2D pocket start point

[Thad]

How do you control where the cutter starts and finishes it's "boundary cut" around a simple 2D pocket? We always use spiral inside to out. Obviously, it finishes in the same place that it starts. Selecting/changing the start point in the chain manager (or anywhere else) doesn't do it. Back when I was using v7.2 and v8, wherever you clicked to select your chain, that is where the boundary cut would start and stop. You could stategically break the chain where needed to manipulate your start point. I have yet to see this work in v9. Therefore, I have never seen the usefulness of the new (v9) dynamic start point.

 

I have a small pocket that is 3 X 1.75 inches and I'm cutting it with a 1.0 cutter. No matter where I put my start point, the results are the same. It ramps down and then goes straight for the corner of the pocket to start it's boundary cut. This is not an ideal situation.

 

Thad

[kccadcam]

I figured it out.

keep tool down must be on (Strange)

and you must have lead-in,lead-out turned on

I made a rectangle 3 X 1.75 with a 1 inch cutter,

.01 finish pass on the walls and .02 lead in,out and it seems to work with the dynamic start point.

[Thad]

Kevin,

 

I used your settings and it worked here too. It's just not the toolpath that I want.

 

I want to avoid a finish pass if at all possible. It appears that you can only control your start point if you use a finish pass. Do you agree? Maybe I can learn to live with the finish pass.

 

Thad

 

P.S. What type of pocket did you use? I was using parallel spiral.

[kccadcam]

Yes I used parallel spiral.

And yes, it only works on the finish pass.

remember, you can crank up the feed rate on the finish pass now (yipeeeeeeee)!

[Brendan P]

Thad,I'm not sure if i understand what you want to do,but here goes....

 

When doing a 2D pocket,if you add a "createpointposition" inside your pocket, (to where ever you want the tool to plunge in)then "chain the point and boundry"

It will start at the point that you want.

However,you may need to pre drill a start hole.

I'm not sure if it will still work if you use ramp on entry.

Still not sure if this is what you mean either.

[CAM-mando]

Re read original post. Now I got ya. Im slow sometimes.

 

Anyway I know this isnt the answer, but wouldnt a finish pass be the same as a rough pass in terms of speed if you just increase the finish pass spacing to the same as the stepover amount for pocketing.

 

Kevin,

 

quote:

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If A is success in life, then A equals X plus Y plus Z. Work is X; Y is play; and Z is keeping your mouth shut.

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I think I had an overtravel in negative Z recently.

 

[ 05-13-2003, 11:41 PM: Message edited by: CAMmando ]

[Thad]

quote:

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but wouldnt a finish pass be the same as a rough pass in terms of speed if you just increase the finish pass spacing to the same as the stepover amount for pocketing.

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CAMmando,

 

That is exactly what we do if we use a finish pass. Now, with a small pocket, is where the "problems" come in. There isn't enough room to take a good size finish cut so we end up taking the .010 victory lap around the pocket's perimeter. I think this is a waste of time. OTOH, if we went with a smaller cutter to allow a bigger finish pass, the smaller cutter now has to take MORE passes to mill that pocket and you haven't gained much. Or am I just being too anal about this?

 

I wish MC had an arc on/off to a pocket's perimeter as a standard pocketing feature. Then you could ramp on and off the pocket walls without being tied to a finish cut. A guy wearing V-neck sweaters figured that out.

 

Thad

[Marty A]

hi thad

 

you could stategically break the chain where needed to manipulate your start point.

 

 

i know you won't see this till later

but what exacly do you mean. i am way caught up here and am now learning 9.1. i did a pocket and it seemed to look the same as 8.1.1. am i missing something here. see ya

 

marty

[CAM-mando]

quote:

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victory lap around the pocket's perimeter

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[Thad]

Marty,

 

If you want the pocket start at a certain place when "finishing" the pocket's perimeter, you can break the geometry at that point and then make that your start point for your pocket. MC used to always use that start point, but now it doesn't unless ...(read above). Remember how I showed you how to break a pocket wall at an open area (burnout, open end of a pocket, etc.), so the cutter wouldn't drag up the wall on the retract? Wherever you put that break point, that is where the cutter would start cutting the pocket's perimeter.

 

Thad

[Thad]

I think I found the problem..... operator error. By default, I have "start finish pass at closest entity" selected. This seems to be overrriding the start point that I select. DOH!

 

Thad

[kccadcam]

DOH!