1) The pressure in hot press method is low, so the requirement to the press machine is also low, and graphite or cast-iron molds can be used instead of the ones made of high-strength alloy steel.

2) The bonding strength is high, so this method can be applied to produce complex-shape products and the reject rate can be lowered.

3) The products can be sintered with molds, so their expansion and contraction can be controlled and their sizes can be kept well. After stripping, there will be no elastic aftereffect on the pressed blanks.

4) The heating time is short and the production period is also short. This is convenient for small batch production.

5) The low pressure of this method reduces the possibility of diamonds’ crush.

6) The blank materials are sealed in molds, and will not contact with air. The heating time is short. Protective gas may not be used. These simplify the sintering process.

7) The sintering process can be better controlled.

The hot press method also has some disadvantages:

1) There are many production links in this method, and its production efficiency is not high.

2) This method needs many graphite molds, and needs many times of mold loading and stripping.

3) The graphite molds are apt to be damaged, for example, be burned to be defective or be cracked by expansion.

1) The forming of the tools does not need heating equipment, and the operation is easy.

2) The mold need not to be heat-resistant, and has a longer service life.

3) The forming production efficiency is high. The tools can be sintered in bulk.

4) The density of the formed blanks is lower than the one got via the hot press method, and their porosity is higher. This can help the cooling when these tools are used in grinding or cutting.

5) The formed waste products can be recycled timely.

The cold press method also has some disadvantages:

1) After sintering, the size of the pressed blanks changes considerably, especially for those complex-shape tools.

2) The bonding strength between the pressed blank and the tool’s body is low, and issues may arise from these bonding positions.

3) The pressure in the cold press is high. This may lead to the crush of the diamonds, and then influence the performance of the tools. There is a raw blanks’ movement procedure in the cold press method, and the raw blanks may be bumped and broken.

4) The requirement to the forming performance of the raw materials is high. The molds need to be made of high-strength alloy steel.

5) The requirement to the workers’ blank-pressing skills is rather high.

1) Cold-Press Mode: This mode is to first press the working layer (containing diamonds) and the transition layer (not containing diamonds) of the diamond segments to their forms directly on the grinding wheel’s body, and let the segments connect with the wheel’s body via teeth, slots or other manners. Then, put the grinding wheels into sintering furnaces to sinter without press.

2) Semi-Hot-Press Mode: This mode is an improved version of the cold-press mode. When the diamond grinding wheels are being sintered in the furnace, appropriate molds will be applied and some pressure will be added, but the pressure is much lower than the one in the hot-press mode.

3) Hot-Press Mode: This mode is to directly sinter the diamond segments in molds under a certain pressure in the dedicated sintering press machine, and then fix or connect the diamond segments onto the grinding wheel’s body via high-frequency welding, laser welding or mechanical mosaic method.

The first method is usually called cold press. It first uses a press machine to cold press the mixture of diamonds and bond powder to their profiles, and then put them in a kiln with reduction atmosphere to sinter them. Though its yield is big, its production procedure and equipment are complex; the blanks after the cold pressing are subject to damage in movements; and the sintering period can be several hours. Also, as the blanks are not pressed during the sintering, the end products’ density is low, so they are subject to deformation, and their quality can not be guaranteed.

The second method is usually called hot press. It puts the diamond mixture into a mold, and then uses a dedicated sintering press machine to press it to its profile and sinter it to an end product at one time. Its production procedure is simple; its sintering density is high; and the end products’ quality is good. Its production period is normally within 15 minutes. This method is widely used by the industry.