I am anxiously awaiting the arrival of the Taig cnc mill I just
bought. Can I get some suggestions as to a type and basic
assortment of endmills to get, and where to get them. I will start
milling WAX and graduate to metal later. It comes with a 1/8" and
1/4" collet. Do I need more collets of different sizes.
Congratulations! The Taig's a real workhorse, and while it was
designed for metal, wax is not a problem for it. It's good to have
more collet sizes, especially 5/16" (the largest) and 3/16" ( usual
in mid-range endmills). They aren't expensive. You don't say what
you're planning to do, so it's difficult to recommend any particular
tools, but a basic assortment to get you started would include some
large and medium-sized flat-end endmills, both 4-flute for side-cuts
in hard materials and 2-flute for slots. These are good for making
flat surfaces which meet vertical walls at right angles; most
traditional machining chores are based on this; it's also called
2.5d machining. Make sure the endmills you get are center-cutting, if
you plan to start in the middle of a piece of material instead of
moving in from an edge.
CNC makes it possible to also cut forms with compound curvature, by
moving in the X and/or Y directions while simultaneously varying the
height (Z). For this sort of contoured surface, you need a collection
of round-nosed endmills, also called ball-end cutters. They make
smooth surfaces with many parallel passes; the smaller the tool, the
closer together these have to be to minimize the "cusps" or tiny
waves in the surface. Depending on the detail in your part, you
choose the largest cutter that can get into it; using too small a
cutter just takes more time for the same result. So get a set of
ball-end cutters starting with 5/16" and going down to the smallest
you think you'll need. 2-flute, 3-flute, and 4-flute endmills are
all useful for various jobs and materials.
If you have extremely tiny details to get into, then you need a very
small cutter; this is where the 10,000 rpm max spindle speed of the
Taig can become a limitation, as the tool must spin fast enough to
get the material out of the way as it moves, or the tool will break.
Wax is fairly forgiving in this regard, as a tool's flutes can take a
much bigger chipload of wax than of metal, but when you're using
endmills at.015" diameter and smaller, there's not a lot of room for
error. It is possible to fit a high-speed spindle to the Taig, if
that's a major part of what you plan to do.
As well as flat and ball-nose endmills, there are other forms of
cutters that can be handy. Conical engraving cutters, which have half
the diameter removed, leaving the other half to act as a cutting
surface, are useful for fine linear detailing, and you can stone the
tips to soften the points, making something like a ball-nose, but
much less fragile. There are also variations which lie somewhere
between conical cutters and endmills; these can be useful in
situations where the detail is fine but an absolutely vertical wall
isn't important. Here are a few suppliers on the 'net:
I have read alot about keeping the endmills sharp. Does this apply
as much to wax? Do I need to get a sharpening setup?
One of the nice things about cutting wax is that it doesn't dull the
tools; at least I've never noticed it happening. Even when cutting
metal, it's a lot more common to break them than to dull them, at
least at first. And sharpening multiflute endmills isn't something
most people can do accurately; the tooling required is prohibitively
expensive. For the sizes we're talking about, it's not generally even
economical to send them out for resharpening; if you've managed to
wear one out, figure it has paid for itself.