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  #11  
Old 09-16-2020, 10:27 AM
Jim Becker Jim Becker is offline
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Tim, it will only get to the speed that it can actually go, given acceleration, deceleration and short distances. Setting to say, 600ipm doesn't matter because it will never get to that speed cutting, especially small things. I've also learned to pay careful attention to raster direction for 3D carving and try to orient things so that the "longer" strokes are taken advantage of when rastering with the grain, for example.
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Last edited by Jim Becker; 09-16-2020 at 10:54 AM.
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  #12  
Old 09-16-2020, 12:44 PM
barney barney is offline
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If you can't speed up feed dropping rpms has the same effect.
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  #13  
Old 09-16-2020, 12:48 PM
sgodding sgodding is offline
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I agree with Jim that part size and acceleration make a big difference in the actual achieved feed rate.

Having said that, I've be very surprised if a Panther can't achieve feed rates of 200-300 ipm on long cuts (or higher!) without problems. Gary Campbell always told me to push the speed until either the bit breaks or limitations in the machine cause cut problems, then back down a little. Granted, that advice is for production cutting. If you're trying not to break bits, then maybe not the best advice.

It can go faster than you think, though. On my old Stinger 3, I used to do carvings with a 1/8" tapered ballnose at 400 ipm, just being careful to leave a relief cut at the start so it didn't plunge into the material at that speed. Just saying.
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  #14  
Old 09-16-2020, 01:08 PM
TimPa TimPa is offline
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the part in question is 1 1/2" wide x 6" long, so machine not likely to reach full speed. but at that size, 200 ipm is wicked fast. my quest is cut quality first, bit longevity second (although tied hand-in-hand).

the top needs to be clean cut, hence the downcut bits. so i think i will try an upcut for the cutout, then a downcut for the onion skin. i will try at 12k/140ipm see how they turn out. but i will try everything offered by you guys, to try to get there.

trying to cut out about 50 units a day... so minimal sanding is important

thanks again everyone!
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Last edited by TimPa; 09-16-2020 at 01:17 PM.
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  #15  
Old 09-16-2020, 02:57 PM
Jim Becker Jim Becker is offline
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Quote:
Originally Posted by TimPa View Post
t
the top needs to be clean cut, hence the downcut bits. so i think i will try an upcut for the cutout, then a downcut for the onion skin. i will try at 12k/140ipm see how they turn out. but i will try everything offered by you guys, to try to get there.
Wouldn't you want the opposite? Clean start of the cut with the down-cut and then remove material down to the 'skin with the upcut?
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  #16  
Old 09-16-2020, 03:21 PM
Ed Hazel Ed Hazel is offline
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Quote:
Originally Posted by TimPa View Post

the top needs to be clean cut, hence the downcut bits. so i think i will try an upcut for the cutout, then a downcut for the onion skin.
On solid wood I use a 3/8 compression bit, climb cut, then do a final pass conventional cut taking off .010 the full depth. Sometimes faster is smoother.
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  #17  
Old 09-17-2020, 07:17 AM
TimPa TimPa is offline
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Quote:
Originally Posted by Jim Becker View Post
Wouldn't you want the opposite? Clean start of the cut with the down-cut and then remove material down to the 'skin with the upcut?
i may have used the term onion skin incorrectly. the final pass i was referrring to was using an allowance to remove a final amount on the entire edge. an upcut there will leave a ragged top. thanks for the input!
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  #18  
Old 09-17-2020, 08:29 AM
Jim Becker Jim Becker is offline
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Quote:
Originally Posted by TimPa View Post
i may have used the term onion skin incorrectly. the final pass i was referrring to was using an allowance to remove a final amount on the entire edge. an upcut there will leave a ragged top. thanks for the input!
Ah...allowance with last pass. For that I like to use a compression bit because one cutter preserves both the bottom and top edges for that last pass. The first pass should be just deeper than the change between up-cut and down-cut. The .25" Whiteside bit has a small up-cut section (~.19") and works nicely for most materials.
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SR-44 (2018), 1.7kw spindle, Performance Premium, USB, Keypad, T-Slot table (y-axis configuration), WinCNC, VCarve Pro upgraded to Aspire

Non CNC stuff...

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Festool "a good collection"
Stubby - lathe
Oneida Cyclone
more...

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Commission work for equestrian tack storage and other custom furniture and cabinetry
Located Bucks County PA
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bvww.etsy.com
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  #19  
Old 09-17-2020, 10:45 AM
guitarwes guitarwes is offline
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Quote:
Originally Posted by TimPa View Post
i may have used the term onion skin incorrectly. the final pass i was referrring to was using an allowance to remove a final amount on the entire edge. an upcut there will leave a ragged top. thanks for the input!
If you use the climb cut direction first then the conventional cut for onion skin cutout pass second you usually don't have to do an offset because the bit will pull itself towards the material on the conventional cut leaving a smooth edge. Use a downcut bit for the climb cut pass, then use a compression bit for the full conventional cutout pass.
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  #20  
Old 09-17-2020, 02:03 PM
TimPa TimPa is offline
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Quote:
Originally Posted by guitarwes View Post
If you use the climb cut direction first then the conventional cut for onion skin cutout pass second you usually don't have to do an offset because the bit will pull itself towards the material on the conventional cut leaving a smooth edge. Use a downcut bit for the climb cut pass, then use a compression bit for the full conventional cutout pass.
i remeber you mentioning that from before (no allowance neeeded for onion skin), but i havent tried it yet.

i was worried that i don't have enough hold down (small pieces) for a full pass (with any cutter). but with your method it should stay put for a "shave". will give it a go with the next batch.
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