How to choose a milling cutter? The key is to look at these points.

A milling cutter is a rotary cutter with one or more teeth used for milling. When working, each cutter tooth intermittently cuts off the margin of the workpiece. Milling cutters are mainly used for processing planes, steps, grooves, forming surfaces and cutting tools on milling machines.

Key points for selecting milling cutter body and tool holder:

1. Is the milling cutter used on a CNC machining center or an ordinary milling machine?

2. The material and hardness of the milling cutter.

3. The specifications of the milling cutter, such as: blade length, overall length, blade diameter, shank diameter, etc.

If it is used on a CNC machining center, solid carbide should be used. White steel can be used on ordinary milling machines.

The hardness of white steel milling cutter is softer than that of cemented carbide milling cutter. High-speed steel cutters are cheap, have good toughness, but are not strong, easy to use, and have relatively poor wear resistance and thermal hardness. The thermal hardness of high-speed steel milling cutters is about 600 degrees, and the hardness is about 65HRC. It is obvious that white steel is used for milling. In the case of harder materials, it is easy to burn the knife if the coolant is not in place. This is one of the reasons why the thermal hardness is not high.

Cemented carbide milling cutters have good thermal hardness, wear resistance, but poor impact resistance, and the blade will break if you drop it. Cemented carbide is a material made by powder metallurgy, and its hardness can reach about 90HRA. Up to about 900-1000 degrees. Therefore, white steel is suitable for ordinary milling machines, and alloy milling cutters are used for CNC machining centers.

Selection of milling cutter diameter

The selection of milling cutter diameter varies greatly depending on the product and production batch. The selection of cutter diameter mainly depends on the specifications of the equipment and the processing size of the workpiece.

①Plane milling cutter

When selecting the diameter of a face milling cutter, it is mainly necessary to consider that the required power of the cutter should be within the power range of the machine tool, and the diameter of the machine tool spindle can also be used as the basis for selection. The diameter of the face milling cutter can be selected according to D=1.5d (d is the diameter of the spindle). In mass production, the tool diameter can also be selected according to 1.6 times the cutting width of the workpiece.

②End mill

The selection of the diameter of the end mill should mainly consider the requirements of the workpiece processing size, and ensure that the power required by the tool is within the rated power range of the machine tool. If it is a small-diameter end mill, the main consideration should be whether the maximum number of revolutions of the machine tool can reach the minimum cutting speed (60m/min) of the tool.

③Slot milling cutter

The diameter and width of the slot milling cutter should be selected according to the size of the workpiece to be processed, and the cutting power should be within the allowable power range of the machine tool.

Choice of milling cutter blades

1. For fine milling, it is best to choose a ground blade. This kind of blade has better dimensional accuracy, so the positioning accuracy of the cutting edge in milling is higher, and better machining accuracy and surface roughness can be obtained. In addition, the development trend of milling inserts used in finishing is to grind out the chip flutes to form a large positive cutting edge, allowing the insert to cut at a small feed and a small depth of cut. However, for carbide inserts without sharp rake angles, when small feed and small depth of cut are used, the tool tip will rub against the workpiece and the tool life will be short.

2. It is more appropriate to choose pressed blades in some processing occasions, and sometimes it is necessary to choose ground blades. It is best to choose a pressed blade for roughing, which can reduce the processing cost. The dimensional accuracy and edge sharpness of the pressed blade are worse than that of the ground blade, but the pressed blade has better edge strength, impact resistance during rough machining, and can withstand greater depth of cut and feed. The pressed blade sometimes has a chip groove on the rake face, which can reduce the cutting force, and at the same time, it can reduce the friction with the workpiece and the chip, and reduce the power demand.

3. However, the surface of the pressed blade is not as tight as that of the polished blade, and the dimensional accuracy is poor. The height of the blades on the milling cutter body is quite different. Because the pressed blade is cheap, it is widely used in production.

4. The ground blade with large rake angle can be used for milling viscous materials (such as stainless steel). Through the shearing action of the sharp blade, the friction between the blade and the workpiece material is reduced, and the chips can leave the front of the blade faster.

5. As another combination, the pressed blade can be installed in the blade seat of most milling cutters, and then a polished scraper blade can be configured. The squeegee blade removes rough machining knife marks, and can obtain better surface roughness than only the pressing blade. Moreover, the use of doctor blades can reduce cycle time and reduce costs. Scratching technology is an advanced technology that has been widely used in the fields of turning, grooving and cutting and drilling.