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California firm supplies solar-powered rotomolding units

Issue: April 2017

Not to throw shade on traditional methods of manufacturing, but Karl von Kries, CEO and founder of a company that supplies rotomolding machines, and his company, LightManufacturing, are blazing a new trail that doesn’t require a factory — or generate energy bills.

Founded in California in 2010, LightManufacturing supplies solar-powered rotomolding machines. Each of the machines, known as solar rotational molding systems (SRMs), rely on energy captured by heliostats — special mirrors that direct sunlight onto a mold to achieve optimal heating. Solar cells power the movement of the mirrors and machine arms.

A LightManufacturing solar rotational molding system

“You can make useful parts entirely off-grid, and you can do it at a much lower cost than with a traditional grid-tied facility,” said von Kries, who calls the setup “manufacturing without the factory.”

LightManufacturing recently updated its latest version of the SRM by replacing the unit’s standard motors with stepper motors. The new motors give users more control over the position of molds within their machines, so heat can be focused in particular areas for discrete amounts of time.

“The advantage of step-motor control is that you can put the mold into any position you want inside the machine — great for loading and unloading parts,” von Kries said. “And with optional motion control software that we’re developing, step motors pave the way [for] advanced molding techniques that leverage motion control and beam-based heating.”

There are two models available: the one-chamber SRM1, which costs about $50,000, and the two-chamber SRM2. Starting at about $100,000, the SRM2 comes complete with 20 heliostats and can make products as big as a 650-gallon water tank. The machines can use any rotational molding resin, including PE, PP and nylon, and manufacture the same sort of products as traditionally powered versions, including toys, road barriers and kayaks.

“With ours, really all you’re really paying for is our gear and you can drop it on farmland or unimproved land and be molding within a week,” he said. In all, the entire manufacturing complex — including heliostat setup, raw material and part storage, and rotomolding machine — takes up about 1,000 square feet; 12 systems can squeeze onto an acre of bare ground.

While the solar-powered heliostats are most at home in the sun, the SRMs aren’t limited to beach weather. Unlike solar-powered, or photovoltaic batteries, heliostats don’t convert energy — they simply focus it. “We’re all so used to solar [energy applications] being solar electric, they’re great, but the conversion efficiency of photovoltaics is only about 20 percent,” von Kries said. He explained that heliostats deliver a much greater return. “We’re reflecting more than 80 percent onto the target.”

Heliostats -- special mirrors that move in concert with the sun, directing rays onto a mold -- power a solar rotational molding system.

According to the Solar Energy Industries Association, in the U.S., photovoltaic arrays are found primarily in the desert Southwest. By comparison, von Kries believes that about 49 percent of the Earth’s land mass gets enough sun to make SRMs feasible; even northern climates are candidates — as long as seasonal-only production is acceptable. Areas like California, Texas and Florida are especially hospitable, offering the potential for eight to 10 hours of production per day, with the possibility of a second shift devoted to more labor-intensive activities, such as packaging. Rotomolding is “surprisingly tolerant of partial cloud cover,” von Kries said.

The systems offer numerous advantages, he said. They’re environmentally friendly, and compared to in-factory units, are much more economical, as well.

By going green, companies can benefit from the goodwill of their customers and qualify for government incentives, where available. They can also locate — or relocate — easily to gain access to customers, reducing time-to-market and transportation costs.

Several LightManufacturing setups are already at work in the U.S., which is a testament to how far the technology has come since its early days, when von Kries admits he had doubts. Now that the systems have generated interest in the U.S. and abroad, though, the light bulbs continue to go off for him and LightManufacturing’s team of about 20 people. With patents pending in dozens of countries, he said they’re looking at ways to extend the technology to areas such as vacuum forming.

“Rotomolding was the first of what we would like to think will be many industrial solar thermal applications,” he said. “But we’re looking outside the plastics realm, as well.”

Karen Hanna, copy editor

khanna@plasticsmachinerymagazine.com

Contact

LightManufacturing

Pismo Beach, Calif.

415-796-6475

www.lightmanufacturingsystems.com