By: Rhoda Miel
October 22, 2013
DÜSSELDORF, GERMANY — Harald Schmidt is happy to point out that his company's first micromolding machine doesn't look like anything else on the market.
The Mold Hotrunner Solutions Inc. (Hall 1/A9) press is a modular cell, built up vertically and complete with material dryers, filters to meet medical clean room requirements, cooling, magnetic clamps and the tie-barless press itself, capable of producing micro gears in a five-second cycle. It's all housed within a compact package that looks more like a high-end closet system than a plastics machine.
"This was designed by plastics engineers, not mechanical engineers," Schmidt said during a news conference at K 2013. "The key is understanding everything that is happening from a complete understanding of rheology."
The MHS press is built around the company's hot-runner system, using MHS' hot runners and valve controls on the 32-cavity system. It is capable of producing 150 million micro parts per year. The modular design makes it easy to add on other production systems such as post-molding assembly or reel-to-reel molding, he said.
The system on display at K 2013 uses about two grams of material per cycle and can operate all day on four pounds of resin, he said.
Because of that very small shot size, micro molded parts are highly sensitive to temperature variations, Schmidt said, so the company relies on its own proprietary system using hot runners to bring the resin to the right temperature right at the valve.
"The days are over that you would use force to push the plastic as far as you can," Schmidt said. "Today, we use gating and technology in the mold for a more controlled delivery."
MHS, based in Georgetown, Ontario, said its micromolding system is the first to allow for high- volume production. The multi-cavity system can easily adapt from a single mold for prototyping to up to 32 cavities for full production.
On the other end of the scale, MHS has a new line of Rheo-Pro slide manifolds specifically designed for very large injection molds. The slider system allows for more controlled material flow within very large parts.
Schmidt said MHS' system is already in production on an injection molded part more than one meter deep and one meter in length. That capability makes is possible to injection mold parts that previously would have been slated for thermoforming.
MHS also introduced a new generation of back-to-back valve gates for use on small stack mold systems, often used in caps and closures.