Investigating the impact of design parameters on the clearance in non-assembly mechanisms fabricated by selective laser sintering

The pursuit towards improved efficiency and sustainability has led to the exploration of innovative assembly approaches. Non-assembly mechanisms are one such innovative approach that integrates components with relative motion into a single, functional unit, eliminating the need for a secondary assembly process. The non-assembly mechanisms represent a paradigm shift in manufacturing practice facilitated by Additive Manufacturing. Polymer-Laser Sintering (P-LS) enables such fabrication however, various design and process parameters significantly influence their functionality. The existing Design for Additive Manufacturing guidelines overlook these parameters and are not adequate to produce a realistic motion behavior every time. This paper presents a quantitative approach towards the fabrication of fully functional non-assembly mechanisms using two common materials, Polyamide 12 and Glass beads filled polyamide. The non-assembly mechanism fabricated using the SLS process was investigated using sliding kinematic joints. Response surface methodology was employed to study the influence of factors such as the design clearance between the moving and fixed member, build orientation slider length and rail thickness on the joint functionality. The clearance between fixed and moving members is measured as a response to quantitatively evaluate the functionality of the fabricated non-assembly mechanism and the influence of each parameter on the achieved clearance was determined. Further, the established design consideration for fabricating a non-assembly mechanism was validated with a case study. The findings contribute to the advancement of manufacturing practices by offering insights into the adoption of non-assembly mechanisms.