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Alliance Overview and Opportunities for Photopolymer Materials and Systems Characterization - Shared screen with speaker view
Laura Kramer
What technique are you using to measure conversion and Rp?
Spencer Loveless
What is the effect on power of the uv cure on cure time? Is it exponential or linear?
Matt westman
Aren't those techniques limited to transparent materials?
TJ Root
As a follow up to the question from Spencer, is there any insight that can be added on the difference between the total light energy delivered and the shape of that light energy curve
Matt westman
What value if any do find in swelling experiments for conversion determination?
David Walker
I'm assuming conversion is of double bonds in the formulation used; but isn't it possible to open up these double bounds without always growing chains and increasing molecular weight? This could lead to low MW leachable content. Is double bond content the only characterization metric we want to consider long term?
Spencer Loveless
On the heat topic, would a quick heat shock or uv shock keep the parts better within tolerance? As far as a post process not during printing
TJ Root
How effective/thorough do we feel that regular multi point irradiance measurements and corrections serve to maintain the consistency of output? Is that kind of an 80% solution or does it leave too much unchecked?
Chris Hazel
Are there any standard methods for DMA/Rheology testing of cured photopolymers? Specifically in combined mode loading (compression and shear).
Paul Snowwhite
I have done microwave in additive. It works, we found inconstant heating, but we did not advance it.
TJ Root
more 80-20 rule than uniformity sorry
RJ Viereckl
Does a green part absorb unreacted monomer from the vat? Would that depend on the degree of cure / conversion? Or would it be expected to be removed during the post print wash?
Nick Wren (3M)
Jerry, is this published work? I'd like to read more on your model, thanks
Spencer Loveless
What about vat films? Any advancements so the parts do not adhere to a ptfe or non ptfe or similar film?
TJ Root
I think pot life is a huge factor in production printability as well
Nick Wren (3M)
Witness parts are great for QC. Measurement after post-processing is a quick check on process consistency
TJ Root
We do it on every initial qualification print for materials but lack of a good standard coupon contributes to not running it every build
Matt westman
ISO/ASTM 59902-19 is a standard for test artifacts for geometric capability assessment. There are multiple standard coupons within that standard.
Raymond Weitekamp
In addition to the “resin replenishment” that Jeff Klang mentioned - we also see many production DLP shops filtering used resin with an inexpensive “paint strainer” paper/mesh filter.
David Walker
Many big manufacturers do not risk re-using resins for a end-user manufactured part (i.e. non-prototype model). They toss the resin. So it's important that pot-life in the vat is longer for the manufacturing run. Hence the challenge of two-part chemistries with shorter stability times.
David Walker
Wouldn't the equivalent be background inhibitor content?
Dr. Dianne Poster (NIST)
Thank you, great webinar!
Raymond Weitekamp
Thank you! Really fun.
TJ Root
Thank you! super high quality!
Chris Hazel
thank you everyone!
David Walker
Thank you all!
Callie Higgins
Thank you everyone!
Parag Shah
Great discussion and insights from all the panelists
Michael Gould
It's good to share the road with other committed folks!