Mill shapes

P/M Tool Steels. In conventionally produced high alloy tool steels (slowly cooled cast ingots), carbide tends to segregate (48). Segregated clusters of carbide persist even after hot working, and cause undesirable effects on tool fabrication and tool performance. P/M tool steels, on the other hand, provide very fine and uniform carbides in the compact, the final bar stock, and the tools. Several tool steel suppHers consoHdate gas-atomized tool steel powder by HIP to intermediate shapes, which are then hot-worked to final mill shapes. Water-atomized tool steel powder is also available (see also T OOL materials). ... 

Its greatest deficiency is processability—it is hardly thermoplastic at all Hercules sells mill shapes which must be machined into 6nd products, while Formica has developed a continuous compactionsintering machine for producing it in sheet and laminate form (3). In addition, its modulus, strength, and heat distortion temperature are no better than conventional medium-density polyethylene. Bar, plate, and rod stock sell for 2 up, before machining. 

Industry estimates indicate that up to 5% of the total resin production finds its way into prototype or mill shape plastic products. By mill shapes is meant those primary uniform configuration subject to established cross-sectional and length tolerances. While this estimate is necessarily conjectural, the best available information indicates that this range is accurate. Modem Plastics magazine estimated mill shape production for 1968 in acrylics, cellulose, nylon, acetal, polycarbonate, high density polyethylene, polypropylene, poly(vinyl chloride), and copolymers to approach 336.4 million pounds. Total United States resin production for 1968 slightly exceeded 16 billion pounds. 

Much of the mill shape production is converted in house by the processors themselves— such as in the case of polyethelene film for... 

A multitude of mill shape sizes are commercially available to reduce machined part waste and cost. 

The materials mentioned above are stock inventory items with quality plastic service centers. Most cities in the United States with a population of 150,000 or more enjoy the services of a reputable plastic mill shape service center. 

These centers stock mill shapes in the following configurations ... 

Certain sectors of the mill shapes industry has indeed market oriented itself. The needs of the researcher, designer, prototyper, production planner, manufacturing manager and even the mainten-... 

Current mill shapes pricing falls into three categories ... 

This is because of lower raw materials costs through increased production on the part of the resin manufacturers as well as continuing manufacturing efficiencies effected by the mill shape processors. 

Distributor pricing of mill shapes represents a discount from the above prices, excepting fluorocarbons, of approximately 30%. Of course, large (O.E.M.) original equipment manufacturer special runs affect a further discount which is variable depending on the size, type, and quantity of the product involved. 

The sales and distribution channels of plastic mill shapes are less sophisticated and not as structured as distribution of ferrous and non-ferrous metals. The industry growth has been so rapid that maturity of distribution as found in other mill shapes industries has not had time to evolve. Currently there are almost twenty mill shape producers of mechanical plastics. These producers supply the market through distributors, direct to the O.E.M. and in one instance a national producer employs the above marketing modes plus utilizing its own fifty stocking service centers. This places the company in the closest possible contact geographically with all its markets. 

It is important to note that some manufacturers of mill shapes in order to cope with continuing need for greater in-depth material and applications needs of potential customers have augmented the sales effort of their branch service centers with centrally located product... 

This additional marketing service has allowed a much greater in-depth penetration of plastic material capabilities. Such service is available through less than a handful of plastic mill shape processors. 

This section is fabricated from a standard mill shape. 

The part is sold as a fabricated part to the end-using brewery. However, the mill shape itself is available if the brewery personnel elect to machine the part themselves. 

These two instances represent related areas where specific properties of plastic mill shapes properly evaluated and correctly designed can extend part wear life, reduce installation cost and reduce handling, and create greater production efficiencies, at perhaps the same or a lower cost. 

Three primary installations in an integrated steel plant are the blast furnace, the steel furnaces, and the rolling mills. The blast furnace converts iron ore to pig iron the steel furnaces convert the pig iron to steel and the rolling mills shape the steel into sheets, slabs, or bars. 

If the mills could roll perfect mill shape (see Fig. I), there would be no need for loops and tensioning devices and, except for some fan-out problems, the tight-line pull-through slitting-line concept would satisfy the tight coiling needs of the industry. 

Figure 3 Typical mill shape slit strip cross section.

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