Embed Size (px)
Citation preview
Smart and Innovative Machining
Ken Gredick | Engineering Manager | June 16, 2016
EDM Turning
When Do I Choose Machining? Tight Tolerance • Complex Geometry • Repeatable Process • Surface Finishes
Metal Sintering Injection Molding
Grinding EDM Milling Turning
The Challenging Way
Machining
The Original Design
The Original Process Flow Machining initial quantity of 50 parts
OP 10: Saw
OP: 20/30- Turning
Turned Blank
OP 40: Milling
Milled Pocket
OP 50: Heat Treating
OP 60: Grinding
OP 70: Wire EDM
Finish Small Square
Collaboration
Leads to…
Designer Buyer Manufacturer
Design for Manufacturing (DFM) Leads to an Updated Print
Updated Process Flow
From
To
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
Smart and Innovative Machining
Designer: Reduced
Lead Time
Buyer: Reduced
Cost
Machining for: • Complex Geometry
• Tight Tolerance • Surface Finish
• Repeatable
Manufacturer: Streamlined
Process
Molding Factors & Considerations
Praxis Overview
Contract manufacturer of titanium components Medical Device Manufacturing since 2008
Solely focus on titanium PM ISO 13485 Certified | Production and Design
Overview
Titanium Metal Injection Molding
Technology overview Value proposition Cost comparison to machining Considerations for molding Limitations of molding Secondary operations for MIM
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
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
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)
MIM Candidate Requirements
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
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
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
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
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
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
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)
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.
Value proposition
• Enhanced profitability over conventional alternatives • Complex, small to medium sized parts
• Enhanced design flexibility • Comparable material performance • High volume manufacturing capability
Thank you
Jobe Piemme
Chief Technology Officer
Praxis Technology
518-812-0112
