When Ozzie the goose had his leg amputated after it broke, it seemed very unlikely that he would ever walk again. But Ozzie’s rescuer, Sue Burger, did not give up on him. Burger shared Ozzie’s story on a radio show on RSG and told listeners “For the first month, he spent his life hanging in a hammock with his legs hanging out the bottom of a blanket with two holes in it.”
Her story was heard and with the help of digital and 3D printing companies namely, BunnyCorp, 3D Printing Systems and the Centre for Rapid Prototyping and Manufacturing at Central University of Technology, Ozzie had a custom-made leg built for him, a first for South Africa. This is not a fairy tale in which bunnies make new legs for geese using magic. The designers measured Ozzie’s stump, did multiple fittings to ensure that he was comfortable with the prosthesis, and then “printed” his new leg. This technology – and the steps made to build a new leg for a goose – will eventually pave the way for similar procedures to help other animals, as well as humans.
But it is possible that the growth in this apparently miraculous technology – known as additive manufacturing by those in the industry and as “3D printing” in general parlance – could hurt those working with it, as health and safety standards struggle to keep up with the growth in the industry. This is where occupational hygiene comes in.
Occupational hygiene involves anticipating, recognising, evaluating and controlling health hazards in the work environment to protect workers’ health and wellbeing. This multi–disciplinary field involves chemistry, physics, physiology, engineering, mathematics, mathematical modelling, toxicology, physical hazards and risk assessment. An occupational hygienist ensures that employees not only go home safely, but that they also go home as healthy as (or healthier than) when they came to work.
New manufacturing frontiers
Also known as rapid prototyping, additive fabrication, layer manufacturing or freeform manufacturing, the process has been hailed as the next industrial revolution and a new path for manufacturing.
Each day brings a new printing adventure in the world of additive manufacturing, whether it is a functional replica pistol, art, designer jewellery, robot-like hands, 3D-printed dresses, prosthetic legs, car parts or Boeing aircrafts. In 2001 Richard van As, a South African who lost four of his fingers in a woodworking accident, used 3D printing to build himself a new hand, which he dubbed “Robohand”. Using the same technology, he built a hand for a five-year-old boy who had lost his fingers due to amniotic band syndrome (a congenital condition that can lead to a number of deformities). In the near future, additive manufacturing will open up even more manufacturing frontiers.
When most people hear about 3D printing they imagine familiar desktop printers. But whereas a desktop printer is two dimensional and uses ink to print, a 3D printer can create ready-to-use three dimensional objects in a variety of materials. Additive manufacturing involves building up parts, layer by layer.
It starts with a computer design of a digital 3D solid model, which could be anything from a rocket engine part to a bionic ear. The machine reads the data from the computer design and follows instructions, building the objects one very thin layer at a time, whether from plastic, metal, ceramic, paper or wax. The ability to join thin layers of liquid, powder or sheets together means that people can produce parts which would be difficult or even impossible to produce using any other manufacturing method.
Although additive manufacturing has been around for more than 30 years, South Africa had a late start and, until 1994, only three systems were available in the country. But today, there are about 1?400 3D printers available, with 300 in science councils or higher education institutions, according to the Rapid Product Development Association of South Africa.
The additive manufacturing process is considered an “enclosed process”, because most materials require a contamination-free environment. So at first glance it appears safe for people to work with 3D printing. However, loading raw materials and additives into the machine, sieving materials, cleaning machinery and finishing off manufactured products can expose workers to a variety of hazardous chemical substances. These include silica sand, chromite, nylon, resins and titanium.
Workers can inhale the substances and powder deposits in their eyes and on their skin can lead to irritation and allergic reactions to some of the raw materials and additives. But information regarding the health risks associated with additive manufacturing is scarce. We are not sure what safety levels are required and how much of these raw materials workers can be safely exposed to. There are only two studies that address the possible health effects associated with additive manufacturing, and both express the importance of further investigation and the need for proper occupational health and safety practices for additive manufacturing.
Possible health risks
South African occupational health legislation requires employers to assess the possible health risks to which employees may be exposed. A fundamental requirement of the Occupational Health and Safety Act – namely the Regulations for Hazardous Chemical Substances (1995) – states that exposure of employees to substances hazardous to their health should be prevented or, where this is not reasonably possible, adequately controlled. Although it is the responsibility of the employer to ensure the monitoring of worker exposure, an occupational hygienist is essential to identify and evaluate potential health hazards. Exposure to chemicals used in additive manufacturing may not produce immediate symptoms and therefore needs to be monitored over time.
With limited literature available and previous studies already out of date, my PhD will identify the health risks associated with all the manufacturing processes located at the Council for Scientific and Industrial Research, Vaal University of Technology, Central University of Technology and Stellenbosch University.
It will also assess levels of exposure to the chemicals used in the processes. This will provide important information for training employees on the health consequences of being exposed to the materials used in additive manufacturing and deliver control measures necessary to eliminate or reduce employee exposure.
Sonette du Plessis attends North West University.