[Case Study] Repair and Polishing of Resin Hopper through Welding and Grinding

Welding repair of resin hopper and scratch removal by polishing.

At the bento manufacturing factory, we use a hopper made of resin (polypropylene) for the machine that packs cooked rice into bento boxes. Due to frequent installation and removal for cleaning, the welded legs can come off, and cracks can appear at the joints. Similarly, the chute made of resin (nylon) shows signs of aging, such as splinters, fuzziness, and scratches on the surface, making it difficult to clean. Issues: 1. Parts are purchased from the machine manufacturer, but they are never cheap. 2. We attempt self-repair (such as securing with tape), but it peels off again quickly. 3. It is very unfortunate that the hopper, which is still usable in terms of surface condition, cannot be used because the joints have come off. 4. The chute also seems to have a lot of life left, but if the dirt cannot be removed, the risk of mold and bacterial growth increases.

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