Additive Manufacturing and Reverse Engineering





Ping-Pong Ball Launcher



Reverse engineering a cordless electric screwdriver as part of a group to design and manufacture a ball firing device using various Additive Manufacturing processes



KEY SKILLS





Additive Manufacturing



Problem Solving



Teamwork



CAD Modelling



CAD Rendering



OVERVIEW





BRIEF



As a group of 6, we were tasked to select a battery-operated product and disassemble it, to create a new product that could be 3D printed. This product had to use a 3D scanning technique such as Photogrammetry, as well as 2 Additive Manufacturing processes in the design.



DELIVERABLES



  • 60 Page Report
  • Group Presentation
  • Physical Testing and Manufacture


SOLUTION



Additive manufacturing principles were effectively used to convert the electric screwdriver to a ping pong ball firer, with a track and mechanism design that fires the balls successfully. The design utilises the advantages of additive manufacture such as print in place, materials and complex geometry that cannot be replicated with injection moulding, resulting in AM being the only feasible method to design the product.



SOFTWARE USED





Siemens NX11



Cura



Blender



PRODUCT SELECTION AND BREAKDOWN





The chosen product was a cordless electric screwdriver which includes a variable motor speed trigger, torque adjustments settings (max torque 4Nm), motor directional control, LED lights, power indicators, Li-ion battery (up to one hour of charge), ergonomic rubberised grips and a mechanism to allow the user to change the orientation of the screwdriver for ease of use. This product was carefully taken apart, ensuring there was no damage to the electrical components, as shown above.



3D SCANNING





The casing for the screwdriver was 3D scanned using Laser Scanning due to the simple shape, that could be integrated as a funnel for the balls when entering the track system, along with its surface detail features which had been captured by the 3D scanner. This scan was verified in Materialise Magics for bad edges and holes, then was cleaned up to give the final smooth surface. This allowed the part to be FDM 3D printed without any print errors.



PRODUCT OVERVIEW





Using these components and the 3D scan, a number of designs and mechanisms were made. The product was split into 4 main sections; gearing, ball feeder, firing mechanism and overall casing. The products gearing utilises a split ring epicyclic gear train to reduce the motor speed by over 300 times allowing it to be utilised in the chosen firing mechanism. The gears are printed using SLA to enhance the accuracy and reduce the overall noise output of the product. The firing mechanism utilises the elastic potential energy of FDM 3D printing as the integrated gear/spring is wound then released which fires the ball over 2 metres consistently.


FINAL PRODUCT IMAGES







Faheem Aziz (MEng, DIS)



Product Design Engineer