How to Make a Plastic Injection Mold

Plastic injection mold is used to make plastic products in many industries, especially for high volume production requirement, if you have a plastic product that requirement millions parts, make a plastic injection mold will save you a lot of unit part cost.

To proceed with the injection molding process, they must be plastic injection mold and the molding equipment, like injection machine, dryer machine, etc.

But to make plastic injection mold that takes time, below we will be discussing about how long will take to make a plastic injection mold.

What is the lead time for a plastic injection mold project?

The lead time for plastic injection mold generally depends on the complexity, size and customer standards, quality of plastic injection mold, For example, a low-production project with five-hundred samples, then we can make this plastic injection mold with pre-harden steel, this will be more fast than high quality plastic injection mold, if making high quality plastic injection mold, then need to use harden mold steel.

If small part and simple geometry will stake very short time compare to the large and complex part design. Normally some plastic injection molds for some small parts will take around 15- 30 working days,

On the other hand, for a big-scale project with complex shapes with high volume requirement production plastic injection mold, such as intricate designs or multiple cavities, the mold manufacturing lead time can take from 2-4 months. The volume of parts needed for such can range from 100,000 to 1000,000 and many need multiple chilling mechanisms, slide cams, and ejection components.

But if you want to know the mold manufacturing lead time for your plastic injection mold, you are welcome to contact us, we are China injection mold company, we can quote you a free price for your plastic injection mold, no matter you will work with us or not, we still welcome to contact us.

Process to Make a Plastic Injection Mold

When we discuss about lead time for making plastic injection mold, then we may need to know the process to make plastic injection mold, there are many steps involved to make a plastic injection mold, and all of those jobs mut be done by a professional mold company, below we are talk about that.

1. Product Design and Analysis

The first step for plastic injection mold manufacturing is part design, develop a detailed 3D model of the desired part using CAD software (e.g., SolidWorks, Creo, or CATIA). You can find a design company to design your part according to your sample, sketch, or ideas, if you do not know any design company, you can contact us as well, we will provide you some suggestions.

Design for Manufacturability (DFM):

Once we finished the part design, then we need to do the DFM report, which means to check if the part design the manufacturable, those include the material selection, draft angles, wall thickness, undercuts, parting line, if have risk we will list out to improve the part design.

2. Mold Design

After DFM step if finished and approved then we start mold design, the professional mold design will use UG or SolidWorks, or other similar 3D software the design the complex the mold, those include the moldbase, cavity and core, cooling channels, spure, runner, gate, lifter, slider, screws, ejector pins layout, and verting groove, etc.

Mold design is one of the most important factor to make high quality and long last plastic injection mold, poor mold design will break the mold very soon, so mold design has to be done with a professional mold design, a expert design should be at least having 10 years design experience.

3. Mold Material Selection for Mold Components

Once the mold design is complete, then next start to select the mold materials, before starting mold manufacturing, normally need to know the purpose of the plastic injection mold, for example, what is surface requirement, what is mold life time requirement, what is plastic material will be used, those information we will also list in the DFM report, but selecting the mold materials should be follow on this factors. Below are some common steel we use for plastic injection molds.

P20 Steel: this is common mold steel for low volume plastic injection molds or using as A/B plates for high quality plastic injection molds.

H13 Steel, DIN 1.2344, DIN 1.2343, 2083: those are hardening steel that could meet up to HRC 48-54, those steels are used for high quality plastic injection molds, mold lifetime normally can last 1 millions short or even more.

Stainless Steel: this still is sued for molds requiring corrosion resistance. Some special plastic material that rusts the mold steel like PVC, ABS V0 materials, in that case stainless steel will be a better option.

4. CNC Machining of Mold Components

Rough Machining: Use CNC machining, turning, and drilling to create rough shapes of the mold components, mold cavity and core.

5. Heat treatment: for the hardened steel, once the rough machining, need to do the heat treatment so that the steel can meet HRC 48-54, if use pre-harden steel then no need to do this step.

6. Fine CNC machining: after the heat treatment, fine CNC machining and griding needed, the fine CNC machining will cut the final extra steel which left from the rough machining, because they will be some extra steel left from the rough machining to protect distortion from the heat treatment.

EDM Machining or wire cutting:

Once the fine CNC machining complete, EDM (Electrical Discharge Machining) process will start to make some deep rib and small corner, and wire cutting to achieve the final dimensions and intricate details of the cavity, core, and other mold parts. EDM machining is slow and most of place have to use EDM machining, and this is one of most process for mold making.

7. Polishing and surface etching:

After every machining is finished, then polishing will start, EDM machining will left rough surface on the EDM etching area, if leave those surface on the mold cavity, it will be very hard to demold, especially for the deep ribs, the ribs will break in the cavity and core, so polishing will be done to all of mold cavity some of mold that requirement VDI etching surface finish to the cavity side for good looking. In that case VDI texture will be added to the cavity side accordingly.

8. Mold Assembly

Fitting and Assembly: Assemble the cavity, core, ejector system, and cooling channels.

9. Mold Testing and Trial Runs

Initial Trial (T0 Sample): Perform initial mold trials to produce sample parts.

Dimensional Inspection: Measure the parts for dimensional accuracy, shrinkage, and surface finish.

Mold Adjustment: Modify the mold based on trial results (e.g., adjusting gate size, cooling channels, or ejector system).

10. Final Approval and Production

Final Testing: Conduct additional trials until the part quality meets specifications.

Approval: Once the mold produces consistent, high-quality parts, it is approved for mass production.

Mass Production: The mold is installed in an injection molding machine for full-scale production.

End words

It looks like that very complex to make plastic injection molds, the answer is year, making mold is not easy, it must be done with professional mold maker, if you have a project that need plastic injection mold, then find a professional supplier will help you a lot. if you do not know where to find, then you may come to google to check, there are many mold factories from China and the world that you can find from there.

Read more about CAD, product design and related technology at SolidSmack.com

Source: https://www.solidsmack.com/manufacturing/how-to-make-a-plastic-injection-mold/