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© 2016 Solvay Specialty Polymers 1
OMTEC 2016
Design for Manufacturability (DFM) Session Presentation by Solvay Specialty Polymers
Speaker: Jim Hicks – Technical Development Engineer
© 2016 Solvay Specialty Polymers 2
With our Orthopedic customers, Our greatest Design for Manufacturability (DFM) pain point within the orthopedic community is the engineering staff’s lack of polymer experience, and the best design strategy for change involves forming early partnerships with the polymer supplier and processors.
Session Topic Statement
© 2016 Solvay Specialty Polymers 3
The role of the Polymer supplier in the DFM process
• Understand the requirements of the application and device.
• Provide material choice options
• Help the engineering team find the right balance of: - Material properties – short and long term - Material availability – beyond just whether
we have the product in stock
- Material supply chain – direct sell, custom compounder or stock shape convertor
- Primary processing – Injection molding, thermoformed or machined
- Post processing – Marking, welding, insertions and assembly
Goal: Help the customer follow the path of least resistance to bring a design to production
© 2016 Solvay Specialty Polymers 4
Designing with plastic is not difficult, just different.
• Our orthopedic customers have great design engineers that come up with creative new devices. - Many are very knowledgeable about
designing in metal but do not have much experience with plastics.
• Remember these simple rules when converting a traditional metal design to plastic: - Pick your polymer based on whether you
want toughness or strength. - Sharp inside corners are not your friend in
plastics! - Not every dimensional tolerance needs to
be translated from the metal design. - Uniform wall thickness = predictable
designs
Good plastic parts are a function of the right design and the right material!
© 2016 Solvay Specialty Polymers 5
Define what the part is expected to do and the critical-to-quality parameters
• If you are converting a metal part to plastic, step back and define actual use conditions, loads and deflections.
• Simulate the current design in metal and test.
• Translate design to plastic and begin modifications to achieve similar behavior, not similar properties.
• Take advantage of CAE and Moldflow analysis to troubleshoot design and manufacturing before production.
Many traditional metal parts have few defined performance criteria. They just work.
© 2016 Solvay Specialty Polymers 6
Partner at the beginning of the design process
• Use the experience and knowledge of skilled molding shops and polymer engineers to look for potential problems early in the design process
• Consider consolidating multiple parts into the new design.
• Take advantage of the best attributes of metal and plastics. Combine the ability to have higher tolerance standardized metal inserts with lower cost plastic structures.
• Design a plastic part as if it is to be molded long term. Even if the part is to be machined in the early design or as part of a limited launch, be prepared for this option.
Do not wait until the part design is locked to start looking for processing partners
Don’t design alone. Find partners that can help in the whole process.
SLIDE FIT
Metal Plastic
© 2016 Solvay Specialty Polymers 7
Key takeaways for plastic part design and manufacturing
• Define critical dimensions and allow others to float….Do not over tolerance!
• Take advantage of plastic simulations and Computer Modeling to predict behavior.
• Metal – Plastic hybrid design can allow easier manufacturing by simplifying steps and combining parts.
• And most important, get the tool maker, plastic processor, and the polymer supplier involved as early as possible!
DFM is a team effort - Make maximum use of internal and external resources!
© 2016 Solvay Specialty Polymers 8
Design For Manufacturability (DFM) The best design strategy involves forming the right team: polymer experts, processors, tool builders, fabricators….
Final Thoughts
Safety Data Sheets (SDS) are available by emailing us or contacting your sales representative. Always consult the appropriate SDS before using any of our products.
Neither Solvay Specialty Polymers nor any of its affiliates makes any warranty, express or implied, including merchantability or fitness for use, or accepts any liability in connection with this product, related information or its use. Some applications of which Solvay’s products may be proposed to be used are regulated or restricted by applicable laws and regulations or by national or international standards and in some cases by Solvay’s recommendation, including applications of food/feed, water treatment, medical, pharmaceuticals, and personal care. Only products designated as part of the Solviva® family of biomaterials may be considered as candidates for use in implantable medical devices. The user alone must finally determine suitability of any information or products for any contemplated use in compliance with applicable law, the manner of use and whether any patents are infringed. The information and the products are for use by technically skilled persons at their own discretion and risk and does not relate to the use of this product in combination with any other substance or any other process. This is not a license under any patent or other proprietary right.
All trademarks and registered trademarks are property of the companies that comprise the Solvay Group or their respective owners.
© 2016, Solvay Specialty Polymers. All rights reserved.
www.solvay.com
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paragonmedical.com
OMTEC 2016 DFM Rapid Fire
Mike Street Paragon Medical
Sr. Manufacturing Engineer/Prototype Manager
paragonmedical.com
DFM Oversights
With orthopaedic customers, our greatest DFM pain point is secondary operation oversights and the best strategy to change that is early engagement and collaboration.
paragonmedical.com
What is considered a secondary operation?
• For Paragon Medical… – An operation driven by print specifications that
occurs after primary machining. – Operations that are mostly manual and difficult
or impossible to validate. – Requirements can be subjective…
cosmetics for example
paragonmedical.com
Secondary Operations • Coatings
– Hard Coat Chrome – PVD Coatings – Anodization, etc.
• Assembly – Press Fits – Staking and Swaging
• Welding • Cosmetic Requirements
paragonmedical.com
Welding Pain Points
• Stringent weld specifications – Requires expensive testing
• Radiographic X-ray • Destructive metallurgical testing • Mechanical testing
– What happens if a failure is detected? • Scrap entire lot? • Deviation?
paragonmedical.com
Welding Pain Points
• Controlling weld quality – Mostly manual process
• Difficult to validate • Variation between operators • Variation due to environmental factors • Verification necessary to ensure
specification conformance
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Welding Pain Points
• Manufacturing Example – Instrument assembly with 10 weld junctions
• GTAW Welding and Laser Welding • Metallurgical Testing required on weld joints • 3 assemblies per lot of 50 sectioned for testing • $14,000 per lot testing cost • 4 week additional lead time • Resulted in 38% cost increase per assembly
paragonmedical.com
Welding Pain Points
• Example of common issues
paragonmedical.com
Welding Pain Points
• Example- Alternatives to welding
paragonmedical.com
Welding Pain Points
• Alternatives – Staking or Swaging – Threaded Junctions
• Epoxied threads • Peened Threads
– Single Piece solutions – Welding as secondary fixation
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Welding Pain Points
• If Welding can not be avoided – Early engagement with manufacturing
• Proper design of weld junctions to ensure success • Weld callouts scrutinized • Test pieces developed • Verification protocol developed
paragonmedical.com
DFM in General
• Ultimately the best way to mitigate manufacturing issues is collaboration between the design team and the manufacturing team early in the project
