What I learned (scraped) today re: tapered pockets

[Chris Rizzo]

I was just doing some circular pockets which were deeper than the L.O.C. on my roughing tool, so I had depth cuts selected with tapered walls....sounded like a good idea.

 

HOWEVER my selected geometry was at depth (say -1.25") and my top of stock was well, top of stock....(Z 0).

 

Mastercam calculated the tapered circular pocket from my SELECTED GEOMETRY down, NOT the top of stock down. So I got a tapered pocket (cone), that was OVERCUT at Z0

 

I was expecting MC to project my geo to the top of stock, and start the inward taper there..not start the taper from my selected geometry, which tapered "outward" z+, and "inward" z-.

 

Please someone tell me I'm not crazy.

[BernieT]

You're not crazy -

 

I just recently ran into the same thing on a standing insert. Geometry was on the lower (bottom) of the insert and MC tapered from the geo upwards and inward - would have scrapped the part if I hadn't been lucky and noticed it in backplot.

 

Don't know if this is new or not, have never noticed it before - but I don't use this feature often, either.

 

Ver 9.1 SP 2

[Teh Bear without Brains kinda idiot]

I use this function all the time in pockets and contours ,you must select contour right and check the backplot .

Never scrapped anything and use it all the time .

You must be cautious - but when you run swep2d toolpath you have no objections ?

You can scrap easily there .

[mold100]

+1 Winnie,

 

I also use this and am very cautious when doing so. Check 2 or 3 times then post.

[Jim at Gentex]

quote:

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you must select contour right and check the backplot .

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Winnie teh wise bear!

 

[Thad]

Chris,

 

Is there a reason why you selected the lower geometry or did you just arbitrarily pick it? Just askin'. I don't think I've even used tapered pockets.

 

Look on the bright side. You've saved everyone reading this from scapping a part in this fashion. Way to take one for the team! (Funny - joke funny, not funny - ha ha you scrapped a part funny.)

 

Thad

[Fred @ Slate Industries]

I have a "Tally" in front of my Monitor

Of How many times Backplot alone has saved

Me. 26 times in 5 years

In the same time frame 15 times the block was completely Un salvagable!!!!

[Chris Rizzo]

I had a round hole (bore), with a slot in it at the top...the wire driving geo for my bore thus only existed at the "bottom" of the hole...so that's where I selected it. I had it running just fine, but switched to a larger tool and bigger stepdown, and did'nt check the backplot for my adjustments. So it was my own fault for that...

 

BUT in creating the tapered pocket, MC violated my driving geometry at top of stock.

 

Happy to share, though!

[Thad]

Chris,

 

Sounds like I would've done it too, based on your circumstances.

 

Thad

[Teh Bear without Brains kinda idiot]

Guys ,this Mastercam approach at first drove me crazy , but I found some reasons and great things

Make the good toolpath for pocket ,let me speak metric for depth 50 mm .

make copy of it 2 times

Now split your toolpath to 3 :

from 0 to -15 ,from -15 to -30 ,and from -30 to -50.

Now every toopath that you`ll make with simple regen will be good vecause it is from real geometry !!!!

 

HTH

 

PS I always run backplot (and not alwais veryfy ),safe and fast ,and I use to trust backplot if it shows undercut or contradicts to verify .

 

Teh in backplot I trust