Machined vs. Molded
- 2. Smart and Innovative Machining Ken Gredick | Engineering Manager | June 16, 2016
- 3. EDMTurning When Do I Choose Machining? Tight Tolerance • Complex Geometry • Repeatable Process • Surface Finishes Metal Sintering Injection Molding GrindingEDMMilling Turning The Challenging Way Machining
- 5. The Original Process Flow Machining initial quantity of 50 parts
- 6. OP 10: Saw
- 7. OP: 20/30- Turning Turned Blank
- 8. OP 40: Milling Milled Pocket
- 9. OP 50: Heat Treating
- 10. OP 60: Grinding
- 11. OP 70: Wire EDM Finish Small Square
- 12. Collaboration Leads to… Designer Buyer Manufacturer
- 13. Design for Manufacturing (DFM) Leads to an Updated Print
- 14. Updated Process Flow From To
- 15. Lot Size 50 Part Price: $178.00 Total: $8,900.00 Lot Size 1,000 Part Price: $60.00 Total: $60,000.00 Lot Size 1,000 Part Price: $37.40 Total: $37,400.00 Cost of Original Design “DFM” Cost of New Design Lot Size 50 Part Price: $116.00 Total: $5,800.00 Savings Lot Size 50 Total Savings: $3,100.00 Lot Size 1,000 Total Savings: $22,600.00
- 16. Smart and Innovative Machining Designer: Reduced Lead Time Buyer: Reduced Cost Machining for: • Complex Geometry • Tight Tolerance • Surface Finish • Repeatable Manufacturer: Streamlined Process
- 18. Praxis Overview Contract manufacturer of titanium components Medical Device Manufacturing since 2008 Solely focus on titanium PM ISO 13485 Certified | Production and Design
- 19. Overview Titanium Metal Injection Molding Technology overview Value proposition Cost comparison to machining Considerations for molding Limitations of molding Secondary operations for MIM
- 20. MIM – Metal Molding Technology Metal Injection Molding MIM is a forming process using powdered metal, high pressure and thermal energy to efficiently make small, complex parts. The design versatility of plastic injection molding with the performance of metal
- 21. General MIM Process Step 1: Feedstock Formation • Mixture of powdered metal with binder Step 2: Injection Molding • Binder melts and flows into the mold carrying metal powder which forms a green part Step 3: De-binding • Removal of the binder via thermal or chemical methods Step 4: Sintering • A thermal process at ~70-90% of a materials melt temperature, the component undergoes significant shrinkage (~12-20% linear) resulting in a density of >98% Additional Secondary Processing: HIP, heat treating, machining, surface finish, cleaning, passivation, laser marking
- 22. Value of titanium MIM MIM provides cost savings through better material utilization Reduction in part weight through design Reduction in raw material usage Typically COGS reduction of 25% minimum to initiate MIM project Increased profitability through reduced COGS Enhanced design flexibility Well suited for parts <50 g Combination of components Adding complexity may not add cost Maintain bar stock material performance (Ti-6Al-4V)
- 24. Manufacturing method considerations Machining Factor Molding Simpler 3D geometry >25% effective density Geometry Complex 3D geometry <25% effective density N/A Size <150 g (0.3 lbs) <6” OAL >0.02” wall thickness < +/-0.001” Tolerances > +/-0.001” to +/-0.003” <10k Annual Volume >10k Note: general considerations
- 25. Effective density Bar stock versus powder - Ti-6Al-4V Powder cost is ~3x of bar stock Powder material costs are equal to bar stock after 73% of bar stock has been machined away MIM candidates have low effective densities Typically ~25% of the material density Effective Density = part mass / initial volume
- 26. MIM Considerations Annual volumes Design Freeze Upfront costs and lead times Mold cost & lead time Product development cost & lead time Secondary operations Existing product: convert from machined to MIM New product: design for MIM
- 27. Mold: Timelines and Approximate Costs Description Lead time / costs Prototype Mold 1-6 weeks $5k - $20k Production Mold 6-12 weeks $15k - $100k Mold life: typically 100k cycles without maintenance
- 28. Design Guidelines Desirable • Aspect ratios of 5:1 or less preferred • Uniform wall thickness is desired, with max variation around 5X • Wall thickness larger than 0.020 in and smaller than 0.5 in • Minimum draft 0.5° • Cored out features to reduce part weight • Flat surfaces Allowable • Asymmetry • Ribs and bosses • Grooves and threads • Decorative features (i.e. texture, logo, lettering) Avoid • Undercuts, no drafts • Small diameter holes <0.050” • Sharp corners or points • Wall thickness <0.020” • Large parts, parts with high aspect ratio
- 29. MIM Design Considerations Gating Location, removal, vestige Parting line Mismatch and flash allowances Ejector mark Protrusions and depression allowances Injection molded specific issues Mating components Critical surfaces Functional / cosmetic allowances
- 30. Dimensional Capabilities • Dimensional precision of +/- 0.1% to +/- 0.5% • Influenced by feature type and geometry • Typical mass: 0.01g to 150g • Wall thickness: from 0.5 mm (0.020 in) to 12 mm (0.5 in) • Size range is heavily geometry dependent • Surface finish • Bead blast finish of ~32 µ in. Ra • Polished finish of <10 µ in. Ra • Minimum radius 0.07 mm (0.003 in)
- 31. Secondary Operations for MIM • Potential secondary operations of MIM components: • Machining • Tolerances exceeding +/-0.1% will require secondary machining • Drilling & tapping • Polishing & grinding • Passivation & anodizing • Laser welding MIM product and mold cost can be optimized based on mold complexity, secondary operations and annual volume.
- 32. Value proposition • Enhanced profitability over conventional alternatives • Complex, small to medium sized parts • Enhanced design flexibility • Comparable material performance • High volume manufacturing capability
- 33. Thank you Jobe Piemme Chief Technology Officer Praxis Technology jpiemme@praxisti.com 518-812-0112