Urethane Casting for Prototypes and Tooling
At Broadview, we think so. We believe that combining the old with the new is generally the best approach to engineering, and we bet that you’ll agree. For example, consider Urethane Casting.
A process of creating prototypes that has been around longer than many of us have been alive, is still a viable and often preferred method of creating high-performing and aesthetic prototypes and tooling. This is especially effective when combined with 3D printing for making master patterns.
Over time, as skilled model makers have retired and 3D printing has evolved to replace them, many shops have given up on urethane casting. It can be a messy and difficult process that involves a separate capital equipment investment and dedicated shop space. This said, there are still many advantages of urethane casting that 3D printing, cannot yet, and may never replace.
We are huge fans and users of 3D printing. We offer 3D printing as a service to all of our clients and we enjoy counting you among them. We can provide the fast turnaround 3D prints you need while allowing you to avoid the capital expense of owning your own equipment and hiring the staff to learn and run it.
3D printing still has shortcomings. There are several process types, and generally, no single one of them can provide all the aspects that a user desires in a prototype or production part. This is why large OEM and component part companies have had to rely on several different expensive processes. This is where urethane casting shines!
Some Advantages of Urethane Casting
Material Properties: Materials are generally performance based thermosets with high strength, flexibility, weatherability, chemical resistance and have the ability to mimic many production grade, injection molded plastics.
Surface Quality: Urethane parts are molded in silicone tools created from a finished pattern, which saves finish time, increases strength and improves aesthetic issues resulting from typical 3D printed part layering.
Texture and Polish: Custom textures, high polish and graphics can be incorporated in the master patterns and repeated in each casting from the mold.
Color: most materials can be custom color matched to provide the finished production part appearance.
Speed: once the silicone mold is completed several parts per day can be molded. Multiple cavity molds are also possible for faster results.
Size: Unlike 3D printing, urethane casting is not limited by build chamber size, and does not risk huge losses of material and time if the build fails…which is not uncommon, even in the best 3D printers.
Expense: By using a master pattern for the silicone mold, finish only has to be applied to one 3d printed part. Once the mold is complete many copies can be made at a much reduced cost.
Process Flexibility: Secondary operations such as inserts, multiple finishes on same part and multi-shot materials can all be accomplished with urethane casting.
Broadview has continued to invest in our model shop to offer lower cost, repeatable prototypes. We like to call it Silicone/Urethane casting. Many industry veterans refer to it as RTV, which is an acronym for Room Temperature Vulcanizing. This is certainly not a new process and actually predates 3D printing. Urethane casting has been used for many decades by model shops supporting consumer products, automotive, medical and many other industries.
In years-gone-by, a skilled pattern maker would hand-fabricate a model or pattern from a 2D drawing, and then use that for a pattern to make a silicone mold. A urethane polymer would be cast into that mold to create parts. The cast parts were very durable, and the urethane offered a large variety of plastic material properties, including those that would closely resemble production injection molded parts. The part finish also matched the high aesthetic level of the original pattern.
In the 90s, model shops started to utilize 3D printed patterns to shorten the time required to make patterns and also replace the many highly skilled model makers that were retiring. As 3D printing improved, the pattern making time was reduced and by the end of the decade, 3D printed master models (patterns) became the norm rather than the exception.
As mentioned above, urethane cast parts are often used to replicate prototype injection molding parts, without the huge cost and time commitment of metal tooling. Even with today’s high-speed CNC machines, urethane casting remains a viable application for many prototype parts. We also have many clients that call on us to use silicone/urethane casting for short-run production part applications.
Additional Urethane Applications
Prototype parts for show models and testing
Prototype parts that need moderate quantities and moderate prices compared to 3D printing multiple models
Large variety of colors needed of the same part
Unique part geometries that do not fit injection molding well (thick walls, undercuts, etc.)
Low annual volume products
Opportunities for multiple shots of large parts to yield parts that are in spec
Specialized machine and robot components
Jigs and fixtures
Transparent, tinted, and textured parts
Nearly any creative applications that you can think of
At Broadview, we are committed to this technology and have even hired additional model shop team members over the past year. The loyal patronage of our clients for over thirty years speaks to our expertise in this field, in addition to the other prototyping and engineering services that we offer.
One such client is Landscape Forms. Please click on the picture or link below to learn more about their story:
