From a purchasing decision perspective, the most important thing to remember when choosing cutting inserts is not to ignore aspects that are difficult to observe. Without cutting tests, even careful inspection can make it difficult to distinguish between high-quality and low-quality inserts. Choosing inexpensive inserts because they all look similar will inevitably increase costs in subsequent machining.
When selecting insert grades, it is ideal to consult the tool manufacturer's technical experts. In addition, some basic concepts can be used to narrow down the range of inserts available. Most tool manufacturers use a numbering system that reflects the characteristics of the inserts. The first digit of an insert grade indicates its category; for example, 4 indicates a grade for machining steel, 3 for casting iron, and 2 for stainless steel. Within each category, the last two digits indicate the hardness of the insert. A smaller number indicates higher hardness but also greater brittleness; a larger number indicates lower hardness but better toughness. To find the required insert category, machining workshops should ideally start from the middle of the product catalog and search forward or backward according to its performance.
Finally, if a cutting insert is not achieving optimal cutting performance, evidence can help determine a solution. Careful examination of the cutting edge with a magnifying glass can reveal the root of the problem. If the inspection shows significant abrasive wear or minor deformation on the cutting edge, the insert's hardness is too low, requiring a higher grade. If the insert has chipped or small pieces are missing from the cutting edge, a lower hardness, higher toughness grade may be necessary. By understanding how cutting inserts are manufactured and how different insert grades are customized for specific machining processes, various targeted measures can be taken to improve machining efficiency and reduce costs.
