Tech Talk: Casting Urethanes and Silicone Materials

By <a href="https://mfg.trimech.com/author/sarah-case/" target="_self">Sarah Smith</a>

By Sarah Smith

Posted on June 22, 2023

TriMech Advanced Manufacturing services provides Silicone Casting, Urethane Casting and 3D Printing Services to engineers and businesses. Our knowledgeable staff can help to guide you on what process and material is the right fit for your project, helping you to achieve success. Our team takes pride in creating accurate, well finished, and on-time parts, whether it be a single one-off custom piece or a run of five thousand parts.

One service that TriMech offers that sets us apart from other 3D printing service bureaus is our Silicone Casting and Urethane Casting offerings. Today, we’ll speak with TriMech’s Casting Department Manager, Derek Becker, to get an in-depth overview and insight into when and why to choose casting methods to produce parts.

What is casting?

Casting is a manufacturing process that creates duplicate parts based on the geometry of an original part, also referred to as a master. We have two options to create a mold master, one is to use a client supplied original part, and the second is to 3D print the mold master using client supplied CAD files. We then create a mold using the master pattern, usually comprised of a top and bottom portion that fit together tightly by aligning the molds in a particular orientation.

Mold creation takes skill, as there are a lot of details to consider such as the placement of features like the parting line, channels, vents, and gates that allow for material to be poured into a closed mold, and for the release of air pockets and excess material.

When is casting a good choice?

Casting bridges the gap between 3D printing and injection molding. 3D printing large parts becomes less economical at scale and injection molding becomes more economical at high quantities such as 10,000 units per production run. Casting is a great option that sits squarely between the two. Our casting department runs anywhere from 1 to upward of 5,000 parts in an order. Casting is cheaper than injection molding at these quantities, faster, and is produced in the USA in our Casting facility.

“Casting bridges the gap between 3D printing and injection molding.”

Injection molding requires a significant investment in tooling, and once that tooling has been produced it does not allow for any changes in the design to be made. If design iterations need to be made, you’ll be left with no choice but to pay for retooling. Whereas casting allows you to create a medium volume run that can be used in end production and tested prior to moving into high volume productions. The cost and speed of urethane casting lends itself to recurring large run orders that are placed annually and shipped on a recurring schedule, allowing for clients to achieve better inventory management.

What services does the casting department offer?

We offer urethane casting, silicone casting, compression molded silicone, roto casting, and thermal casting. Our casting facility is ITAR compliant and handles projects with exacting technical specifications, such as military, aerospace, and medical applications.

Urethane Casting: We have a variety of urethane materials available, with special material properties such as FR ratings. These materials come in standard colors but can also be specially tinted when color matched parts are a requirement. Brass threaded inserts can be cast in place, giving extra utility to an already robust part.

Urethane-Casting Part

Urethane-Casting Part

Silicone Casting: Many shore durometers can be met with silicone casting. Parts can be clear for applications such as fluid dynamics and visual inspections or aesthetics or colored creating an opaque end part. For a more durable silicone we can use a compression mold for added tear resistance.

Custom Silicone Part

Custom Silicone Part

Roto Casting: allows for hollow cast parts. This is a great way to achieve bladders, inflation bulbs, or lower density displays, as the hollow internal void can be back filled with a lighter lower density material.

Roto Casting

Roto Casting

What makes casting unique and valuable to clients?

Our facility uses tried and true equipment of pressure pot tanks, furnaces, roto casting machines, thermoformers, hydraulic presses, and 3D printers combined with over 50 years of artisan experience used to complete a wide range of services. Our in-house 3D printing services allow us to quickly print mold masters for expedited projects and talk in real time amongst our team about the best strategy to complete challenging and technically demanding jobs.

“Casting is a mixture of science and art.”

Casting is a mixture of science and art, requiring a chemistry like approach paired with detailed craftsmanship. Each of our urethane parts requires an expertly hand-carved silicone mold with precision alignment features. Our craftsmen are also responsible for custom tints, surface and edge quality, and the sheen.

How long are lead-times?

Lead times will vary based on the size and complexity of a project. We have turned jobs around very quickly, in as little as one day for an ultra-critical component, but most projects require more time from the order date for the first batch of parts to ship.

How do I place an order?

To get a quote contact our team to talk through the details and requirements of your project.

Article by <a href="https://mfg.trimech.com/author/sarah-case/" target="_self">Sarah Smith</a>

Article by Sarah Smith