3-D printing could very well be the solution for in vitro diagnostic instruments companies in need of once-costly fluidic manifold prototypes.

Heidi Lechner, IDEX Corp.

While fluidic manifolds can help designers of in vitro diagnostic instruments improve the performance of their products, they have traditionally only been practical for large, established instrument makers. That is changing, however, and today, even startups on tight timelines and with restricted development budgets can benefit from them.

That is good news, because many designers of in vitro diagnostic instruments embrace the concept of utilizing a fluidic manifold to minimize the size of a device, reduce leaks, improve the reliability of the flow path, and get consistent fluidic performance in every instrument. Certain process thresholds have made manifolds a practical solution for only large, established instrument manufacturers.

Even startups on tight timelines and development budgets can now acquire limited-run prototypes in materials suitable for proof-of-concept. 3-D printing could very well be the solution, providing yet another example of how additive manufacturing is spurring innovation in the device space.

At IDEX Health & Science, we form manifolds by curing a photopolymer resin on a build surface. A laser beam traces the part geometry and solidifies the resin. The build surface, immersed in a vat of this resin, is lowered by a fraction of an inch to build the next layer. This 3D printing process is called stereolithography. IDEX Health & Science's Manifold-in-a-Week process produces prototypes intended for initial design analysis. This seven-day process helps accelerate time to market by providing faster manifold delivery and enabling rapid design iterations. In this process, we work to optimize the form, fit, function, and manufacturability of your fluidic path by collaborating early in a project.

 "It changes the whole discussion," said sales engineer Ed Beldowski of IDEX Health & Science (www.idex-hs.com), describing a recent manifold design project with a northeast biomedical startup developing a point of care device. "The customer submitted the initial design request through our website for a very small, fast-turn manifold onto which they planned to assemble several small valves and a pressure regulator. Working with us, he liked the real-time availability of our engineers. Also, as a startup, working with an established corporation like IDEX Health & Science increased his confidence in collaborating with us."

"Speed was really the primary factor for us," emphasized the undisclosed startup company's founder/chief technical officer "If we'd done it the old-fashioned way, where we'd get the fluidics module in six to eight weeks, the cycle times for making these iterations would have been a lot longer and would have cost a lot more. So, being able to get quick turnaround on fluidic modules was key."

There was a need on the part of the startup company to shrink everything down into a very compact beta unit much closer to the final form that would go to market, says Mark Joiner, director of engineering at IDEX Health & Science,

"We believed there were still iterations ahead. The instrument probably wasn't in final form yet-- and he agreed," Joiner recalls.

Manifold-based fluidics were needed. "After estimating the hard cost of making just one multi-layer bonded manifold, where the per-unit cost can be expensive because of production set-up time, process time, and finishing work, our team suggested, using 3-D printing processes. The customer was definitely interested, provided IDEX Health & Science could produce a very clear material that would fully expose the entire flow path. This was needed because he still wanted to visualize and improve his process," Joiner said.

3-D printing has historically been used to form larger objects with less sophisticated features, according to Joiner. "The IDEX Health & Science process starts with a liquefied resin in a vat. As the vat is raised incrementally of about 0.002 inch (0.05 mm) at a time, a laser describes a design on the surface. That design becomes the formed object as the laser cures and sets the material in the additive production process. Resin is cured only in the areas where you want material, leaving other areas where you want the channel open. The threshold of limitations that the industry has encountered up to now, has been around those very minute passages. The smaller the diameter of the channel, the harder it is to keep it open because the material outside the channel will collapse due to the heat energy surrounding it. After a couple of trials, we were successful in forming the tracks accurately, with absolutely no blockage or collapse."

Once the piece was accurately formed and cured, manufacturing technicians at the IDEX Health & Science facility in Bristol, CT performed a series of specialized secondary processes. Fluidic ports were finished and sealing surfaces were smoothed to prevent leaks. "To make the manifold functional, components such as valves and fluidic connections were added," Joiner said. "Because this material is a thermoset, not a thermoplastic, it can be brittle. The IDEX expertise enabled the proper torque for sealing component ports and connections without introducing stress cracks in the process. We worked on that quite a lot, because it can create the critical difference and provide the level of precision that sets us apart from other rapid prototyping services as the fluidic experts."

Beldowski mentioned he was set to speak with a customer seeking one piece to qualify a design, and it was a pretty complex manifold that would cost a lot of money and take a lot of time and resources. "Now, because of the clarity of this material, the compatibility with his benign chemicals and his short delivery window, Manifold-in-a-Week is a good option for him. Earlier, he told me that they've had SLA printing capability in-house for five or 10 years. So I asked him, 'Do you think we could print your new manifold design on your machine?' But he said, 'There's no way. The materials are not transparent, and it doesn't have very good resolution.' When I shared with him our ability in printing internal passages down to 0.030 in. (0.76 mm) he said, 'Wow. I'm very interested. Show me.' It literally changes the entire discussion."

Heidi Lechner is online marketing manager at IDEX Corp.