Groove Type and Obstruction Type Chip Breaker - Advantages And Disadvantages of Chip Breaker
|fig:a. Groove type chip breaker; fig:b. Obstruction type chip breaker|
The chips formed during the metal-cutting process are sharp, hard and hot. The continuous chips are dangerous to the machine operator as well as the cutting tool tip. The disadvantages of the continuous chip are
- Continuous chip gets entangled around the tool and the job. It increases cutting resistance and vibration, cause difficulty to work.
- It may spoil the machined surface.
- It causes crater wear of tool.
- Continuous chip deflects the coolant and lubricant away from cutting zone.
Creating a perfect chip is not possible, but it can be aided by using inserts with chip breaker. Chip breaker is an example of forced chip breaking. It is used when the self breaking of curled chip did not happen. The purpose of chip breaker is to control these continuous chip formed during the high-speed cutting process. Chip breaker deflects the continuous chip to a sharp angle so that chip gets break to small pieces (manageable sizes). It helps the removal of chip either by using cutting fluid or simply allow them to fall into chip pan of the machine.
The chip breaker is installed on the rake face of the machine tool. They are usually parallel to cutting edge, however, in some cases, they are inclined to cutting edge to direct chip to the desired angle. The width of chip breaker depends on the work material feed rate, depth of cut and approach angle.
Advantages of chip breaker
- Ensure safety for operator
- Increase tool life
- Facilitate the removal of chips from cutting zone
- Reduce the cutting resistance and vibration, hence increase machine performance.
- Machined surface do not get spoiled by continuous chips
- Increase productivity (decrease time loss) – small chips take less volume than continuous chip, so it does not need chip disposal as frequent as continuous chip.
- Lower the temperature at a cutting region that helps to reduce chemical attack on the tool.
Disadvantages of chip breaker
- Frequent chip braking and hitting at flank of tool may causes harmful vibration.
- Some cases the use of chip breaker causes the spoilage of surface finish quality.
- Heat and stress concentrated at sharp cutting edge, results the rapid failure of cutting edge.
Types of chip breakerThe chip breaker classified into groove type and obstruction type
Difference between Groove type chip breaker and Obstruction type chip beakerGroove type chip breaker : A small groove is provided behind the leading cutting edge of the tool insert on the rake face (fig: a). The geometry of groove determines the radius of chip curvature.
Obstruction type chip breaker : Obstruction type either integral or attached to the cutting tool (fig: b). Attached chip breakers can be made adjustable to the different cutting condition. One of the advantage of obstruction type chip breaker is that it cause less wear on tool face than groove type chip breaker
- A crater wear formed on the plain tool can act as a chip breaker
- The tool wear process is extensively effected by the presence of chip breaker.