What Is a Metal Sawing?
A metal sawing is a doughnut-shaped saw blade attached to a cutting machine and used to cut materials or process grooves.
The material is made of high-speed tool steel (HSS), making it possible to process various materials.
Since it can be reground and used, it can be used as many times as necessary until the circular diameter of the blade becomes smaller than the limit of the cutting machine. Since the rotational speed is slower than that of a high-speed cutting machine using a cutting wheel, it can process while reducing spark dispersion and dust generation.
Uses of Metal Sawing
In addition to cutting round, square, and L-shaped angle materials, metal sawing cut materials vulnerable to frictional heat, such as vinyl chloride pipe and aluminum, are unsuitable for high-speed cutting machines.
However, for materials such as nonferrous metals and PVC pipes, selecting a blade suitable for each material is necessary.
Since they are less likely to generate sparks, they are suitable for use in places where fire must be avoided.
Also, depending on the type, the angle of the vise or clamp that holds the material in place can be freely changed, allowing angled cutting.
Principle of Metal Sawing
Although they are the same cutting machine, their features are significantly different from high-speed cutting machines that use cutting wheels.
First, metal sawing does not rotate as fast as high-speed cutting machines, which reduces dust generation. Still, the blades wear out more quickly than grinding wheels, so they need to be resharpened more often, and if the blade diameter becomes too small after repeated grinding, replacing it is costly and time-consuming.
The grinding wheel has a relatively long life and can continue cutting for a long time. Still, the processing speed is slightly slower than that of a metal sawing, and because the grinding wheel rotates at high speed, sparks and dust are generated in large quantities, so sufficient care must be taken in the work environment before operation.
In addition, metal sawing is less affected by heat, so burrs are less likely to appear on the cross-section after cutting, and the cut surface has the advantage of a clean finish.
In both cases, if the blade is applied too forcefully to the material, it can lead to blade breakage, which is very dangerous, so work with caution.
Difference Between a Metal Sawing and a Hand Sawing
A hand saw is a so-called “saw,” a metal strip with a cutting edge.
While metal sawing is made entirely of hard materials such as HSS, hand saws use HSS only for the cutting edge. The metal band is elastic and becomes flexible when force is applied. The metal is attached to the handle, cutting the object manually.
The cutting edge is the most significant difference between metal and hand sawing. The hand saw has “clippers” on both sides of the blade to improve cutting performance. Metal sawing does not have this “clam.”
Cutting Conditions for Metal Sawing
Cutting conditions for metal sawing vary depending on the type of material to be cut, the fabric of the metal sawing, and the work performed in each process.
Cutting speed is adjusted using the following guidelines.
Cases of Slow Cutting Speed
- The case for prioritizing the life of the metal sawing
- Cases where the work material is hard
- Cases where rough cutting is performed
- The case of starting a new operation
- Case of metal sawing with significant wear progression
Cases for Higher Cutting Speeds
- Cases of a material grade with good machinability
- Cases that require a high degree of finishing (for near-finish grinding or precision detailing)
The following guidelines are used to adjust the feed rate per blade.
Cases Requiring a Smaller Feed Rate
- Cases of materials that are too unstable to attach to the cutting machine and materials that are thin-walled or unstable in shape.
- Cases where thin and flexible metal sawing must be used for cutting.
- Cases that require a high level of finishing (for finishing cutting near completion or for precise finishing of details).
- Cases with a small chip in the cutting edge, and the feed rate is not less than the minimum feed rate even if the feed rate is lowered.
- Cases where deep grooves are cut.
Case of Increasing The Feed Rate
- Cases of materials with good machinability
- Case of interrupted workpiece surfaces
- Cases of significantly increased flank wear
- Cases in which the machine is vibrating and vibration marks are left on the workpiece.
Grinding of Metal Sawing
When metal sawing blades are repeatedly sharpened, they gradually become smaller in diameter. As long as the blade can reach the material to be cut, it can be reground and used repeatedly. However, the metal sawing must be replaced if the blade can no longer reach the material needing cutting.
If regrinding is performed as soon as possible, it will avoid problems such as cracks in the metal sawing. In addition, the maintenance of chips on the cutting machine can extend the life of the metal sawing and reduce running costs.