Plastic molds are one of the indispensable tools in modern industrial manufacturing of injection molding. Through plastic molds, plastic products with precise shapes, beautiful appearance, and stable performance can be produced, and are widely used in various fields such as home appliances, automobiles, medical equipment, toy injection molding, and more. However, producing high-quality and qualified plastic molds is not an easy task. In this answer, I will introduce some important measures and precautions for producing qualified plastic molds.https://www.sino-mold.com

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Select high-quality materials:

The materials for plastic molds are usually steel or alloys. To produce high-quality molds, high-quality and suitable materials should be selected, and ensure that there are no quality issues during the processing and manufacturing process.

Mold steel type:

Mold steel is a type of tool steel that is specifically designed to be used in the production of molds, which are used to shape materials like plastic and metal. There are several types of mold steel, including:

P20 (1.2311) – This is a low-alloyed tool steel that is commonly used for injection molds and compression molds.

H13 (1.2344) – This is a hot work tool steel that is used for die casting dies and extrusion dies.

NAK80 (P21) – This is a pre-hardened mold steel that is used for high precision and high gloss plastic molds.

S136 (1.2083) – This is a corrosion-resistant mold steel that is used for high-quality plastic molds.

 420 (1.2085) – This is a stainless mold steel that is used for molds that require high corrosion resistance.

 718 (1.2738) – This is a pre-hardened mold steel that is used for large plastic molds, such as those used in the automotive industry.

Suitable properties:

Each type of mold steel has its unique properties, such as hardness, toughness, and corrosion resistance, which make it suitable for specific applications. We need to choose according to the product requirements

Small deformation

good processing performance: working in a high-temperature environment and heat treatment, the deformation should be small.

good polishing performance and purity.

Excellent wear resistance.

Especially when the raw material utilized in producing the product incorporates a glass fiber-based hardness filler, it tends to hasten the degradation of the working face of the mold. Thus, it is essential to use a mold with adequate hardness and wear resistance…

Good corrosion resistance

Several materials may come into contact with steel, exerting a chemical corrosion effect on it. To preserve the mold’s corrosion resistance, it is crucial to use corrosion-resistant alloy steel or high-quality carbon steel. When necessary, the mold’s surface should also be plated with chrome or nickel.

sufficient working strength for steel selected.

The selected steel should have sufficient core strength.

The physical properties of die steel are usually selected

P20 Mold Steel

Hardness: 30-35 HRC

Toughness: Medium

Wear Resistance: Medium

Corrosion Resistance: Medium

Thermal Conductivity: Medium

Machinability: Good

Dimensional Stability: Good

H13 Mold Steel

Hardness: 48-52 HRC

Toughness: Good

Wear Resistance: Good

Corrosion Resistance: Good

Thermal Conductivity: High

Machinability: Fair

Dimensional Stability: Good

S136 Mold Steel

Hardness: 48-52 HRC

Toughness: Good

Wear Resistance: Good

Corrosion Resistance: Fair

Thermal Conductivity: Medium

Machinability: Good

Dimensional Stability: Good

718 Mold Steel

Hardness: 30-36 HRC

Toughness: Medium

Wear Resistance: Medium

Corrosion Resistance: Medium

Thermal Conductivity: Medium

Machinability: Good

Dimensional Stability: Good

Please note that these physical properties are rough guidelines and the actual physical properties will depend on the specific mold steel material and manufacturing process.

Reasonable design:

Reasonable mold design can increase the service life of the mold, while also improving production efficiency and product quality. Therefore, when designing the mold, factors such as the mold’s structure, process, and processing difficulty should be considered to ensure that the mold can meet the production requirements of the product

Define the requirements

Before starting the design process, you need to define the requirements for the mold. This includes the part design, the type of plastic material, the production volume, and the required tolerances

Choose the mold type

There are different types of plastic molds such as injection molds, blow molds, and compression molds. Choose the mold type based on the part design, the production volume, and the plastic material.

Design the part geometry:

The part geometry determines the shape and size of the mold. Design the part geometry using computer-aided design (CAD) software, and ensure that it is suitable for the chosen mold type.

Select the mold material:

The mold material should be chosen based on the plastic material, the production volume, and the required tolerances. Common mold materials include steel, aluminum, and copper alloys.

Design the mold components:

The mold components include the mold base, cavity, core, ejector pins, and cooling system. Design these components using CAD software and ensure that they are suitable for the chosen mold type and mold material.

Consider the mold flow analysis:

Conduct a mold flow analysis to simulate the flow of plastic material in the mold. This helps identify potential defects such as air traps, weld lines, and sink marks.

Optimize the mold design:

Use the results of the mold flow analysis to optimize the mold design. This includes adjusting the gate location, venting, cooling system and so on.

Create detailed mold drawings:

1. Create detailed drawings of the mold components, including dimensions, tolerances, and surface finish requirements.

2. Obtain the mold design: The first step in creating mold drawings is to obtain the mold design. This can be done by either designing the mold yourself or by receiving a mold design from a client or colleague.

3. Determine the mold requirements: Next, you’ll need to determine the specific requirements of the mold design. This can include factors such as size, shape, material, and the types of products the mold will produce.

4. Create a 3D model: Using a computer-aided design (CAD) program, create a 3D model of the mold design. This will allow you to view the mold from different angles and make changes as needed.

5. Generate 2D drawings: Using the 3D model, generate 2D drawings of the mold design. These drawings should include detailed measurements, angles, and dimensions. You may also want to include notes on the materials and tolerances required for the mold.

 6. Add annotations: Add annotations to the 2D drawings to provide additional information about the mold design. This can include details about the manufacturing process, specific mold features, and any special considerations that need to be taken into account during production.

 7. Review and revise: Review the mold drawings with your team or client to ensure that all requirements have been met. Revise the drawings as necessary based on feedback and suggestions.

 8. Finalize the drawings: Once the mold drawings are complete, finalize them and distribute copies to all relevant parties. These drawings will serve as a blueprint for the mold production process, so it’s important to ensure that they are accurate and detailed.

If you have any questions about the design, you can always ask us for help. Of course, we will give you a quotation after the design is finished. Kindly email: sales02@sino-mold.com  #Sinomold  #Sinotech #sinomold industrial #moldmaking #plasticinjectionmolding #moldsupplierChina

Build and test the mold:

Once the mold design is complete, build the mold and test it using the plastic material. Identify and resolve any issues that arise during testing.

1. At the beginning of injection molding, the injection volume should be gradually increased.
2. Adjust the injection molding process parameters according to the actual condition of the product during injection molding.
3. Do not come into contact with the water in the upper socket of the mold or the heater inside the mold, as this may cause damage to the heater and temperature control components located within the mold.
4. Before heating the preform mold, it is advisable to begin by adjusting the temperature of the main channel. Once the main channel temperature has reached the desired setting, the shunt switch can then be activated to prevent premature decomposition and discoloration of the material.
5. Configure the necessary equipment and process parameters, and proceed to initiate the mold actions in the prescribed sequence.
6. Systematically conduct multiple rounds of no-load testing on the die, ensuring to verify the proper functioning of the mold valve needle, synchronization of the joints, and positioning of the slider system
7. The preform cylinder is not equipped with a cooling water system and therefore should not be subjected to heating. Exposing it to high temperatures can potentially result in damage and distortion of the mold parts and seals.

8.  Establish connections for water, gas, electricity, and hydraulic lines by the requirements of the injection molding machine and mold. Verify and ensure that the pipelines are unobstructed before securing them in place.   

Precision processing:

Plastic molds require precision processing to achieve accurate dimensions and surface quality. In the processing process, advanced processing equipment and technology should be used, and the processing process should be strictly controlled and monitored to ensure the accuracy and quality of the mold.

advanced processing equipment

CNC machines:

Computer Numerical Control (CNC) machines are computer-controlled machines that use pre-programmed instructions to control cutting tools and other machining operations. CNC machines are widely used in precision processing because they offer high accuracy, repeatability, and flexibility.

Lathes

Lathes are machines that rotate a workpiece while a cutting tool is used to remove material from the workpiece. Lathes are used to create round objects such as shafts, bolts, and other precision components.

Milling machines

Milling machines are used to remove material from a workpiece by rotating a cutting tool. They are commonly used to create flat surfaces, slots, and other features on precision components.

Grinders

Grinders are machines that use abrasive wheels or belts to remove material from a workpiece. They are commonly used to create precise shapes and surfaces on hardened materials.

EDM machines:

Electrical Discharge Machining (EDM) machines use electrical sparks to remove material from a workpiece. They are often used to create intricate shapes and features in hard materials.

Coordinate measuring machines

Coordinate measuring machines (CMMs) are used to measure the dimensions and geometries of precision components. CMMs use a probe to touch various points on a workpiece and record their positions, allowing for precise measurements of complex shapes and features.

technology

The plastic mold-making process can benefit greatly from advanced technologies that improve precision, efficiency, and quality. Here are some advanced technologies that can be used in plastic mold making:

1. Computer-Aided Design (CAD): CAD software is used to create detailed 3D models of the mold design, allowing for precise control over the shape and features of the mold.

 2. Computer-Aided Manufacturing (CAM): CAM software can be used to generate tool paths for CNC machines, ensuring that the mold is machined with high precision and accuracy.

 3. High-speed machining: High-speed machining techniques, such as high-speed milling and EDM, can be used to produce molds with very tight tolerances and complex geometries.

 4. Additive manufacturing: 3D printing can be used to create plastic molds with complex shapes and internal structures that are difficult to achieve with traditional machining methods.

 5. Simulation software: Mold flow simulation software can be used to simulate the filling and cooling of the plastic material in the mold, allowing for optimization of the mold design and processing parameters to improve part quality and reduce cycle time.

6. Sino-Mold: Sino-Mold could assitant the creation of a virtual model of the mold and its production process, which can be used to optimize the mold design and production parameters before physical production begins.

Strict inspection:

During the production of plastic molds, strict inspection and testing should be carried out to ensure that the quality and performance of the mold meet the requirements. This includes testing the size, hardness,and surface quality of the mold, as well as evaluating the service life and durability of the mold.

1. Material inspection: Before starting mold production, it’s important to conduct a material inspection to ensure that the material meets the required specifications. This can include verifying the material composition, hardness, and other key properties.
2. Dimensional inspection: During the machining and fabrication process, it’s important to conduct regular dimensional inspections to ensure that the mold is being produced according to the design specifications. This can include using precision measurement tools such as micrometers, calipers, and height gauges to verify the accuracy of critical dimensions.
3. Visual inspection: Conducting regular visual inspections throughout the mold-making process can help identify any defects or issues early on. This can include inspecting the surface finish of the mold, looking for any cracks or defects, and verifying the correct placement of any inserts or components.
4. Functional testing: Once the mold is complete, it’s important to conduct functional testing to ensure that it performs as expected. This can include using the mold to produce sample parts and conducting quality inspections on those parts to ensure that they meet the required specifications.
5. Ongoing maintenance: Regular maintenance of the mold is critical to ensure that it continues to perform as expected over time. This can include regular cleaning and lubrication, inspections for wear and tear, and repairs or replacements as needed.

Quality control:

Inspection and testing can help ensure that the mold is machined correctly, with the proper dimensions, tolerances, and surface finishes. This is essential for ensuring that the molded plastic parts are of high quality and meet the desired specifications.

1. Design validation: Before starting mold production, it’s important to validate the mold design to ensure that it meets the required specifications. This can include using computer-aided design (CAD) software to check for potential design issues or conducting a design review with key stakeholders.
2. Material selection: Choosing the right material for the mold is important to ensure that it can withstand the required temperature, pressure, and wear and tear. Conducting material testing and verification can help ensure that the material meets the required specifications.
3. Machining and fabrication: During the machining and fabrication process, it’s important to conduct regular inspections to ensure that the mold is being produced according to the design specifications. This can include using precision measurement tools to verify dimensional accuracy and conducting visual inspections for any defects or issues.
4. Testing and validation: Once the mold is complete, it’s important to conduct testing and validation to ensure that it performs as expected. This can include using the mold to produce sample parts and conducting quality inspections on those parts to ensure that they meet the required specifications。
5. Ongoing maintenance: Regular maintenance of the mold is critical to ensure that it continues to perform as expected over time. This can include cleaning and lubrication, regular inspections for wear and tear, and repairs or replacements as needed.

Safety:

A defective or improperly made mold can cause safety hazards during the plastic molding process, such as part failure or damage to the molding equipment. Inspection and testing can help identify any potential safety issues before the mold is put into production.

Cost savings:

Catching defects early in the mold-making process can save time and money by avoiding the need to rework or replace the mold later on. This can also prevent production delays and reduce the risk of defects and lower mold-damaged materials in the final plastic parts.

1. Optimize the design: Reducing the complexity of the mold design can help reduce the cost of manufacturing. You can achieve this by simplifying the geometry, minimizing undercuts, and using standard components wherever possible.
2. .Select the right material: Choosing the right material for the mold can help reduce costs. For example, using aluminum or other less expensive metals can be a more cost-effective alternative to steel.
3. Choose the right manufacturing method: Selecting the appropriate manufacturing method can help reduce the cost of mold making. For example, using 3D printing to create prototype molds or low-volume production can be a more affordable option.

4、Work with an experienced mold maker: Partnering with an experienced and reputable mold maker can help you reduce costs by leveraging their knowledge and expertise in mold design, materials, and manufacturing processes.

5、Implement efficient processes: Streamlining your manufacturing process and reducing waste can help reduce the cost of plastic mold making. This can include using automated processes, optimizing tool paths, and reducing setup and changeover times.

By implementing these strategies, you can reduce the cost of plastic mold-making without sacrificing quality or performance.

Customer satisfaction:

A well-made mold is essential for producing high-quality plastic parts that meet the needs and expectations of customers. Inspection and testing can help ensure that the mold meets the desired quality standards and specifications, leading to higher customer satisfaction.

Some personal protective equipment and testing techniques used in plastic mold -making include visual inspection, dimensional measurement, hardness testing, and material testing. It is important to establish a comprehensive inspection and testing plan as part of the mold-making process to ensure that all necessary checks are carried out and documented.

Good maintenance:

Plastic molds need to be regularly mold remediation to extend their service life. During use, excessive wear and damage should be avoided, damaged parts should be replaced or repaired timely, and lubrication and cleaning of surfaces should be carried out regularly.

1、Clean the mold regularly: Regular cleaning is critical to ensure that the mold is free from any residue or buildup. Use a soft-bristled brush or an air gun to remove any loose debris, and then use mild detergent and warm water to clean the mold.

2、Check for wear and tear: Inspect the mold regularly for any signs of wear and tear, such as cracks or dents. If you notice any damage, repair or replace the mold as needed.

3、Lubricate moving parts: Apply lubricant to the moving parts of the mold to reduce friction and prevent wear. Be sure to use a lubricant that is compatible with the plastic material being used.

4、Store the mold properly: When not in use, store the mold in a dry and cool place to prevent damage from humidity or extreme temperatures.

5、Use the mold correctly: Follow the manufacturer’s instructions for using the mold, and ensure that the molding process is optimized for the specific plastic material being used.

6、By following these steps, you can help ensure that your plastic mold is well-maintained and ready to perform effectively over time.

Focus on safety precautions and environmental protection:

During the production of plastic molds, injection molding safety, and environmental protection should be emphasized, and relevant laws, regulations, and standards should be followed. Appropriate measures should be taken to prevent material pollution, potential health risks,wastewater,outdoor air and gas emissions, and other issues. 

All the workers must be trained and focus on health-related concerns: eye protection, and preventing human exposure.Having a strong cleaning solution to handle existing moisture problems and moisture control problems.

The workshop is equipped with safety protection equipment: such as an eye protection mask, safety glasses, safety shoes, respiratory protection respirators, and properly seated.

In summary, producing qualified plastic molds requires careful handling and control in many aspects such as materials, design, processing, inspection, and maintenance. Only in this way can high-quality plastic products be produced and suitable for injection molding machines.