Additive manufacturing is increasingly making an impact in many industries, and medical devices are no exception. Regulated medical devices manufactured with additive techniques have been available for the past decade and are increasing in frequency. The main advantages of additive manufacturing in the medical field, when compared to traditional 5 or 6-axis machines, are the freedom to generate organic shapes and features that are easier to fit patients’ needs, especially for implants With the freedom to generate new shapes comes a number of challenges. Additive manufacturing is different from the standardized materials we use for traditional manufacturing technologies, and we can’t simply make a part identical to the precursor and assume that it will behave the same way. More on this later…
In a regulated environment, we have to document and prove the safety and effectiveness of the devices we create. This starts with qualifying raw materials in additives. If you review new standards coming out of ASTM, you will see that the control of how the pallets, powders, and other modes are generated needs to be carefully controlled, as they will be blended into a single piece of material that can include impurities leading to device failures or infections, or both. Selecting vendors with quality management systems and auditing them for medical grade operations is critical. Quality agreements, discussed in another post need to carefully outline what’s acceptable for materials you will use to make your products. Additionally, characterization of these materials before and after they become your product is important to understand your thresholds for acceptable materials. Biocompatibility is a critical test, and the standards come with a handy logic flow to figure out what you should test for based on your intended use. Well this all sounds boring, but in summary, garbage in garbage out,.
Once the raw materials come through the door, and you find them acceptable using the preliminary tests you conducted, you are ready to use them. But how do you use them day to day? Do you have standard operating procedures (SOPs) and work instructions (WIs) to handle the raw materials safely so what you receive is what you manufacture with? Ok, I knew you would, just checking. You will also need to qualify the machines you print with. Every part that comes into contact with the raw materials is a risk point. Do they introduce contaminants? Does the surrounding area? You should print some example products and get those biocompatibility tested, too, to document your work. Ok, I think we are almost there, everything is working great. You already know to check printed parts against a CAD model to know the critical dimensions are acceptable, and should have functional tests in the form of a verification and validation protocol to test.
Everything is running smoothly, time to scale up! Well, every new machine needs a calibration protocol, a check, the SOPs to run through, equipment validation (what we call IQ/OQ/PQ, because it’s fun to say IQ OQ PQ!) As you can imagine, time and raw materials are money, so a smooth operation that can run 24/7 is key, but wait, you need to stop machines, clean according to your SOPs, and restart. If there is a drift in prints, you need to recalibrate. You also need to figure out post-processes for dimensional or functional needs. Sometimes heat treatments, machining, etc. are necessary to increase strength to a level comparable to the traditional raw materials. This all seems more and more like a logistical challenge than a process change. You can’t seem to drag and drop your culture to an additive one. Luckily you are reading this before you take action, so you can think ahead and figure out the magical GANTT charts of process times, bottlenecks, and staffing.
Well we are exhausted, but glad we could help.