Very few additive rapid
manufacturing materials are approved by the FDA, so food processing and
biomedical applications are limited. As a result, subtractive rapid
manufacturing is often a more effective and lucrative option.
Every
human body part is unique, requiring that a range of biomedical parts
be custom designed for each person. Thanks to improved CAD/CAM
technologies, this has created a growing demand for everything from
personalized hearing aids and orthodontics to prosthetics and
pre-surgical models.
Every one of these reverse
engineered products requires some type of rapid manufacturing to
produce it. It’s a beautiful thing that both additive and subtractive
rapid manufacturing processes begin with an STL file – the same format
that comes from the initial scanning process!
The popular STL format is
also the best way to create 3D models of the human body, as it yields
complex, organic surfaces. More than any other format, these models are
best displayed, manipulated and saved as triangular faceted surfaces.
As a result, reverse engineering and rapid manufacturing can work
together seamlessly.
The Chamberlain Group, for
example, creates anatomically accurate human hearts used by surgeons to
practice new procedures. They use a desktop 3D laser scanner to
capture all the detail of a lifelike model, and export it as an STL
file. A 3D printer then produces a perfect model for silicone casting.
Reverse engineering and
rapid manufacturing also work in concert to dramatically improve the
process of making medical prostheses. Rather than spend tedious hours
hand sculpting, anaplastologists use a 3D laser scanner and desktop
mill to quickly produce prosthetic parts with improved accuracy and
realism.
The prosthetic parts are
valued for possessing lifelike details, including every wrinkle and
pore in the skin. The subtractive rapid manufacturing process
also offers faster production, saving the anaplastologist important
clinical energy
for the patient.
While technology is opening up many possibilities for engineers, it’s important to
consider functional testing when creating a part. If a model does not have the same
material properties as the final part, it is worthless for functional testing.
Rather than build a part
layer by layer, the subtractive process starts with a homogeneous block
of plastic and mills away unwanted material to reveal the
desired part. Subtractive materials include popular engineered plastics
such as ABS, Delrin, and nylon – the same materials used in the actual
manufactured products. The parts make accurate testing possible for a
range of physical tests and meet many FDA and other government
regulations.
Subtractive rapid
manufacturing produces parts with structural, thermal, and electrical
physical properties that are identical to their final production parts.
They also have tight dimensional accuracies and smooth surfaces. Fit
and assembly models successfully simulate snap fits, fluid-tight seals,
and thermal and electrical conductivity between parts.
This kind of accuracy is
vital, whether it’s for a prosthetic knee that needs to meet strict
medical requirements or slick new cell phone casing. The future is
bright and loaded with profitable opportunities. The key to making the
most of it is using the right combination of reverse engineering and
rapid manufacturing technologies.
MPF
Source: :: Make Parts Fast ::
