The creation of plastic objects through additive printing is relatively well established. However, 3D printers that use metal are rarer, which is perhaps unsurprising given the difficulties handling harder materials. In addition, more infrastructure is involved.
The problem in relation to medical implants has been overcome for several different devices. The research group has developed a process that is fast and which allows for devices to be fashioned using titanium. The devices created to date include an intricately designed titanium spacer, which can be used for spinal fusion surgeries and titanium scaffolds, which assist with large bone defects.
With the first device, spinal fusions are undertaken to alleviate back pain, overcoming the medical complication which arises from two vertebrae rubbing together as a disc of cartilage fails. With the second medical implant, titanium scaffolds act to provide strength and support to portions of other bones removed as the result of surgery. They also provide support for bone regrowth. In addition, suitable nutrient intake has also been found to significantly affect the integrity of the fracture repair.
Commenting on the success with the new printer, lead researcher Sam Morton told Controlled Environments magazine: “The metal 3D printer allows us to make designs that could never be fabricated by traditional manufacturing processes.”
The engineer adds: “It allows us to make actual biomedical devices out of that we can then test and get feedback on from the surgeons we’re working with.”
The need to move towards 3D printing for the metal implants is to gain better flexibility and to be able to fashion devices to suit a range of patients. Plastic cannot be used because it is insufficiently strong; moreover, medical studies have shown that plastic is not able to facilitate bone regrowth. The printer resembles a traditional plastic 3D printer, consisting of a robotic arm designed to sweep a thin layer of titanium dust across a metal plate. A high-power laser is then used to melt the dust in the specific pattern of the bottom layer. This process repeats until the part is finished, with the typical time required to manufacture a device around three hours.
