Precautions for sharpening cutting tools

10 March 2023

Cutting Tool Material

Common cutting tool materials in cutting tool grinding include high-speed steel, powder metallurgy high-speed steel, cemented carbide, PCD, CBN, cermet, and other superhard materials.

▶High-speed steel cutting tools are sharp and have good toughness, while cemented carbide cutting tools have high hardness but poor toughness.

▶The density of cemented carbide cutting tools is significantly greater than that of high-speed steel cutting tools.

▶These two materials are the main materials for drills, reamers, milling cutters and taps.

▶The performance of powder metallurgy high-speed steel is between the above two materials, and it is mainly used to manufacture rough milling cutters and taps.


Cutting Tool Grinder

Since the cutting tool material is very hard, generally only grinding can be used to change its shape.

Common cutting tool grinding machines in the manufacture and grinding of cutting tools are as follows:

1. Groove grinding machine: Grinding the groove or back of cutting tools such as drill bits and end mills.

2. Top angle grinding machine: grind the cone top angle (or eccentric relief angle) of the drill bit.

3. Chisel edge repairing machine: correct the chisel edge of the drill bit.

4. Manual universal cutting tool grinding machine: grinding outer circle, groove, back, top angle, chisel edge, plane, rake face, etc. It is often used for cutting tools with small quantities and complex shapes.

5. CNC grinding machine: generally five-axis linkage, the function is determined by the software. It is generally used for grinding cutting tools with large quantities and high precision requirements, but not complicated, such as drill bits, end mills, reamers, etc. The main suppliers of such grinding machines are Germany, Switzerland, the United States, Australia, and Japan.

 Precautions for sharpening cutting tools

Grinding Wheel

1. Abrasive grains

Grinding wheel grains of different materials are suitable for grinding cutting tools of different materials. Different parts of the cutting tool need to use different abrasive grain sizes to ensure the best combination of edge protection and processing efficiency.

Aluminum Oxide: Used for grinding HSS cutting tools. Grinding wheels are inexpensive and easily modified into different shapes for grinding complex cutting tools (corundum type).

Silicon carbide: used to correct CBN grinding wheel and diamond grinding wheel.

CBN (Cubic Boron Carbide): For grinding HSS cutting tools. Expensive, but durable.

Internationally, the grinding wheel is represented by B, such as B107, where 107 represents the diameter of the abrasive grain.

Diamond: used to grind HM cutting tools, expensive but durable. D is used on the grinding wheel, such as D64, where 64 represents the diameter of the abrasive grain.

2. Shape

In order to facilitate the grinding of different parts of the tool, the grinding wheel should have different shapes. The most commonly used are:

Parallel grinding wheel (1A1): grinding top angle, outer diameter, back, etc.

Disc grinding wheel (12V9, 11V9): Grinding spiral grooves, main and auxiliary cutting edges of milling cutters, trimming chisel edges, etc.

The shape of the grinding wheel (including plane, angle, and fillet R) needs to be corrected after a period of use. The grinding wheel must often use cleaning stones to remove the chips filled between the abrasive grains to improve the grinding ability of the grinding wheel.

 Precautions for sharpening cutting tools

Grinding Standard

Whether there is a good set of cutting tool grinding standards is the standard to measure whether a grinding center is professional. In the grinding standard, the technical parameters of the cutting edge of different cutting tools are generally stipulated when cutting different materials, including edge angle, apex angle, rake angle, back angle, chamfering edge, chamfering and other parameters (in carbide drill bit Among them, the process of passivating the insert is called "chamfering". The width of the chamfering edge is related to the material to be cut, generally between 0.03-0.25mm. The process of chamfering on the edge (tool point) is called "chamfering". ". Each professional company has its own grinding standards summed up over the years.

Rear angle:

The relief angle of the insert is very important for cutting tools. If the relief angle is too large, the insert will jump easily; if the relief angle is too small, the friction will be too large and the cutting will be unfavorable.

The relief angle of the cutting tool varies with the material to be cut, the type of cutting tool, and the diameter of the cutting tool. In general, the relief angle decreases as the diameter of the cutting tool increases. In addition, if the material to be cut is hard, the relief angle will be smaller, otherwise, the relief angle will be larger.


Cutting Tool Inspection Equipment

Cutting tool testing equipment is generally divided into three categories: tool setting instrument, projector, and universal tool measuring instrument. The tool setting instrument is mainly used for tool setting preparation (such as length, etc.) of CNC equipment such as machining centers, and is also used to detect parameters such as angle, radius, and step length; the function of the projector is also used to detect parameters such as angle, radius, and step length. But the above two generally cannot measure the back angle of the cutting tool. The universal tool measuring instrument can measure most of the geometric parameters of the cutting tool, including the relief angle.

Therefore, the cutting tool professional grinding center must be equipped with a universal tool measuring instrument. But there are not many suppliers of this equipment, and there are German and French products on the market.


Grinding Mechanic

The best equipment also requires personnel to operate, and the training of grinding technicians is naturally one of the most critical links. Good technicians can reduce many unnecessary problems.


For the grinding of cutting tools, MORESUPERHARD provides regrinding and retipping services for customers.

Helping customers to further reduce production costs while protecting the environment and recycling non-renewable resources.

Choose More SuperHard Products Co., Ltd. , we will always be by your side to help you meet and overcome any metal cutting challenge you encounter!


Contact us now
 Home  Whatsapp  E-Mail  Inquiry