The finest details in two-component injection molding, the tightest form and position tolerances, burrs of just a few hundredths of a millimeter, up to 20,000 pieces from one aluminum mold, assured cleanroom quality despite the transfer process – 1zu1 and Weidmann Medical Technology AG pushed the limits of what was possible when developing a device for in-vitro diagnosis.
1zu1 completed its long-planned cleanroom towards the end of 2015 – just in time for an order from the Swiss company Weidmann Medical Technology AG. The job in question was no cakewalk. In its new cleanroom, the Dornbirn-based high-tech company was asked to produce a dozen different parts with its aluminum tools – each consisting of up to 20,000 pieces and in compliance with the highest quality standards.
“This was a high-end project. Every requirement was a bit more demanding than usual,” recalls Wolfgang Spiegel, head of 1zu1's Tooling division. Daniel Quidiello, project manager at Weidmann, also openly admits: “We were initially skeptical about achieving sustainable feasibility and quality.”
Mr. Quidiello, Weidmann Medical Technology AG has been developing innovative plastic injection-molding components for the medical technology and medical industry for many years. What made this project particularly challenging?
Daniel Quidiello: The collaboration with 1zu1 marked the conclusion of a challenging development project by an internationally active medical technology company, which lasted over two years. The goal was to produce a device for in-vitro diagnosis with which samples, for example blood, saliva or plasma, could be screened for viruses and bacteria directly by a doctor or in a hospital.
Until now, doctors often had to send these samples to central laboratories and wait days for the results. The new analyzer can diagnose up to 22 pathogens within minutes. A quick and precise diagnosis of diseases such as meningitis or influenza is thus possible directly at the point of care.
How did the project go from your point of view?
Quidiello: In summer 2013, we received an order from our customer to develop the cartridge. This is the heart of the new device and consists of twelve individual parts. The cartridge is about 15 centimeters long and contains several chambers containing liquids that are used to microbiologically examine the samples.
For construction of the prototypes, in the summer of 2013 we approached 1zu1, with whom we had been working closely together for more than ten years. After that it all happened very quickly – at the end of September we placed the order for the first nine injection molds. Six weeks later the injection-molded parts were on our desk at our headquarters on Lake Zurich.
A tight schedule. From 1zu1's perspective, what were the challenges in this project?
Wolfgang Spiegel: To produce nine injection-molding tools at once is an extraordinary order for us. The biggest challenge, however, was certainly the specifications for the parts.
At 1zu1, we manufacture our tools in aluminum. They can be manufactured quickly and very precisely on our modern lathes and milling machines. Thanks to their modular design, we can adapt or change parts of the tool later if necessary. This has huge advantages for product development: Aluminum tools can be produced much faster and more cost-effectively than the steel ones that are subsequently used for series production. This enables us to deliver the first parts very quickly.
Of course, the aluminum tools are not so durable. The big question for us was therefore: Can we achieve the required quality for the large quantities requested by the customer? We originally guaranteed Weidmann, the customer, 2,500 pieces per tool. Ultimately, our tools proved to be very durable and we produced up to 20,000 pieces in the required high quality.
Quidiello: Due to the high stability of the tools, we were even able to dispense with the pre-series tools, which we usually produce after the prototype phase.
Mr. Quidiello, can you provide some details about the design? What exactly was the challenge?
Quidiello: The various parts of this cartridge have very fine structures. For the various microbiological analyses, the liquids are transported and mixed inside the cartridge. There are more than 20 variants. Some of the channels have cross-sections of half a millimeter. The tiny valves required for this must be absolutely tight with unimpeded movement.
Tightness is also particularly important for this device in other respects. Imagine if a patient's sample containing pathogens were to escape from a doctor's surgery. The effects could be fatal. The hinges in some areas of the cartridge must therefore close just as tightly as the chambers containing the analysis fluids. After filling, these are sealed using a special process that requires injection-molded parts with the highest possible surface quality. This means that only burrs or webs within a few hundredths of a millimeter are permissible.
As the customer, were you aware of the challenges for these initial, smaller series?
Quidiello: Of course! At Weidmann we understood the problems and were initially even skeptical with regard to long-term feasibility. In order to meet the requirements, we worked closely with 1zu1 on the design of the tools.
Spiegel: This close collaboration was very important for the project. Together, we questioned each design in terms of cost efficiency and safety, and motivated each other to implement innovations in the area of tooling technology. There was repeated dialog with the end customer.
During which phase of the project did you move production to the cleanroom?
Quidiello: In 2013 and 2014, we tested the technical functionality of the parts in two prototype phases using standard injection molding. Thanks to the modular design of the aluminum tools, we were able to implement changes with little effort. In the third phase, which began in early 2016, the tests were carried out at the customer's premises with a focus on the medical technology. The new cleanroom at 1zu1 was very convenient for this.
Spiegel: The microbiological tests require absolute cleanliness. The presence of foreign DNA inside the chambers containing the analysis fluids would falsify the results. Our cleanroom corresponds to cleanroom Class 8; however we often achieve even better results, as our contact-plate microbial tests demonstrate. We use the facility for production with raw materials that are approved for medical applications.
We experienced a real challenge with the parts produced via two-component injection molding, because we had to transfer them manually between the two machines. In a cleanroom, any manual intervention naturally involves a risk of contamination. However, we also mastered this hurdle by exercising particular care.
The two companies, Weidmann Medical Technology AG and 1zu1 Prototypes, have been working together for more than ten years. Did you nevertheless learn anything new about each other?
Spiegel: For me, this project has shown how collaboration with a strong ethos of partnership can inspire us to achieve top performance.
Quidiello: I can only underline that. Thanks to the good cooperation, open communication and regular exchange of experience, we both benefited greatly from the project and learned a lot.
Interviewed: Daniel Quidiello is senior project manager at Weidmann Medical Technology AG, one of the leading independent Swiss injection-molding system suppliers for the medical/medical technology industry. Wolfgang Spiegel is head of the Tooling division at 1zu1 in Dornbirn. The interview was conducted by Wolfgang Pendl; photos by Darko Todorovic.