Summer 2001

Product Spotlight
The Indispensable Injection Mold Shop

Lighthouse employees manufacture plastic components in the injection mold shop

"Our machines are rated by how many tons of pressure it takes to clamp a mold shut and prevent it from unlocking," explains Ben Mariano, Seattle Lighthouse injection mold shop Senior Lead. "Our smallest machine is rated at 75 tons, and our largest is rated at 550 tons." Using six different injection machines, and approximately thirty different molds over the course of a year, the shop produces thousands of plastic components used in assembling Lighthouse products. In-house injection molded parts are used in our canteens, paper trimmers, easels, kitchen utensils and Anglematic® mops.

"Our canteen cap machine runs constantly," continues Mariano, "and uses about 250 pounds of resin in pellet form daily. Our 550-ton machine goes through about 1,000 pounds of resin daily, producing the boards for our paper trimmers."

In simple terms, the injection mold process works something like this:

Resin in the form of small pellets is poured into a hopper. A relatively small amount of coloring agent pellets is added. Pellets are gravity-fed into an injection nozzle. Bands around the nozzle heat the plastic pellets to about 400° Fahrenheit. A hydraulic screw mixes the molten plastic and forces it into a mold. Once full, the mold is clamped and held shut. Plastic remains inside from a few seconds to ten minutes, depending on the size of part being made. Circulating water then cools the mold until the part is ready. Completed components then emerge from the machine, attached to plastic rods called runners. Parts are removed from runners by hand and placed in the proper bins. Runners are then ground up and reused.

Four out of five workers in the injection mold shop are visually impaired. David Stanley, who is totally blind, has worked at the Lighthouse for four years. "I've been in the injection mold area for about a year and a half," explains David. Originally from Spokane, David attended the Washington State School for the Blind in Vancouver from 1986 to 1992. "After finishing at the School for the Blind I attended the OTC (Occupational Training Center) at the Department of Services for the Blind," continues David. "While I was going to the OTC I moved into Center Park, which is basically right next door to the Lighthouse. I walk to work and walk home. It's very convenient. I really enjoy what I do; working around these fantastic machines and producing all of these parts. I also really like the people I work with."

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