Development of a Low-Cost SCARA Robot Arm for Small-Scale Assembly Lines

Abstract Small-scale manufacturing industries often face severe economic barriers when attempting to integrate automated pick-and-place systems into their daily production workflows. Traditional industrial robots are typically over-engineered for light payload tasks, featuring excessive precision ratings and heavy payload tolerances that render them cost-prohibitive for small and medium enterprises. This economic disparity limits technological adoption, leaving smaller workshops vulnerable to rising labor costs, human fatigue, repetitive strain injuries, and inconsistent product quality during repetitive assembly tasks. This study presents a comprehensive investigation into the design, fabrication, and performance evaluation of a low-cost Selective Compliance Assembly Robot Arm specifically tailored for light-duty pick-and-place applications in resource-constrained environments. The mechanical architecture successfully utilizes easily accessible aluminum extrusion profiles, custom three-dimensional printed structural brackets, and standard stepper motors controlled by an open-source microcontroller board. By replacing expensive proprietary hardware with modular, commercially available components, the project addresses both capital constraints and maintenance accessibility. The experimental evaluation assessed positioning accuracy, repeatability, payload capacity, and thermal stability across a designated workspace envelope over extended operational cycles. The results indicate that the developed prototype achieves a positional repeatability within acceptable tolerances for small-scale packaging and sorting tasks while reducing capital expenditure by over seventy percent compared to commercial alternatives. Furthermore, this research demonstrates that affordable, locally fabricated robotic systems can successfully bridge the automation gap for resource-constrained manufacturing environments, fostering local innovation, upskilling technical personnel, and ensuring long-term operational sustainability across independent regional supply chains. Keywords: Industrial Automation, Pick-and-Place, Prototyping, Small-Scale Manufacturing, Stepper Motors.