What is injection molding molds

Injection molding molds, also known as injection molds, are specialized tools used in the process of injection molding to shape melted material (typically plastic) into a specific form. Injection molding molds are widely used in many businesses that deal with plastic raw material shaping.

The Injection molding mold is made up of two main parts: the cavity and the core, which work together to create the final product. The cavity forms the exterior of the product, while the core shapes its interior. Injection molds are typically made of metal and are designed to be highly precise and durable, allowing for the production of consistent, high-quality parts.

Injection molding molds can produce several copies of the same arts in a single shot. The liquid hardens or sets inside the molds adopt their shapes. Injection molding molds consist of two primary components: the injection molds (A plate) and the ejector molds (B plate). These molds work together to form the shapes that you want.

Some injection molding molds allow previously molded parts to be reinserted to allow a new plastic layer to form around the first part. This is often referred to as over molding. This system can allow for production of one-piece tires and wheels.

Plastic Injection Mold

Plastic Injection Mold

Advantages and Disadvantages of injection molding molds

Advantages of Injection Molding Molds:
  1. High Precision: Injection molding molds are designed to be highly precise and accurate, allowing for consistent and uniform products to be produced with each cycle.
  2. Efficiency: Injection molding is a highly automated process, which allows for high production speeds and low labor costs.
  3. Cost-effective: Injection molding molds have a high upfront cost, but once created, they can be used to produce many identical parts at a low cost per part.
  4. Versatility: Injection molding can be used to produce parts in a wide range of sizes and shapes, making it a versatile manufacturing method.
  5. Material Selection: Injection molding can be used with a wide range of materials, including plastics, rubber, and metal alloys.
Disadvantages of Injection Molding Molds:
  1. High Upfront Cost: The cost of creating an injection mold can be quite high, making it difficult for small businesses or startups to enter the market.
  2. Long Lead Time: The process of creating an injection mold can take several weeks or months, which can lead to long lead times for production.
  3. Complex Tooling: Injection molding molds are highly complex tools, requiring specialized knowledge and skills to design and manufacture.
  4. Material Waste: Injection molding often generates a significant amount of material waste, which can be costly to dispose of.
  5. Limited Design Flexibility: Once an injection mold has been created, it can be difficult and expensive to make changes to the design of the product.

Steel Selection for Injection Molding molds

The selection of steel for injection molding molds is an important factor in the overall quality and longevity of the mold. The type of steel used can impact factors such as the mold’s hardness, wear resistance, corrosion resistance, and thermal stability. Some of the most commonly used steels for injection molding molds include:

  1. P20 Steel: This is a low-alloy, pre-hardened steel that is often used for injection molding molds that require high toughness and good wear resistance.
  2. H13 Steel: H13 steel is a high-alloy steel that offers excellent heat resistance and wear resistance, making it well suited for use in high-heat applications, such as hot runner molds.
  3. S136 Steel: S136 is a high-alloy stainless steel that offers excellent corrosion resistance, making it ideal for molds used in harsh environments or for producing parts that will be exposed to corrosive materials.
  4. NAK80 Steel: NAK80 is a pre-hardened, high-alloy steel that offers high toughness and good dimensional stability, making it a popular choice for precision molds.
  5. 420 Steel: 420 steel is a low-alloy, martensitic stainless steel that offers good wear resistance and corrosion resistance, making it a popular choice for mold inserts and other mold components.

The specific type of steel used for a given mold will depend on the specific requirements of the mold and the end-use application of the molded parts.

Quality Control and Inspection when make injection molding molds

Quality control and inspection are critical steps in the process of making injection molding molds, as they help ensure that the molds meet the required specifications and will produce high-quality parts. Some common quality control and inspection steps in the production of injection molding molds include:

  1. Design Review: Before the mold is manufactured, the design is reviewed to ensure that it meets the required specifications and can be produced using the selected manufacturing methods.
  2. Material Inspection: The raw materials used to make the mold, such as steel, are inspected to ensure that they meet the required specifications and are free of defects.
  3. Machining Inspection: During the machining process, the mold components are inspected to ensure that they meet the required tolerances and that they have been machined correctly.
  4. Assembly Inspection: After the mold components have been machined, they are assembled and inspected to ensure that they fit together properly and that all moving parts move smoothly.
  5. Hardness Testing: The hardness of the mold components is tested to ensure that it meets the required specifications and that the mold will be able to withstand the high stresses of the injection molding process.
  6. Dimensional Inspection: The dimensions of the mold components are measured to ensure that they meet the required tolerances and that the mold will produce parts with the correct dimensions.
  7. Function Testing: The mold is tested to ensure that it functions correctly and that all moving parts move smoothly.

By following these quality control and inspection steps, the manufacturer can ensure that the injection molding mold will produce high-quality parts and will perform reliably over its expected lifespan.

Nowadays, you can find many companies that produce injection molding molds for your businesses. Each offers you many kind of service, such as mold trial and mold sampling. If you cannot make the designs of the molds, the companies can make the designs for you, based onInjection Molding Molds your needs.

If you find difficulties in finding injection molding molds in your town, you can go online and order injection molding molds in online catalogs. Many manufactures promote their products here, so you can have many options. In the catalogs, they usually provide detailed information about he molds that are really helpful. Here are some references you can consider.

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Typical Problems Encountered During manufacturing of injection molding molds

During the manufacturing of injection molding molds, a variety of problems can arise, which can lead to defects in the mold or the molded parts. Some common problems encountered during the manufacturing of injection molding molds include:

  1. Warping: Warping can occur when the mold components are not heated evenly during the hardening process, causing them to deform.
  2. Cracking: Cracks can occur in the mold components during the hardening process, reducing the strength of the mold and leading to premature failure.
  3. Porosity: Porosity can occur in the mold components if the steel is not heated or cooled properly, leaving pockets of air in the material that can weaken it.
  4. Improper machining: Improper machining can result in rough or uneven surfaces, which can cause problems with part ejection or result in defects in the molded parts.
  5. Improper assembly: If the mold components are not assembled correctly, they may not fit together properly or may not function as intended, leading to defects in the molded parts.
  6. Improper hardness: If the hardness of the mold components are not within the required range, the mold may be too soft and may wear out quickly, or it may be too hard and may be brittle, leading to cracks and other problems.
  7. Improper dimensional tolerances: If the dimensional tolerances are not met, the mold may produce parts that are not the correct size, leading to problems with part fit and function.
  8. Sink marks: If the wall thickness is not balance in the part design then sink marks issue may caused,
  9. Air trap: If venting gap is not design in the injection molding mold well, then Air trap issue will caused and make poor quality molded part.

By following strict quality control and inspection procedures, and by using the appropriate materials and manufacturing methods, manufacturers can reduce the risk of these problems and ensure that the injection molding molds they produce will perform reliably and produce high-quality parts.

Plastic Molds by SINCERE TECH

The injection molding molds made by this mould manufacturer is excellent in interchangeable cores molds design and making. The plastic molds can be interchangeable on molding machines.  The company offers customer design service, prototyping, mold making, manufacturing process control, mold flow analysis service, and reverse engineering. It also offers cold runner mold and hot runner mold.

The company provides 100% workmanship and performance level in Taiwan. The mold base is Hasco standard, European standard, and world standard, while the molds have high gloss polishing finish. In order to help you choose the molds, the company offers mold sampling and mold trial. These will help you find injection molding molds that fulfill your business needs.


Located in Dongguan, China, is professional China Mold company, this company offers several types of injection molding molds, such as alloy mold, die casting mold, plastic injection mold, metal mold, stamping mold, etc. The molds have very high quality steel for the core and cavity slide, such as 13, SK136, 8407, and or the customer indicate the steel brand.

DST injection molding molds also facture high cooling system, perfect surface finish, low tolerance, long life, and fast delivery. If you are interested in the molds, you can send the clear part drawing in a form of 2D or 3D. It will be better if you have both along with your special requirement to the molds.