Canadian Plastics

Canada’s small LSM industry gets boost after Austrian firm sets up shop in Ontario

Canada is still playing catch-up to the U.S. in liquid silicone molding (LSM). But last summer, Austrian LSM guru Starlim, opened its North American headquarters in Ontario, injecting the country with...

February 1, 2006   By Rebecca Reid, associate editor



Canada is still playing catch-up to the U.S. in liquid silicone molding (LSM). But last summer, Austrian LSM guru Starlim, opened its North American headquarters in Ontario, injecting the country with some of the expertise it needs.

Also referred to as liquid injection molding (LIM), LSM is a different process to thermoplastic injection molding, despite being processed on similar machinery. John Timmerman, vice-president of marketing and sales at Starlim North America said LSM requires a unique set of skills, especially when it comes to making molds for liquid silicone applications. the founder of Starlim’s parent company, Starlim/Sterner operates two distinct wings: Sterner for liquid silicone molds and Starlim for the actual molding.

However, this lack of expertise is not surprising, he said, considering there are literally no academic institutions teaching the process. As a result, there only a handful of companies are involved in the process. And processors looking to diversify, making the jump from thermoplastic injection molding to LSM isn’t easy.

“For some Canadian companies, the cost of entering LSM would depend on its productivity,” Timmerman explained. “If they were as productive (as U.S. firms) they would be able to compete.”

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The U.S. has been able to compete with Canadian firms that can offer lower costs, by ramping up their productivity. Canadian manufacturing firms have not followed suit. The lack of education coupled with the productivity gap has resulted in discrepancy between the size and sophistication of LSM operations. And with North America being one of the largest markets for liquid silicone, Timmerman said Canadian manufacturers are missing out.

Even with the relatively higher dollar, Canadian companies would have to lower costs and increase productivity to do it, he said. Because if plastics processors are really serious about conducting LSM, they’re going to have to free up some manpower to dedicate to the process.

Although Bolton, Ont. is home to Silcotech North America, a fairly large liquid silicone molder, which started up operations in 1999, the presence of Starlim adds significantly to LSM capacity of the country. In addition, Montreal-based Delta Rim Composites Inc. has been doing LSM since 1990.

Starlim’s facility has 10 Engel-made liquid silicone injection molding machines. It will increase to between 60 and 70. The machines have clamp forces of 90 or 150 metric tons. Additionally, the molding is a fully automated process; the facility is run by between 10 to 15 employees at any given time, and not one is a machine operator.

By the end of the year, Starlim will have produced 500 million parts.

So far, Timmerman said the London facility has a part reject rate of zero, and Starlim worldwide has only a reject rate of 0.6 on some three billion parts.

That’s because Starlim has to produce these products, such as connector seals for automotive applications, in high volumes. When each car contains between 100 and 200 of these components, and when automotive OEMs are turning to just-in-time sourcing, they can’t afford any human error either wasting or contaminating materials, especially when it costs US$10 to 15 per kg and can not be recycled.

At Starlim’s facility, liquid silicone is pumped from drums in the basement into the Engel LSM molding machines on the factory floor. There are two drums, which meter out the correction portions of the ‘A’ and ‘B’ materials mixed to produce liquid silicone. When the drums are empty, they are changed manually — one of the only processes that isn’t automated. The other manual process is moving finished parts from the shop floor to either storage, or to be cleaned before being moved to storage.

Starlim ships all its products in plastic bins. A cardboard container splitting open and spilling the contents onto the shop floor could make some components fail quality control. And anyone walking on the shop floor is required to wear disposable shoe covers.

Eventually, Starlim plans to leverage the educational institutions in London, Ont., to increase expertise in the process. London is home to the University of Western Ontario and Fanshawe College, plus a large medical research community.

Plus it’s only about 200 km from Windsor, Ont., which also has a large technical college, and right across the border from Detroit – North America’s automotive Mecca. Automotive is also a big user of liquid silicone as a rubber alternative.

“They are such large users of silicone that our usage tends to mirror the market,” he said.

TAKING THE HEAT

Thermoplastic elastomers (TPEs) are also increasingly being used in the automotive industry to replace rubber, but liquid silicone’s high heat-tolerance make it viable for applications where TPEs would simply melt under the pressure. Plus they become brittle at temperatures below 40 degrees Celsisus.

Also, TPEs have poor creep resistance, he said. This has traditionally prevented them being used for sealing, he said, except for short-term sealing. Thermoplastic vulcanizates (TPVs), however, are starting to penetrate the auto market in weather seals.

Liquid silicone’s biggest disadvantage is that once it tears, even a bit, it becomes easy to split, Timmerman said. But otherwise it has some properties very advantageous to both the automotive and medical markets.

KITCHEN CHEMISTRY

Silicone is a non-volatile, inorganic material, making it impervious to organic fluids like motor oil and gasoline, unlike TPEs, which are petrochemical-based.

Its inorganic nature is one of the biggest value propositions for the medical industry. Human bodies won’t absorb, break down or digest liquid silicone, which is the last thing any patient (or a doctor) wants in a tube placed in an organ to drain excess fluids. It’s not rocket science: it’s the same kitchen chemistry as oil and water.

This characteristic has also made it a mainstay in babycare items and toys like nipples and pacifiers, where unlike diapers, high absorption rates are not desirable.

Baby pacifiers are still primarily made of natural rubber in less wealthy countries but those made of liquid silicone offer some key benefits in terms of health and safety, Timmerman noted.

Liquid silicone has excellent clarity, compared to natural rubber, which is brown, making it easier for parents to tell when the pacifier has become soiled. Plus, the material’s high-heat tolerance means it can be thrown in the dishwasher and won’t degrade. When rubber degrades, it breaks apart, and if it breaks apart in the baby’s mouth, in the worst case, it could cause choking. And if swallowed, a chemical called nitrosamines would be released that medical experts believe, cause cancer. Liquid silicone can’t be digested; it would simply pass through.

Liquid silicone’s clarity also makes it easier to colour, compared with TPEs and especially TPVs, which only come in black, and in some cases, colour-matched black.

FITTING THE MOLD

Although liquid silicone shares properties with thermoplastics, it also shares properties with rubber. Yet making a mold for liquid silicone requires a unique set of skills, Timmerman said.

Even though Canada supplies 50 per cent of the molds for plastics processing in the U.S., molds for LSM are difficult to source in Canada. And Canadian moldmakers supplying LSM molds generally do it as an adjunct to primary business, which is making molds for thermoplastics, Timmerman. U.S. firms devoted specifically to LSM molds have the advantage of more time and resource, he added.

One key difference between molds for thermoplastics and LSM is that it’s much easier to control flash with thermoplastic molds, Timmerman noted. Thermoplastics shrink when cooled, so it takes a lot more pressure to get flash. Liquid silicone on the other hand, doesn’t shrink, so controlling the pressure is paramount. Flash can ruin a part, and when the material is as expensive as LSM, the mo
lds need to be top-notch.


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