Photocentric – the British manufacturer of 3D printers using light-cured resins, has also joined the campaign to help combat the COVID-19 pandemic. They used their large format 3D printing devices to manufacture respirator valves. The first to design 3D printing of ventilator valves, were Itlaian engineers from Isinnova, who helped the Brescia hospital. What seemed almost impossible a week ago is now becoming reality. Now most companies from the world of 3D printing are joining in the production of both medical equipment and personal protective equipment.
Photocentric has mass-produced ventilator valves to increase the availability of devices that are key in the fight against a pandemic. To make 3D prints, they used the model available in the GrabCAD repository by Filip Kober – the model was created in several variants of air flow. Despite the fact that the project was made available to a wide audience, its implementation had to be taken care of by the manufacturer, whose materials and production methods meet certain safety requirements.
As Photocentric declares, the materials from which the valve components are made are made of materials that are tested for cytotoxicity and skin contact. The materials used by Photocentric can be compared in composition to dental amalgams used as fillings for dental defects – viricides have also been added to the material to increase patient safety. Safety is a priority in this case, which is why Covance, the American certification body, has agreed to conduct 3D printing tests – if everything goes well, they will receive class I products in the next few days.
Specialists from Photocentric also emphasize that classic FDM or SLA printers are not able to make such a number of elements in the expected quality. FDM printers will not reach the expected resolution, and the rough surface promotes the growth of microorganisms. 3D printers, working in SLA technology, use consumables that in most cases would not pass all safety tests, and at the same time the manufacturing process would be much longer than in the case of Photocentric technology.
Let’s look at the technical details of the printouts. The design uses vertical arrangement of models to fit as many models on the work table as possible and create them without the need for support structures. Similar settings were used in the previously described case study on the production of pens. It was checked what number they could produce at the same time using three machines – Liquid Crystal Magna, Titan and Maximus.
|Liquid Crystal Magna||Liquid Crystal Titan||Liquid Crystal Maximus|
|Number of elements in one 3D printing process||104||171||220|
|Working area [mm]||510 x 280||700 x 392||920 x 510|
|3D printing time [hours]||8||11,5||9|
|Number of items per hour||13||14,9||24|
|3D print resolution [µm]||+/- 100||+/- 75||+/- 150|
|The maximum number of elements that can be produced in a week||1560||1710||2933|
So far, Photocentric has produced 600 pieces, but their processing capacity allows to create up to 40,000 items per week. Currently, the company is in contact with representatives of hospitals in Great Britain.