PRODUCT DESIGN SPECIFICATION MANUFACTURE REQUIREMENTS Processes Materials Assembly Packing Quantity Delivery date PERFORMANCE REQUIREMENTS Function(s) Appearance Reliability Environment Ex-works cost Ergonomics Quality Weight Noise OPERATION REQUIREMENT Installation Use Maintenance Safety DISPOSAL Standards Legislation Company policy Hazards ACCEPTANCE STANDARDS Inspection Testing Patents Figure 1. - Product Design Specification criteria

Fig. 3 - Influence of quantity on cost Figure 2. - Alternative manufacturing Processes for lever; a) – cast iron, b) – die forged steel, c) - hammer forged steel, d) - welded steel

Fig. 4 - Modern rocking lever; a) – thick to prevent bending, b) – little or no bending