3D Systems DuraForm TPU Elastomer User manual

DuraForm® TPU Elastomer
Material Guide
Original Instuctions
3D SYSTEMS, INC. 75-D059 REV_A

3D SYSTEMS, INC. 75-D059 REV_AI
CONTENTS
1PRINTING PARTS WITH DURAFORM® TPU ELASTOMER MATERIAL ..................................1
SAFETY NOTICE: MATERIALS ............................................................................1
How the DuraForm TPU Elastomer process works. ........................................................1
Warm-Up Stage .........................................................................................2
Print Stage .............................................................................................2
Potential Print Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Interaction of Variables.................................................................................3
As the Print Continues .................................................................................3
Cool-down Stage ........................................................................................3
Condensation in the Process ............................................................................3
PRINT MODE FOR DuraForm TPU Elastomer ................................................................4
Setpoints .............................................................................................4
PRELIMINARY PRINTS AND PART PRINTS .................................................................4
Offline IR Calibration.....................................................................................4
Scale and Offset Print ....................................................................................4
Calculating Scale/Offset Values................................................................................ 4
SETTING UP A PRINT ...................................................................................4
Build Setup Tips .........................................................................................4
Orienting STL Files.......................................................................................5
Fine Feature Definition .................................................................................5
Laser Beam Offsets ....................................................................................5
Feature Strength ......................................................................................5
Surface Finish .........................................................................................5
PART PLACEMENT AND ORIENTATION GUIDELINES........................................................6
Cylinders ...............................................................................................6
Triangles ...............................................................................................6
Cross-sections ..........................................................................................6
Duplicating .............................................................................................7
Features and Stair-stepping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Closed Boxes, Cylinders, andShapes .......................................................................7
Nesting ................................................................................................7
Mating Surfaces.........................................................................................7
BEFORE EVERY PRINT .................................................................................7
RESTARTING A TERMINATED PRINT......................................................................8
BUILD REMOVAL ......................................................................................8
SIFTING MATERIAL ....................................................................................8
RECYCLING MATERIAL .................................................................................9
BLENDING FRESH AND USED MATERIAL ....................................................................9
CLEANING UP THE SLS SYSTEM ..........................................................................9
2CLEANING PRINTED PARTS ......................................................................10
TOOLS AND CLEANING MEDIA .........................................................................10
CLEANING PROCEDURES ..............................................................................10

3D SYSTEMS, INC. 75-D059 REV_AII
3PROPERTIES AND HANDLING ....................................................................11
SAFETY DATA SHEET ...................................................................................11
MATERIALHANDLING.................................................................................11
MATERIAL STORAGe AND DISPOSAL ....................................................................11
General Storage Information ............................................................................11
Storing DuraForm TPU Elastomer ........................................................................11
Material Disposal.......................................................................................11
4SOLVING PROBLEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
INTRODUCTION TO PROBLEM SOLVING .................................................................... 12
Reasons to observe a print: ............................................................................12
Problem Description Format .............................................................................12
BONUS Z ...........................................................................................13
CLUMPING ..........................................................................................13
CRACKING OF PRINT BED..............................................................................14
CRYSTALS AND CONDENSATION ........................................................................14
CURLING DURING PRINT ..............................................................................14
CURLING, POST-PRINT ................................................................................15
GLAZING, DURING PRINT .............................................................................16
GROWTH ............................................................................................16
MELTING, PRINT BED .................................................................................17
MISSED SCAN ........................................................................................17
ORANGE PEEL........................................................................................18
POWDER FLUFF ......................................................................................18
RIPPLES, FEED BED ...................................................................................18
SHORT FEEDS ........................................................................................19
STRAY VECTORS ......................................................................................19
WASH OUT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5APPENDIX A - LEGAL NOTICES ...................................................................21
COPYRIGHT AND CORPORATE IDENTITY ................................................................21
LIMITATIONS OF WARRANTY AND LIABILITY .............................................................21
TRADEMARKS AND REGISTERED TRADEMARKS ...........................................................21

3D SYSTEMS, INC. 75-D059 REV_A1
1PRINTING PARTS WITH DURAFORM® TPU ELASTOMER MATERIAL
DuraForm TPU Elastomer is an engineered production thermoplastic elastomer for use in 3D Systems’ sPro™ 60 SLS system. This
material can produce durable, rubber-like functional and end-use parts that require no additional post-processing. It offers
similar benets as DuraForm Flex, but operates at a lower temperature. This guide describes how to use your sPro 60 SLS system
to print parts using 3D Systems’ proprietary DuraForm® TPU Elastomer material . This chapter describes the printing process and
includes the following topics:
• Safety Notice: Materials
• How the DuraForm TPU Elastomer Process Works
• Build Modes for DuraForm TPU Elastomer
• Preliminary Prints and Part Prints
• Setting Up a Print
• Part Placement and Orientation Guidelines
• Before Every Print
• Restarting a Terminated Print
• Sifting Material
• Recycling Material
• Cleaning Up the SLS System
SAFETY NOTICE: MATERIALS
DuraForm TPU Elastomer has been designed for and tested in 3D Systems’ sPro 60 SLS system .
Caution: Using any material other than those certied by 3D Systems may cause health hazards and may limit
the warranty of the SLS system.
HOW THE DURAFORM TPU ELASTOMER PROCESS WORKS.
The DuraForm TPU Elastomer material process has the following characteristics:
• The material is heated to slightly below its melting point.
NOTE: The temperature setpoints may vary slightly from machine to machine due to differences in material
conditions and sensors.
• The material is processed in an inert atmosphere (5.5% oxygen maximum).
• The material’s melt transition allows it to be transformed from a solid to a low-viscosity liquid using a small amount of
laser energy.
• The material requires the use of a textured roller and wipers to ensure powder tumbling across the bed. Contact 3D
Systems customer support for more information on a textured roller.
• Printing with the material consists of 3 stages:
• Warm-Up Stage
• Print Stage
• Cool-down Stage
WARNING! The operator must use an approved vacuum cleaner to clean up excess material . 3D Systems
recommends an ESD or explosion-proof model.Contact 3D Systems Customer Service for purchasing options .

3D SYSTEMS, INC. 75-D059 REV_A2
Warm-Up Stage
Front cut-view of print chamber during the warm-up stage
• The warm-up stage stabilizes the temperature in the process chamber, print bed, and the two feeds.
• This stage lasts approximately 45 minutes. The print bed piston indexes down in small increments (typically 0.125 mm
[0.005 inches]) while the roller delivers material.
• During this stage, the system gradually increases the print bed temperature to the necessary point (i.e. below the
material’s melting point).
Print Stage
• The print stage maintains the print bed and feed bed temperatures.
• Laser energy is used to melt the material in each successive cross-section of the print.
NOTE: Laser power settings vary depending on the desired print output.
Front cut-view of print chamber during the print stage
Potential Print Problems
• Excessive laser energy will affect material outside the cross-section of the part and cause growth.
• Insucient laser energy does not fuse the parts completely, which results in porous, weak parts.
• If the print bed temperature is too low, the parts will curl as the laser scans them.
• If the print bed temperature is too high, the parts will be dicult to remove from the surrounding material.
• If feed temperatures are too low, the parts will be cooled too quickly when the material is rolled across the bed and the
parts will curl.
• If feed temperatures are too high, the part bed can end up with a rough texture after adding a layer of powder.

3D SYSTEMS, INC. 75-D059 REV_A3
Interaction of Variables
Many of the print problems described involve variables that interact with each other.For example, excessive print bed heat or
excessive laser power can cause growth.
As the Print Continues
• The print bed piston indexes down, the parts are covered and begin to slowly cool.
• The mass and geometry of the parts inuence the cooling rate. If the cooling rate is too high, the parts can develop post-
print curl or warp. If the cooling rate is too low, growth can occur.
• A part’s position in the print also inuences the cooling rate. The rst parts printed have the highest cooling rate. First-
order phase changes, such as solidication, occur isothermally; the top of these parts will not cool until the entire part has
solidied. This slows the cooling rate of parts subsequently built.
NOTE: A piston heater heats the bottom of the print bed piston and helps slow the cooling rate. The part
piston cylinder heater heats the print bed walls and is also used to slow the cooling rate and create a constant
temperature across the print bed.
After the initial nitrogen purge, there is make-up nitrogen gas owing at a constant rate through the print chamber during the
print process as well as across the laser window and the IR sensor heads.
Cool-down Stage
• The cool-down stage allows the material, parts, and SLS system to cool enough to safely remove the print cake from the
print chamber.
• Nitrogen is required for this process and the inert level in the chamber needs to be maintained.
• The length of this stage depends on the size of the print. A larger print will take longer to cool down.
• When this stage ends the material and the SLS system are still hot.
• Printed parts will be easier to break out when the part cake is still warm and when the surface of the print cake is at or above
50°C. Please refer to the Customer Information Bulletin (Tips & Info) document for more detailed information. You may contact
your 3D Systems representative for help with maintaining the print cake surface temperature at 50°C.
• Removing the parts from the print cake too soon can cause the parts to warp and/or discolor.
• Some part geometries are more susceptible to post-print warp than others.
Condensation in the Process
The DuraForm TPU Elastomer contains a small amount of volatile material that vaporizes during processing.This material
condenses on cool surfaces in the SLS system print chamber.
See “Crystals and Condensation” on page 14 for information on resolving problems with condensation.
• Heating the nitrogen gas ow across the laser window prevents the condensing material from depositing on the laser
window.
NOTE: It is normal to see some slight condensation (or lm) on the laser window after a print. However,
excessive condensation on the laser window can block laser power which can cause weak or porous parts.
• Heating the IR sensor core and owing nitrogen gas across the IR sensor head helps prevent condensation from forming
on the IR sensor lenses. Excessive condensation on the lenses will cause inaccurate readings of temperatures, leading to
hard or melted material in the print bed. The IR sensor should be inspected before each build and cleaned if necessary.
The laser window should be cleaned before each build.
See “Cleaning the Laser Window” on page 9.

3D SYSTEMS, INC. 75-D059 REV_A4
Build Setup Tips
• The optimum print area for parts is a 330x280 mm (12.9x10.9 inches)
rectangle.
• You may nd it advantageous to organize the STL les into layers for
the print job. Separate the layers of parts in Z by 2.50 mm (0.09 inches).
• Due to the processing temperatures, parts placed at the bottom layer
of the print may not cool evenly and may tend to curl during printing.
See the sections “Curling, During Print” on page 16 and “Curling, Post-
Print” on page 15.
• If the STL le has a thick cross-section, you might want to place it higher
in the print cylinder, such as Z = 127 mm (5 inches).
• Thick cross-sections that have features with X-Y slices or Z depth greater
than 12.7 mm (0.5 inches) are more likely to experience post-print curl.
See the section “Curling, During Print” on page 16
STL les in separate layers
PRINT MODE FOR DuraForm TPU Elastomer
A material conguration le for DuraForm TPU Elastomer is offered by 3D Systems. The process settings in this conguration
le provide a good starting point for printing.
Please refer to the Customer Information Bulletin (Tips & Info) document for more detailed information about the material
conguration, including the key process parameters and the expected mechanical properties and densities.
Setpoints
• Laser Power Set points and Heater Setpoints (both print and feed beds) will vary due to sensor variations and
customer-specic requirements.
• The Laser Power Set point can affect part durability and elongation. Refer to the DuraForm TPU Elastomer Customer
Information Bulletin (Tips & Info) for a list of tested laser powers and expected mechanical results.
NOTE: 3D Systems recommends monitoring the build until you develop the appropriate operating conditions
for your system and application.
PRELIMINARY PRINTS AND PART PRINTS
Before the rst print, you must perform an oine IR calibration. Refer to your printer’s User Guide for detailed instructions.
Oine IR Calibration
1. Put the system in Manual Operations mode and then close and lock the print chamber door (select the material, if
needed).
2. Click the IR Calibration button.
Scale and Offset Print
When printing parts with DuraForm TPU Elastomer, you will need to perform at least one preliminary print to ne-tune the
default parameters and optimize them for your machine.
.Either the eld engineer or the operator will print a preliminary part to verify the appropriate scale and offset parameters. For
details, see “Calculating Scale/Offset Values” on page 4.
Use parameters from the preliminary prints to print actual parts . During printing, continue to monitor the laser and heater
setpoints by checking the quality of the parts and material during breakout.
Calculating Scale/Offset Values
Refer to the Build Setup Help in the Build Setup software.
SETTING UP A PRINT
Refer to the Build Setup Help in the Build Setup software.

3D SYSTEMS, INC. 75-D059 REV_A5
Orienting STL Files
You can use the Build Setup application to orient an STL le to
improve features such as thin walls, small pegs, text, small
protrusions, or cuts.
Fine Feature Denition
While parts will have good detail on both upward- and
downward-facing surfaces, generally theupward-facing surface
will have the best denition.
Laser Beam Offsets
Outline/Fill Laser beam offsets adjust the outline of a part to compensate for the width of the laser beam . This does not
compensate for regular shrinkage. Beam offset performs a topological offset that moves the outside skin of the part towards
the inside; features like posts become smaller and holes become larger . Beam offset is performed on each slice of the part as it
is sliced .
The beam offset values are set using the following offset parameters: X Fill Offset, Y Fill Offset, X Outline Offset, and Y Outline
Offset . These parameters are set using the Scale & Offset Editor in Print (Build) Setup .
If offset values are too large, very small features (less than 0.5mm) may not print . Build Setup allows the user to preview the print
slices.
Feature Strength
Orient features (such as snaps and pegs) that are subject to bending stress in the X-Y plane, so that layers run the lengthof the
features.
Surface Finish
Curved surfaces built in the Z direction may displaystepping
due to the layered process .
Posts built in X-Y plane for
strength of lengthwise layers

3D SYSTEMS, INC. 75-D059 REV_A6
Avoid
Preferred
Avoid
Preferred
Cylinders
Cylinders print better if placed vertically in the print area.
This eliminates Z stepping on the sides of the cylinder. If the
cylinder is long and has a small diameter, it can be placed on
its side.
Building a cylinder horizontally may be faster, but building it
vertically will produce a better surface nish. If the cylinder
has another smaller cylinder attached to it and is lying down,
the smaller cylinder should face upward. If the cylinder is
standing up, the smaller cylinder should be oriented in the
direction of the roller.
Ideally and if space is not an issue, cylinders should be built
on their side and at an angle of 30-45 degrees in Z.
Triangles
Place the triangular shapes in the print so that none of the
three sides are perpendicular to the direction of the roller
motion and that the base of the triangle is not facing the top.
This offers less resistance to the material as it ows across
the print bed, thus reducing the possibility of shifting, and
will result in a atter base.
Cross-sections
Larger cross-sections should be placed in the upper part of
the print to reduce the occurrence of post-print curl.
If the cross-section covers more than half the print area, it
should be rotated around the Y-axis enough so that the total
area that is being scanned on any given slice is minimal. This
will reduce the chance that you will short feed a large section.
Rotating around the Y-axis will yield better part strength than
rotating around the X-axis, but may still cause a short feed if
the section is too long in X.
Orientation for Cylinders
Orientation for Triangles
Orientation for Cross-Section
PART PLACEMENT AND ORIENTATION GUIDELINES
Whenever possible, there are several guidelines that need to be followed to ensure that parts print properly and to get the most
life out of the material .

3D SYSTEMS, INC. 75-D059 REV_A7
Duplicating
When duplicating parts, pay attention to the cross-sections of
all of the parts. To avoid heavy cross-sections on a given layer,
make sure the parts are not aligned vertically. This will reduce
the chance of short feeding the part bed. To improve print
quality, try to ensure that the time required for each layer
is as consistent as possible. It is also possible to duplicate
parameters amongst parts. See the Build Setup help menu
documentation for further details.
Features and Stair-stepping
Orient parts to achieve desired features . Detailed features and lettering print better on the upward-facing surfaces of a part .
Downward-facing surfaces exhibit a reduced, or softened, stair-stepping effect .
Closed Boxes, Cylinders, andShapes
Geometries that are closed on all sides but one should be placed in theprint with the open side facing up . This reduces heat
buildup in the print cake and the part, making breakout easier and extending material life .
Nesting
You can nest smaller parts within larger ones to utilize more
of the print area, as long as the smaller parts can be removed
after printing. If you nest parts, you should maintain a minimum
clearance of 0.25 inches (6.35mm) between the closest walls of
each part. The part containing the nested parts should always be
oriented with the open side up.
Orientation for Duplicating
Orientation for Nesting
Mating Surfaces
Parts that are to be printed in more than one piece or parts that will have mating surfaces, should always be oriented the same
in the print. It is preferable that the mating surfaces be printed facing upward for atness. If this is not possible, print the
mating surfaces in the Z-axis. The least desirable choice for orientation would be to print the parts with the mating surfaces
facing down.
BEFORE EVERY PRINT
Prior to every build, perform the Daily User maintenance tasks as highlighted below. Review the User Maintenance Checklist
for weekly and monthly tasks.
1. Inspect and clean the laser window as well as the Laser Window Assembly O-Rings. See “Cleaning Up the SLS System” on
page 9. Replace the O-Rings if they look worn (PM replace ~1 year).
2. Inspect and clean the IR blackbody.