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Causes of Chip Interruption in Turning

Feb. 27, 2020

In the process, when continuous band-shaped chips are produced during the process, not only the workpiece machining surface and the cutting edge will be easily damaged, but the operator's safety will be threatened in serious cases. Therefore, necessary technological measures are taken to control chip type and chip breaking. It has always been an extremely important process issue in the machining industry. So what causes chip breaking? The CNC Turning Motorcycle Parts Exporter will come to tell you next.


Chips are the product of chip layer deformation. Therefore, changing the cutting conditions is an effective way to change the type of chips and achieve chip breaking. The factors affecting chip processing conditions mainly include workpiece materials, tool geometry, and chip usage.


In general, chips need to meet the following basic conditions: chips must not be entangled on the tool, workpiece and its adjacent tools and equipment; chips must not splash to ensure the safety of the operator and observer; chips should not scratch the workpiece during finishing The processed surface affects the quality of the processed surface; guarantees the predetermined durability of the tool, and does not prematurely wear and try to prevent its damage; when the chips flow out, it does not hinder the injection of cutting fluid; the chips will not scratch the machine guide or other parts, etc.


The classification of chip shape

Due to the different degrees of plastic deformation, different kinds of chips may be generated. When processing plastic materials, band-shaped chips, node-shaped chips, or granular chips are mainly formed. When processing brittle materials, generally chipped chips are formed.


CNC Turning


CNC Turning


1. Banded Chips: Banded chips are continuous and have a smooth bottom and a fluffy chip on the back. Such chips are apt to occur when using a tool with a larger rake angle to process plastic metal materials at a higher cutting speed. It is the result of insufficient deformation of the cutting layer. When band-shaped chips are generated, the cutting process is stable and the surface roughness of the workpiece is small, but the chips are not easy to break, often causing entanglement, pulling the workpiece, and even affecting the operation, so it cannot be ignored.

2. Nodular Chips: Nodular chips are chips with smooth bottom surface, obvious cracks on the back, and deep cracks, as shown in Figure 1-1b. This kind of chip is easy to produce when using a tool with a reduced rake angle to process plastic materials at a lower cutting speed. It is the product of more fully deformed chip layer, which has reached the degree of shear cracking. When nodular chips are generated, the chip work is not stable and the surface roughness of the workpiece is large.

3. Granular chips: Granular chips are a kind of uniform granular chips. Such chips are easily produced when using small rake tools to process plastic metal materials at very low cutting speeds. It is the product of the full deformation of the cutting layer, which has reached the extent that the material has shear failure and the chips break along the thickness. When granular chips are generated, the cutting work is not stable and the workpiece surface roughness is large.

4. Chipping chip: chipping chip is an irregular fine-grained chip. When cutting brittle materials, after the elastic deformation of the cutting layer, almost no plastic deformation stage, the chip formed by sudden cracking. When a chipped chip is formed, the cutting work is unstable, a large impact force is applied on the blade, and the processed surface is rough and uneven.


As can be seen from the above, the type of chips varies with the workpiece material and CNC Turning conditions. Therefore, in the process of processing, you can judge whether the chip conditions are appropriate by observing the chip morphology, and you can also change the chip morphology by changing the cutting conditions, so that it is transformed in a direction that is conducive to production.