Metal cutting tool selection requirements

In metal cutting, cutting tool selection is almost a problem that every process engineer must face.

There are many issues to consider when selecting cutting tools, and correspondingly there are many principles, such as efficiency principles, machining accuracy principles, stability principles, economic principles, and so on.

First of all, the principle of efficiency. The efficiency principle is inseparable from other principles, especially the economic principle. The main purpose of requiring efficiency is to ensure the economy of the entire process. But efficiency is particularly important, so it is independent and discussed separately.

The efficiency principle is first of all efficiency under the premise of ensuring acceptable processing accuracy and acceptable stability. Without this basic condition, efficiency cannot be discussed.

Secondly, we will not emphasize efficiency under all conditions. The pursuit of efficiency has some constraints. The improvement of the processing efficiency of one part needs to be adapted to the efficiency of other parts, and the improvement of the efficiency of one process needs to be adapted to the efficiency of other processes. As long as the production capacity of this process is improved, the production capacity of the entire production line can be improved, the production capacity of the entire product can be improved, and the manufacturing cycle can be shortened. This is what many companies expect. The requirements for stand-alone or flexible manufacturing systems are different. They are less constrained, that is, they have less correlation with other processes. Due to flexibility, the shortening of the manufacturing cycle of a certain part or process often means that the equipment can be put into the production of other parts or other processes, thereby creating more benefits.

According to the survey data of foreign modern metal processing enterprises, the proportion of cutting tools themselves in the manufacturing cost is not very high, usually between 2% and 4%, and the high can reach about 7%. But the impact of cutting tools on processing efficiency is very huge. Whether a device worth hundreds of thousands of dollars can play its due role often depends on a tool of several dollars. A cost analysis example I once got showed that reducing the purchase price by 30% (referring to no change in tool performance) or extending the tool life by 50% (usually relying on the technological advancement of the tool manufacturer) can only reduce manufacturing costs1 % Because the tool cost only accounts for 4% of the total manufacturing cost. However, if the processing parameters can be increased by 20%, the manufacturing cost can be reduced by about 15%. Although if the cutting speed is increased by 20%, the cutting tool cost will increase by 50%, but the total cost is still greatly reduced due to the shortened processing cycle.