Cutting Color Core with a V-Bit

[chris77]

I am trying to Vcarve out text using a 1/2 x 45 degree V-Bit. I am getting "fuzzies" around the cut. I have tried different settings on the spindle RPM and the feed rate but cannot get rid of the "fuzzies". I have had luck using a 1/4 x 30 degree x .040 flat bottom engraving bit but I need the text to be bolder than the engraving bit produces. I have attached some images. If you need more information let me know.

Thanks for the help.

Chris

[gkas]

What type of wood is the sign? The softer the wood, the more fuzzies. I clean up most of the fuzzies with a small (a little larger than a toothbrush) brass wire brush. If it's a Vcarve, and not overly time consuming, I run a second Vcarve pass with the same toolpath. That clears up a lot of junk. If it fits in your finishing strategy, coat with a 50/50 mix of Zinsser SealCoat Sanding Sealer and Denatured Alcohol, then brush again.

[chris77]

This is not wood it is color core. Color core is a HDPE plastic.

[dealguy11]

Fuzzies in plastic seem to be about what side of the bit is cutting. On a v-carve, one side is always going into the material and the other is always going out and one of those sides has fuzzies. One way to address that is to run the path twice, the second time in the opposite direction to the first. There isn't an option for the v portion of the v-carve to run climb or conventional, so I think you'd have to do this by copying the vectors and using the node-editing tool to change the direction of the vector in the copy, then create another toolpath (unless I'm just not paying attention tonight and the option really is there).

[Mobius]

The only way I've managed to get rid of most of the fuzzies on HDPE is to use a flat bottom engraving bit. Or if possible, use a small end-mill for a clearance toolpath and then the V-bit to touch-up.

I believe the issue stems mostly from the fact that a v-bit comes to a point. If you even have a slight bit of run-out, the tip of the bit will make a spiral motion as it travels along the cutting path. And because HDPE is dense and homogeneous, the small areas that weren't cut stay attached, leaving the fuzzies. With a flat bottom bit, if your feedrate isn't too high and the run-out is less than the flat diameter, those 'missed' areas get cut, leaving less fuzzies.

Even running through a second time with a V-bit doesn't help, because the fuzzies just get pushed out of the way, rather than being cut.

If I need to use a V-bit on HDPE, then I take a dental pick and scratch along the bottom of the carved groove. This usually cleans out the fuzzies quickly. Not fun on complex signs though, which is why I try to avoid V-bits on HDPE when possible.

[Mobius]

Fuzzies in plastic seem to be about what side of the bit is cutting. On a v-carve, one side is always going into the material and the other is always going out and one of those sides has fuzzies. One way to address that is to run the path twice, the second time in the opposite direction to the first. There isn't an option for the v portion of the v-carve to run climb or conventional, so I think you'd have to do this by copying the vectors and using the node-editing tool to change the direction of the vector in the copy, then create another toolpath (unless I'm just not paying attention tonight and the option really is there).

My experience is the the fuzzies in HDPE aren't on the sides, only right in the middle of the V groove.

[Bob Reda]

There is a special bit made for colorcore. You can find one at centurion tools

Bob

[Adrian]

I use v-bits with three cutting edges on colour core type materials. Always get a nice clean cut.

[martin54]

Have you tried using engraving bits? I haven't cut a lot of it but what I have cut has been with an engraving bit which has a flat bottom rather than a point. I have engraving bits with flats as large as 3mm for cutting text.

[Charlie_l]

Use a V having a round or flat tip.

[laflippin]

Chris,

I recently bought a 1/2" 45 deg V-bit for use in engraving for some of my Zank V-Inlay projects. The one I purchased sounded good to me at first blush--the bit design allows the user to remove and replace the cutting knife-edge at much lower cost than replacing the entire bit when it dulls. However, something I didn't really appreciate until I started using the bit: Unlike every other V-bit in my collection, the 1/2" 45 deg V-bit with replaceable blade has only one cutting edge and that seems to dramatically affect its performance.

In practice I found that many of the project pieces that I cut using this bit were unusable because of the very high occurrence of chipping in the pieces. I'm not 100% positive of the reason for this but, all other factors being equal, it does make sense to me that a bit that makes only half as many cuts through a given length of wood at a given feed-rate might very well cause chipping. I suppose one solution would be to experiment with lowering the typical feed-rate with this specific V-bit; however, in practice I have pretty much put the 45 deg bit on the shelf and gone back to 1/2" 60 deg V-bits, which have two cutting edges and give much, much cleaner performance under my typical cutting conditions.

Lee

[martin54]

laflippin, the spindle speed & feed settings will always vary with the number of flutes a cutter has, for a single flute bit you would need to either raise the spindle speed, decrease the feed rate or a combination of the two. it really is just a case of experimenting until you get it right A single flute bit should give as good a finish as a 2 flute bit if set up correctly.

[laflippin]

To paraphrase Churchill, "I have nothing to fear but inertia itself"....however, your comment rings profondly true, Martin, so I may dust off that single-flute bit and try a few additional more exps with it. The idea behind using that bit is still valid, i.e., to buy a tiny amount more practical engraving depth on very fine detail within Zank V-Inlay projects.