With the intensification of domestic and foreign manufacturing technology competition, automated production technology has become the current development direction. All processing and manufacturing enterprises have begun to use automated, highly intelligent, and efficient CNC processing equipment.
▶Long and continuous chips will be wrapped around the tool or workpiece, which seriously affects the automatic processing, reduces the machined surface quality of the workpiece, and also increases the wear of the tool, which directly restricts production efficiency and increases the production cost.
▶In order to ensure the normal operation of automated cutting processing, improve the utilization rate of the equipment, and improve the quality of surface processing, chip breaking and discharge in the automatic processing stage have become the key issues of efficient processing research, and are also the key for enterprises to quickly respond to the market.
Principle of Chip Breaking
In the process of metal cutting, whether the chip is easy to break is directly related to the deformation of the chip.
Chips formed during the cutting process will undergo relatively large plastic deformation, and their hardness will increase, while their plasticity and toughness will decrease significantly.
This phenomenon is called cold work hardening.
After cold work hardening, the chip becomes hard and brittle, and it breaks easily when it is subjected to alternating bending or impact loads.
The greater the plastic deformation experienced by the chip, the more obvious the hard and brittle phenomenon, and the easier it is to break.
In other words, the basic principle of chip breaking is to achieve chip breaking with the help of "external force" on the basis of "cold work hardening".
Common Chip Types in Machining
According to the specific conditions of workpiece material, tool geometric parameters and cutting amount, etc., chip shapes generally include: banded chips, C-shaped chips, chipped chips, pagoda-shaped chips, clockwork-shaped chips, long-tight spiral chips, spiral chips Roll crumbs, etc., as shown in the figure below:
When cutting plastic metal materials at high speed, if chip-breaking measures are not taken, it is easy to form strip-shaped chips.
Therefore, the formation of banded crumbs should be avoided as much as possible.
But sometimes, it is also desirable to obtain strip chips so that the chips can be discharged smoothly.
When turning general carbon steel and alloy steel materials, if a turning tool with a chip breaker is used, it is easy to form C-shaped chips.
C-shaped chips do not have the disadvantages of ribbon chips. However, most of the C-shaped chips are broken when they collide with the flank of the turning tool or the surface of the workpiece.
The high frequency of chip breaking and breaking will affect the smoothness of the cutting process, thereby affecting the roughness of the machined surface.
Therefore, it is generally not desirable to obtain C-shaped chips during finishing but to obtain long spiral chips to make the cutting process more stable.
Turning steel parts with a large depth of cut and high feed rate on a heavy-duty lathe, the chips are wide and thick. If C-shaped chips are formed, it is easy to damage the cutting edge, and even fly and hurt people.
Therefore, the arc radius of the groove bottom of the chip breaker is usually increased, so that the chips collide and break on the machined surface in a clockwork shape, and fall by their own weight.
Long-tight spiral chips
The formation process of long and tight curls is relatively stable, and the cleaning is also convenient. It is a relatively good chip shape on ordinary lathes.
Chips of this shape are desired during CNC machining, machine tools, or automatic wire machining because such chips do not wrap around the tool and workpiece. And easy to clean.
When turning brittle materials such as cast iron, brittle brass, and cast bronze, it is very easy to form needle-like or fragment-like chips, which are easy to splash and hurt people, and are easy to damage the machine tool. If the chip rolling measure is adopted, the chips can be connected into short rolls.
In short, the specific conditions of cutting processing are different, and the shapes of chips that are expected to be obtained are also different, but no matter what shape of chips, chip breaking must be reliable.