Medical Injection Molding – A Case Study

medical devices

In this medical injection molding case studies article, I am going to let you know what a mold and molding manufacturer needs to do during a project of custom medical mold and molding.

The background of why I want to write this article

In response to many recent inquiries about medical injection molds. Such as goggles, test tubes, and other medical accessories and mold operation solutions for medical equipment shells.

So I write this article here, hoping to help you in need.

The spring of 2020 is extraordinary. Just a few days before the Chinese New Year, the coronavirus is generally spreading wildly in China.

About ten days later, China has to lock down the entire province to control this situation.

The fact of the coronavirus is spread droplet transmission makes people realize the importance of using daily protections.

medical devices, goggles,Protective masks
And it immediately causes all goggles, and protective masks sold out, both online and offline, at home and abroad.

The situation keeps going on until the end of February in China. At the same time, the coronavirus is quietly spreading in other countries.

At this time, these protective supplies have become very scarce, which has never seen in the past century.

However, this is not only a challenge, but also an opportunity for companies that manufacture and import or export medical equipment and accessories.

What is medical injection mold and molding?

But do you know how to make these medical accessories such as goggles, protective masks, and test tubes?

Many times, it involves molds, or technical medical injection molds.

So, what you need to settle down at present is to find a good injection mold maker for medical products.

And ask them to customize the injection mold you need according to your requirements.

Five-Star provides total solutions for injection molds from design, manufacture to assembly and production. Every medical mold component Five-Star manufacture is durable.

Our capabilities include diameters ranging from .004 to 1.25 inches while holding tolerances down to .0001 inches and surface finishes down to 4 micros (Ra or RMS).

Five-Star Tooling has rich experience in manufacturing injection molds for biological consumables such as Incubate plate, Tubes, Cuvettes, and Medical devices.

We have precision equipment such as DMG 5axis machines, high-speed CNC and Charmilles Wire cutting machines, and so on.

Some of the Injection mold for medical parts including,
Incubate plate medical mold
tube with screw cap medical mold
cuvettes medical mold
pipette medical mold
Tissue Culture Dish medical mold
Plastic bottles for magnetic beads medical mold
Reaction cup medical mold

Experience of Five-Star Tooling in Making Injection Mould of Medical Puncture Device(Case Study 1)

medical injection molding
Medical molds are very demanding molds, and the product inspection standards are incredibly high.

Besides high-precision processing, to understand the usage of the medical injection mold and the national inspection standards of the Quality Supervision Bureau is necessary.

Some products require clinical testing for approval. So the medical mold before delivery out also needs to test and test to reach the customer’s standard.

The medical puncture needle mold is a kind of precision injection mold. The product needs to contact with the human body, so the inspection requirements of the product are stringent.

If there is no experience in making such a mold, it is difficult to do it well, and there is an excellent probability of scrap.

Here’s the adventure to make the mold for this puncture needle:
puncture needle

May use below process when making medical molds:

High precision Wire cutting
High precision CNC
Precision EDM
precision EDM

Below how Five-Star solve the problem when making Medical injection molds

How to improve medical injection molds to avoid water leakage

Luer size
The main difficulty of the needle is that the accuracy of the core size of the needle tip, and even the equipment with high processing accuracy may not be able to process in place.

The size of the Luer’s joint at the bottom is design according to the slope of 6:100, and it should strictly test according to the national standard, and the actual accuracy may be 0.005-0.01mm.

Otherwise, there will be water leakage, and the core processing scrap rate is very high.

How to choose the right material

Second of all, it should go with high hardness mold steel. Steel materials with HRC above 35 ° are most suitable.

Generally, we always use nak80 / S136 steel materials. The thermal deformation of the mold is small, and the discharge is excellent.

When process Medical injection molds, will use which equipment and why?

Thirdly, the control of injection molding processing accuracy is particularly important because the puncture needle product is minimal.

The smallest hole size is only 1mm in diameter, and the concentricity of the core must be guaranteed.

This situation is a challenge for the medical mold processing technicians and processing equipment.

So, when selecting processing equipment, we chose imported high-speed turning machines and tried to use the equipment which has not used for more than five years.

It’s vital because the actual processing accuracy of equipment that has used over a long time has deviated, which will directly affect the product.

If the needle uses the copper electrodes to make, it will not feel comfortable to wear.

After the custom high-speed CNC machining in place, finished with precision EDM. (And it is essential to control the spark gap.)
Mold medical Five-Star

The right choice of the gate

Fourthly: the choice of the gate. Generally, this product will use a multi-cavity structure. The mold uses an imported hot runner with a submarine gate.

Because the entrance is on the inclined surface, it is easy to break unclear. For this reason, EDM is particularly essential, and the spark gap should be within 0.03.
choice of the gate

Take attention when assembly the needle with the cap

Lastly is to assembly the needle with the cap. The production of the needle cap is relatively simple compared to the needle.

There is no high detection standard, as long as it can match with the needle.
assembly the needle with the cap

Conclusion of the case study 1

As you know, every procedure and process of the design, manufacturing, and assembly of the medical mold is essential and closely related.

There is also much testing on medicinal products. It’s more than just two products to assemble well. They need to pass various quality inspection.


1. Delivery time for Medical Injection Molds?

Usually, the delivery time is 3 to 8 weeks. It depends on the mold size and complexity.

2. Tolerance for Medical Injection Molds?

We can hold mould tolerance +/- 0.01mm, product tolerance +/- 0.02mm.

3. Do Medical Products have Special Requirements on Molds?

Medical injection mold generally has a high requirement for service life and has high specifications for mold steel.
So we must use good steel as medical mold has high requirements for product smoothness, production, and precision.
Therefore, Five-Star always uses the steel 718 or better, so the medical mold life will be at least 300,000 shots.

4. What is the Standard of Making Medical Injection Molds?

Almost every different product has different standards. The requirements of medical mold are very high. The primary production standards are reflected in the products. For example, there are many products with international standard sizes. The rules of mold are mainly automatic production, multi-cavity, without any burr or flash.

5. How many injection molds are required for a customized medical syringe?

For the production of disposable syringes, five molds are needed. They are syringe mold, plunger mold, washer mold, needle cap mold, and needle seat mold, plus ejector pin to form a complete syringe. At Five-Star, we can produce molds for medical syringe from 2 cavities to 24 cavities.

6. In general, where do many manufacturers specialized in injection molding medical devices and molds locate?

It is mostly located in coastal cities, such as Jiangsu, Shanghai, Zhejiang, and Guangdong.

Five-Star medical injection molds


The requirements of medical mold are very high. The primary production standard is reflected in the products.

For example, many pharmaceutical products are equipped with a Luer joint, which is a production standard.

If the mold factory does not understand this standard, it will be troublesome.

Besides, there are also many products with national standard dimensions.

The rule of mold surface is mainly in full-automatic production or multi-cavity, without any burr and flash.

Especially the place where contacts blood or human body contact, which could easily cause medical accidents with small flaws.

Only when we understand the above requirements, can we start to make medical injection mold.

To be fully capable, we need high standard mold designers and high-precision processing technology and production concept.

I hope this article about medical injection molds helps you in some way. For more information, please contact our professional team.

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