DESIGN FOR AM

RODENT RADIATION APPARATUS

The Department of Medical Physics at the University of the Free State (UFS) makes use of radiation apparatus when doing research on rodents. This is done with a medical linear accelerator (LINAC) machine. The Product Development Technology Station (PDTS) assisted the department to manufacture these jigs through Additive Manufacturing (AM). The original device was manufactured many years ago from acrylic with an in-house process.

The acrylic sample was reverse engineered and the design was adapted for the AM process. The PDTS then 3D printed the device from SLS nylon and other materials.

The design of the existing apparatus was improved and AM technology makes it possible to easily customise according to the client’s specific needs. The AM process also significantly reduces manufacturing time.

The rodent radiation device assists with more effective and efficient research. The availability of more jigs also reduces the testing period and improves the standard of radiology and cancer treatment.

RUST INOCULATOR

The Department of Plant Sciences at the University of the Free State (UFS) uses an instrument, called the inoculator, in research of rust on cereal crops. It requested the Product Development Technology Station (PDTS) to help manufacture this instrument for research on plant fungi. The inoculator, which was originally designed in 1971 and never updated, is used to apply collected rust spores onto uninfected plants to accelerate the spreading of rust.

The original design was very complicated and required special skills and numerous manufacturing processes. The PDTS made use of Additive Manufacturing (AM) that requires no additional processes. Through this a product was designed that costs a fraction of the price of the original model and is also much less time consuming to assemble.

The station did research on the theory behind the inoculator’s systems and learned it is based on pilot tubes, much the same as a spray paint applicator. The inoculator was redesigned and based on the design of an air brush and prototypes 3D printed in nylon.

The product performed exceptionally well – to such an extent that the UFS patented the design in the United States of America and South Africa and commercialised the inoculator.

ADDITIVE
MANUFACTURED RIFLE SIGHTS

The Product Development Technology Station (PDTS) assisted a client to design and manufacture cost effective rifle sights for sharpshooting as new sights were very expensive. The station used various iron sights as reference and decided on the Additive Manufacturing (AM) process to manufacture certain components of the product.

A new unique design was made for this purpose and therefore differed from existing iron designs of rifle sights. AM gives more freedom of design, which no other manufacturing technology provides.

The PDTS chose nylon for its durability, light weight and lower cost. The design was based on a brass railslide system and tried to keep most of the moving parts low profile in order to keep a low centre of mass.

The rifle sight was 3D printed in nylon and features 5 mm brass round bars for the rails and two M4 threaded rods for adjusting the slides. The adjusting dials rotate on spring-loaded bearings that divide the rotation in increments. Each increment gives an adjustment of only 0.07 mm. The rest of the hardware is stainless steel for durability.

This AM produced rifle sight is one of a kind and the client was satisfied to such an extent that he can commercialise the product.

DYNAMIC HAND SPLINT

Stroke patients often experience unusual stiffness of the hand, which is also referred to as spasticity. Therapists make use of dynamic hand splints as part of the rehabilitation process of these patients.

The Product Development Technology Station developed a patient specific Dynamic Hand Splint produced by Additive Manufacturing (AM).

This allows for local production of complex hand splints that are tailored to the patient’s specific needs and this is done in a cost and time effective manner. Traditional dynamic hand splints are expensive and have extensive manufacturing lead times due to the patient specific and complex nature of the devices.

The ability of AM to produce on demand and custom medical devices has made it an attractive technology in the medical orthoses and prosthetics environment.

AM design principles such as mass customisation, compliant mechanisms and part consolidation were utilized to produce a novel Dynamic Hand Splint. This improved functionality, replicating hand biomechanics which allows motion in a specific direction while also restricting and supporting undesired motion.

The use of AM therefore made it possible to produce an aesthetically pleasing low cost durable Dynamic Hand Splint which can be easily customised according to patient’s requirements.