Envisiontec Perfactory System is unlike any other Rapid Prototyping
system in that it builds the model upside-down. The model leaves
the resin tank, instead of submerging into it. As it builds
in 0.015-0.025mm layers, this technique leaves hardly any evidence of
layer construction and thus, virtually eliminates hand-removal
of obstructive materials (a major issue on very small and complex
models). Consequently, the result is a resin model with a high
degree of accuracy that requires practically no post finishing.
An .stl file drives the system, and the light sensitive Acrylic
resin solidifies when it is exposed to the light source. Instead
of using laser lighting to cure a resin, our Rapid Prototyping
technique uses a standard light bulb augmented with an array
of one million tiny mirrors (1280 x 1024 pixel), which are
housed in the high resolution digital light processor and
independently controlled by a computer. The mirrors can be
positioned to reflect the light projected by the bulb onto
the build platform by tilting the mirrors toward the light
source to project it where it is needed to cure the resin.
By tilting the mirrors away from the light, we are able to
block the light and generate a bitmap mask image of an individual
.stl layer. This results in one layer being cured in one operation,
rather than a single layer busily tracing around every aspect
of the geometry.
The Build Platform
The build platform consists of two pieces of ground glass.
The first layer of the model attaches to the upper piece,
which is fixed to the Z-height control. The other side of
the model is fixed to the lower plate of glass, which constitutes
the resin holding tray and helps regulate the thickness when
the two plates of glass come together.
By squeezing out the excess resin, the desired layer thickness
becomes trapped between them. When the light source is activated,
the first model layer bonds to the upper glass plate, while
the other side of the model layer is fixed to the lower glass
plate. The vacuum diffuser module initiates separation of
the lower glass tray from the cured layer through a sophisticated
tilting mechanism that peels the glass from the model. As
the plates open, they let more resin in between. The process
is then repeated layer by layer. The unique up-side-down technique
means the model leaves the resin as it is being built rather
than submerging into it.
Upside-down build technique
The Envisiontec Perfactory System.
Highly detailed ring patterns in finished
13 parts built in PIC100 resin