Хонинговальные головки

Bearing preload needs to be carefully controlled and understood. Insufficient preload leads to low stiffness while excessive preload leads to higher temperature rise and even seizure. As rotational speed increases several factors cause an increase in preload: [4] Schematic drawing showing general arrangement of lubrication system 3/8 Steel tubing External by-pass line added to all […]

According to DIN 8589-11, reciprocating grinding is a peripheral longitudinal grinding process with a back-and-forth feed motion, in which the feed motion takes place gradually in small steps with a relatively high feedrate [DIN 8589]. 16.2.1 Process Characterization Reciprocating grinding is used for generating plain surfaces of usually large lateral dimensions. The grinding spindle is […]

Electroplated CBN wheels consist of a single layer of CBN crystals on a profiled metal hub. As discussed in Chapter 4, this leads to limits on finish and profile tolerances unless the surface is conditioned after plating which adds significantly to the cost. Therefore, the wheels are used more typically in roughing operations and under […]

The vast majority of standard grinders still use conventional abrasives at wheel speeds of 43 m/s or less. The wheel life is relatively long so any benefits from upgrading to CBN have to come from improved cycle time or quality. However, an analysis of about 30 different cylindrical grinders currently on the market reveals the […]

The preferred approach is to ensure that the quill design has been optimized for use with vitrified CBN as illustrated in the Figure 18.6. The quill length should be reduced to a minimum and the Wheel screw Conventional quill mounting diameter increased. The standard wheel screw used for conventional wheels should be eliminated and the […]

Dynamic contact length depends on the force between the grinding wheel and the workpiece in the same way that contact area between an automobile tyre and the road depends on the weight of the automobile. Dynamic contact length is given by Rowe, Morgan, and Qi [1993]. where Rr is a roughness factor that depends on […]

Higher wheel speeds allow higher infeed rates to be employed. Increasing wheel speed without increasing infeed rate reduces chip thickness as can be seen from Equation 19.30. In this case, roughness is reduced and grinding forces are reduced although specific energy is increased due to the size effect. The purpose of increasing wheel speed is […]

All roundness problems predicted by simulation were experienced in practice when grinding a workpiece with a flat and sometimes when grinding an initially circular workpiece. The simulation technique was tested by comparison with an experimental shape measured after grinding. The pregrinding shape of the workpiece with a flat is shown in Figure 19.40. The workpiece […]

20.1 INTRODUCTION A wide variety of applications verify the great potential of high-performance ceramics for components with special requirements. For example, hip joint endoprostheses on aluminum oxide or zirconium oxide bases, components for slide bearings and burners of silicon carbide, as well as ceramic com­ponents for roller bearings or valves are made of silicon nitride […]

A further grain wear type is microcrystalline grain splintering. This wear type is caused by microcracks resulting from mechanical and thermal tensions. These microcracks lead to a micro­fracture, or even to partial grain break-off. 9.3.7 Grain Break-Out In the case of total grain break-off, whole abrasive grains are detached from the bond. The reason is […]