introduction to powder metallurgy david whittaker · introduction to powder metallurgy • what is...
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INTRODUCTION TO POWDER METALLURGY
DAVID WHITTAKER
INTRODUCTION TO POWDER METALLURGY
• What is Powder Metallurgy (PM)?
• Why choose PM?
• Product characteristics that drive the adoption of
PM
• Economic benefits of PM – case study example
WHAT IS PM?
PM processes involve: • Mixing/blending of powder “ingredients” to
produce a feedstock
• Consolidation of the feedstock into a product shape
• Sintering to provide strength and integrity
• (Optional “secondary” or finishing operations)
CONVENTIONAL PM
METAL INJECTION MOULDING (MIM)
WHY CHOOSE PM?
PM is adopted for one (or both) of 2 basic reasons: • It allows some product characteristic to be attained
that would not be possible with conventional manufacturing methods (Product uniqueness)
• It is the most cost-effective option of a number of competing technologies for the manufacture of the product (Product cost-effectiveness)
PRODUCT UNIQUENESS - 1
PRODUCT UNIQUENESS - 2
PRODUCT UNIQUENESS - 3
PRODUCT UNIQUENESS - 4
PRODUCT UNIQUENESS - 5
PRODUCT COST-EFFECTIVENESS
PRODUCT COST-EFFECTIVENESS
PM’s cost effectiveness is based: • High material utilisation
• Low energy consumption
compared with competing technologies
PRODUCT COST-EFFECTIVENESS
Energy requirementRaw Material Utilisation Manufacturing Process per kg of finished part
90 casting 30 - 38
95 sintering 29
85 cold or warm extrusion 41
75 - 80 hot drop forging 46 - 49
40 - 50 machining processes 66 - 82
% 75 50 25 0 0 25 50 75 MJ
PRODUCT CHARACTERISTICS THAT DRIVE THE ADOPTION OF PM?
• Geometrical complexity
• Close dimensional tolerance requirements
• High production volume requirements
EXAMPLES OF TYPICAL GEOMETRICAL COMPLEXITY
WHY HIGH PRODUCTION VOLUMES?
• PM tooling is relatively expensive and this cost
needs to be amortised over large numbers of products
• Tool changeover times = lost production time, therefore large batch runs required
ECONOMIC BENEFITS OF PM – CASE STUDY
ECONOMIC BENEFITS OF PM – CASE STUDY
ECONOMIC BENEFITS OF PM – CASE STUDY
ECONOMIC BENEFITS OF PM – CASE STUDY
Machined Gear % Total Manufacturing
Cost
PM Gear % of Total Cost for Machined Gear
Raw Material Cost inc. 2% scrap and 46% material lost in machining
15.1
Raw Material Cost inc. 5% scrap allowance
10.0
Process steps: - Turning,
trimming and drilling
- Broaching of groove
- Milling of teeth - Heat treatment - Grinding of
end faces - Deburring - Inspection - Tooling costs
8.5
3.2
47.5
1.9
5.9
0.5 0.3 17.1
Process steps: - Pressing - Sintering - Heat Treatment - Grinding of end
faces - Deburring - Inspection - Tooling costs
2.4 2.6 1.9
5.9
0.5 0.3 8.2
TOTAL COSTS 100.0 31.8
ECONOMIC BENEFITS OF PM – CASE STUDY
COMPONENT % COST ADVANTAGE FOR PM ROUTE
Oil pump gear for commercial vehicle 68.2
Hydraulic pump rotor 57.7
Differential bevel gear 25.9
Sychroniser hub for manual gearbox 57.1
FREE REFERENCE TEXT From EPMA