2. Praxis Overview
Contract manufacturer of titanium components
Medical Device Manufacturing since 2008
Solely focus on titanium PM
ISO 13485 Certified | Production and Design
3. Overview
Titanium Metal Injection Molding
Technology overview
Value proposition
Cost comparison to machining
Considerations for molding
Limitations of molding
Secondary operations for MIM
4. 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
5. 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
6. 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)
8. 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
9. 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
10. 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
11. 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
12. 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
13. 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
14. 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)
15. 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.
16. Value proposition
• Enhanced profitability over conventional alternatives
• Complex, small to medium sized parts
• Enhanced design flexibility
• Comparable material performance
• High volume manufacturing capability