This unit shown in Figure 15.38 is a cantilevered hydraulic-powered dresser with three sleeve bearings for radial stiffness and two ABEC 7 thrust bearings for axial stiffness. It is a unit designed for heavy-duty plunge-dressing applications on internal grinders. Rolls can be counterbored to wrap around the spindle to accommodate up to 3 roll widths. […]
Рубрика: Handbook of Machining with Grinding Wheels
Work Results
In creep feed grinding, surface roughnesses are much smaller due to the engagement of a higher number of cutting edges and due to smaller feedrates than in the case of reciprocating grinding. Since the functional surface properties of a workpiece are often important, creep feed grinding has a clear advantage here. This can be traced […]
Rough Machining/Finish Grinding
For manufacturers that choose to rough machine the part, Thielenhaus [n. d.] provides a grinder/superfinisher to microfinish the faces to create a good sealing surface. This is particularly suited for applications such as aluminum cylinder heads with hardened liners that create step problems for machining. The process uses small conventional abrasive segments in a rotating […]
AUTOMOTIVE CAMLOBE GRINDING
Camlobe grinding has been the leading driver of high-speed grinding over the last 25 years. It is a high-cost process, making up more than 40% of total camshaft manufacturing costs [Wedeniwski 1989]. The operation is very capital-equipment intensive resulting in pressures from end users to reduce cycle times while offering machine tool builders sufficient end […]
Flexible Multipurpose Grinders
This refers to a class of grinders that must have the flexibility to perform a range of grinding operations that may also include face and OD grinding in a broad range of parts. Multispindle (a) At load/unload position (b) At grind position [Bryant (1995)] FIGURE 18.22 Bryant UL2 loader for shoe centerless mode […]
Failure to Turn
A different problem can arise with heavy workpieces if there is insufficient control wheel friction to turn the workpiece on contact with the grinding wheel. Heavy workpieces are unlikely to suffer the problem of “spinning.” In fact, heavy workpieces are more likely to suffer the problem of failing to turn at all under the action […]
Direct-Effect Charts
Direct-effect charts are the result of the experimental design described in Section 19.10.7. An example is shown in Figure 19.29. The example is for workpiece roughness in high-speed CBN grinding of AISI 52100. The results clearly show that high wheel speed reduces roughness. A chart for grinding ratio is shown in Figure 19.30 for the […]
DYNAMIC STABILITY 19.13.1 Threshold Conditions
Substituting s = jm in Equation 19.76, it is possible to solve the characteristic equation to find the unstable limit frequencies and the corresponding limits of grinding force stiffness at the threshold of instability. Noting that m = n. Q., the frequencies are given by where A and B are the real and imginary parts […]
Dynamic Compliance of the Mechanical System
The dynamic compliance of the mechanical system, which consists of the workpiece, the grinding wheel, and the grinding machine, is represented by and u = cosacos(a — в) where a is the angle between the direction of the depth of cut and the direction of the natural frequency mode of the mechanical system, в is […]
ADDITIVES
An important group of cooling lubricant additives are polar additives, whose molecules contain polar groups (Figure 10.2). Polar additives are mostly unsaturated hydrocarbon compounds such as fatty acids, fatty alcohol, and fatty acid esters. Due to their polarity, these agents firmly deposit on the workpiece surface and form an adhering lubricating film. Additionally, there are […]