
Surgical Simulation on 3D Printed Brain Models
Neurosurgical society improves patient outcomes with PolyJet brain modelsNeurosurgical society improves patient outcomes with PolyJet brain models
Read Case StudyThe opaque flexible material has been over-molded into the transparent rigid material. This was achieved via a single print.
PolyJet is one of the only 3D printing technologies capable of manufacturing parts in multiple durometers and colors. It is most significantly used for high fidelity prototypes and models, but its move towards more rugged short-term applications has strengthened in recent years thanks to material developments which include biocompatible options and materials with higher tensile and higher heat deflection mechanical properties.
PolyJet can 3D print in rigid and flexible in a single build directly from a 3D CAD file to created over-molded parts. Through dozens of material combinations, PolyJet delivers parts with shore hardness ranging from 40-90A in multiple colors and opacities. Designers often turn to PolyJet because it can print a design within hours, providing immediacy to a project without increasing the project’s overall cost. Because PolyJet doesn’t require tooling to deliver an over-molded part, it is frequently used during early concept prototyping for designs requiring an elastomeric surface, such as grips or buttons, before moving into final product development stages.
PolyJet is the only rapid prototyping technology available that delivers immediate over-mold concept realizations that incorporate all material deviations in a single part without tooling or any manual application.
For low volume production of over-mold or insert molded parts, urethane casting is the most cost effective process. Urethane casting achieves a similar durometer range and material quality of injection molding; however it eliminates the need for a hard tool. Urethane casting uses 3D printed master patterns to significantly reduce the cost of manufacturing a cast product. The 3D printed master pattern is used to form a soft tool or silicone mold. Urethane casting requires two silicone molds to create the substrate and over-molded elastomeric material. The process achieves similar bond strength to injection molding.
One significant advantage urethane casting offers is its ability to produce micro-welded inserts. Similar to insert molding, micro-welded inserts are cast directly into the part. Micro-welded inserts are on average a 50-100% stronger bond than bonded inserts and over 100% stronger bond than heat staked inserts.
This cast urethane over-molded part features rigid (in black) and elastomeric (in blue) materials. Urethane casting offers strong material bonding for over-mold applications.
Injection molding becomes the most cost-effective choice when part volume is high. Because over-molding with injection molding requires more than one tool, the cost for over-molding can quickly become a barrier to part production. The lower the part volume, the more likely urethane casting is the right solution. However, because urethane casting uses a soft tool, its tool life is shorter and therefore higher volumes become less cost sensible to execute with urethane casting. Testing out the prototype through urethane casting – which simulates injection molding without hard tooling – provides for the best design readiness when finally moving into large volume production with injection molding.
Stratasys Direct Manufacturing offers a range of thermoplastic elastomers (TPEs) alongside the most common and hardy injection mold plastics such as ABS, PC and nylon. Our over-mold injection molding solutions are most commonly used to produce consumer goods such as bottles, medical cart manufacturing such as telemedicine robots used in hospitals, transportation goods such as panels and screens, and many similar large volume applications that require frequent human interaction or use and therefore require a soft touch surface of some manner.
Common Multi-Shot Mold Applications:
Neurosurgical society improves patient outcomes with PolyJet brain models
Read Case StudyThe 33.5 lb/in (6 kg/cm) tear strength of Agilus is twice as strong as the previous flexible material offered at Stratasys Direct.
Read the ArticleOptimize designs for full color and graphic textures on prototypes and concept models.
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