Columbus, Ohio — Rick Barnes brought his 45 years of plastics experience to Columbus, where he detailed safety around injection molding machines at the Environmental Health and Safety Summit.
Barnes retired in 2015, then became a senior instructor at the Paulson Plastics Academy, which is part of Paulson Training Programs Inc. The plastics veteran said most minor injuries in factories come from four main primary causes: poor training, poor housekeeping, poor enforcement and poor maintenance.
In his presentation, Barnes looked at general machine safety: cuts from knives and sharp mold components; slips and falls from clambering over obstacles, climbing on equipment and oil and spilled resin; and burns.
Barnes showed a Paulson video that said the heating barrel is the hottest part of the injection molding press, ranging from 350°F-800°F, depending on the type of plastic being molded. Other hazard points include high-pressure areas like loose hydraulic hoses and hot runner plugs and mold plates, as well as electricity from wires coming off heater bands.
Barnes said employees must be trained and aware of pinch points that are in the clamp system, the injection unit and ejector plates in the mold.
A big danger is reaching past or under the press safety guards, or failing to lockout and tag-out the machine before entering the mold area.
Improper cleaning of buildup of plastic from injection nozzles can cause leakage that over time creates a crusted-on residue nicknamed a "doughnut," or a "bonnet." He showed a photo of a guy burning off the material — a dangerous practice as it flames up.
Cuts are a common hazard, particularly at small molding shops, where parts get hand trimmed, Barnes said. Dull knives cause the worker to bear down more. That can cause lacerations. "Knives should be kept as sharp as possible at all times," he said. He added that a stainless-steel butcher's glove is the best protection for the hand holding the part.
A worker can get cut on sharp edges on equipment as well as some mold components. Barnes said the ejector pin should be retracted back into the mold before working on the tool.
"Ejector pins have very sharp edges and they are very small," he said. Sliding mold cores are perfectly square, so they have "razor-sharp edges," he added.
Removing a cold slug from a frozen nozzle should be treated with caution and proper safety gear, according to Barnes. There can be an explosion of built-up molten plastic.
Even compressed air hoses can be dangerous. Never drive a forklift over an air line, since it could rupture. And never use the hose to "clean yourself off," Barnes said, because you could accidentally bring the air across your ear and rupture an eardrum. He said the compressed air also could force dust into your skin, causing infections.
But he described something even worse, such as a deep scratch or shallow cut that can allow the compressed air to enter the skin, inflating the muscle underneath and causing excruciating pain.
In a factory, there are better ways to clean yourself off that won't risk turning your arm into one like Popeye's, Barnes said.