Cutting material selection

Furthermore, for 2020 the EU has committed to cutting its emissions to 20% below 1990 levels for 2050 EU leaders have endorsed the objective of reducing Europe s greenhouse gas emissions by 80—95% compared to 1990 levels. LCA has been developed as a useful tool to evaluate the environmental impacts of products and processes. It is very useful for material selection, representing a very important step to design more sustainable products. Some considerations on composite products must be assumed ... 

H. J. Swinheart (Ed.), Cutting Tools Materials Selections, Am. Soc. of Tools and Manufactory Eng., Dearborn, Michigan, 1986. 

Inserts are available in a range of cutting materials, sizes, shapes, cutting geometries and grades suited to a vast range of applications, a selection is shown in Fig. 7.3. 

Discusses cutting-edge methodologies in PEM material selection and fabrica-... 

In addition some samples were reformed by pressing into sheets small samples were then cut for ageing in air drculated ovens at various temperatures, between 120 and 150°C, both in and out of contact with copper. These oven ageing trials were conducted in order to validate the extrapolation to higher temperatures so that future material selection based solely on DSC measurement of OIT could be vahdated. The time to failure in the oven ageing trials was assessed by a simple three-point bending test, since it was found that the polypropylene lost aU mechanical integrity rather rapidly once the oxidation process was under way. The time to failure was reported as OIT at the lower temperatures and these results incorporated into the Arrhenius plots. 

Thermoplastic materials are also used in batch production scenarios, albeit in a different manner. Instead of being used as raw materials, they are more likely to be used in an intermediate product, as a sheet that gets formed and cut, as a block that gets machined, as a film that gets converted to another shape, etc. In these scenarios, the material selection process is very similar to the process used in the fabrication of standardized parts for mass production. As such, the information presented in later chapters can also be used to evaluate the materials used in these intermediate products. 

Tuff, a compressed volcanic material, is the primary constituent of Yucca Mountain, near Las Vegas, Nevada, the site selected by Congress in 1987 for assessment for spent fuel disposal. An underground laboratory, to consist of many kilometers of tunnels and test rooms, is to be cut into the mountain with special boring equipment to determine if the site is suitable for a repository. 

The method of action of the polymers is thought to be encapsulation of drill cuttings and exposed shales on the borehole wall by the nonionic materials, and selective adsorption of anionic polymers on positively charged sites of exposed clays which limits the extent of possible swelling. The latter method appears to be tme particularly for certain anionic polymers because of the low concentrations that can be used to achieve shale protection (8). 

Fig. 2. Methodology for the selection of tool material, grade, shape, size, and geometry, and cutting conditions for a given appHcation (8).

Petroleum asphalts, compared to native asphalts, are organic with only trace amounts of inorganic materials. They derive their characteristics from the nature of their cmde origins with some variation possible by choice of manufacturing process. Although there are a number of refineries or refinery units whose prime function is to produce asphalt, petroleum asphalt is primarily a product of integrated refineries (Fig. 1). Cmdes may be selected for these refineries for a variety of other product requirements and the asphalt (or residuum) produced may vary somewhat in characteristics from one refinery-cmde system to another and even by cut-point (Table 2) and asphalt content (Fig. 2) (5,6). The approximate asphalt yields (%) from various cmde oils are as follows ... 

Bending. The smallest radius over which strip of a particular alloy can be formed without failing is important in the selection of materials for a given appHcation. The industry tests formabiHty using samples cut from strip material to rank materials and thereby indicate whether a particular alloy/temper is suited for an appHcation (15). Performance of the material in actual stamping is the best final judge of suitabiHty. 

Fortunately the situation in practice is not quite as complex as it might seem. In general, very acceptable designs are achieved by using impact data obtained under conditions which relate as closely as possible to the service conditions. Impact strength values available in the literature may be used for the initial selection of a material on the basis of a desired level of toughness. Then, wherever possible this should be backed up by tests on the plastic article, or a specimen cut from it, to ensure that the material, as moulded, is in a satisfactory state to perform its function. 

Notwithstanding the guidance given below under Evaluation and selection of subcontractors, this requirement does not relieve you of the responsibility for ensuring the quality of subcontracted parts, materials, and services. Therefore, it would be unwise to place orders on a customer-specified subcontractor without first going through your evaluation and selection process. You can obviously take some short cuts but don t make assumptions. The customer will not be sympathetic when you are late on delivery or your price escalates. If you find a subcontractor that can meet all your product/service requirements at a lower price you can submit details to your customer for approval. 

The increasing diversity of operations, new materials and processes and the constant demand for improved production efficiency can only be met by various additives and compounding agents being blended into the oil to enhance its performance. Additives tend to be expensive and the selection of enhanced cutting fluid is only justified by overall production economies. 

Abrasion-resistant duties may involve abrasion in an aqueous phase or abrasion by dry particulate materials. The selection of the polyurethane type is most important to obtain the best results. Polyester-based polyurethanes perform best in dry abrasion due to their low hysteresis properties and excellent resistance to cut initiation and propagation. However, polyester polyurethanes are susceptible to hydrolytic degradation, and therefore polyether polyurethanes are normally used for aqueous abrasion duties. 

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