The causes of CBN cutting tools chipping

The abnormal cutting tools chipping is the most troublesome problems for tool users, which will cause a series of problems such as increased processing costs, scrap or rework of workpieces, and low processing efficiency. Especially for the expensive CBN cutting tools, chipping/cutting will cause a lot of waste, so it is very important to choose the right CBN cutting tools.

1.The performance factors of the CBN cutting tools itself, the larger CBN particles and the suitable binder will have a high tensile strength when sintered as a whole. This is also the advantage of the integral CBN cutting tools commonly used in rough machining. In addition to high-purity raw materials during the production process of CBN cutting tools, CBN micropowders need to be processed by many procedures such as deoxidation, and the bulk density is checked. This is also the biggest reason for the uneven quality of CBN cutting tools on the market. The other is the synthesis process, which directly determines the shape and size of the polycrystalline grains of the CBN cutting tools during synthesis.

2.The selection factors of CBN cutting tools, welding composite CBN cutting tools generally control the cutting depth within 0.3mm or even small to ensure the safety of use. If there is strong interrupted cutting, any welding composite CBN cutting tools in the world cannot guarantee that the tool will not collapse. When you can only choose the whole CBN cutting tools.

3.Tool model selection factors, the impact resistance of CBN cutting tools of the same performance grade is round cutting tools, the commonly used 25 degrees, 45 degrees, 75 degrees, 83 degrees, and 90 degrees (the tool entering angle after the card is installed); except for the main The negative chamfer width, angle and cutting edge treatment of the CBN cutting tools outside the deflection angle affect the strength of the cutting tools.

4.The influence of cutting parameters: In terms of cutting force, reducing the amount of cutting is the most feasible way; such as intermittent turning or slender shaft machining needs to reduce the speed.

5.The reason of machine tool itself, first of all, the overall system rigidity of the machine tool must be good to avoid processing vibration; when roughing, pay attention to avoid "stuffy car".

6.Extrusion length of the tool bar: excessive extension of the tool bar may lead to vibration and cutting tools collapse risk. The best extension length is within the size of the tool.

7.Tool bar quality factors: good quality tool bar has excellent thermal conductivity, good rigidity and good seismic performance; Although the price is a little higher, but the impact on the total cost of processing is not great, and will significantly reduce the unnecessary waste of the cutting tools.

8.The use of cutting fluid: CBN cutting tools can use coolant during rough machining of gray cast iron and other materials, but there is a risk of CBN cutting tools cracks caused by thermal stress and chipping.

9.In some cases, the impact resistance and wear resistance of the cutting tools itself are not contradictory. For example, during heavy-duty rough machining of cast iron parts, although YG turning tools have good impact resistance, the rapid wear of the tool will produce strong cutting resistance, which will also lead to chipping, which brings great challenges to tool developers and users Misunderstanding-the tool is not impact resistant, in fact, the root cause is that it is not wear resistant.