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Medical Device Moulding – A Test Tube with Moving Components and Membrane Cap

Updated: Aug 16, 2022

Disclaimer: the lower part of the tube and its components will remain not disclosed due to confidentiality issues.



Rapid injection molded prototypes for innovative medical test tubes to fight Covid-19 pandemic.


  • Test tube’s membrane cap design optimization for molding

  • Test tube’s inner components: valve and hammer design consultancy and DFM

  • CNC machining 3 aluminium tools for low-volume injection molding in less than 3 weeks.

  • Molding first samples


First prototypes delivered for robot assembly testing in less than 2 months with design changes and consultancy included under 10 000 EUR which could be up to 2 times cheaper and faster than with traditional molding.

Swissinnov GmbH is a medical products developing company which has set its main goal as to transform creative thoughts into the real products. Swissinnov believes that talents and ideas are the core assets of organizations which strive to venture into new businesses to obtain new customers and to differentiate itself from its competitors. To help such organizations Swissinnov offers a global perspective of product development and the capacity to completely foster their businesses at various levels.

When Swissinnov first contacted Micromolds it was instantly clear that the RFQ received was of a high quality and that the company knows how to work with injection molders.

“When you get an email with a subject name ‘rapid mold’ you immediately feel the pressure from the client but also know that this is exactly what we can offer” – says

Dominykas Turčinskas, CCO at Micromolds

Part Design for Molding

The goal of this project was to develop a medical test tube which would have an inner moving components and membrane cap. For this reason, the test tube is not just a test tube – it becomes an actual medical device with certain requirements:

· Material: PP highly transparent (PP copolymer)

· Design constraints: Thin wall 0.1 mm-0.6mm

· Surface finish: high polished

· Device has to stay in storage for 12 months

· Sealing has to insure 100% tightness during storage (5 to 40°C)

· Low friction to operate valve during operation

· Parts will contain disposable unit

It took us total of 6 iterations of major design changes to come up with a final V6 design of a whole device. It is essential that on such high value and time-sensitive projects both parties would sustain tight and quick communication. We are proud that the machining of the molds started in 4 weeks which shows an outstanding speed to confirm and agree on a total of 6 versions of design variations.

Design for Manufacturability (DFM)

The main challenge in design stage is to balance between the functionality and manufacturability of the product. To achieve this balance, it is essential that the product developers would share the most of information they can so that know-how of injection molding could be implemented in the project objectives. In this way both parties can come up with a new design variation that previously could not be even imagined.

Material Selection and Tooling

Material selection and sourcing in a medical device development projects plays also a critical role. Not only had the design requirements to be met but also the documentation of material sourcing and supplying had to be prepared and submitted. This includes:

· HRAF form

· Medical Polymers Request form

· Customer agreement letter

· Statement of Medical Compliance

As Micromolds has its material supplying partners and experience in filing the documentation it was a huge help and time saver for the client.


The tube and the remaining 2 components were produced in separate 3 aluminium molds. We used our CNC mills and aluminum material to machine the tools as this allows us to achieve short lead times and low-cost machining. The most important advantage is that all the components and the tube itself fit in our micromolding machine and micro molds. This allows us to cut the costs even more. The tooling stage for all 3 molds in total took us 3 weeks not to mention highly polished mold surfaces. The cost of these molds settled around 10 000EUR in total with modifications included which is no less than twice cheaper than traditional molding. We are so proud that we can deliver such results for our highly valuable clients.


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