Whether it’s for medical or electronics, extremely small parts are in demand. The miniaturization trend has been growing (so to speak) for decades. Micro molding technology has been following this trend on down. Some molded parts are smaller than the thickness of a human hair. By small, think amazingly tiny. “Our smallest molded form is over one thousand parts per plastic pellet. That’s extreme,” Brent Hahn, Isometric’s director of global sales, told Design News. “We handle up to six-inch parts, but they still have micro-features that may be single microns in size.”
As for the markets for extremely small parts, there are many-, from fiberoptic connectors, strain reliefs, ferrules, and LEDs that go in ever-shrinking electronics- to parts that go inside the human body, such as ear tubes, heart valves, intraocular surgical instruments, and disposables. “Our main customer base has been medical and drug delivery device OEMs. Our value is in solving miniaturized device problems for fitting into tiny spaces such as surgical endoscopes, insulin pumps, wearable devices, transdermal needle arrays to name a few,” Donna Bibber, VP of business development at Isometric, told Design News. “We also produce implantables, where the parts hold a slow-release drug in the body that dissolves. Or the parts hold a hernia mesh together with material that is designed to dissolve.”
The business of making incredibly small parts comes with a few obstacles. “Trying to find material that will fill thin walls with high aspect ratios is a challenge that we are very good at solving,” said Bibber. “When you get down to the small level, you still need strength in the part. The material selection matters. An additional obstacle is validating these parts. We’re validating to single micron tolerances that takes a very detailed process map and corresponding PFMEA.”
In addition to micro-molding, some small parts can be produced using additive manufacturing. “3D micro printing is used to flush out geometrical designs early on in the product development stages,” said Bibber. Isometric Micro Molding uses micro 3D printing for prototyping. “We've been successful in assisting customers with DFM/DFA early in the development phase so scalability can be reviewed even at the prototype stage very quickly, in just a few days”, said Bibber. “It’s important for us to 3D print something that is scalable, so the customer has something in hand that fits the needs all the way through the product development cycle. This saves much time and money on the back end of the development cycle.”
One of the reasons for using micro 3D printing for prototyping, but not for production has to do with available materials at this time. “Most 3D printing materials are thermosets, however, and not typical of the materials used later on in the development cycle,” said Bibber. “With miniaturized medical and drug delivery applications, customers need thermoplastic and FDA-predicate materials that have been through regulatory certification.”
The features and part sizes have to also represent micro molding and automated assemblies. “Our smallest part we printed was a one-thousandth of an inch (0.001” (25 microns) thick part. Also possible with micro 3D printing are high aspect ratio components such as 0.002” thick tubes over 1.5” long, transdermal needles with extremely sharp needle points, and microfluidic channels and holes < 0.004” (100 microns),” said Brent Hahn.
“In the midst of a significant demand for miniaturized device innovations, Isometric Micro Molding, Inc. is well-positioned with capabilities to partner with our customers to create not only new products but platforms of products resulting in significant intellectual property and value”, says Bibber.
Here are some details of the Microns Matter Proven Process that explains how the Isometric Micro Molding creates solutions for all of the variables that can steal microns away from making good parts.
Rob Spiegel has covered manufacturing for 19 years, 17 of them for Design News. Other topics he has covered include automation, supply chain technology, alternative energy, and cybersecurity. For 10 years, he was the owner and publisher of the food magazine Chile Pepper.