The rapid prototyping process - coesum.it · Rapid prototyping processes There are numerous rapid...
Transcript of The rapid prototyping process - coesum.it · Rapid prototyping processes There are numerous rapid...
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The rapid prototyping
process
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Index
Rapid prototyping processes
Three-dimensional printing (3DP)
Three-dimensional printing (3DP): Pros and Cons
Selective laser sintering (SLS)
Selective laser sintering (SLS): pros and cons
Stereolithography (SLA)
Stereolithography (SLA): Pros and Cons
Fused deposition modeling (FDM)
Fused deposition modeling (FDM): Pros and Cons
Computerized Numerical Control Processing (CNC)
Computerized Numerical Control (CNC) Processing: Pros and Cons
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Rapid prototyping processes
There are numerous rapid prototyping processes, here is a summary table:
Process Description Resistance Finish
Three-dimensional printing (3DP) UV photopolymer jet printing
Low Additive layers in general of 0.089 - 0.203 (mm)
Selective laser sintering (SLS) Laser sintering of powders 5,300 - 11,300 (psi) 36.5 -77.9 (mpa)
Additive layers in general of 0.102 (mm)
Stereolithography (SLA) Laser light photopolymerization
2,500 - 10,000 (psi) 17.2 -68.9 (mpa)
Additive layers typically 0.051 - 0.152 (mm)
Fused deposition modeling (FDM) Cast extrusions 5,200 - 9,800 (psi) 35.9 -67.6 (mpa)
Additive layers typically 0.127 - 0.330 (mm)
Computerized Numerical Control Processing (CNC)
Milling using CNC milling machines
3,000 - 20,000 (psi) 20.7 -137.9 (mpa)
Surface milled with subtractive technique (smooth)
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Three-dimensional printing (3DP)
It works like a jet printer. The
heads move on a bed of dust
releasing micro drops of liquid
that will allow the solidification
of the powder only in the
selected areas. The process is
repeated layer by layer until the
piece to be produced is
completed. At the end of the
cycle the piece is extracted from
the process chamber and the
powder is removed.
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Three-dimensional printing (3DP): Pros and cons
PROS
Faster and more economical
additive process for prototyping.
Colored models can provide more
information and have a more
pleasant appearance.
The material is non-toxic plaster,
inexpensive and easily available.
The process is able to produce
parts with complex geometries.
CONS
The choice of materials is
not very wide.
The pieces are rough and
not very resistant.
It is useful for producing
pieces with complex
geometries, but does not
provide information on the
final feasibility of the
project.
The construction layers are visible to the naked eye.
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Selective laser sintering (SLS)
It is based on the use of the laser, which
sinterizes the powdered material layer by
layer, from the bottom to the top. The
pieces made with selective laser sintering
can be precise and have a longer life
compared to the pieces made with
stereolithography, but the finish is fairly
coarse, grainy and sandy to the touch. A
reduced resistance is created between the
melted particles, so the pieces are more
delicate and compared to those
machined with CNC machines or injection
molded using the same type of material.
Furthermore, the number of available
powder materials is limited.
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Selective laser sintering (SLS): Pros and cons
PROS
The pieces are precise
and show a longer life
compared to those made
with stereolithography.
The process makes it
possible to produce
pieces with complex
geometries.
CONS
The surface of the pieces is granular
/ sandy and usually not indicated for
functional testing due to reduced
mechanical properties.
Useful for producing pieces with
complex geometries, but does not
provide information on the final
feasibility of the project.
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Stereolithography (SLA)
Additive production process; the
piece is made inside a tank
containing a resin sensitive to UV
radiation. With a computerized laser
the product is cured by building it
section by section on the surface of
the liquid resin. The process is
repeated until completion of the
particular, making adhere each new
polymerized layer to the underlying
layer. Stereolithography was the first
"rapid prototyping" technique.
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Stereolithography (SLA): Pros and cons
PROS
For conceptual models or models to
be used as matrices for other
prototyping methods, such as casting
from a silicone mold and capable of
producing pieces with complex
geometries and excellent surface
finishes compared to other additive
processes.
The costs are very competitive and the
the technology is available from
numerous suppliers.
CONS
Prototypes are much more delicate than those
made with industrial resins, so they are not
suitable for performing functional tests.
Moreover, since the resin polymerizes with UV
light, exposure to sunlight causes the resin
polymerization process to continue and with
passage of time the pieces become more
fragile.
Useful for producing pieces with complex
geometries, but can not provide information on
the final feasibility of the project.
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Fused deposition modeling (FDM)
Make the pieces from the bottom up
using a computerized print head. The raw
material of the process is an extruded
resin filament, which the machine
selectively re-creates and deposits on the
previous layer for each section of the
desired piece. The FDM process produces
parts in ABS or PC, which are therefore
more resistant than parts made with other
additive processes. However, it is possible
to obtain porous pieces, with evident
effects of scaling or ginning on the outer
surface, in particular at the junctions
between the layers. Furthermore, with this
process it can be difficult to achieve close
tolerances.
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Fused deposition modeling (FDM): Pros and cons
PROS
The pieces are strong
enough and suitable for
some types of functional
testing.
The process is capable of
producing pieces with
complex geometries.
CONS
The surface finish of the piece is poor,
with a pronounced ginning effect.
Compared to SLA and SLS, it has longer
lead times.
It is useful for producing pieces with
complex geometries, but does not provide
information on the final feasibility of the
project.
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Computerized Numerical Control Processing (CNC)
This method consists in fixing a block of
plastic or metal material on the CNC milling
machine, where it is processed in order to
obtain the final piece. The strength and
surface finish obtained are superior to those
of any additive process. There are also all the
homogeneous properties of the plastic
because the pieces are made of solid resin
blocks made specifically for this kind of
processing. The wide choice of materials
allows the pieces to be made with all the
properties of the chosen material.
Good tolerances make the parts suitable for
functional and assembly tests. The prototypes
can be delivered to the customer in a few
days, as for the additive processes. The
process removes the material rather than
adding it, so it can sometimes be difficult to
mill undercuts. Furthermore, milling tends to
be more expensive than additive processes.
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Computerized Numerical Control (CNC) Processing: Pros and cons
PROS
Full mechanical strength of
the pieces as they use real
technical polymers and
metals.
CONS
There may be geometric limitations
with respect to additive processes,
moreover it typically involves higher
costs, associated with the greater
resources necessary to produce them.
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For a FREE consultation on your project, write to our engineering team at
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Answer within 24 hours
Within 24 hours of your request you will receive our quote for the production of rapid prototypes. Our technical
consultant will help you to give you an overview of available technologies and choose the solution closest to your needs.
The best prototyping technologies to achieve what you need while respecting your aesthetic, functionality, mechanical strength and much more.
FREE feasibility study included in the estimate
Our consultant will always carry out a prior analysis of the shared project to optimize the design according to the
production process. This will save you time, choose the technology that best suits your need and get the right
answers from the tests you will make on the prototype.
Conformity checks BEFORE shipment
Before proceeding with the shipment of your
order, our employee will check the details to
verify the geometry and the tolerance of the tolerances in accordance with what has been
announced in the estimation.
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