Are fluffy edges normal?

[MeanderBolt]

While this is not a 'real' problem as I will post process things anyway, I have been curious about the edges of my pieces. I am using poplar if this makes any difference...
As is is milling the edges are nice and smooth (except for the tabs (necessary evil I suppose)) in all places except for the very edge of the cut on the top of the board. There is a sort of fluffy edge that happens. I have played with different spindle speeds, but it still seems to fluff. Also, there are times where it it like it will build a 3 or 4 inch streamer of wood thread.
Like I said, this is not a real problem as the cuts seem to be accurate (except where I goofed up in a calculation or placement).
Here is a piss poor picture to give you an idea of what I am talking about.

IMG_20140406_135730.jpg (181.13 KiB) Viewed 2054 times

[twforeman]

What kind of bit are you using?

I tend to use straight cut carbide router bits for wood (since they are made for routing wood.)

Fluff does happen sometimes, but it depends on the materials, what kind of bit you are using and how sharp it is.

[Nigel K Tolley]

Are you doing a fairly light cut (vertically) with an upcutting spiral? That would explain it.

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[MeanderBolt]

I am using 2 Flute spiral cut end mill. I have only run 2 jobs on this mill so I don't think that it would be anywhere near dull (but anything is possible).

I do have some straight edge bits. I'll give them a try.

[edwardrford]

To expand a little on Nigel's point:

If you use an upcut spiral bit with a shallow depth passt, the top of the work piece will have that edge (if it's soft material).

If you use a downcut spiral bit, and your last pass is not very thick, you will see the same results on the bottom of the workpiece.

-Edward

[MeanderBolt]

Okay. Good information. These were up cutting (One of the ones that came with the machine). So, if I go to the straight flute This would all be resolved outright?

[twforeman]

Well, maybe. It really depends on the material. Some woods are kind of stringy and will fuzz a little.

You just have to try different style bits and see what gives you the results that make you happy.

[PsyKo]

Hello

It happens when you're cutting perpendicular to the fiber of the wood.
Make sure your endmill is sharp. Sometimes "new" endmill does not means "sharp" endmill.

[Nigel K Tolley]

Good point. Carbide is not "sharp" for this sort of thing. HSS is far sharper.

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[TDA]

Looks like your bit is not right for your application.

A couple quick things about bits.

First, while a straight flute cutter can help with this it's not necessarily the only or best solution. A lot of times this kind of issue is caused by the rake angle of the tool. This is the angle of attack into the material. So a higher rake upcut tool will also help with this. The problem you run into is that a lot of tools are made as multipurpose. They will pick a rake angle that will work ok for most materials but not great in any. As an example if you get a straight flute cutter with the wrong rake it will chip up the top edge. You won't get the fraying as bad but it will still damage the top/bottom surface.

Also keep in mind in the HSS vs carbide debate that the HSS only starts sharper. Basically, carbide is a sintered material. So the sharpest the edge can get is down to the grain of the carbide. Although, with the high grade carbides out there this is much better than it used to be. So yes HSS does possibly start with a sharper edge. The problem is that it doesn't keep it. Basically while cutting you are constantly damaging the fine edge of the tool. The finer the edge the easier it's destroyed. So the HSS will catch up to the carbide pretty quickly . After that the HSS is going to degrade MUCH faster than the carbide (this is especially true in MDF or ply).