Background: Belt-driven pressure washer units have an engine and a pump mounted on a sheet metal frame, connected via a belt-pulley system to transmit power. For safety, a sheet metal guard is installed around the belt-drive, which is bolted to the engine, pump and frame from different sides. Two types of belt guards, used in 25 different pressure washer models, received customer complaints about cracking during operation—a major safety concern. I was tasked with redesigning these guards to reduce the cracking issue.
Problem Analysis: Analyzed the existing belt-guard designs to identify failure points. Key findings:
Weld Weakness: Welded joints were prone to cracking, as welding was the weakest link in the design.
Stress Concentration: The component shapes contributed to stress concentration points, leading to cracks.
Excessive Cutouts: Oversized cutouts for the shafts made the guards flimsy and more susceptible to vibration-induced failure.
Concept Development: Developed new designs to address the identified issues:
Reduced Welding: Reduced welding by 75% by incorporating more bends in the design, which reduced the risk of cracking and lowered manufacturing costs.
Improved Shape: Redesigned the components with smoother transitions to better distribute stress and minimize stress concentration.
Optimized Cutouts: Reduced the size of the cutouts for shafts, increasing the material strength in critical areas to reduce flimsiness.
Prototyping & Testing: Created 3D-printed PLA prototypes of the new designs to test fit and tolerances across all 25 pressure washer models. Ensured proper alignment with the engine, pump, and frame. Verified that the design modifications met safety and performance requirements.
Final Design & Manufacturing Preparation: Finalized the designs for both types of belt guards after successful prototype validation. Generated detailed CAD drawings with GD&T (Geometric Dimensioning & Tolerancing) specifications. The final drawings and 3D-printed prototypes were prepared for submission to the supplier for sample production. Assigned new stock keeping numbers (SKU) for both designs. The prototypes and drawings would be used for the First Article Inspection (FAI) to ensure the manufactured parts meet design specifications before full-scale production.
