Machining A Master Model
The making of Parts, Patterns, Tools and Molds usually
begins with obtaining or creating a model, a physical
representation of your final part.
This
model can be a carving, a sculpture, or more commonly in
today’s world, a machined master model. From very large,
expensive mills to desktop mills such as this Roland
MDX-650, machining parts has never been more accessible.
And with tremendous advances in software design and
machinable media, it has never been easier or more
accurate.
Choosing the material
Whether you plan to machine a positive part, or a negative
mold, from which to cast a positive part, choosing the
right machinable material is critical.
In many cases, it is impractical to machine your parts out
of your final product material, which is why Freeman offers
the widest variety of easily machinable materials,
from
RenShape modeling
and
tooling boards
to
machinable wax,
Perfect Plank specialty
lumber,
Medium Density
fiberboard,
Repro UltraLight
and more.
Each material has its own unique characteristics which will
affect how the models are machined, how long they will
last, and what you can do with the models once they are
machined. This, and other videos, and our website are
designed to help you choose the best materials for each
project.
Software
Most Computer-Aided Drawing, or CAD programs work
seamlessly with CNC machines to produce precise and
accurate models.
Simple
parts, such as this puzzle piece, can be programmed in
minutes. Primary considerations are choice of material,
cutter, spindle speed, and feed rate.
More complex parts require more careful considerations of
aspects such as tool paths, cutting intervals, and
finishing margins.
Some
Roland CNC machines
feature built-in scanning abilities, allowing you to
accurately input an existing part, model, or sculpture into
CAD software, which then can be machined into a different
material.
After a surfacing pass, most parts are best machined with
one or more roughing processes in order to remove a greater
amount of material in a shorter time. These passes often
use larger bit sizes and faster feed rates because the
final surface finish isn’t affected.
After the rouging passes, most parts are machined with one
or more finishing processes in order to produce a
dimensionally accurate model. These passes often use
smaller bit sizes and slower feed rates to produce a nice,
smooth finish.
Molding
Once our model is created, we can now recreate this model
for prototyping, testing, or short-run production using any
of a number of liquid tooling systems designed to simulate
the properties of many final-product materials, all without
the expense of injection molds or other costly tooling.