PP-equivalent plastic

PP-equivalent plastic is a resin-based material simulating the properties of Polypropylene. It is opaque in nature and comes in a milky white color. The parts have an inherent smooth surface finish.

Since PP-equivalent parts are fabricated in Stereolithography (SLA) technology, there is support structure generation under the overhanging and protruding features. Therefore, although complex and intricate structures can be fabricated in this material, the part quality and surface finish will get slightly hampered as the support structure removal will leave minor burr marks on the surface.

Support structures in PP-equivalent plastic

PP-equivalent parts are flexible in nature and therefore are excellent candidates for snap-fit assemblies and live-hinges. They are also dimensionally very accurate.

But SLA technology is usually accompanied by a polishing process, therefore, these minor burr marks can be eliminated to obtain a smooth surface finish. But in complex geometries it becomes difficult to polish the parts in hard-to-reach places, thereby leading to a gradient in the surface finish. This surface gradient accentuates when the parts are painted. PP-equivalent parts can be painted to give them any desired color and finish. Painting usually adds a layer thickness of 100–200µm.

Accurate critical features

PP-equivalent parts are flexible in nature and therefore are excellent candidates for snap-fit assemblies and live-hinges. Although flexible, the parts are slightly brittle in nature. PP-equivalent plastic parts are dimensionally very accurate (Accuracy of around (+/-) 150µm), and thus they find application in functional and proof-of-concept prototypes, and automotive styling/designing parts.

Butterfly hinge

Highlights:

Strong and flexible
Excellent feature resolution and dimensional accuracy
Smooth surface finish

Shortcomings:

Support structure generation
White color may turn orangey if exposed to humidity and moisture.

Applications:

Functional and Proof of concept prototypes
Enclosures and Snap-fit assemblies
Automotive styling parts
Master patterns for Vacuum casting

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