We’re constantly giving you the scoop on the latest in orthopedic devices from our clinical and design perspective, but have you ever wondered about the steps that go into manufacturing these devices? There’s a lot of work in the process that turns an idea into an actual physical product, and often times it’s something we don’t think about.
During our recent trip to Northeast Indiana, we had the opportunity to visit a number of manufacturing sites and learn the high-tech processes and technology that go into producing orthopedic implants and instruments. Here’s how it works!
Design and prototyping
When an idea for a new device is developed, it often goes to a design engineer within the company who deals with the overall structure of the device. He or she will often use a rapid prototyper to fabricate a mockup of the device to get a better idea of its physical properties before it’s approved and sent to the manufacturer. Some manufacturers we visited actually have an in-house team of design engineers. With more experience in the machining and milling processes, these design engineers work alongside clients to further refine the design of a product to make it cheaper and faster to produce without compromising quality or structural integrity.
Pretty much all the implants and instruments we saw were produced from a single block of metal or PEEK composite plastic. The metal blocks (or rods) are secured to the inside of large industrial multi-axis milling machines (CNC’s). These milling machines consist of a number of robotic arms and drilling tips that can carve very fine features. They’re basically the same machines that you would find carving automobile parts, except on a smaller scale. A white, milky looking cooling liquid is aggressively sprayed onto the drill bit as it’s carving the part to cool it, as well as to remove metal shards.
Often, the five most important faces of a block of metal are milled, with the sixth kept intact as the base. After milling is complete, a wire electrical discharge machining (EDM) cutter removes the base, and the sixth face is milled. It’s important that as much of the implant or instrument is milled at a time; moving a partially finished piece between different machines or adjusting their position could potentially cause variations between parts, and also naturally increases the amount of time it takes to produce a finished part.
Finishing, inspection, and passivation
Though milling is done with industrial robots, most of the remaining tasks are done by the hands of skilled machinists and technicians. If the implant or instrument requires a dull or matte finish, it next goes to a sandblaster to remove the metal’s shine. Technicians also will use a rotary sander to deburr and finish the part. Around this time, the parts will also be laser-etched with information, such as the part’s ID number and manufacturing date. A sampling of the finished parts then goes to the quality lab, where technicians use automated instruments, as well as their eyes and hands, to meticulously check various properties of the parts. We also saw a device called an optical comparator that projects a magnified silhouette of a finished piece onto a screen which is compared with a schematic of the piece printed on mylar. Finally, all the parts are then cleaned ultrasonically using water, and then passivated using nitrate or citrate to prevent corrosion.
Packing and sterilization
Our finished medical devices are almost done, but unlike automobile parts, these parts can’t simply be placed into plastic bags or cardboard boxes to be shipped out. Larger companies often will sterile package the finished parts in-house, however, some of the smaller companies we visited outsourced this step to another firm nearby.
To ensure that the packaged, finished goods are sterile enough to be used in a surgical environment, they’re often sent to a third-party (such as Iotron) to irradiate the parts using radiation or gas. Over at Iotron, pallets of parts move down a long conveyor belt into an area called the “shield”, which is a concrete-lined, maze-like passageway with a giant electron beam gun at the heart of it. Now that the parts are finished, packaged, and sterilized, they’re ready to be shipped out and used in operating rooms everywhere!
We’d like to thank the Northeast Indiana Regional Partnership and the participating companies for the tour.