Rotary plastic drum used for chemical or electrolytic surface treatments of small metal parts

摘要

The internal drum casing is polygonal, made of individual side panels (4). These are flat, rectangular and perforated. Parallel to the axis, within each panel, there is a rectangular reinforcing rib (5). The rib is integral to the panel, the material homogeneous throughout. An Independent claim is included for the method of making the drum, in which the casing sides (2) are made by a cutting process from a long, prismatic, thick-walled slab of synthetic material. Preferred features: Reinforcing ribs appear on one or both sides of the panel. Ribs run along the panel bordering the long edges. In making the drum, the thick slab is pressed or press-sintered from polypropylene or polyethylene in a mold. The polypropylene used is temperature-stabilized. Alternatively polyethylene of high molecular weight: 300,000 to 800,000, is used. Its molecular weight may be ultra-high: 1,000,000 - 8,000,000. Contacting long edges are joined at an angle (e.g. at 120 deg ) using a heated element, hot air welding or an extrusion welding process. Drum lifting flights are attached. The sides (2) are made by a computer numerically controlled machining process (CNC).