Why are Some Defaults the Way the Are???

[kathy]

Whoopeee! Our Machine Shop supervisor is starting to help with some programming.

 

He had a very good observation: the default setting for lead in/lead out on a contour has Exit/Enter at mid point check on. Of course, I had already checked it off on my seat, but everytime I load an update, I have to go back an fix everything again..

Anyway - why would anyone want to Enter/Exit at mid point in the first place? We always Enter/Exit at the corners to min. tool marking.

 

Kathy

 

[ 07-22-2002, 07:27 PM: Message edited by: kathy ]

[Scott Bond]

Hi Kathy -- here's two cents worth

quote:

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why would anyone want to Enter/Exit at mid point in the first place?

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If I where makeing a pocket that had corner

radii that was smaller than the radii on the end mill, it would be easier to start at the mid point of one of the lines.

[Tony]

Always Mid point,With a shallow lead in angle and as much radius as I can fit in there.

MoldMaker mentality I guess...

[Finecut]

Kathy,

There are times when one needs to enter/exit at the mid point in a closed contour. For example, if you have a square or rectangle and one wants to remove the material inside. There are two basic ways, pocket or contour. We all know how a pocket cycle works, it removes all the material.But lets say one wants to remove a slug.Why pocket? If you do a inside contour you dont want to start in a corner, if at all possible. If you start at mid wall you need to break the geo at the mid point or use start at mid-point in the lead in/ out box. It does it for you,

Now if the machine is worth its salt you wont always see a witness mark. I usually take a skin pass of .01 to clean up.

 

Does that help?

 

Finecut

[BernieT]

Kathy, I agree with all the above posts. Starting in a corner of a contour can sometimes cause the lead in/lead out to gouge. I am happy there is the option to 'start at midpoint'. Sometimes in the past I would have to break the geometry before the toolpath was satisfactory, which screwed up all previous toolpaths using that entity! Now I can just check the midpoint option.

 

HTH, BerTau

[jeff]

Well stated Finecut,

I almost always use the midpoint option with lead in-out.

comes in very handy and the overlap function makes for no witness marks.

[pactec]

Most importantly, the overlap dist. setting is the one to use in conjunction with entering at midpoints if you don't want witness marks on your walls. These could be used on outside profiles but what would be the point, use them on internal pockets and you'll be smilin' when you remove the coolant and see the pocket.

Don't forget that V9 allows a dynamic start point for any closed contour.

 

Cheers...

[Ray Sander from Battelle]

Talk about bad defaults. When 9 first came out in Job setup the Tool Offset Registers was set to “Add” 1 to the length. I knew a lot of folks who crashed parts with this. You selected say tool 2 and you would expect the offset register to also be 2 but it added 1 to it. Those who were lucky had in a shorter tool in T3 than T2.

 

[kathy]

Thank You All !! This is what I really like about this forum..

 

Spence will be back from vacation, and I will forward to him all of your very good answers. He was the one that asked the question.

 

For about 99% of the applicable parts we do here, we are routing about the contour once with an 'O-Flute' or fibberglass/graphite cutter. These do not bottom cut, so I control my lead-in with a point that has been pre-drilled, or a long lead-in that is off the material. In this case, the mid point start will kill me every time!

 

Kathy

 

Next 'Default Field' gripe. On Xform, Scale; How come the cursor jumps to the 'Number of Steps' first? I would rather it jump to the 'Scale Factor' first.

[Zero]

I know this isn't a default, but it is a "why is it this way?" question. In version 9, if you generate a toolpath and then go back into the toolpath geometry, and select remove drive surfaces, all already selected surfaces appear white. Now if you start selecting surfaces to remove they should just go back to their original unselected color with all drive surfaces staying white right? (at least this is how it was in v 7 & 8). Nope....the surfaces you pick to deselect now appear white and all active drive surfaces go back to their original color

 

I see where this could get very confusing on a complex model , so...."why is it this way"?