Transcript RP Unit 6

UNIT -6
Rapid Tooling
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Copper polyamide
 Copper polyamide is a new metal plastic
composite designed for short run tooling
applications (100 to 400 parts) from
common plastics.
 Tooling inserts are produced directly in
the SLS machine with a layer thickness
of 75 µm.
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 Subsequent finishing is necessary before
their integration in the tool base.
 No furnace cycle is required and
unfinished tool insert can be produced in a
day.
 During the CAD stage, Copper polyamide
inserts a shelled and cooling lines, ejector
pin guides, gates and runners are included
in the design and built directly during the
SLS process.
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 Then the insert surface are sealed with
epoxy and finished with sand paper
and finally the shell inserts are packed
up with a metal alloy.
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Advantages
 Inserts produced from copper polyamide
are easy to machine and finish.
 Heat
resistant
and
thermal
conductivity are better in most plastic
tooling materials.
 The cycle times of moulds employing
copper polyamide inserts are similar to
those of metal tooling.
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Direct Metal Laser
Sintering
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Working principle:
 Direct Metal Laser Sintering is an
additive manufacturing process that uses
a laser beam to fabricate metal parts by
sintering of metal powders smeared on a
substrate with recoater system.
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Salient features of Direct Metal
Laser Sintering Machine:
Make and model:
 EOSINT M250 x-tended rapid prototyping
machine made in Germany.
 Laser used is carbon dioxide which is
240 watts.
 Build size is 250x250x150 mm3.
 Metal Powder is steel , Bronze, Nickel,
titanium.
 Surface roughness: 10 microns.
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Dimensional Accuracy : -+ 100 microns.
Hardness is 40-45 HRC.
Porosity less than 0.5%.
Tooling for plastic moulds: Tool life upto
10 lakh parts.
Tooling for die casting: tool life upto
5000 parts.
Layer Thickness is 0.1 mm.
Laser Beam diameter is 0.4 mm.
Layer thickness 20-40 microns.
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Post Processing:
 Short peening and polishing to improve
surface finish.
 Infiltration with high temperature epoxy
resin to reduce porosity.
 Conventional
machining,
threading,
milling etc.
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DMLS APPLICATIONS
Metal Parts
 Functional
Testing
 Form and Fit
Dies and Moulds
New Materials
 Plastic Moulding  Metal Matrix
 Die Casting
 Alloys
 Investment
Casting
 Rubber Moulding
 Metal Stamping
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LENS (Laser Engineering Net
Shaping) OR DMD
 LENS is an additive manufacturing
process that uses the high power laser
to fabricate fully dense parts by melting
metal powders feed through the nozzles.
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 The LENS process is unique since it
goes from raw materials directly to
metal parts without any secondary
operations.
 It can produce parts in a wide range of
alloys, including titanium, stainless steel,
aluminum, Inconel.
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 The LENS uses 4 nozzles to make 3
dimensional, high density, parts and
molds from the inside out.
 The nozzles direct a stream of metal
powder in argon gas at a movable central
point while a high-powered laser beam
heats the point.
 Throughout the process, the substrate
continuously moves, guided by data
derived from a thin layer of a CAD solid
model.
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 Layer by layer the nozzles and laser
worked together to gradually build up the
model.
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Features:
 Make and Model: DMD 1050 5 axis rapid
prototyping machine POM Incorporations
USA.
 Laser type is diode with power of 1000W
 Build Size is 300x200x300 mm3.
 Metal Powder Stainless Steel, titanium
,cermets ,ion, super alloys.
 5 axis metal deposition capability.
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 DMD cam software for 5 axis deposition
power generation.
 Closed loop feedback system to monitor
the layer thickness.
 DMD vision system for image capturing
and automatic NC tool path generation.
 Integrated DMD data base technology for
process parameters.
 Pyrometer for melt cool temperature
measurement.
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Advantages
 Good grain structure.
 Good
metallurgical
properties
reasonable speeds.
 Fully dense Parts are obtained.
at
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 DMD APPLICATIONS
 Conformal cooling
 Die Casting
 Plastic Injection Moulds
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 Hard Facing /Coating
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Oil Industries
Wood Industries
Stamping
Trimming
Forging
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 Remanufacturing
 Turbine Components
 Large Components with large lead time
 Expensive Components
 Special Applications
 Lattice Structures
 Valve Seat Cladding
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PROMETAL SYSTEMS
 Prometal systems are directed towards
building injection tools and dies as the
powder used is steel based which is
durable enough to withstand high
pressure and temperature. The model
is built from bottom to top with layers
printed in the shape of crossection of
parts.
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 The resulting green model is then
sintered and infiltrated with bronze to
give the part dexterity and full density.
The pro metal systems is one of the few
rapid prototyping techniques to have
metal material capability of 3D printing
process incorporated in the pro metal
system.
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 Prometal system hardware:
 Build and feed piston
 These pistons provide 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 materials. This
provides z-motion of the part build.
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Print Gantry
 The printed gantry provide x,y motion of
part building process. It houses print
head wiper for powder landscaping and
the layer drying unit.
Powder overflow system
 The powder overflow system is an
opening opposite the feed piston where
excess powder scrap across the build
piston is collected.
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Software:
 The prometal starts with standard STL
file format, which is imported in to the
prometal software where it is sliced and
placed in an orientation with the shortest
z-height. This has fastest build capability
like other rapid prototyping system in x-y
direction. The part can be manually
reoriented if necessary.
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Machine Preparation for
build:
 Check powder at the feed piston.
 Check whether wiper blade has
landscape build area.
 Check binder fill and take up.
 Excess powder should be vacuumed
away around the builder gantry.
 Lubricate parts of the system regularly.
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 Build Technique:
 The prometal builds parts in layer by
layer fashion. The following is the general
description of part build process.
 The bottom crossection of the part is
printed on the 1st layer of the powder The
jets prints in y direction as gantry moves
in the printer head width increments in x
direction.
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 When layer is printed the gantry remains
in the left side of the table while the build
area piston lowers the slice thickness
amount.
 The feed piston raises by small amount
and the gantry sweeps across part bed
and over flow, spreading across a new
layer of powder ,with excess powder
been captured in overflow.
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 The next layer is printed and the process
is repeated until it reaches the top layer
of part.
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Post Processing:
 The following are the post processing
steps for the part to be infiltrated with
bronze, the typical infiltration method.
Powder Removal:
 Excess powder must be removed by
brushing, vacuuming.
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Thermal cycle 1: Sintering
 Once powder is removed from the part it
is placed in the owen and heated to a
temperature high enough to burn off the
polymeric binder.
Thermal Cycle 2: Infiltration
 The part is cycled in a furnace again only
this time, bronze is melted and wicked
into steel skeleton until a fully dense part
is created with 60% steel and 40%
bronze.
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Finishing:
 Depending on the application of the
component finishing can be done with
conventional machining, polishing and
sanding technique to the desired quality.
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Uses of Prometal:
 Used in manufacturing environment.
 Moulds are used in conventional injection
moulding process as they are steel
based materials.
 Parts are used in injection moulding
extrusion dies, direct metal parts blow
moulding patterns.
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Advantages:
 Capacity to fabricate direct metal parts
from the CAD data.
Disadvantage:
 Post processing is required.
 Product time is long.
 Chances of part deformation during
thermal cycle.
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 Direct Metal:- The capability of a RP
system to fabricate components with
metallic based materials
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 Green Form:- A soft unfinished
component that requires additional heat
treatment in order to achieve full strength
and density
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