I have done a lot of successful inlays, but am really having problems with this one. I first tried in walnut with a 30 degree vbit (first time trying a 30) It chipped on two tries. Running low on walnut and thinking maybe it was to soft, I tried this board which I think is Hickory. This one I offset the vectors to make a little more area for the vbit to get in and used a 60 degree bit. Really bad chipping again. The bit is fairly new to me, but has done a good job on a couple of previous jobs. This is the first 3 tooth v bit I have used so I am not sure if I am off on feed and speed or?
I am using a pass depth of .075" Clearance pass stepover of .09, final of .015, Spindle speed 12000, with a feed rate of 140ipm and a plunge of 30
Any suggestions appreciated. I figure I will give it one more shot and if it doesn't work, I am going to have to find a new picture to inlay that isn't so busy.
Have you tried a sealer on the board before carving ? I have tried using a shellac sanding sealer on boards I was cutting small text into which helped a lot with chipping, the other thing I found was that I had to slow the feed rate right down to aviod chipping, not done much inlay work but if the inlay is very busy with lots of fine detail then I would think the same would apply.
As an experiment, I would try 16,000rpm, with both the feed and plunge set at 20 ipm on a scrap piece of walnut (maybe the back of the ruined part?)
I'm thinking that should minimize or eliminate the chipping. And yes, I know the feed is slow. But, if it gets the job done, it's worth the wait.
If no chipping occurs, you could try increasing the feed rate, but I wouldn't go any more than 60 ipm. The design looks "prone" to chipout based on your photo. I'll bet at 40 to 60 ipm, you would start seeing chipout again
You could always pull the vectors out in that area and cut the part at your normal 100ipm,,, which in my book is a tad fast.. Then come back and step it down at .020 per pass and 40ipm just in that area. After looking closer at it you might try profiling everything with a small V bit to score it first... Then come back with the larger bit.
Thanks Martin, Michael, and cbr_speedster, for the suggestions. I think that board should have enough thickness that I can give it a shot on the other side. I usually have plenty of glue ups and sanding to do so just letting the machine take its time usually isn't a big deal. Would you guys keep the pass depth the same or reduce that also?
KWiK wrote:Would you guys keep the pass depth the same or reduce that also?
I can't say for sure, since I don't have quite enough info to go on.
Some considerations I take into account are...
- how rigid my machine is
- bit size and shank diameter
- how my machine has performed in the past at various depth pass settings in similar material
I didn't make a recommendation for pass Depth because I figured you would be a better judge of that as you "know" your machine (and bits) better than I.
Your 0.075" sounds conservative but at the slower "test feed rate" I mentioned, I would probably at least double that pass depth on my machine
Chirping generally occurs in corners where the cutter changes direction or there is a sudden increase in engagement. Generally I don't worry too much about that.
Looking at your picture, the "V" groove "cut" does not look good.
Can you give some detail on the cutter you are using. What brand is it? What shank size is it?
I use some Freud Lasercut "V" groove bits that are awesome.
I have also used a variety of other bits most with as least decent results.
You said you this that bit successfully before? Something must be different from the successful cutting and to this cutting. What are the differences? Material? Wood? Cutter? Depth of cut? Size of material? Clamping?
I am just wondering why your cut looks the way it looks. Bad fuzzies in bottom of cut but not top.
Is the cutter chipped? Carbide chips REALLY easy and should NEVER be allowed to touch any other carbide cutters in storage.
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC
Thanks Leo,
The vbit is this one I didn't realize it was a 3 flute cutter. That is part of the reason I moved the feed rate up. The main thing I know of that has changed is this is a lot denser pattern, and of course no two pieces of wood are the same. I had a nice 60 degree all carbide cutter but it recently had a run-in with something it shouldn't have, and I haven't gotten around to replacing it yet.
I always store it in the case, and it hasn't been bumped , the edges still feel super sharp. It isn't the cutter that is getting chipped, it is the wood that is chipping
I clearly see the chipping at the top surface between the "V" carve areas. Is THAT what you are referring to?
Looks like Cherry from the pic but I could be way off.
That area WILL tend to chip as the grain direction has no strength at all.
A good Maple will most likely be a LOT better.
Also, Martin mentioned a sealer coat of Shellac but I don't have a really high confidence level on that.
I often use a paint mask when painting the "V" grooves. It is like contact paper but has characteristics that are designed just for this purpose.
When I do that sort of work I will sand the wood to 220, then apply 3-4 coats of spray shellac sanding 220 between, let dry really good then apply paint mask. The results are CRISP.
I have done really tight patterns with not as good a cutter and gotten great results - in Cherry.
Perhaps also your feedrate may be a bit high as Mr Tyler said. These guys have TONS of experience doing this stuff.
I am more on the grain than anything else though. I think you should try the sealer and paint mask. That stuff will help to hold the wood together. Slowing the feedrate certainly will not hurt.
I believe it is very possible to get nice sharp clean cuts with the pattern you have.
Imagine the Possibilities of a Creative mind, combined with the functionality of CNC
I see these posts on here all the time. and the one thing that never gets mentioned is the moisture content of the wood.
Wood that is considered air died, is often at 11 to 14 percent moisture content.
Where as kiln dried wood, properly dried and stored, should be around 6 to 8 percent moisture content.
It has been my experience, that kiln dried wood, will always machine and finish smoother and cleaner.
Where as air dried wood, always has a tendency to tear out deeper and larger, with some woods worst than others.
Air dried wood, will also dull your tooling twice as fast.
I would drop, a new cutter down to full depth, 18,000 rpm and 200 ipm, then use my feed rate over ride, to adjust the speed.
Will Williamson willmade.com
Williamson Lumber & Millwork Inc.
Capac, Michigan
Well I tried again on the back side of that piece. I think it it birch, but admit I get mixed up on some of the species some times. Anyhow, I had to drop the rpm back down, my ears couldn't stand the screaming The cuts did turn out better, but still not great. At that point I gave up and searched for a new public domain viking image, and went back to the walnut (the inlay is going into maple) There is a tiny bit of chipping but overall it turned out much better. I did have to reduce the rpm again, ... somewhere between 9 and 10K got the bit to quite screaming. I think it was mainly the cuts so close together that was giving me the problems. I agree with Will, but this is the same walnut that I had tried the other image in and the results were horrible.
Leo, what rpm and fr do you run this bit at normally. I had forgotten that originally I had started out with a higher rpm, and the slowed it down until the screaming was under control.
The cuts did turn out better, but still not great. At that point I gave up and searched for a new public domain viking image, and went back to the walnut (the inlay is going into maple) There is a tiny bit of chipping but overall it turned out much better. I did have to reduce the rpm again, ... somewhere between 9 and 10K got the bit to quite screaming. I think it was mainly the cuts so close together that was giving me the problems. I agree with Will, but this is the same walnut that I had tried the other image in and the results were horrible.