M R Mold Discovers Potential of LSR Technology

There’s nothing new about liquid injection molded elastomers – they’ve been widely used in manufacturing for some time by such industries as aerospace, healthcare and electronics to name a few.  To emphasize this point, Rick Finnie, president of M R Mold & Engineering Corp. in Brea, CA, has been building molds for liquid silicone rubber (LSR) for 20 years.

But it wasn’t until about a two years ago that he started offering molds for LSR as a primary part of his services, and opened up a whole new world in which to grow his company.

Rick talks about an experience he had while on an Society of the Plastics Industry (SPI) sponsored trip to Asia in 1999, saying it was probably the first point at which he realized his company’s focus was in need of an adjustment.  The company built and marketed primarily injection molds for plastic during its 17 years in business.

Finnie was touring an injection mold manufacturing plant in China when he came upon someone working on a mold he himself had quoted.  Now he knew what happened to that job.

"I came away from that trip realizing that U.S. manufacturers are clueless about what Chinese companies are really like,” he says.  “They’ve got everything they need to completely replace us (moldmakers).  It was very obvious to me that it wasn’t a joke – that these are real mold shops and there are a lot of them.”

The experience in Asia and the fact that business had slowed down for his company over the previous couple of years influenced Finnie to begin thinking differently about how to go about servicing customers and remain competitive, viable.

“I was really focused on injection mold tooling and suddenly I realized we had a niche market within our company that we hadn’t done anything with,” he explains.  “That was LSR.  We didn’t market it or treat it as a primary service, but there was definitely potential there that we had to try to tap.”

Finnie explains that silicones and rubbers work opposite of plastic.  They are kept at room temperature or kept chilled.  When molding LSR you inject it into a hot mold, but unlike plastic you can’t remold it because its chemical properties won’t allow it to re-melt.  In addition, you use cold runner systems instead of the traditional hot runners plastics require.

“I had talked to John Timmerman, Manager of Thermoset Group at Engel Machinery, and they wanted me to build an LSR tool they could run on their electric molding machine to show its sequential valve gating capabilities,” he explains.  “So I built an eight-cavity sequential valve gated, cold-runner family mold that fabricates syringe tips varying in size from .875” to .500” in size.”

Sequential valve gating, while not new to the plastic injection mold industry, is still an unfamiliar process in the U.S. LSR molding industry, Finnie explains, though Austrian mold builders are quite familiar with it.  The Austrians, in fact, are Finnie’s main competition.

“The Austrians are very sophisticated in building molds for LSR,” he says.  “I’m one of only about a dozen shops that builds them in the U.S.”

Engel ran the mold at the Plastec Show in Anaheim, CA, earlier this month.  Finnie also exhibited the process on a laptop computer at the Society of Plastics Engineers (SPE) LSR InfoTech 2004, held this month. The reactions he received were varied, but definitely positive, he says.

“I have a lot of potential customers inquiring about LSR molds,” Finnie says.  “We’re able to not only assist customers with prototyping and research and development of the molds, but we also sample and build production tooling for them as well.”

While M R Mold still builds injection molds for plastic, he says today about 75% of his business is in LSR as compared to 50% or less in 2001. The company’s sales are up a modest 10% but Finnie sees potential for far bigger increases in 2004.

For the last year, Finnie has been working diligently on building his LSR business and researching ways to improve on the process.  Feedback from customers has led his company to build more robust molds than is typical because many customers complained that LSR mold manifolds are difficult to clean and too prone to breaking during assembly and disassembly.

“Ours can be disassembled from the parting line so that the cured rubber can be cleaned out without fear of damaging the mold,” Finnie says.  “We even made a custom robotic arm to remove the molded parts that is a permanent part of the mold, unlike end-of-arm tooling.  We’re one of the only companies in the country doing that, too.”

To find out more about M R Mold and its LSR capabilities, visit their website at www.mrmold.com.