PP compounds achieve tight fit for safe deposit boxes
By Ryan Paxton
Diebold's LM Series of safe deposit boxes have undergone a number of transformations since their introduction in 1982. Once made from metal, they have now returned to using plastics to cut production ...
Diebold’s LM Series of safe deposit boxes have undergone a number of transformations since their introduction in 1982. Once made from metal, they have now returned to using plastics to cut production costs. The boxes are made of two separate materials supplied by Multibase: one used for the base of the box, and the other for a lid that incorporates a living hinge. Both materials need to function together within tight tolerances, despite the fact that the base and lid have with different shrinkage rates.
“The molder was actually able to eliminate a cooling fixture,” says Tim Fisher of Multibase. “Instead, the lids are molded, and then the base boxes are used as a structural cooling mechanism to attain the desired fit between top and bottom components.”
Multipro 4615X, a mixed mineral-filled, impact-modified polypropylene (PP), was used for the base unit because of its impact resistance and flexural strength to ensure the walls would not buckle.
Multipro 0710C, a minimally-filled calcium carbonate, impact-modified PP, was used for the lid because it provides physical flexibility combined with durability, which is essential to the long-term performance of the living hinge.
Multibase Inc. 800-343-5626
