Metal bonds for production grinding tend to be based on bronze in the copper-tin alloy range of 85:15 to 60:40 with various fillers and other small alloy components. Metal bonds are the most resilient and wear resistant of any of the bonds discussed, but also create the highest grinding forces and the most problems in […]
Рубрика: Handbook of Machining with Grinding Wheels
The Dressing Affected Layer
The other effect of very fine dress infeed depths is related to the fact that the dress depth becomes comparable to or significantly less than the depth to which the surface of the wheel has been affected by previous grinding. The surface of any grinding wheel is significantly modified compared to its bulk structure. The […]
Grinding Parameters
2.1 INTRODUCTION Grinding, in comparison to turning or milling, is often considered somewhat of a “black art” where wheel life and cycle times cannot be determined from standard tables and charts. Certainly precision grinding, being a finishing process with chip formation at submicron dimensions occurring by extrusion created at cutting edges with extreme negative rake […]
GRINDING WHEEL TOPOGRAPHY
3.2.1 Introduction In the case of grinding, the cutting process is the sum of singular microscopic cutting processes, whose temporal and local superposition leads to a macroscopic material removal. As a consequence, the cause-and-effect principle of grinding can only be described on the basis of the cutting behavior of the individual abrasive grains [Sawluk 1964]. […]
Static and Dynamic Unbalance
“Static” unbalance is the term employed for unbalance within a single plane. Balancing of static unbalance may be performed either at zero speed or at running speed. Wheels are initially balanced statically off the machine but more frequently balanced at a fixed running speed. A confusion of terms TABLE 4.3 Standard Fits for Wheel Bore […]
Forced Vibrations
Forced vibrations can be eliminated in three ways. First is to eliminate the energy at its source. Wheels, motors, belts, and workpieces should all be balanced as should the three-phase power supply. Ultra-precision bearings and ball screws should be used and properly maintained in work and wheel spindles and slides. Second, the grinder should be […]
POLYCRYSTALLINE DIAMOND (PCD)
Since 1960, several other methods of growing diamond have been developed. In 1970, DuPont launched a polycrystalline material produced by the sudden heat and pressure of an explosive shock. The material was wurtzitic in nature and produced mainly at micron particle sizes suitable more for lapping and polishing than grinding or as a precursor for […]
Grit Size and Form-Holding Capability
Table 6.2 and Table 6.3 give values for typical form-holding capabilities and roughness as a function of grit size for standard precision-plated and postplated conditioned wheels. Roughness values will vary somewhat depending on workpiece hardness. The values indicated are those for grinding aerospace alloys in the hardness range 30 to 50 HrC using CBN abrasive. […]
Dressing
7.1 INTRODUCTION Understanding the procedures and mechanisms of dressing grinding wheels is critical to obtaining optimum performance in grinding. The available dressing methods are numerous and confusing — even the basic terminology varies from one manual or paper to another. For the purposes of this discussion, the following terms will be used: • Truing: Creating […]
Touch Dressing
When dressing a conventional wheel, a similar break in period occurs but is generally too rapid to be observed, and the dress infeed amount is such that most or all of the layer affected by grinding is removed and a fresh surface layer is created each dress. This is not so for CBN where the […]