Injection molding, blow molding and liquid silicone rubber (LSR) molding are three remarkably efficient manufacturing processes for producing large volumes of highly accurate and often very complex parts. One of the challenges of bringing products to market with these processes is that producing functional prototypes with the right mechanical properties requires expensive tools with long lead times.
Additive manufacturing addresses this problem by producing tooling for these and other types of molding that can be used to make limited runs of prototypes or low volume production parts from the same material and with the same physical properties as the final production parts. Molds made by additive manufacturing make it possible to evaluate more design iterations in less time at a lower cost, enabling companies to get products to market faster and reduce engineering and prototyping expenses.
Aluminum and rubber tools are a thing of the past
Until recently, the best option for companies making or buying injection molded parts was to manufacture an aluminum tool, called a soft tool, and use it to produce functional prototypes of the production material. Soft tools are less expensive than steel tooling but their cost and lead time are still substantial. Blow molded prototypes are also normally produced with aluminum tools that are expensive and have long lead times. Prototypes of LSR rubber parts are normally produced by manual casting using molds made of soft metal, modeling board or room temperature vulcanization (RTV) rubber. RTV molds are less expensive than machined metal molds but making LSR parts with RTV molds is a multi-stage process requiring considerable time and labor to make the patterns and molds.
As a case in point, Turck builds junction boxes, cordsets and splitters using injection molding with an over-molding process. Creating a prototype of an over-molded part used to require building a steel mold which took about 10 weeks to build and five weeks to modify for each design iteration, so it took about 6 months to get a new product to market.
Plasel Precision Plastics produced blow molded prototypes by CNC machining on an aluminum mold which took up to 20 days of production time and cost $5,000. Design Reality produced molds for making functional prototypes of LSR respirators by CNC machining of modeling board or aluminum, which took 24 hours and cost $2,000.
Reduce lead time and cost
Additive manufacturing drastically reduces the lead time and cost required to produce molds for all of these applications so it can produce prototypes for functional testing at a fraction of the lead time and cost of traditional prototype mold tooling. Additive manufacturing can produce high resolution molds with smooth surfaces that are ideal for building injection molds capable of producing prototype parts in production-grade thermoplastics. Blow molders are also adopting additive manufacturing to produce blow molds that can withstand both the temperature and pressure of the blow molding process. Additive manufacturing provides dramatic time and cost savings in producing molds for LSR parts.
The numbers speak for themselves
The results speak for themselves. Turck reduced the time to first injection molded prototypes by 97% to two days with additive manufacturing and reduced the cost of tooling, assuming three iterations, by 23% from $30,000 to $23,000. The company has reduced the typical time required to bring a new product to market by 33% to four months.
Plasel used additive manufacturing to reduce the time required to produce 100 blow molded prototypes 90% to two days and reduced the cost by 94% to $280. The faster turnaround time made it possible for the customer to introduce its new product weeks faster than was required in the past. Design Reality now produces LSR respirator prototypes in molds produced by additive manufacturing in only eighteen hours, 75% less time than was required with CNC, and for $1,000, half the cost of CNC.
Additive manufacturing of injection molds, blow molds and LSR molds makes it possible to produce functional prototypes with the same mechanical properties as production parts at a much lower cost and in a fraction of the time required by conventional prototyping methods.
Fisher Unitech can help you seamlessly convert to printed mold tooling by guiding you through the selection process and providing telephone support, software releases and updates, free exchange of parts, and on-site service calls.
This is the third in a series of blog posts in which we will discuss the advantages of using additive manufacturing to produce different types of manufacturing aids.
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About the Author
Jerry Fireman is a technology writer who specializes in writing about computer aided design (CAD), 3D printing, computer-aided engineering (CAE), the Internet of Things (IoT), electronic engineering, pharmaceutical research and manufacturing, test and measurement and a variety of other topics.