The common machining methods are forced feed and pressure feed.

1. Forced feed mode: it is processed on an ordinary machine grinder, and the cutting depth and workpiece accuracy are determined according to the dynamic accuracy of the machine tool.

2. Pressure feed mode: the grinding tool selectively processes the protruding part of the workpiece surface, so as to improve the precision of Dalian precision machining.

What attracts people's attention is laser machining technology. It can also be used to cut aerospace materials such as titanium, titanium alloy, chromium alloy and high-strength steel. It can also be used to cut quartz glass and ceramics. Its cutting efficiency is much higher than that of diamond grinding wheel. It is an ideal processing method.

Broaching is a type of machining operation. It is a cutting process that uses broaching machine (broach) to process various internal and external formed surfaces.

I brief introduction

Broaching tool is a very complex component, which is made of a single piece. The material is mainly high-speed steel, and cemented carbide as tool material is only used for machining of gray cast iron.

Unlike many other cutting operations, the main consideration is tool wear or tool life.

In broaching, several teeth mesh at the same time, and the chip width is often large. Chip removal can be very problematic, so low viscosity oil is usually required.

From the point of view of the supply and delivery of cutting fluid, internal broaching is more problematic than external broaching, and horizontal broaching is more difficult than vertical broaching.

II classification

Cutting with broach as cutting tool. When the broach moves in a straight line relative to the workpiece, the machining allowance of the workpiece is cut off successively by the tool teeth with increasing size one by one on the broach (Fig. 1). Generally, one working stroke can be machined and formed, which is an efficient finishing method. However, broaching is mainly used for mass production because of its complex structure, high manufacturing cost and certain specificity. Broaching can be divided into internal broaching and external broaching according to the characteristics of the machined surface.

① Internal broaching: it is used to process through holes and through slots in holes with various cross-section shapes, such as round holes, square holes, polygonal holes, spline holes, key slot holes, internal gears, etc. Before broaching, there should be machined holes so that the broach can be inserted. The broaching hole diameter range is 8 ~ 125mm, and the hole depth does not exceed 5 times of the hole diameter. Under special circumstances, the aperture range can be as small as 3mm, as large as 400mm, and the hole depth can be up to 10m.

② External broaching: it is used to process non closed surfaces, such as plane, forming surface, groove, tenon, blade tenon and external gear. It is especially suitable for processing large plane and composite surfaces in mass production, such as cylinder block, bearing seat and connecting rod of automobile and tractor. The dimension accuracy of broaching profile can reach it8 ~ 5, and the surface roughness is ra2 5 ~ 0.04 μ m, broaching gear accuracy can reach grade 6 ~ 8 (JB179-83).

In broaching, the sequence and methods of cutting machining allowance from the workpiece include formal, progressive, wheel cutting and comprehensive wheel cutting. ① In form. High machining precision, small surface roughness, but low efficiency; The broach has a long length and is mainly used to process small and medium-sized circular holes and forming surfaces with high precision requirements. ② The involute type is suitable for rough broaching complex machined surfaces, such as square holes, polygonal holes and spline holes. The broach used in this way is easy to manufacture, but the machined surface quality is poor. ③ Wheel cutting has high cutting efficiency and can reduce the broach length, but the machined surface quality is poor. It is mainly used to process round holes with large size, more machining allowance and low precision requirements. ④ Comprehensive wheel cutting type is rough broaching with wheel cutting method and fine broaching with forming method. It has both advantages and is widely used in round hole broaching.

Boring is an inner diameter cutting process that uses a tool to expand a hole or other circular contour. Its application range generally ranges from semi rough machining to finish machining. The tool used is usually a single edge boring tool (called boring bar).