cutting air... not so good.

 

Anyway, I think cutting the top pocket first is the answer.

 

Thanks again.

 

P.S. I think what I was looking for was a combination Pocket/Facing operation where the toolpath would not violate the first boundary selected, yet overlap the second selected boundary. Kind of a silly thought of mine, but that would solve this problem for me.

[gcode]

old school..

backplot the pocket toolpath

save the cut geometry

trim out what you don't want

chain what's left with comp off

[Reko]

Hey, that's interesting. I never thought of that. I'd like to give it a try, but I've didn't know you could save the toolpaths' geometry.

 

How do you do that?

[pip]

Backplot your toolpath, in the backplot contoll panel there is an icon of a disket. Press and then tell it which layer to save your path to, now you have the toolpath (tool centre) saved as geo on whichever layer you chose.

[Reko]

Hey, I tried that. Cool. That comes in handy. Thanks gcode, thanks pip.

 

[Mr. Wizzard]

Saving time and doing as little work as possible is my rule of thumb! Shawn'ald hit the sweet spot with suggesting pocket the blue down to the red and then doing the red, in my opinion. That's the way i ususally do pockets like yours. It saves time creating more geometry, offsetting chains, etc....

Just my opinion.

[gcode]

You could also run a pocket toolpath on this

then run the hifeed utilty. That takes a little work to set up but would really impress your boss

[Verndog]

quote:

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Saving time and doing as little work as possible is my rule of thumb!

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Depends on material being cut and how many parts you are running. You have to consider spindle time at 2-3 times the value (cost) vs programmers time when making these decisions. If that were a "production part" and anything more then 5 minutes or so cycle time I'd hand drive all that toolpath by drawing GEO...Xform / offset and trim to cut near ZERO air cutting. Cycle time comes first...my time second for production IMO.

 

Edit...woops just read the inside is deeper??? WTF??? Do the blue first then inside deeper 2nd.

[SydwazShawn]

You can run pocket without finish, then do seperate operation for contour, so it doesnt countour both chains.

[Joe788]

quote:

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Depends on material being cut and how many parts you are running. You have to consider spindle time at 2-3 times the value (cost) vs programmers time when making these decisions.

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I consider it the exact opposite. Unless you've got a $500,000 machine and a low budget programmer, the programmer usually costs more than the machine.

[Verndog]

quote:

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I consider it the exact opposite. Unless you've got a $500,000 machine and a low budget programmer, the programmer usually costs more than the machine.

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$500,000. was propably lower then the average cost of a spindle at the last shop I was at, with 1 spindle at $2,000,000. Its not just the machine cost. The footprint cost for the machine tool, the material cost that sits and its footprint, the cutters and support tooling footprint all add to WAY more money then a computer, desk, programmer footprint with 20K worth of equipment. That will way more then offset the extra 5-7 $ per hour for a top programmer vs top setup person.

 

Were not just talking about a programmer vs a machine. We are talking about cycle time that will usually mean machine + operator vs programmer. Does the programmer spend 2 hrs to save 1 hr cycle time? In many cases the answer should be yes.

 

Point being, it's not always cut and dried to do things in the least amount of your time only as #1 consideration.

[Reko]

Thanks for all the extra input.

 

Just to expand on why I was doing the deeper pocket first, the deeper pocket goes 4-6" deep and I use a high feed Mitsubishi for that. The material comes out pretty fast and the radius on the insert doesn't matter for that pocket.

 

Then, I machine the top pocket with a 1" inserted endmill and then come back with a finish endmill for a sharp corner at the bottom of that pocket.

 

Because I can't use a feedmill for this top pocket, it made sense to me to get most of the material out by machining the bottom pocket first. That is what led to my initial question.

 

Anyway, thanks again for all of the input.