The price of molds differs from their own standards. The society of plastic industry(SPI), a professional mold research association in America, divided molds into 5 standards, which have different manufacturing requirements. All of these molds are only suitable for the injection molding machine with 400 tons or less. In the following paper, we will introduce you these 5 kinds of molds:

Class 101 molds:

It rated for 1,000,000 times or more cycles, typically using in mass-up production, with the best raw material, so that the price is  expensive. The mold design requirements:

1. Itis necessary to have detailed information of mold design.

2. Solidityof the mold base must at least reaches the level of 280

3. Solidity standard of the mold surface(including cavities and cores) must be withinthe range of 450  Other accessories such as slider, lifter, coping should be made of hard tool steel.

4. Ejector machine must have guiding elements.

5. Slidersmust be equipped with wear plates.

6. Temperature controller should be installed in cavities and cores,sliders and wherever if possible.

7. For the service life of mold, the erosion of cooling water pipelinewill decrease the quality of products so that injection molding manufacturing cycle will be increased. Therefore it is suggested that the embedded parts of cooling water pipeline should be dealt with erosion resistant treatment..

8. All kind of this moldshould be equipped with parting line locks

 Class 102 molds:

Its cycle can reaches no more than 1,000,000 times for mass-up production, and its requirements as blow:

1. Itis necessary to have detailed information of mold design.

2. Solidityof the mold base must reaches the level of 280 BHN .

3. Cavities and coresmust be within the range of solidity level of 450 BHN. Other functional parts should be dealt with heat treatment.

4. Temperature controller should be installed in cavities and cores,sliders wherever possible.

5. All kind of this moldshould be equipped with parting line locks.

Class 103 molds:

Its cycle can reaches 500,000 times for medium production with the cost- effective advantage.

1. Itis necessary to have detailed information of mold design.

2. Solidityof the mold base must reaches the level of 165

3. Cavities and coresmust be reach the solidity level of 280 BHN or above.

4. Other accessories are optional.

Class 104 molds:

Its cycle reaches 100,000 times for low- volume production. It has a reasonable price, but also has a shortcoming: low wear resistant.

1. It is suggested that providing the mold design .

2. Mold base material may be made of mild steel or aluminum.

3. Cavitiescan be aluminum, steel or other identified materials.

4. Other accessories are optional.

 Class 105 molds:

This type of mold is the cheapest one with the cycle not more than 500 times using only for the limited number of prototype pieces. The mold structure may be made of casting materials, epoxy resin or other materials which have sufficient solidity.