Plastic injection molding is a way to make stuff. It’s a process that involves injecting melted plastic into a mold cavity. The plastic cools and hardens into the shape of the cavity. After that, the mold opens up, and the part is ejected. It’s a popular manufacturing method because it’s fast and can make large quantities of parts. It’s also a great way to make lots of parts with consistent quality. That’s why you see so many plastic parts in cars, medical devices, and consumer goods. You can make anything from a tiny gear to a big car bumper or a huge trash can. You can also make parts that have different colors or different materials all in one shot. That’s called multi-shot or two-shot molding.

Steps for Custom Injection Mold Making

If you want to make a lot of plastic parts, you need a custom plastic mold. It’s the only way to get consistent, high-quality parts. If you want to make your own custom injection molds, here’s what you need to know. First, you need to design your mold. You can do this with computer-aided design (CAD) software. This lets you make a 3D model of your mold. You can then make a physical prototype of your mold using 3D printing or other rapid prototyping techniques. Once you have your design, you can start making your mold. This usually involves CNC machining or electrical discharge machining (EDM) to make the mold cavities and other features. After your mold is done, you need to test it. You need to make sure it makes good parts. You may need to make changes to your mold design or make other adjustments.

Injection molds are the most important tools for making plastic parts. To customize an injection mold, you need to do the following:

Determine Design Requirements

Before you start customizing an injection mold, you need to determine the design requirements for the desired plastic part, including size, shape, material, etc. These requirements will help determine the specifications and design of the mold.

There are many factors to consider when determining design requirements. For example, factors such as required plastic part size, shape, quantity, production efficiency and cost. Additionally, the type of plastic used needs to be considered, which will help determine the material and construction of the mold.

Find the Right Manufacturer

Look for experienced manufacturers, especially those with experience in the specific type of injection mold you need. You can find these manufacturers through a web search or through recommendations from other businesses.

When looking for a manufacturer, consider the manufacturer’s experience, capabilities, and reputation. You can find some manufacturers who have made similar molds and communicate with them to understand their manufacturing process and experience. Additionally, you can search the Internet for manufacturer reviews and ratings to help you make your decision.

Determine the Specifications and Design of the Injection Mold

When you talk to the manufacturer, you’ll need to tell them all about the mold you want. You’ll need to tell them how big it is, what it’s made out of, how many pieces it makes at once, what kind of machine you’re going to run it on, and all that kind of stuff.

When we talk about injection mold specifications and design, there are a few things we need to consider:

(1) Mold size: The size of the mold should be determined based on the size and quantity of the plastic parts you need.

(2) Mold material: You should choose the mold material based on factors like the type of plastic you’re using, production efficiency, and cost.

(3) Number of mold cavities: The number of mold cavities depends on how many plastic parts you need and how quickly you want to produce them.

(4) Injection molding machine specifications: The specifications of your injection molding machine should match the specifications and design of your mold.

Sign a Contract

Once you and the manufacturer have agreed on everything, you need to sign a contract. The contract should clearly state the specifications, design, price, payment method, delivery date and other details of the injection mold.

Before you sign the contract, you need to make sure that all the details are clearly spelled out in the contract. You need to make sure that the contract contains important information such as the specifications and design of the mold, price, payment method, delivery date, warranty terms, etc.

Manufacturing Injection Molds

Once the contract is signed, the manufacturer will start making the injection mold. The manufacturing process can take weeks or months, depending on the specifications and design of the mold, as well as the manufacturer’s production capabilities and workload.

Detailed Process of Injection Mold Design

Pre-design Preparation

(1) Talk to the client to figure out what they want for the injection mold design.

(2) Look at the plastic part to see what it looks like, how it’s used, what it needs to look like on the outside and inside, and what it’s made of.

(3) Make sure the plastic part can be made into a mold.

(4) Figure out what kind of injection molding machine you need and what size it should be.

Formulation of Molding Process Card

(1) What’s the product? Draw it. How heavy is it? How thick are the walls? How big is the part? Are there any undercuts? Are there any inserts?

(2) What kind of plastic are you using? What’s it called? What’s the model number? Who makes it? What color is it? How do you dry it?

(3) What size machine are you using? How far apart are the tie bars? What kind of screw is in the machine? How much power does the machine use? How much injection pressure can the machine make? How far does the screw move?

(4) What are the conditions for molding? What temperature is the material? How much pressure do you use? How fast do you inject? How much tonnage do you use?

Injection Mold Structure Design Steps

(1) Figure out how many cavities you need. Look at how much plastic you can inject, how much force you can use to clamp the mold, how accurate the part needs to be, and how much money you want to spend.

(2) Decide where to split the mold. The rule is to make the mold as simple as possible, easy to take apart, and not mess up how the part looks or works.

(3) Decide how to lay out the cavities. Try to make them all the same.

(4) Decide how to get the plastic into the mold. This includes the big channels, the little channels, the holes, and the places to put the cold plastic.

(5) Decide how to remove the mold. Design different ways to remove the mold based on what parts of the plastic part are left in the mold.

(6) Decide how to control the temperature. The temperature control system is mainly decided by what kind of plastic you’re using.

(7) Decide how to install and fix the mold when the cavity or core is a block. Decide how to divide the inserts and use them at the same time, how to machine them, and how to install and fix them.

(8) Decide how to let the air out. Usually, you can let the air out by using the gap between the mold parting surface and the ejection mechanism. But for big and high-speed injection molds, you have to design ways to let the air out.

(9) Choose the main sizes of the injection mold. Calculate the working sizes of the molded parts according to the corresponding formulas and determine the side wall thickness of the mold cavity, cavity bottom plate, core backing plate, thickness of the moving mold plate, thickness of the block-type cavity plate, and closing height of the injection mold.

(10) Choose standard mold frames. Based on the main sizes of the designed and calculated injection mold, choose the standard mold frame of the injection mold and try to choose standard mold parts as much as possible.

(11) Sketching the mold structure. Sketching the complete structure of the injection mold is a very important task in mold design.

(12) Checking the mold and injection machine dimensions. Check the parameters of the injection machine being used: including the maximum injection volume, injection pressure, clamping force, and the dimensions, opening stroke, and ejection mechanism of the mold installation part.

(13) Reviewing the injection mold structure design. Conduct a preliminary review and get the user’s consent, while it is necessary to confirm and modify the requirements proposed by the user.

(14) Drawing the assembly drawing of the mold. Clearly indicate the assembly relationship of each part of the injection mold, necessary dimensions, serial numbers, itemized tables, header, and technical requirements (the contents of technical requirements include:
A. Requirements for the performance of the mold structure, such as assembly requirements for the ejection mechanism and core pulling mechanism.
B. Requirements for mold assembly process, such as fitting clearance of the parting surface and parallelism of the upper and lower surfaces of the mold.
C. Mold usage requirements.
D. Requirements for anti-oxidation treatment, mold number, engraving, oil seal, and storage.
E. Requirements for trial molding and inspection).

(15) Draw the part drawings of the mold. The sequence of disassembly and drawing of part drawings from the assembly drawing or part drawings: first internal, then external, first complex, then simple, first molded parts, then structural parts.

(16) Review the design drawings. The final review of injection mold design is the last check of injection mold design, and attention should be paid to the processing performance of parts.

Process of Injection Mold Making

To make an injection mold, you have to go through these steps:

1. Design: The manufacturer will use CAD software to design the injection mold. At this stage, the manufacturer will determine the design parameters of the mold, such as its shape, size, and structure.

2. Manufacturing: The manufacturer will use machine tools or CNC machine tools to manufacture various parts of the mold, such as the mold shell, mold core, and injection channel.

3. Assembly: The manufacturer will put all the parts together to make a complete injection mold.

4. Debugging: After the injection mold is made, the manufacturer will test it to make sure it works right. They might have to test it a few times to make sure it’s good.

5. Delivery: Once the injection mold is made and tested without any problems, the manufacturer will send it to the customer.

6. Testing and Production: Once you get the injection mold, you need to test and produce it. Testing can help you know the quality and performance of the mold, including its accuracy, stability, and lifespan. The testing process may include trial runs and debugging.

Once you’re done testing, you can start producing with the injection mold. While you’re producing, you need to take care of the mold so it keeps working and lasts a long time.

ZetarMold: China Custom Plastic Injection Mold, Injection Molding Manufacturing Factor

As a professional injection mold manufacturer, we know that every step of mold design and production is crucial in plastic product projects. Here is a detailed process of a typical plastic product project from mold design and production:

Pre-processing of Products

When we receive the client’s products, our first job is to do some pre-processing on the products, not to rush to split the mold. The key to this stage is to check the product structure and tolerances, make necessary modifications, and understand the demolding situation of the product and the possible flash conditions. Through these processes, we can determine the parting surface, structure, and gate position of the product, but the final confirmation needs to be communicated with the client.

Identification of Product Flaws

Before we start designing the mold, we need to analyze the product structure. To minimize the number of corrections during the design process, we need to fully understand the client’s requirements for the mold. This includes information such as the tonnage, model, and type of injection machine used by the client. If we don’t confirm this information, the mold may not match the client’s equipment, which will affect production efficiency and mold acceptance.

Analysis of Product Issues and Material Characteristics

Before we design the mold, we need to carefully analyze the product’s issues, flash, material, and its shrinkage rate. It’s crucial to confirm the plastic material and shrinkage rate used in the final product, as well as any possible additives or modified materials. Understanding the assembly relationship and usage of the product is also essential, as this information directly affects the design of the mold structure.

Design of Mold Waterway

Once you have collected the above information, you can start designing the mold. The first step is to determine the parting surface. The principle is to keep it simple and avoid complex structures as much as possible. The design of the parting surface should follow the trend of the product, so that the mold can be easily fitted. When using software for design, you must be familiar with the principles of each command, so that you can use them flexibly. At the same time, consider the arrangement of sliders and cores. Make sure that the angle of the inclined guide post is moderate. The slider structure should be designed according to the requirements of the product’s undercut.

Design of Sliders

The design of sliders should be flexible, but the angle should not be too large, with the typical angle being controlled below 15 degrees. The shape of the slider can be chosen according to specific needs, but trigonometric relationships should be fully utilized to achieve the product’s undercut demolding.

Through the above steps, we can comprehensively consider the client’s requirements and design efficient, applicable molds, providing reliable support for the client’s plastic product projects.

Conclusion

In this article, we’ve gone through the whole process of making injection molds for custom plastic products. From figuring out design requirements to final production testing, every step is important. Making custom injection molds involves many things, like talking to clients, looking at product structures, thinking about material properties, designing the mold, and making it. By working with experienced manufacturers, you can make sure the mold is good quality and works well.

We hope this article can provide you with some useful reference and guidance in the process of making injection molds for custom plastic products. Making custom injection molds is a complex and precise process that requires joint efforts and support from all parties and professional knowledge.

When making custom injection molds, you need to determine the design requirements, find a suitable manufacturer, specify the specifications and design of the injection mold, sign a contract, manufacture the injection mold, test it, and then put it into production. During the entire process, you need to consider the quality, price, delivery date, etc., and maintain good communication and cooperation with the manufacturer.