The coating ceramics also display can effectively process the modular cast iron。 In the past, the aluminum oxide ceramics application which not the coating tough good such as nitriding silicon and the silicon carbide textile fiber strengthened the work piece material chemistry paralysis limit。 Today but could resist the scrap distortion process through the use to have the high thermal coating cutting tool life already remarkably to increase。 But certain early this domains work piece processing use aluminum oxides spread the layer crystals to have to strengthen the ceramics, today most research concentrate in the TiN coating nitriding silicon。 This kind of coating can remarkably open up the tough good ceramics the application scope。
When machining, the work piece has processed the surface is depends upon the cutting tool and the work piece makes the relative motion to obtain。According to the surface method of formation, the machining may pide into the knife point path law, the formed cutting tool law, the generating process three kinds。
The knife point path law is depends upon the knife point to be opposite in the work piece surface path, obtains the superficial geometry shape which the work piece requests, like the turning outer annulus, the shaping plane, the grinding outer annulus, with the profile turning forming surface and so on, the knife point path are decided the cutting tool and the work piece relative motion which provides in the engine bed;
The formed cutting tool law abbreviation forming, is with the formed cutting tool which matches with the work piece final superficial outline, or the formed grinding wheel and so on processes the formed surface, like formed turning, formed milling and form grinding and so on, because forms the cutting tool the manufacture quite to be difficult, therefore only uses in processing the short formed surface generally;
The generating process name rolls cuts method, is when the processing the cutting tool and the work piece do unfold the movement relatively, the cutting tool and the work piece centrode make the pure trundle mutually, between both maintains the definite transmission ratio relations, obtains the processing surface is the knife edge in this kind of movement envelope, in the gear processing rolls the tooth, the gear shaping, the shaving, the top horizontal jade piece tooth and rubs the tooth and so on to be the generating process processing。Some machining has at the same time the knife point path law and the formed cutting tool method characteristic, like thread turning。
The machining quality mainly is refers to the work piece the processing precision and the surface quality (including surface roughness, residual stress and superficial hardening)。Along with the technical progress, the machining quality enhances unceasingly。The 18th century later periods, the machining precision counts by the millimeter; At the beginning of 20th century, machining precision Gao Yida 0。01 millimeter; To the 50's, the machining precision has reached a micron level; The 70's, the machining precision enhances to 0。1 micron。
The influence machining quality primary factor has aspects and so on engine bed, cutting tool, jig, work piece semifinished materials, technique and processing environment。Must improve the machining quality, must take the suitable measure to the above various aspects, like reduces the engine bed work error, selects the cutting tool correctly, improves the semifinished materials quality, the reasonable arrangement craft, the improvement environmental condition and so on。
Enhances the cutting specifications to enhance the material excision rate, is enhances the machining efficiency the essential way。The commonly used highly effective machining method has the high-speed cutting, the force cutting, the plasma arc heating cuts and vibrates the cutting and so on。
The grinding speed is called the high-speed grinding in 45 meters/second above cuttings。Uses the high-speed cutting (or grinding) both may enhance the efficiency, and may reduce the surface roughness。The high-speed cutting (or grinding) requests the engine bed to have the high speed, the high rigidity, the high efficiency and the vibration-proof good craft system; Requests the cutting tool to have the reasonable geometry parameter and the convenience tight way, but also must consider the safe reliable chip breaking method。