Polymer based molds and methods of manufacturing there of
Polymer-based molds and methods of manufacturing are described. The method includes depositing two or more layers of a first material having a glass transition temperature (Tg) lower than about 70° C., in order to form a first portion of the mold and then depositing two or more layers of a second material having a Tg higher than about 80° C. to form a second portion of the mold. The method may further include depositing two or more layers of a material having a Tg lower than about 70° C. forming a third portion of the mold to cover the second portion.
1. A method of preparing a polymeric mold for injection molding, the method comprising:
depositing, in layers, a first material having a glass transition temperature (Tg) lower than about 80° C., whereby forming a first portion of the polymeric mold; and
depositing, in layers, a second material having a Tg higher than about 80° C., whereby forming a second portion of the polymeric mold,
wherein the second portion at least partially covers the first portion, the second portion is thinner than the first portion and faces a cavity in the polymeric mold.
2. The method of claim 1 , further comprising:
depositing, in layers, a material that when polymerized has a Tg lower than about 80° C., thereby forming a third portion of the mold to cover the second portion.
3. The method of claim 2 , wherein the thickness of the third portion is less than 300 μm.
4. The method of claim 1 , wherein depositing is done by ink jet printing.
5. The method of claim 1 , wherein the second material when polymerized has a heat deflection temperature (HTD) higher than about 80° C.
6. The method of claim 1 , wherein the second portion has a thickness of at least 1 mm.
7. The method of claim 1 , wherein the second material when polymerized comprises multi-functional monomers and oligomers in a concentration higher than 45% by weight.
8. The method of claim 1 , wherein the second material when polymerized comprises monomers and oligomers having a Tg higher than 100° C. in a concentration higher than 45% by weight.
9. The method of claim 1 , further comprising:
determining geometries of the first and second portions according to a temperature distribution in the polymeric mold expected during the injection molding.
10. The method of claim 9 , wherein the second portion is thicker at areas of higher expected temperature.
11. The method of claim 9 , further comprising:
determining the temperature distribution based on a computer simulation of the injection molding process.
12. The method of claim 1 , wherein the first material when polymerized has a Tg lower than about 60° C. and the second material when polymerized has a Tg higher than about 90° C.
13. The method of claim 1 , further comprising:
determining geometries of the first and second portions such that a geometrical distortion of the second portion during printing is less than 1 mm.