Concept modellers

•Concept modellers, often called
office modellers, are a class of
rapid prototyping (RP) system
designed specifically to make
models quickly and inexpensively,
without a great deal of effort

•The systems are usually small,
inexpensive, quiet, and require
very little or no training to
operate.
•For these reasons, the systems are
targeted to reside in design office
environments, where they can
ideally be operated much like a
standard printer, only the prints
from these systems are in three
dimensions

Ink Jet Printing
•Ink jet printing comes from the printer
and plotter industry where the
technique involves shooting tiny
droplets of ink on paper to produce
graphic images.
•RP ink jet techniques utilize ink jet
technology to shoot droplets of liquid-
to-solid compound and form a layer of
an RP model.

•The additive fabrication technique of
inkjet printing is based on the 2D
printer technique of using a jet to
deposit tiny drops of ink onto paper.
•In the additive process, the ink is
replaced with thermoplastic and wax
materials, which are held in a melted
state.

•When printed, liquid drops of these
materials instantly cool and solidify to
form a layer of the part.
•For this reason, the process if often
referred to as thermal phase change
inkjet printing
•Inkjet printing offers the advantages of
excellent accuracy and surface finishes.

•However, the limitations include slow
build speeds, few material options,
and fragile parts.
•As a result, the most common
application of inkjet printing is
prototypes used for form and fit
testing
•Other applications include jewellery,
medical devices, and high-precisions
products

•Several manufactures have developed
different inkjet printing devices that
use the basic technique described
above.
•Inkjet printers from Solidscape Inc.,
such as the ModelMaker (MM), use a
single jet for the build material and
another jet for support material.
•3D Systems has implemented their
MultiJet Modelling (MJM) technology
into their ThermoJet Modeller
machines that utilize several hundred
nozzles to enable faster build times

Types of printing techniques
Common ink jet printing
techniques, such as
a) Sanders Model Maker
b) Multi-Jet Modelling
c) Z402 Ink Jet System
d) Three-Dimensional Printing
e) Genisys Xs printer
f) Object Quadra systems

•The Sanders Model Maker (MM)
series captures the essence of the
ink-jet printing technology, and
builds in a layer-by-layer fashion,
similar to other rapid prototyping
(RP) systems

•The MM uses several different types of
data file formats but has only one base
type for the build and support
materials, wax.
•The MM was developed by Sanders
Prototype, Inc. (SPI), a subsidiary of
Sanders Design in Wilton, NH, in the
early 1990s with the intention of
revolutionizing the industry as it
pertains to accuracy and precision

•The MM system has evolved
through three "models," Model
•Maker (original model), Model
Maker II (MMII, second
generation), and recently Rapid
Tool Maker (RTM)

•The original modeller has a build
envelope of 7" x 7" and the MMII has
an envelope size of 13" x 7", whereas
the RTM has a 12" x 12" working
area.
•While both MMs are desktop models,
the RTM is a self contained unit with
an on-board computer

Software for MM
•Both modellers utilize MW
(MW) software, manufactured
by SPI, to prepare and
manipulate the incoming file
for use in the MM machine

•The software can be operated through
a variety of workstations, from UNIX
to PC , and the current modeller has
an on-board computer that can
function alone after it receives the
prepared file from a "dummy" PC
whose sole purpose is for file slicing
and preparation

Build materials
•Both models use a build and support
material to produce a 3-D model.
•These materials are wax based with
the support having a lower melting
point than the build
•So, the Postprocessing becomes
easier.
•The support material can be removed
easily

• The print-head assembly consist of the print-head,
print-head cap, purge spout,
purge spout cap,
cable, and saddle

•There are two print-heads, one for
building the part and the other for
generating the necessary support
•The jets sit on a carriage that enables
them to move in the X and Y direction
(left to right), while the stage moves in
the Z direction (up and down)

Model maker operation
1.CAD file preparation
2.Slicing
3.Sending the data to the
model maker
4.Building a part
5.Post processing

Advantages and disadvantages
•The power of the MM family of systems
lies primarily with the production of
small, intricately detailed wax patterns
•The jewellery and medical industries have
capitalized on this advantage due to their
needs for highly accurate, small parts
•Perhaps the most apparent drawback of
these systems are the slow build speed
when it comes to fabricating parts larger
than a 3- inch working cube

•The ThermoJet and the Actua 2100, both
made by 3D Systems in Valencia, CA, fall
into the growing area of the rapid
prototyping (RP) market known as
concept modelling.
•Both systems apply the Multi Jet
Modelling (MJM) build style to produce
wax prototypes with an array of ink jets.
•The systems are one of the least
expensive in the line of RP technologies

•The MJM process builds parts by
printing thin consecutive layers of the
molten wax in the shape of the part cross
sections.
•Like most RP systems, the parts are built
onto a movable z stage, which lowers as
the part is "printed."
•Currently, the Actua 2100 system prints
with a layer thickness of 0.0039 inches, or
three passes of 0.0013 inches, whereas
the ThermoJet system prints multiple
passes of thinner layers for higher
resolution

•Three-dimensional printing, or 3DP, is
an MIT-licensed process
•Liquid binder is jetted onto a powder
media using ink jets to "print" a
physical part from computer aided
design (CAD) data

•Z Corporation (Z Corp) incorporates
the 3DP process into the Z402 system.
•The Z402 is the fastest modeller on the
market, with speeds 5 to 10 times
faster than other current rapid
prototyping (RP) systems
•The process is similar to SLS
•Instead of laser, we use a liquid
adhesive to bind the powder
•Surface finish is not as good as SLS
but it is faster than SLS

•The Z402 is currently available in only
one size, which can build models up to
8" x 11" x 8".
•Parts built with the starch material can
be hardened to fit the application
necessary.
•These parts can be hardened by wax
infiltration

i. Build and feed pistons
ii. Binder feed system
iii.Printing head
iv.Powder roller

Build and feed pistons:
•These pistons provide the build
area and supply material for
constructing parts.
•The build piston lowers as part
layers are printed, while the feed
piston raises to provide a layer-by-
layer supply of new material.
•This provides the z motion of the
part build

Binder feed system:
•The liquid binder is fed from
the container to the printer
head by siphon technique, and
excess pulled through the
printer cleaning station is
drained into a separate
container

•The parts are built in layer-by-layer
fashion
•First, blank layers of powder are
spread as a starting point for
building upon.
•This is called “landscaping”.
•This landscaping is done manually
•The remaining steps are carried out
after this landscaping automatically.

Powder removal-After the parts are
taken from the machine, the excess
powder must be removed. It is done
manually by using vacuum cleaner
Heat for infiltration- The part is
placed in a small oven and heated to a
temperature just above that of the
infiltrant wax, to provide a wicking
characteristic as opposed to coating
Infiltration- Immediately after the
part is heated, it is dipped for a few
seconds into a vat of molten wax, then
removed and placed on a sheet to dry.
After drying the part is complete

Uses
•Used as concept-verification models
in a design environment.
•The nontoxic materials allow for the
models to be safely handled in
meetings or the office, directly after
fabrication.
•Parts can be used for investment or
sandcast patterns.

Human face models made through 3D printing

Genisys Xs HP Printer
•The Genisys (and Genisys Xs) system,
produced by Stratasys, Inc. is an office-
friendly modelling system that builds
parts with a durable polyester material
•The current line of Genisys systems are
small, compact table-top rapid
prototyping (RP) machines that deliver
single- material capability, and
interoffice network queues for
operation much like a printer.

Software:
•The software of the Genisys systems,
which is compatible on both Unix and NT
platforms, is designed for ease of
operation
•Parts can be set to be scaled
automatically as well, although there is a
manual scaling feature.
•Multiple parts may be nested in the -x, -y
plane, again with single-click operability

Build Material:
•The current build material is quoted
as a "durable polyester".
•Since the systems have only one
extrusion tip, the support structures
are built of the same material,
requiring mechanical removal upon
completion of the part

Hardware
•The Genisys has a maximum build
capacity of 12" X 8" x 8", whereas the
entire system occupies a space of only 36"
x 32" x 29".
•The unit weighs in at about 210 pounds
and can operate on standard house
current of 110 to 120 Volts AC.
•The polyester material comes stock in
the form of wafers, which are loaded into
a bank of cartridges within the machine.

•One wafer is loaded into the deposition
head, where it is melted and deposited in
thin layers through a single extrusion tip
while tracing the cross section of the part
being built.
•Once the wafer in the head is spent, it is
replaced by another automatically and
the build resumes.
•The build chamber is operated at
ambient temperature, and fabricated
parts can maintain dimensional accuracy
in the range of +0.013 inches

Concept modellers

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Concept modellers