Endmills are common tools that remove material from a substrate material.
Essentially this is a cutting process powered by high-speed rotation of a motor,
a.k.a. spindle, while lateral displacement of the endmill takes place following a
machine pathway, called G-code or M-code. As the substrate is immobilized on a
flat coordinate table a precise removal of material is achieved. Apassis defined by
the lateral movement of that table in XY-plane at constant Z-value. Stepper motors
control the movements along the axles (X-, Y-, and Z-axle), but the profile of the cut
depends on the tooling style (Fig.3.6b). Square tools result in channels with straight
vertical walls with no undercuts that makes them ideal for cutting reservoirs and
chambers. It is the most commonly used endmill style, which is the reason it serves
as reference for spindle speeds and feed rates. To achieve round bottom channels
and a ball style instrument is used.Bull noseis different from the square and the ball
style tools as it has round edges causing round-offs at the corners of the milled
structure. Together with the tapered style tools they are used to obtain slanted,
round-off edges that are often required for injection moulding or hot embossing.
Fig. 3.6 (a) CNC mills from several manufacturers are compared and categorized into price
ranges. Costs were assessed based on quotes of the lowest level mill from each manufacturer,
except for the Tormach mill, which was quoted to be comparable in terms of capabilities to the
other CNC mills. Unlisted specifications were not given by the manufacturer. (b) Endmills—the
most common cutting tool for milling—are available in many profiles, in a variety of materials,
and with a variety of coatings. Mills are also compatible with a variety of other cutting tools, some
of which are shown. (c) Endmills are defined by several characteristics, each of which contributes
to the endmill capabilities and feature quality. [©The Royal Society of Chemistry] [ 1 ]
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