Classification of Molds

1. Various Classifications of Molds

1.1 Classified by Hardness:

Soft Mold, Hard Mold (Quenching Treatment)

1.2 Classified by Quality Grade:

Grade 1, Grade 2, Grade 3, Grade 4

1.3 Classified by Difficulty:

Class A, Class B, Class C, Class D

1.4 Classified by Mold Size:

Extra Large, Large, Medium, Small

2. Definition of Hard Molds and Soft Molds

2.1 Soft Mold:

The mold steel is pre-hardened, eliminating the need for quenching treatment, but it has a lower hardness, below HB 400.

The production lifespan is within 500,000 cycles, and it is widely used.

2.2 Hard Mold:

The mold steel undergoes annealing and is processed through rough machining and finish machining.

After rough machining, it undergoes quenching treatment, reaching a hardness of HRC 48° or higher. 

About 0.2 of machining allowance should be retained after rough machining to account for the deformation that occurs during quenching treatment. The production lifespan is above 500,000 to 1,000,000 cycles, with small molds being the most common application.

Classification of Molds

3. Mold Quality Grades

3.1 Grade One Quality Mold

3.1.1 Mold: Must be capable of a million or more cycles.

This is a first-grade mold, and customers demand the use of the best materials and components to create the finest mold.

3.1.2 Requirements for Grade One Mold:

(1) Detailed mold design (including computer graphics and materials).

(2) The hardness of the mold core must be at least HB280.

(3) The mold cavity must have a minimum hardness of HRC50, and all slides and components must be quenched.

(4) Mid-support bushings must be used for guide pins.

(5) Slides must have wear-resistant plates.

(6) Temperature control monitors must be installed feasibly on the mold, core, or slides.

(7) It is recommended to nickel-plate all cooling channels to prevent rusting and facilitate cleaning.

(8) Locks for parting lines are necessary.

3.2 Grade Two Quality Mold

3.2.1 Mold: Must be capable of five hundred thousand or more cycles.

This is a second and advanced quality mold that must use good materials and components, and there are certain standards for tolerances (dimensional accuracy) in the mold. This mold also requires top-notch quality.

3.2.2 Requirements for Grade Two Mold:

(1) Detailed mold design is recommended.

(2) The hardness of the mold core must be at least HB280.

(3) The mold cavity must have a minimum hardness of HRC48, and all slides and components must undergo heat treatment.

(4) Temperature control monitors must be installed feasibly on the mold, core, or slides.

(5) Locks for parting lines are necessary.

(6) The following requirements will be determined individually and during the quoting process.

3.3 Grade Three Quality Mold

3.3.1 Mold: Must be capable of two hundred and fifty thousand or more cycles.

This is a standard mold requirement, also known as mid-production molds.

3.3.2 Requirements for Grade Three Mold:

(1) It is recommended to create a mold design.

(2) The hardness of the mold blank must be at least HB165.

(3) The mold core must have a minimum hardness of HB280.

(4) Apart from the three basic requirements mentioned above, all others are considered optional additional requirements.

3.4 Grade Four Quality Mold

3.4.1 Mold: Requires approximately ten thousand cycles.

This is a low-production mold, generally with no specific requirements, but the mold quality still needs to be good and acceptable to the customer.

3.4.2 Requirements for Grade Four Mold:

(1) It is recommended to create a mold design.

(2) The mold blank may be a standard copper material or aluminum.

(3) The mold core can be made of aluminum or steel with the customer’s approval.

(4) Apart from the three basic requirements mentioned above, all others are considered optional additional requirements.

4. Mold Complexity

4.1 Grade A:

Molds with multiple slides, complex structures involving multiple inclined partings, core pulling, and rotating core mechanisms.

4.2 Grade B:

Molds with two to four slides, inclined partings two to three times, and complex structures involving core pulling, among others.

4.3 Grade C:

Simple molds with fine sprue entry, one or two slides, and generally straightforward structures like inclined partings.

4.4 Grade D:

Molds with large sprue entry, two-plate molds, and simple structures with no slides or inclined partings.

5. Mold Size

5.1 Extra Large:

Molds with a width exceeding 800mm.

5.2 Large:

Molds with a width between 600 and 800mm (excluding 800).

5.3 Medium:

Molds with a width between 350 and 600mm (excluding 600).

5.4 Small:

Molds with a width below 350mm.

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