I’m having the same issue with Baltic Birch, using the 201 bit, recommended feeds and speeds. Some of my cuts are pocket but most thru-cuts.
Anybody fall down on a good solution?
I’ve found three things that worked for me on Baltic Birch;
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Run a chamfer pass to clean off the hairy bits
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Use a shallow angle spiral downcut bit and avoid plunges, lots of slow ramps, but you’ll need a clean baseboard to cut into to avoid hairy bits on the bottom
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Run a roughing pass with a 201 type bit leaving 0.5 to 1mm stock and then come back with a compression cutter taking about 0.2mm off in each finishing pass. Those have an upcut for about the bottom 6mm and then downcut the rest of the way up so you get clean shearing on both top and bottom, at the expense of tool changes and more CAM time setting up your toolpaths.
HTH
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I usually do #2 of what @LiamN does, but inaddition I will just hit the surface with a 5" RO sander with either 120 or 220 grit to get rid of the fuzzies.
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Then there is this! *@#$%^. Luckily this is a shop project. I also have been hitting it with a RO sander and then a slight roundover. But I can’t do that on every project. Thanks for the advise.
Ouch,
I’ve not had good baltic ply pull apart like that, are those contour cuts? Might be worth running shallower or slower passes, have you tried a new, sharp cutter? This can happen when the cutter edges get dull too.
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My eye was caught recently by this recommendation @themillertree for a Yonico downcut (in the context of another plywood cutting discussion):
I just received it, didn’t have the opportunity to test it yet, but it “feels” right and high quality, so if you are looking for a downcut (which I think is an invaluable tool to have anyway for finishing walls in wood), maybe that’s an option. I also love using my compression bits in plywood (=@LiamN #3)
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Definitely worth trying out a downcut router bit. I use these 2.5in OAL as well as these - 3.0in OAL for those jobs that need it.
Just don’t try to use a downcut bit while peck drilling - trust me - it’s not pretty.
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Yeah, perhaps the cutter. It has probably 20 hours on it - I’d think it would last longer than that. I was using the standard feeds and speeds, but yeah, maybe slow it down.
Oh, yes, I’d also be surprised if it’s dull after just 20 hours, I abused my original Carbide Nomad 201 for longer than that in birch ply and even some MDF, I’ve put the cheap Yonico 21315-SC through even more and they’ve lost their initial sharp but the surface is only a bit hairy.
Is there any heat marking or wood deposit goo on the bit?
How deep / fast are you contour cutting through that ply?
Checking some of my contour (not adaptive clearing) cuts with full engagement across the whole bit, run with my router spindle on the standard Z I was using;
15-18k RPM
3mm depth of cut per pass
1500 mm / min cutting feedrate
I was also doing a 3mm stepover so I was cutting a slot 6.35 + 3mm = 9.35mm wide so I had lots of room for chips to come out.
That roughing pass left 0.5mm stock so I could come back with a finishing pass which was full depth and taking 0.2mm, 0.2mm and finally 0.1mm off the edge to get to the actual cut line.
I found that was an OK early balance between cut speed and nasty vibration as I’d still not got all my V wheels, belts, etc. as tight and sorted as they could be.
HTH
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No, the bit looks clean. I usually just go with the recommended feeds and speeds.
Hum. I’m gonna have to try that roughing pass/finishing pass technique. That may be my best solution until I investigate an compression or down cut bit. I’m trying to do it all in one bit at one time, but it seems I may have to apply some clearing/finishing techniques.
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I’m still fairly new to this so there is still a lot of learning to do on my end. But I’m thankful this forum is here and there are so many willing teachers and helpers. thanks.
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Folks here have been really helpful to me.
BTW,
Don’t be afraid to use the feed rate override in Carbide Motion and slow down cuts that are sounding like there’s vibration or unhappy, it’s a really quick way to find out if you could be going slower or faster.
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Ran across this YouTube. Worth a look.
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Take a look at the endmill with at least 3x magnification, you may be surprised. You can’t tell much naked eye except really grievous damage.
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I can’t tell. So you are saying the upcut Endmill is damaged:dull?
Saying you can’t really tell how sharp an endmill is, or if it’s chipped with your naked eye. That said, this is pretty typical behaviour of an upcut endmill on ply. I think this is why compression mills exist.
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I was referring to the video. But then again I was looking at it without my glasses. As far as my personal emdmill, it’s fairly new, but I’ll give it a good look. And yes, I think I’ll invest in a compression bit for ply. Thanks.
As Mike says a close up look is invaluable for many things, have a look on Amazon or eBay for loupe
Alternatively, if you don’t have a magnifier to hand, a phone camera can be handy, take the pic under some strong light and then zoom in, here’s a shiny new and my slightly beaten up old 201;
Looking closely at the 201 there are brown deposits just behind the cutting edge up to the normal cutting depth I use in wood and I can also see (on the left top) that the cutting edge is rounded over and no longer sharp in those last 6mm or so.
I don’t know what others (Mike?) think about whether this bit is due for retirement but what I generally do is use my older bits for the heavy cutting roughing passes and then reserve my new sharp bits for the finishing passes to keep those sharper longer.
edit - for my compression cutter bit I definitely don’t use it for the roughing passes, I leave enough stock with a regular shallow angle bit at whatever cut depth I can make work in the material and then come back, full depth, with the compression cutter. There doesn’t seem to be much point in blunting just the 6mm on the end of a compression cutter doing roughing out to me.
(for inspecting cutters I say get a 20$ USB “endoscope” (…) on Amazon and get up close and personal:
https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z/maintenance#tool-wear)
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