# Additive Manufacturing Interventions during the COVID-19 Pandemic: South Africa
## 3 Interventions Provided by the AM Community in South Africa
CPRM, in conjunction with their sister company, the Product Development Technology Station (PDTS), have developed novel oscillating respiratory devices (Table 1), also known as flutter devices. The flutter is used to remove mucus from the lungs of patients [44]. Some COVID-19 patients suffer from cough and mucus due to the destruction of pneumocystis and secondary bacterial infections [45], which require the use of flutter devices to remove mucus. CRPM and PDTS use AM processes to redesign the flutters with enhanced features and easy use. Flutters currently use a stainless-steel ball in a cone to create vibrations, which requires that the patient use the flutter only in an upright position, to ensure that gravity can return the stainless-steel ball into the cone. Using AM technology, the engineers at CRPM and PDTS redesigned the fluttered with a plastic spring (Table 1) to replace the function of the stainless-steel ball. The plastic springs were produced using Polyamide 12 (PA 12) and alumide. The AM process was used to design the moulds to produce the plastic spring. This novel development drastically improved the functionality and user experience of the device because the oscillating respiratory device can be used from any angle, even when lying down. Due to the design freedom offered by AM technology, the inlet shape of the flutter is improved by allowing air to be released directly from the lungs such that the COVID-19 patient is restricted from blowing air accumulated in the cheeks. Oxygen connectors and oxygen splitters (Table 1) were also produced to save the lives of COVID-19 patients. As the number of COVID-19 cases rapidly increased in the country [46], it was expected that most hospitals would not have enough oxygen connection points to accommodate all the patients requiring oxygen. CRPM and PDTS use AM technology to produce oxygen connectors, which are commonly referred to as \"Christmas tree connectors\" [47] in hospitals. The oxygen connectors and oxygen splitters were manufactured through an AM (selective laser sintering) [10; 12] process using PA 12 (PA 200) procured from EOS [38]. The design of the oxygen connectors (two-way splitter) will ensure that multiple COVID-19 patients can be supplied with oxygen from the main supply points. Using the unique attributes of AM, the connectors were designed with safety features to ensure that the pipes do not dislodge (Table 1), which is a common challenge when connectors are produced with conventional methods of manufacturing. Using AM technology, CRPM developed a non-invasive ventilation helmet (Table 1), reducing the need for conventional ventilators. It has already been reported by the government that there is a shortfall of ventilators at most hospitals in South Africa. Additively manufactured (SLS-nylon) flanges and a rubber/silicon/TPU neck ring were used to seal the system. The novel non-invasive ventilation helmet provides a safer working condition for clinical professionals, because the design prevents the entry of any droplets from COVID-19 patients when coughing or sneezing. Such designs are appropriate for \"hot zone\" [48] activities. The term \"hot zone\" is used when clinical practitioners are working in close proximity to a patient. Another innovative design for hot zone applications by CRPM and PDTS is the reusable clinician PPE (Table 1). The specialised clinician PPE consists of two parts: the main housing and the soft interface. Both components can be sterilised by autoclaving, which makes them reusable. The soft interface provides a tight seal around the mouth and nose of the clinician. Using the freedom of design provided by AM, the specialised PPE is designed such that N95 (or similar) filters could be attached to the PPE, making it appropriate for the \"hot zone\". The reusable clinician PPE is made from polyamide 12 and alumide.