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Update molding urethane authored by Theodore Brzinski's avatar Theodore Brzinski
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molding-urethane.md
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...@@ -25,10 +25,9 @@ Users have developed different techniques for fabrication of the backing mold. T ...@@ -25,10 +25,9 @@ Users have developed different techniques for fabrication of the backing mold. T
As in both of the examples pictured above, a mold that produces a silicone negative of uniform thickness and with regularly spaced particle wells will lead to the most reproducible and easy-to-produce castings. One innovation that has proven successful and improves the versatility of the backing mold is to machine a dish to precision flatness, then to drill an array of tapped holes into the dish. Any desired particle shape can then be machined or printed with a matching threaded post and screwed into the dish. Thus, a single backing mold can be used to create particles of any shape. Note that the [inverse analysis](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/inverse-analysis) technique to back out the vector forces on urethane particles are only well-developed for circular particles. As in both of the examples pictured above, a mold that produces a silicone negative of uniform thickness and with regularly spaced particle wells will lead to the most reproducible and easy-to-produce castings. One innovation that has proven successful and improves the versatility of the backing mold is to machine a dish to precision flatness, then to drill an array of tapped holes into the dish. Any desired particle shape can then be machined or printed with a matching threaded post and screwed into the dish. Thus, a single backing mold can be used to create particles of any shape. Note that the [inverse analysis](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/inverse-analysis) technique to back out the vector forces on urethane particles are only well-developed for circular particles.
* A modular dish with cylindrical posts of two sizes: * A modular dish with cylindrical posts of two sizes:
![ModDish](uploads/36dffe8e5a1335ee0cf91938a40b0e53/DSC_2294.jpg) ![ModDish](uploads/f5f605ade1fb6af72ac8b6edef9efa8a/DSC_2294__1_.jpg)
* A close-up of the removable posts, with threaded rods revealed: * A close-up of the removable posts, with threaded rods revealed:
![ModPins](uploads/2dc0517f77c8849c4f09fa745e397d40/DSC_2287__4_.jpg) ![ModPins](uploads/876d8d7535221689fbd5ac2d5f31c4c8/DSC_2287__5_.jpg)
Making a mold of the sample Making a mold of the sample
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