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In order to develop new grinding fluids for CBN wheels, the authors have devised an easy and accurate evaluation method for the performance of grinding fluids. This paper reports the grinding performance of various types of metalworking additives evaluated by this method. Observation and analysis of the surface quality of workpieces were done after the grinding tests. It was found that, among all the metalworking additives tested, sulfur-type extreme-pressure additives and phosphorus-- type extreme-pressure additives showed excellent grinding performance, even at a low concentration.
KEY WORDS
Grinding Fluids, Metalworking Fluids; Additives; Grinding
INTRODUCTION
The authors have developed the block-on-ring grinding method (BRG) that uses a block-on-ring friction and wear testing machine, which can evaluate the grinding performance of grinding fluids in a simple and accurate way for the development of grinding fluids for CBN wheels (1).
Using the BRG method devised, the authors studied the grinding performance of the three types of metalworking additives, i.e., oiliness agents, friction modifiers and extreme-pressure agents, at a 5% concentration of each additive added as reported in the previous report. As a result, the authors have found that the extreme-pressure agents show the greatest effect of all the metalworking additives tested (2). However, in the development (or determining the chemical composition) of any new grinding fluid for the CBN wheel, it is very important to study the relationship between the concentration of the metalworking additives added and their grinding performance. There is no report available in the literature which has studied this relationship.
Therefore, this report studies the effects of the concentration of metalworking additives on the grinding performance, and compares the results with the previous report (2).
EXPERIMENTS
Test Oils and Their Properties
The metalworking additives used in the experiment were the same three types - oiliness agents, friction modifiers and extreme-pressure agents - as studied in a previous report (2). Their concentrations ranged from 0.25 to 5 wt.%, in which five concentration levels were selected and tested.
Table 1 shows the chemical compositions and properties of the test oils.
Experimental Apparatus
The apparatus used in the experiments is a Falex block-- on-ring friction and wear testing machine where the ring represented a grinding wheel. By using the electroplating method, the surface of the ring was...