What is Die Casting Mold?

Die Casting Mold Definition

Die casting mold is composed of two parts, which are separated according to the draft angle of the product. The molten metal is injected from the stationary end, and the die casting part is solidified by cooling. The die casting part will stay on the moving side, and the moving side will pass through the thimble Eject the die casting, spray lubricant on the mold after the die casting is taken out. If you want to learn about the glossary of die casting mold, please see here.

In the early stage of the mold, it is necessary to confirm the mold flow analysis and product analysis report, and start simple mold design until the product drawing is approved by the customer; analyze the die-casting material, shape, structure, and size of the product parts from the perspective of die casting processing performance accuracy. ​

Die Casting Mold Cavity

High-pressure Die Casting(HPDC)

Die Casting Mold Core

HPDC is poured metal material in the molten state into the pressure chamber of the die casting machine, filled in the cavity of the die casting mold at a very high speed under the moving of high pressure, and the molten alloy material is cooled and solidified under high pressure to cast the high-efficiency precision casting method.

 

Also die casting mold is a tool for casting metal parts, a tool for completing the die casting process on a dedicated die-casting machine. Need to use a cold chamber die casting machine or a hot chamber die casting machine. The usual pressure for die casting is from several MPa to several tens of MPa, and the initial filling speed is in the range of (0.5~70) m/s. Therefore, high pressure and high speed are important features of die casting.

The Process Analysis Of General Parts Drawing Should Pay Attention To The Following Points:

  1. The material meets the customer's performance requirements

  2. Dimensional accuracy

  3. Easy to fill

  4. Wall thickness, wall connections, ribs, and fillets

  5. Parting, die direction and draft angle

  6. Slide block and mold core cross, undercut, etc

  7. Ejection direction, push rod position

  8. Patterns, text, and symbols

  9. Other special quality requirements

 

Design Manual Of Die Casting Mold:

Die Casting Workshop
  • Biscuit must ensure sufficient fluidity

  • Consider the existing processing range of machinery and equipment

  • CNC, mold saving, EDM processing convenience

  • Emission of gas in the mold

  • Try to consider the post-processing technology

  • Pay attention to the strength of the mold base and insert mold,

  • Design necessary mold temperature device to facilitate performance adjustment during production

  • The balance of the mold when lifting, easy to transport

Die Casting Mold Base

Die Casting Mold Is The Key Process Tool For Casting Production

Whether production can proceed smoothly and the quality of castings can be guaranteed depending on the reasonable mold structure. And the design of the die casting mold is essentially a comprehensive reflection of various factors that may appear in the production process. So it is necessary to analyze the casting structure in the design process, be familiar with the operation process, understand the possibility of the implementation of the process parameters, master the filling conditions in different situations, and consider the impact on the economic effect. Reasonable, practical, and able to meet the production requirements of die casting tools.

The Important Factor Of Die Casting Mold In The Production Process

  1. Determine the accurate shape and casting part size

  2. Determine gate system and the filling condition of the molten metal

  3. Determine overflow system affects the filling conditions of molten metal

  4. The strength of the mold limited the maximum injection pressure

  5. Control and adjust the heat balance of the die-casting process

  6. The quality of castings when they are taken out

  7. The mold casting surface not only affects the quality of the casting and affects the coating spraying

Die Casting Mold Manufacturing Process

CNC, heat treatment, internal stress removal, deep hole drilling, EDM, slow wire walking, grinding machine processing, drilling machine processing, electrode processing, mold matching, lathe, mold saving, nitriding, coating.

Die Casting Machine
Die Casting Machine
CNC Machine
Mold Base Pattern

Die Casting Mold Base

Runner and Overflow

Runner and overflow

Die Casting Dies Structure, More Details:

1. Molding System

The casting shape is molding after the die casting cavity and the moving core are closed. The molding system includes core, cavity, sliders, inserts, and inserts pins.

2. Mold Base System

The mold base included various steel plates, frames, and other structural parts. The function is to combine and fix the various parts of the mold and enable the mold to be installed on the die casting machine.

3. Ejection System

Ejector function to eject the casting parts from the mold, including ejection and returned parts, and the guiding parts. Used same material as forming parts to make the ejector pins and easily damaged parts.

 

4. Runner System

It is connected with the molding part and the pressure chamber to guide the metal material into cavities in a certain direction. It directly affects the speed and pressure of the molten metal molding part. It is composed of a sprue, a runner, an inner gate, etc.

 

5. Overflow System

The overflow system is a channel to remove the air from the pressure chamber. and generally includes venting slots and overflow slots. Sometimes, In order to improve the venting conditions, installed vent plugs in deep cavities.

6. Other

There are other components such as bolts and pins for fastening and positioning parts for positioning in the mold.

Aluminum Die Casting Mold
Magnesium Die Casting Mold
Zinc Die Casting Mold

General Steel Materials For Die Casting Molds:

The selection of die casting molds mainly depends on the temperature and type of the cast metal. How to choose suitable mold steel to increase the mold life of die casting molds, especially high melting point metals.

The temperature of the aluminum alloy melt is usually around 1202~1292℉. The mold life of aluminum alloy die casting molds should be focused on whether mold sticking and early dry cracking of the mold cavity occur. At present, General used aluminum alloy die casting mold steels included: 4Cr5MoSiV1 (H13), 4Cr5MoSiV (H11), 3Cr2W8V, and new steel grades Y10 and HM3.

The melting point of zinc alloy is 752~806℉, and the surface temperature of the zinc alloy die-casting mold cavity will not exceed 400°C. The materials generally used to manufacture zinc alloy die-casting molds are alloy structural steels 40Cr, 30CrMnSi, 40CrMo, etc., alloy mold steels 5CrNiMo, 5CrMnMo, 4Cr5MoSiV, 4Cr5MoSiV1, 3Cr2W8V, CrWMn, etc.

The melting point of magnesium alloy is 1202℉. Die-casting has a good molding feature. The tensile strength of magnesium alloy castings is equivalent to that of aluminum alloy castings, generally up to 250Mpa, up to more than 600Mpa. The most commonly used is H13 steel or materials with similar properties. After machining, the cavity part is quenched and annealed to make the hardness within the range of 46-48HRC. Only the cavity part and special parts of the mold need to use H13 steel, and these parts generally account for 20-30% of the weight of the entire mold. The other parts of the mold are made of low-carbon steel and medium-carbon steel.

For smaller die cast parts with relatively simple geometric switches, molds of standardized modules are often used.

Compared with aluminum alloy, magnesium alloy has lower hot melt, and its iron content is also very low. Therefore, the mold has a longer life.

How To Maintain A Die Casting Mold During The Non-working Period

  1.  After the tool is running for a period of time and before storage, check the important dimensions and the mold components may damage that need to be repaired or replaced.

  2.  After confirming all tool components are no damaged, they must be cleaned up completely. Check whether there is residual material in the cavity, whether the material runner is clean, and whether the parting surface of the mold, top block, and sliding block working surface are strained.

  3.  The surface of the cavity should be carefully inspected. If there is rust or water rust, it should be polished again.

  4.  After the cavity is cleaned, to prevent rust, apply anti-rust oil.

  5.  Before the mold is placed in the storage place, remove the residual cooling water in the mold and the residual oil in the oil pipe, and then use the locking plate to fix the moving plate and the fixed mold to prevent it open.

  6.  Mold storage is required to be in a flat, dry, clean place that is convenient for lifting and handling. The storage should be classified, and similar molds should be placed together.

Mold Maintain