In Moldmaking, Mantle Process Addresses Lead Time and Talent Pool

Is the way injection molds are made getting ready to change? Today, mold cores and cavities are made on CNC machining centers; they are milled out of tool steel. And they will almost entirely continue to be made that way for some time to come.

But a very different means of making cores and cavities that has now fully come to market still uses a CNC machining center — albeit a modified one — and still works in tool steel — albeit initially in a non-solid form. The California-based startup Mantle is now out of beta testing and has begun shipping the production version of its “TrueShape” system for rapid, streamlined creation of injection mold tooling.

The company’s process starts with steel in a paste form and is enabled by 3D printing. It works this way: Metal paste developed by Mantle is 3D printed and CNC machined in a single operation, and then through controlled sintering becomes a fully dense steel mold core or cavity, in material equivalent to H13 or P20. Rough milling and EDM are avoided in this process, as is drilling of the cooling lines, which in TrueShape can easily be 3D printed conformal to the tool geometry.

Tool performance is equivalent to a mold made traditionally (one molder, Tessy Plastics, has taken a TrueShape mold past 1.65 million cycles), but the pacing is much faster: Printing and sintering of a core and cavity take just two to three days, compared to the several weeks of lead time more commonly associated with injection molds. The system consists of machine, software, furnace and material — all supplied by the company — and a video at gbm.media/mantle offers more detail about the operation of the Mantle moldmaking process.

Ted Sorom is Mantle’s cofounder. He says the TrueShape process competes against conventional moldmaking on both cost and time, but time savings are proving to be more significant for driving adoption and potentially transforming how tooling is developed. He expected cost to be the prime factor, but the company’s findings so far reveal something different.

Sorom explains: “For large OEMs [making plastic parts], the cost of tooling is already factored in. They expect it.” By contrast, he says the lead time for molds is a factor increasingly slipping out of their control, affecting how quickly they can adapt and innovate. Mantle’s process answers the mold lead time challenge by providing a production tool so quickly as to eliminate the need for a prototype tool (perhaps machined from aluminum) by eliminating the distinction between production and prototype tooling.

Another Mantle leader, Chief Commercial Officer Paul DiLaura, explains the consequence: “We offer time savings through faster validation,” he says, whether that is validating a fully new design or a design change. Where there is a validation requirement for plastic parts, even a small design change might introduce a major delay.

DiLaura quotes a beta user, Nicolet Plastics, saying one of this company’s leaders noted this difference with the Mantle system: “It lets us get a production tool in prototype time.” This enables validation of both design and process simultaneously. The fast moldmaking “de-risks production,” DiLaura says. “If the part design works, then you begin production with the same tool.”

Sorom notes the time to make a mold with this system is not only shorter, but more predictable as well. This led to another discovery: TrueShape is also an estimating tool. “We know exact time and material use,” he says. “Job quoting is much easier” — an advantage pointed out to Mantle by early users.

But the most significant advantage of the TrueShape system might relate to the people involved in moldmaking, including toolmakers and plastics engineers. These skilled personnel are, of course, still needed.

Someone has to design the mold; someone has to finish, fit and build the mold after the core and cavity are made. TrueShape’s solution can eliminate roughing, EDM and prototyping — not people. But as DiLaura points out, it can allow those people to do more.

Nicolet Plastics is an example of a company able to benefit from this, he says. The injection molder relies on an in-house toolmaking department with experienced team members. Any retirements from this team would likely cause in-house toolmaking capacity to decline, due to the potential difficulty of finding a suitable replacement toolmaker.

Streamlining the process — through easier quoting for engineering and fewer steps in moldmaking — amplifies the capability of knowledgeable people by freeing some of their attention and time. Thus, even if the toolmaking talent pool decreases, the remaining team members might still deliver just as many molds.