Matthew Moeser, Stratasys Test Operator ready to do multiple dogbone tests with the AutoMeasure

Accurate
industrial
testing machine
printed fromSAF™ PA12Testing the quality of parts produced from a newmaterial such as SAF™ PA12 is an arduous process
in that numerous tests need to be completed taking
up many hours in manually taking measurements,loading samples and testing. To free up an operator’stime to focus on more important tasks, Stratasys’engineers developed an automatic measuring

It was straightforward todesign the AutoMeasure,as the H350 allowed me tocreate different iterations
quickly, the parts always
came out on spec, and I
was easily able to DfAM
because of the consistencyof accuracy throughout thebuild volume.”machine, 3D printed from the very material it wasCase Study

tasked with testing at the time: SAF™ PA12.

Nyall Davis

Industrial 3D Printing QA Technician

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The Challenge
The process of bringing new materials to market
for the H350™ involves consistently monitoringand measuring the quality of parts. The mechanicalquality and consistency of the parts is assessedusing uniaxial tensile testing of dogbone samples.
A uniaxial tensile test involves recording the force ittakes to pull the test dogbones apart. This simple
test yields a lot of information on the material. Tests
include Young’s modulus, yield stress, ultimate
tensile strength and elongation at break which help
track how well the material is fused. Monitoringchanges in these properties across a build,
between builds and between machines helps forma picture of machine and material consistency.

Sheer volume of tests puts operators
under time pressure
Performing a single tensile test on a dogbone isfairly quick and easy. First the cross-sectional area
is measured to ensure that results are accurate,
the sample is then loaded into the tensile tester,pulled at a pre-determined rate until failure, andunloaded.
However, when you need to test 30 tensile
dogbones in a single test build, with up to 10
machines working on a single material at a time,
2700 dogbones are produced and tested in asingle month. This schedule is punishing and it’s
hard to keep pace with testing milestones which
are critical to provide the R&D teams with the data
they need to direct development efforts.
The solution was to create an automatic dogbone
measuring machine. A machine able to take afull test build’s of dogbones (30), take 3 repeat
measurements of width and thickness of each andinput these values into the tensile testing software.

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Case
StudyTitle HereThe volume of dogbones tested manually makes testing a new material a long process.

3 3The Solution
Dubbed the AutoMeasure, the machine fully automates the process and removes the need for operator
intervention in the measuring process. When operated manually using calipers, the process takes 30
seconds per dogbone, 15 minutes per build. The automated process removes this time and frees it up
for the operator to work on other, more interesting or involved tasks instead. This leads to ~287 hours ofoperator time saved per year with no changes to safety or data critical parts of the process.
To increase throughput, without putting undue pressure on the operator, the time required for some, or all,of these steps needed to be reduced.
Each step of the tensile testing procedure is indicated below, broken into the required steps and how longeach takes.

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Case
StudyTitle Here

Considerations in finding a solution to cutting down the time taken in the testing process included:•Loading and unloading the samples needed to be done safely and accurately.

•The minimum sample test time is dictated by standard practices. Increasing the number of test
machines would be the only way to increase throughout, requiring significant capital and operational
investment as well as long lead times for equipment.

•Measuring the cross-sectional area of the sample is performed manually, with vernier calipers,and 3 repeats. Cutting out the measurement process altogether or reducing the number of repeat
measurements would reduce the quality of the testing and data.

An additional benefit of the AutoMeasure is an improvement in repreatability of measurements. Removing
the variation of different operators removes the chances for differences in technique influencing
measurement results.
The AutoMeasure reduces the process time and costs, delivers more data to steer R&D more quicky,
improves measurement accuracy and frees operator time to perform other tasks.

4 4Automeasure machine in operation with a tensile testerHigh-quality H350 parts form
the backbone of a high-volume
testing machine

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Case
StudyTitle HereIndustrial 3D printing QA technician Nyall Davidis the brainchild behind the AutoMeasure, whichfeatures 13 printed components, all of which aremanufactured on the H350 using SAF™ PA12.
The SAF printed components make up the entire
structure of the AutoMeasure as well as a numberof functional mechanical parts. These parts aredesigned specifically for manufacture with the H350
and take advantage of the high nesting capabilityof the machine. All 13 parts can be densely nested
into a build slightly less than half of full Z height.
This enables the build to complete in 5 hours,or alternatively for 2 AutoMeasure’s worth ofcomponents to be built in a single build.
SAF technology engineers agree that without theH350 and SAF™ technology, the AutoMeasure
could not have been developed. The following
characteristics of the material allowed the machine
to fulfil its intended purpose to perfection:•SAF™ PA12 is an ideal choice for industrial
machine components which require high accuracy.
To function correctly, accurate parts are required
for external parts such as bearings and screws
to mount correctly so the parts sit as intended.
The chassis comprises 2 large pieces which must
assemble with screws holes located accurately so
the chassis can be put together correctly.

•It allows quick turnaround of functional end use
parts and the design freedom allowed by rapid
design iterations and reduced development time.
The high nesting capability of the SAF process
was a further improvement, facilitating a print of
all components in 5 hours (+24 hour cooldown),
simply not possible with other 3D print processes.

•The accuracy of SAF™ PA12 allows for higher
tolerance features such as bearing seats andadjustment screw holes to be printed directly
into the part with no need for additional, post
manufacture processes.

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Further benefits of manufacturing withSAF™ PA12 using SAF technology

Track for adjustment screws. Working with M3
screws this track is very small and requires the highaccuracy of SAF™ PA12 to operate in a linear andsmooth manner.

The fine feature resolution possible with the H350
and SAF™ PA12 allows for labels to be printed
directly onto the part for clearly displaying thefunctions of buttons.

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StudyTitle Here

Press fit bearing seat printed directly into the partfor a lead screw. For bearings to be fit, these requirea high level of accuracy delivered by SAF™ PA12.

Lead screw nut bolt holes printed directly into thepart. Slight misalignment of this part could cause
issues in the operation of the lead screw, accuracy
is critical making SAF™ PA12 the ideal material.

Design freedom of H350 and SAF technology
allows for cable management to be printed directly
onto the chassis, requiring no assembly afterprinting. Any modifications to the design in future
can be made quickly and parts reprinted.

6 6Operation and Design
The AutoMeasure is divided
into several sections:Chassis
The chassis of the AutoMeasure features mounting
and bolt holes for assembly of components, cablemanagement hooks and channels, press fit bearing
seats and cooling vents for airflow and fans. The
chassis also provides stiffness to ensure thatmeasurements are accurate.

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It is critical that the flat structural parts of thechassis, specifically the DTI gantry are accurate
and free from warp, which does not present aproblem for SAF™ PA12. Design freedom also
allows weight and material to be removed from thispart with no added difficulty in manufacturing.

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Dogbone storage magazine

Operator delivery chute

Capable of storing 30, standard, ATSM D638, Type I
dogbones stacked vertically. These are loaded into
the open top of the magazine.

Once the measurement is complete, the dogbone isejected and fed down the chute for collection by theoperator.

Dogbone feed mechanism
A pusher plate is actuated by a SAF printed rackand pinion system form SAF™ PA12. The mechanism
is gravity fed dogbones from the storage magazine
which pushes them, one by one, into the measurementbay.

Measurement bay
Accepting a dogbone from the feed mechanism,
the measurement bay houses 6 digital dial test
indicators (DTIs), 3 for width, 3 for thickness evenly
distributed along the gauge section of the dogbone.
All 6 measurements are taken simultaneously.
DTI Gantry

Document
Case
StudyTitle HereDTI gantry assembly printed without warp.

The measurements taken from the dogbone are fed
instantaneously to the tensile testing software, readyfor the dogbone to be pulled.

The printed parts are then assembled with aselection of standard, external, electrical andmechanical components. The control board is thenloaded with code, written and developed in-house toproduce a fully functional AutoMeasure. In this case,the SAF™ PA12 parts are left natural with no further
post-processing, however, finishing options for acommercial product could include vapour smoothing,dyeing, spraying and many others.

8Lower costs and increased
productivity with SAF™ PA12As there are only 2 consumables (HAF and powder)
and a simple, agile cooldown procedure, thecost per part with SAF is often lower than othertechnologies. The total assembled cost of theAutoMeasure was calculated to be $583 including
printing and additional components.
The payback period for the AutoMeasure wascalculated as 69 days, with an estimated annual
saving of ~$4493 in operator time alone. In addition,operators save time to focus on other critical tasks.

Machine to machine consistency of the SAF
process allows for this design to be instantly
deployed anywhere in the world. The files can beshared electronically and printed with confidence
that the resulting parts will be within spec. Thismeans that transport costs and delays are
eliminated and the time required to ramp up testingat another facility anywhere in the world is minimal.
As the design is modular and there is no toolingrequired for manufacture, the design is free to bemodified in the future to accommodate testingof dogbones using different standards or othermechanical test pieces such as impact and flexuralmeasurements.

Stratasys Headquarters
7665 Commerce Way,
Eden Prairie, MN 55344+1 800 801 6491 (US Toll Free)+1 952 937-3000 (Intl)+1 952 937-0070 (Fax)

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Rehovot 76124, Israel+972 74 745 4000+972 74 745 5000 (Fax)

Case Study

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