Adhesive bonding cutting tools

Another approach is to coat the cutting tool material with a carbide former, such as titanium or siUcon or their respective carbides by CVD and deposit diamond on top of it. The carbide layer may serve as an iaterface between diamond and the cemented carbide, thus promoting good bonding. Yet another method to obtain adherent diamond coatings is laser-iaduced microwave CVD. By ablating the surface of the substrate with a laser (typically, ArF excimer laser) and coating this surface with diamond by microwave CVD, it is possible to improve the adhesion between the tool and the substrate. Partial success has been achieved ia this direction by many of these techniques. 

Metal cutting tools can reach very high temperatures (400°C) and Al-Samhan and Darwish (2005) have used finite element stress analysis to examine the case of tungsten carbide tips bonded to a steel support. Here, the linear expansion coefficients were 12.1 x 10 for steel, 60 x 10 for the tip, and 40 x 10 for the adhesive. The use of cutting fluids much reduced the stresses. 

In this context, it is important that the bonding area is designed in a way that enough space for the cutting tools ore wire is available. There is no need to remove the old adhesive layer completely. It is recommended to bond on a maximum 1 mm thick layer of the old windshield adhesive after the proper surface preparation with a primer which gives additional corrosion protection when the paint layer suffered damage when removing the windshield. 

One of the disadvantages of adhesive bonding is its low thermal conductivity it is thus advisable to explore the temperature distributions on the bonded tool tips as compared to the brazed one, using an infrared camera. These tests were carried out under the following cutting conditions down-milling operation with no coolant, with a depth of cut 7 mm, width of cut 10 mm, feed rate 21-082 mm/min, and spindle speed 845 rpm. The temperature distribution on the brazed tool corresponds to a temperature of 68 C, while that on the bonded tool ranges between 87 and 96°C. This indicates that for the bonded tool the heat is concentrated in the tool tip. It can thus be concluded that under severe... 

UHMWPE powder compaction and sintering by either extrusion or compression moulding yields similar values in terms of the final mechanical properties of the polymer. The resultant moulded semi-forms can be easily shaped (cut, turned, sawed, milled, or punched) using standard machine tools. UHMWPE is difficult to bond using adhesives but parts can be joined effectively by butt welding or mechanical fasteners. 

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