Handy milling tips

If you read milling tips on the Web or consult professional
literature, you often obtain information about using large
milling machines to machine materials. The Profiler is not
a large milling machine, and it must be used in a different
manner.

In the first place, you use smaller tools with the Profiler. Unless
you are working with very soft material, a 6-mm cutter
is already quite large. Given that you are working with
relatively small tools, it is often advisable to use a fairly high
feed rate (the rate of travel for milling) and restrict the cutting
depth. It is thus better to mill somewhat faster but not
too deep. If you follow the suggestions listed below, your
milling work will look a lot better.

How to mill: As we just mentioned, keep the cutting
depth fairly shallow – the quality degrades quickly with
increasing depth. Mill clockwise on inside curves and anticlockwise
on outside curves. This yields the best appearance
on the final product.

Which cutters: Cutters are available with one, two, three,
or four flutes. This refers to the number of cutting edges
around the circumference of the cutter. Each type has its
own properties. Single- and double-flute cutters are used
for most jobs with the Profiler. Triple- and quad-flute cutters
are primarily used for hard alloys, and the Profiler is not
suitable for these materials.

Single-flute cutters are primarily used with wood and plastics,
but nowadays they are also used with aluminium, due
to the use of stronger cutter materials. Single-flute cutters
enter the material better and have better chip removal than
double-flute cutters.

Double-flute cutters are the best choice for milling plastics
and non-ferrous metals. They produce a smoother finish
and wear less quickly. They are also often used for a final
polishing round.

Cooling: Cooling is almost always necessary [5]. The type
of cooling depends on the material to be machined. As it
is not possible to use liquid-stream cooling with the Profiler,
the following tips can be helpful.

Copper, bronze, brass and aluminium can be cooled quite
well with methylated spirits. Thin oil is also good for cooling
aluminium. You can use a small brush or plant sprayer to
apply the liquid. A couple of handy youngsters remodelled
a paintbrush and fitted it to the machine.

Spindle speed: With plastics, the result is strongly dependent
on the feed rate and spindle speed. A high spindle
speed can be used for milling metals, but this is often inadvisable
with plastics. With a high spindle speed, the plastic
melts and sticks to the tool, and everything gets stuck.

Although many people may not believe it, the feed rate is
often too low. A lot of heat is generated if the cutter moves
slowly through the material, and this causes problems. If
nothing else works, try cooling with compressed air.

Solid-core board (such as Trespa) can be milled very nicely,
but it causes a high rate of tool wear. Always enter the material
very slowly, because the highest rate of cutter wear
occurs during plunge cutting.

Always use single-flute cutters for milling polystyrene and
foams. Cooling is rarely a problem with the correct machining
speeds. If cooling is necessary, you can only use air.

Securing the tool and workpiece: Always insert the
tool as far as possible into the holder. Tools that extend a
long way create troublesome vibrations. The work table
must be flat and stable. The T-slot table (optional accessory)
is very suitable for this purpose. The workpiece must
be held firmly so no vibrations can occur and it cannot slip
(which is much worse). Use clamps to secure the workpiece
firmly in place. Spray-on glue and double-sided tape are
good options for thin or light materials.