Thixomolding Overview

Thixomolding Overview
Introduction to Injection Molding Magnesium
Magnesium Market Growth
NA relatively stable
stable, Asia grows slightly and Europe takes off
90000
NA
80000
Europe
70000
Asia
Ton o
of M g
60000
50000
40000
30000
20000
10000
0
2000
2001
2002
2003
2004
2005
2006
Year
2007
2008
2009
2010
Source: Hydro Magnesium
2011
Magnesium Benefits
Excellent material to reduce weight in an environmental friendly way
•
•
•
•
•
•
•
•
Superior stiffness and strength to weight ratios
E
Excellent
ll t EMI & RFI shielding
hi ldi characteristics
h
t i ti
Ability to absorb energy and dampen vibrations
Favourable heat dissipation characteristics
Provides flexibility in component design
Dent resistant
Can be machined faster than Aluminum
Less wear & tear on Molds than Aluminum (twice the die
life)
• Easy and efficient
ff
to recycle
• 8th most abundant element on the earth’s crust
Mechanical Properties
Magnesium compares favourably to other metals & polymers
Mg
g
Al
Mg
g
AZ91 AM60 A380
Zn
ZA3
1020
Steel
PC
Density (g/cm3)
1.81
1.79
2.68
6.60
7.83
1.20 0.90
Yield (MPa)
188
150
165
221
330
60
35
90
Modulus (GPa)
45
45
71
85 5
85.5
203
23
2.3
25
2.5
9
Elongation (%)
(@ break)
8.1
13.9
3
10
36
125
150
3
Specific
Strength *
104
84
62
33
42
50
39
78
PP
PP
30% GF
1.20
Chart outlines Mg properties measured from ASTM Tensile Bars
Specific Strength = Strength / Density
The Market for Magnesium Components
12 15% annual growth expected to continue over range of applications
12-15%
• Consumer Electronics
– Laptop PC housings, Camera bodies, Camcorder bodies, Mini-disc players,
Cellular telephones, Television housings
• Industrial/Recreational
– Chain saw housings, Power tool
housings,
Motor
end-plates,
Plumbing fixtures, Sporting goods
• Automotive
– Electronics housings, Shift cam
parts, Transmission parts, Seat
backs and risers, Throttle body,
Interior trim, Steering wheels, Wheel
rims
Consumer Electronics Market
Driving forces for using Mg
•
•
•
•
•
•
EMI shielding
Stack height
g reduction
Durability
Thermal management
g
‘Quality’ perception
Market differentiation
Industrial/Recreational Market
Driving forces for using Mg
•
•
•
•
Superior
p
strength
g to weight
g ratio
Durability
Q
y perception
p
p
‘Quality’
Market differentiation
Automotive Market
Driving forces for using Mg
Mg… however cost is always #1
•
•
•
•
•
•
•
•
Mass reduction
C
Component
t consolidation
lid ti
Process consolidation
Thermal management
Vibration dampening
Recyclability
Productivity (20-30% Faster Cycle time than Al)
Tool Life (2 to 4 times better than Al)
Die Casting Machine Overview
Foundry technology is complicated when running magnesium
Cold Chamber Die Casting
• Liquid ladled into cooled shot
sleeve between shots
• Metal is superheated above
650°C (1200°F)
• SF6 or SO2 blanketing gas
Hot Chamber Die Casting
• Machines usually limited to
below 600-tons
600 tons clamping
force
• Plunger immersed in molten
liquid
• Metal is superheated above
650°C (1200°F)
• SF6 or SO2 blanketingg ggas
Environmental Considerations
Benefits of lightweight reduced by usage of SF6 cover gas
• Sulfur hexafluoride (SF6) has global warming potential
23,900 times greater than CO2 and an atmospheric
lifetime of 3,200
3 200 years
– One pound of SF6 has the same global warming impact of 11 tons of CO2
• Many governments around
the world either have limited
or banned usage of SF6
115 lb
( kg)
(52
g)
cylinder
Thixomolding Machine Overview
Flexible system for injection molding magnesium alloys
•
•
•
•
Chipped
Chi
d raw material
t i l
Argon gas system for oxidation protection
Higher processing temperatures
– Melt temperature 1050-1125°F (565610°C)
– Mold temperature 350-575°F (175-300°C)
F t injection
Faster
i j ti speeds
d up tto 236 iin/s
/ (6
(6.0m/s)
0 / )
– Typically 36 – 140 in/s (1.0 – 3.5 m/s)
•
•
•
•
Thermall nozzle
Th
l shut-off
h t ff
Application of mold release
between shots
Increased g
guarding
arding for safet
safety and
cleanliness
Special safety considerations
Thixomolding Process
Simplified description of the process & how it differs from plastics
• Die casting uses ingots, we get the ingots chipped at a
supplier so we can feed it into our screw & barrel
– Machines builders have a specification for the size and distribution of the chips
• Chips are fed into the barrel and augured forward by the
screw through a ring check valve
– Melting comes exclusively from the barrel heaters, so there is no shear heat like in
plastics
• Material is heated into the semi-solid
semi solid state (think of it as
round solids suspended in liquid) and then injected at high
speeds into the die
– For example, a 1mm thick part has to be filled in 10ms (0.01s)
– However, because of this cooling time is typically short. Most of the cooling time is
waiting for the nozzle or hot sprue plug to solidify and the mold to cool
• Once parts are ejected, the mold has to be sprayed with a
lubricant to prevent sticking during the next cycle
– The mold lubricant is typically a small percentage of wax or oil mixed (1-10%) mixed
with water.
Thixomolding®: What is It?
Single step process for making Mg parts using injection molding principles
• Semi
Semi-solid
solid metal forming process
– Some of the material remains solid throughout process
• High
g speed injection
j
molding
g of thixotropic metal alloys
y
– Thixotropy is the property of a solid that when agitated, flows like a liquid
• Patents owned by Thixomat
– JSW and
dH
Husky
k machine
hi b
builders
ild
exclusively
l i l lilicensed
d tto make
k machines.
hi
– Over 50 licensees in 9 countries running 340+ machines
Magnesium Processing
Temperature control is very important as it affects many variables
• Temperature controls solids percentage
• With diff
differentt % solids,
lid come diff
differentt flflow characteristics
h
t i ti &
solidification shrinkage
Pictures of Semi-solid microstructure at varying degrees of solids
Metal Molding System Capabilities
Allowing manufacturers to have the best of both worlds
• Temperature can easily be adjusted to
allow the machine to operate in fully
liquidus Rheo
liquidus,
Rheo, near liquidus
liquidus, Thixo and
extrusion molding regimes
Rheomolding
Near Liquidus (NLM)
Thixomolding®
Extrusion Molding (SSEM)
Flow Visualization
Hybrid between plastic & die cast flow
• 3 flow simulations below help to visualize flow at different
viscosities.
Plastic Flow
Thixo Flow
Die Cast Flow
Benefits of Lower Processing Temperature
Hardware performance & slurry behavior improve with semi
semi-solid
solid molding
Implications of Reduced Processing Temperatures
Hardware Performance
/ Energy Economy
Reduced Energy
Consumption
Slurry Behavior
Increase Mold
Life
Component’s
Integrity
Liquid Content
Alloy’s
Microstructure
Heat Content
Phase Composition
Phase Shape
Phase Size
Flow
o
Behavior
So d cat o
Solidification
Shrinkage
Increased Freezing
Tendency
Heat Treatment Capabilities
Phase Distribution
Secondary Modification
of Microstructure
Metal Molding Benefits
Process consistency and lower temperature result in better parts
•
N
Near
net shape
h
metall part production
d i
– Reduction or elimination of secondary operations
•
Capable
p
of near zero p
porosity
y
– Porosity reduces strength in castings
•
•
•
•
•
•
•
Increased design flexibility
E t d d ttooll life
Extended
lif vs. die
di casting
ti
Lower energy costs
Rapid start
start-up,
up, shut
shut-down
down and alloy changeover
Facility simplicity
Environmental cleanliness
Worker safety
Typical Mg Part Manufacturing Process
Raw M
Material
Supply
y
Many cost drivers favor Metal Molding over Die Casting
Raw Material
(Storage, Distribution, Handling)
Die Cast Machine
Recycling
Thixomolding Machine
Finishing
Operations
O
Post-mold
Operations
Primary
Process
s
Mold
Machining / Drilling
Q.C
Coating
Packaging
Warehouse
Ope
erations
Lower Material Cost
• Less Cold Sprue
• Les Overflows
• Thinner Parts
Storage/ Warehouse
Shipping
•
•
•
•
Operational
Costs
Longer Tool
Life
Lower Energy
Usage
Faster Cycle
Time
Less Labor
Finishing / De-burr
WIP/ Cooling
Painting
Higher Yield
• Less Porosity
• Process Stability
& Control
• Superior Surface
Finish
•
Part Removal, (Robot)
Trim / Degate
More Efficient Material Usage
• No Melt Losses
• Less Scrap
Final Inspection
Less Secondary Operations
• Near Net Shape Molding
• Less Rework Due To Molding Process
Limitation
• Less Labor
Higher Yield Through Secondary Processes
• Less Porosity in Molding Process
Reduces Downstream Defects
• Superior Surface Finish in Molding
Process
• Less Labor
Reduced Transportation Costs
g
p
parts
• Lighter
Superior Mechanical Properties
Steering Wheels can be lightweighted to reduce part costs
Background
• Relationship originated with mold trial using existing
die cast mold
– Replaced shot sleeve with hot sprue
– Molding parts at 35% faster cycle & reduced scrap by 59%
– X-Rays show porosity levels 4 times lower than achieved with their die cast
process
• Exceeded all OEM static & dynamic test requirements
Current Project
• Redesigning next generation Steering Wheel
specifically for Metal Molding
– Die cast part is only 68% of the shot weight
– New Metal Molded part is approximately 30% lighter and has a shot weight
45% lower (resulting in 90% shot utilization)
Typical
yp
Potential Part Cost Improvements
p
Cost of CNC Machining
$3.50
$3.201
Cost of Trimming
$3.00
$2.958
Cost of Cell Automation
Cost of Hot Sprue/Hot Runner
$2 453
$2.453
$2.50
$2.186
Cost of Mold
Maintenance/Replacement &
Cleaning
Misc Costs (Floor Space,
Lubricants & Cover Gas)
$1.987
$2.00
$1.50
Cost of Manpower
Cost of Services (Air, Water &
Power)
Cost of Machine Capital &
Depreciation
$1.00
$0.50
C
Cost
off Machine Maintenance
Cost of Alloy
$0.00
Mg Die Cast X95
HyMET 500 M80 - X95 HyMET 500 M80 - X95 HyMET 500 M80 -X95 Thixomolding
HyMET1000500ton
HT
Thixomolding 500ton
Existing Design
New Design
New Design - No Mg Hot
4-Cavity
HR4Current
Runner
Drop
Premium
Molds
Hybrid between plastic and die-casting tools
• Require
q
tool steels like die-casting
g - H13
• Typical Melt pressures 700-1,000 bar (10,000-15,000
psi).
– More robust, built like ‘Technical Thin wall Mold’
• Cold sprue applications
• Oil heated to 175-260°C (350-500°F)
– Require 3 hot oil Thermolators
– Core,, cavityy and sprue
p
• High temperature tolerances
• Zero draft and high
g L/T achievable
Processing
Melt temperature,
temperature injection speed and mold spray are main parameters
• Clamping force required… 5 to 7 tonnes/in2 of projected
area
• Extremely fast fill times (typically 20-50 ms)
• Minimal
Mi i l shot
h t profiling
fili
• Fast cooling time / short packing period
• Manipulation of mold sprays
• Process comes with it’s own set of defects, similar to
plastic but exaggerated.
–
–
–
–
–
Cold Flows/ weld lines
Porosity
Sinks
Cracks
Solder build-up
Application of Mold Release
Oil or Wax based mixture sprayed onto mold face before each shot
• Used to prevent part from sticking to mold
• Mixed with water from 1% to 10%.
– Mixture varies with part geometry
• Used to cool the mold
Long nozzle/Hot Runner Technology
Moving metal molding into the 21st century
• Benefits similar to Plastics
– Cycle time reduction
– Shot weight
g saving
g
– Runner scrap saving
• Significance to magnesium applications
– Multi-cavity
M li
i molds
ld to iincrease productivity
d i i
– Multiple drops to facilitate large, thin parts with excellent properties
• Progress
og ess
– Hot Sprue completing beta testing
– 4 Drop hot runner being prepared for beta testing
• Multi
Multi-cavity
cavity Powertrain component
• Large structural body component
Hot Sprue or Long Nozzle Example
Used as technology base for hot runner development
Direct part
injection
Long Nozzle
Interface
Cold runner
Hot runner
Machine
nozzle
Runner Concepts
Hot Runner
Cold Runner
Hot Sprue / Long
g Nozzle
Sub-runner
Hot Runner
Metals CE- Key Drivers
Quality yield after painting is largest contributor to part price
• Part Price
– Quality yield
– Cycle time
– Machine Utilization (uptime & availability)
• Part Attributes
– Minimum wall Thickness
– Class ‘A’ surface finish
– Part strength
• Return on Investment (ROI)
– Capital costs
– Margin per part
Metals Automotive – Key Drivers
• Part Price
–
–
–
–
Part weight & shot weight
Cycle
y
time
Machine Utilization (uptime & availability)
Number of post mold operations for dimensional accuracy, corrosion prevention
and appearance
– Tool life
• Lightweighting
– Consistency of mechanical properties
from part to part and within each part
– L/T ratios
• Return
R t
on IInvestment
t
t (ROI)
– Capital costs
– Margin per part
– Availability of Capital
Automotive Magnesium Components
• Interior Components
– Seat Frames, Seat Supports, Segmented Instrument Panels, Instrument Panel
Cross-Car
C
oss Ca Beams,
ea s, Power
o e Op
Option
o Gea
Gear Motor
o o Housings,
ous gs, Electronics,
ec o cs, S
Steering
ee g Wheel
ee
Armatures, Steering Column Assemblies, Steering Column Lock Housings, Pedals,
Inside Door Panels, Interior Creature Comfort Features, Rear View Mirror Brackets,
Miscellaneous Brackets, Air Bag Housings, Lock Housings, Motor Housings, Pedal
Levers, Center & Floor Consoles, Handbrake Assemblies, Gear Shifter Assemblies,
Shift & Turn
Shifter
T
Signal
Si
l Stalks
St lk
• Body & Exterior Components
– Folding Roof Components, Wing Mirror Brackets, Front End Support Module, A & B
Pillars Bumper Reinforcement Beam
Pillars,
Beam, Luggage Rack,
Rack Headlight Housings
Housings, Door
Structures, Tire Rims, Rear Hatch Structures, Sunroof Components
• Powertrain & Drivertrain Components
– Valve Covers, Oil Pans, Rocker Arms, Control Arms, Cylinder Heads, Valve Covers,
Clutch Housings, Transmission Housings, Lower Crank Case/Sump, Cylinder
Blocks, Intake Manifolds, Oil Pump Bodies, Camshaft Drive Chain Cases, Brackets
for Power Option Pump & Compressor, Firewalls, Pistons, Radiator Supports,
Engine Accessory Brackets, Engine Covers, Brake Components
Recent Developments using Hot Runners
Award winning innovation in magnesium processing
Background
•
USCAR s Ultra Large Castings (ULC) project
USCAR’s
project’s
s goal is to assess the
manufacturing feasibility, economics and mass reduction potential of thin
wall structural castings of magnesium applied to automotive weight
reduction
Current Project
•
•
•
•
•
Structural member nicknamed “shotgun” that connects the radiator
support
pp to the firewall on a full sized truck
Part has average wall thickness of 3mm, weighs 2.86kg and has
projected area of 1300 cm2
This part can only be made through Metal Molding with hot runners (due
to mechanical p
properties
p
& L/T restrictions))
Preliminary tests have shown very low porosity & high elongation
Passed crash tests
R
Results
lt
•
•
95% Shot yield, direct part gating with 4 drop hot runner
Winner of International Magnesium Association (IMA) Award of
Excellence for Process
Ford F-150 Weight Reduction
Development project shows the potential for lightweighting
2003 Model Year
Stamped Steel Rad. Support w/ SMC
GOR & Steel fabricated “Shotguns”
Weight = 31.3kg (69lbs)
Future Model Year
2006 Model
M d lY
Year
Magnesium Die Cast Rad. Support*
& Steel fabricated “Shotguns”
Weight = 18.1kg (40lbs)
Saving = 42%
Magnesium Die Cast Rad.
Rad Support
Support*
& Metal Molded “Shotguns”
Weight = 10kg (22lbs)
Savings = 68%
* - Rad. Support not considered structural member ( or primary body structure)
“Affordable ultra-large structural castings are limited by the mechanical properties achievable with conventional High Pressure Die Casting” – Mike Maj,
Advanced Reseach Engineer, Ford Motor Company
Development Opportunities
Better properties tailored to specific applications
Alloy Mixing
• Alloy mixing at the machine
– Ability to mix different alloys to get the mix of
properties desired
• Metal Matrix Composites
(MMCs) to enhance mechanical
properties
– Ability to keep particles well mixed while in
suspension
Metal Matrix Composites
Thixomolding Value
Capitalize on market growth with a new progressive technology
• Magnesium’s favorable properties are a natural fit for
many markets
– Annual Growth projected at 10 – 15%
• Progressive technology with many opportunities
– Technology improvements & innovations will move process into the main stream
• SynergyNet does not sell machines and services, we
offer customers a valuable business partnership focused
on their
h i success …
Adapting Existing Die Cast Molds
• Replace shot sleeve with hot sprue assembly & mold
locating ring
• Benefits include:
– shorter cooling time by eliminating biscuit
– Lower raw material costs by reducing scrap
Shot
Sleeve
Hot Sprue
Assembly
Th k ffor your attention
Thanks
i