High tools

Machining of metals involves extensive plastic deformation (shear strain of ca 2—8) of the work material in a narrow region ahead of the tool. High tool temperatures (ca 1000°C) and freshly generated, chemically active surfaces (underside of the chip and the machined surface) that interact extensively with the tool material, result in tool wear. There are also high mechanical and thermal stresses (often cycHc) on the tool (3). 

As more OH radicals are present in the case of an active anode than for an active cathode, chemical etching is also more important. Consequently, the surfaces are smoother than those obtained by cathodic machining [63,120]. However, when using anodic polarisation, the tool-electrode will be anodically dissolved resulting in high tool wear. 

Laminating High tool and die costs limited to simple shapes and cross section profiles... 

For the industrial use of these composite materials, the processing of these materials in particular is of great importance. Here, the machining shown as problematically, with occurrence of extremely high tools wear. This is caused due to the high hardness and the resulting abrasive effect of the ceramic reinforcement (Chen 1992 Tomac et al. 1992). 

Profile Broaching is a highly productive technology for gear manufacturing. Because of the high tool costs, this process is economic for... 

However, these favorable properties also result in a challenging machinability, which is reflected by high tool wear rates, unfavorable chip geometries, and rough surface qualities. In order to design stable cutting operations, one has to consider the complex interaction of alloying elements, tool materials, and process parameters. 

Viability of fOTming processes for high- Tool-integrated solutions... 

Some success has been demonstrated by research at Queens University, Belfast using rotational moulding for small production runs of large thick walled pressure pipefittings [80]. The advantage of this process is that it does not have the high tooling costs of... 

Compression moulding Low cycle time, low volatile emission, structural integrity High tooling cost, average finish Epoxy, polyester, vinyl ester, polyimide, cyanate ester... 

High tool and die costs high scrap loss limited to relatively small parts not practical for small runs. 

These findings appear to support the view developed in the analysis of the strategy and marketing and sales functions that there is in fact an inverse relationship between high tool and technique use and performance satisfaction levels. It would appear that those who use tools and techniques the most are also those who are the most critical about them. This perhaps indicates the truth in the old saying that familiarity breeds contempt. On the other hand there is also clear evidence in the findings reported here that sometimes those that use them the least are the most satisfied. This appears to be the case for the Media Entertainment and Tourism and Leisure sectors, which uses tools and techniques infrequently but still appear to have a very positive view of their performance when utilised. 

P-BN tools work satisfactorily in hardened steel up to contact temperatures of 1000°C, since there is no chemical reaction between boron nitride and iron. This, however, also depends on the binding phase of the polycrystalline materials and can lead to adhesive wear [24, 25]. In hard steel, the main wear mechanism on the tool is abrasion by hard alloy carbide particles [26]. In the case of Co-based super alloy (Vitallium), the results on hard-BN tool wear are somewhat incongruous [27, 28], while Inconel 718 can be machined under proper selection of the cutting conditions [29]. Apparently, austenitic steels containing a high percentage of Co are difficult to cut by hard-BN tools, due to the formation of cobalt nitrides which leads to high tool wear [8]. 

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