A leading custom profile extruder of plastics attains flawless surface finish quality while doubling die life and increasing productivity by the application of unique, steel-hard coatings to its aluminum extrusion dies.
Its nine extruders produce hundreds of shapes of various thicknesses and lengths in some 20 different plastics. Extrusions range from 1/4" to 14" wide and up to 10"; in diameter. For this variety of shapes about 150 new sizing blocks are designed each year. A typical extruder runs a different die each day for a different product run..
Quality means that every plastic profile emerges from the extruder with an unmarred finish. But before they learned how to prevent it, surface imperfections would often crop up on the tools' and parts' surfaces. Raw plastics, especially abrasive ones, would eventually scratch the aluminum sizing blocks during extrusion. The operator would have to stop to repolish the tool by hand with an emery cloth. This had a dramatic negative impact on production throughput as well as on costs.
The TUFRAM coating imparts previously unattainable levels of hardness, wear and permanent lubricity to the aluminum surfaces of the extruders. The enhancement has a hardness between Rc 40 and Rc 65, approximately that of nitrided steel. When applied to die surfaces, it protects them against scratches, blemishes, marks, and scoring. Taber abrasion tests show that TUFRAM has greater abrasion resistance than case-hardened steel or hard chrome plate. The TUFRAM surface enhancements increase Dande Plastics' productivity by doubling the wear life of the aluminum dies.
Long run and repeat-run products constitute a major share of output. It first prepares each tool by cleaning, then sends it to General Magnaplate for coating. Magnaplate does this in a proprietary multi-step process which combines the advantages of anodizing or hardcoat plating with controlled infusion of low- friction proprietary engineering polymers and/or dry lubricants. By combining the hardness of aluminum oxide ceramic with the proprietary polymers, the TUFRAM "synergistic" surface enhancement becomes an integral part of the aluminum basecoat and exhibits far better wear, friction, and non-slip properties than either the base coat or the coating components alone.
The coatings further improved tool productivity by shortening tool preparation time and speeding changeovers. The coated tools better survive storage between runs, so are ready for reuse with minimal surface preparation.