MuCell Injection Molding

®
MuCell Injection Molding
create value by Microcellular Foaming
Maxéville, Octobre 2014
 Company Trexel
 Equipment / Process / Applications
 Impact on Part Design / Quality / Economics
HISTORY OF FOAMED POLYMERS
First
Foamed
Natural
Rubber
1900 ‘10
Introduction of
Thermoplastics
‘20
‘30
‘40
Chemical
Foaming
Agents
‘50
‘60
Physical
Foaming
Agents
‘70
Microcellular
Extrusion
‘80
Structural
Foam
Molding
‘90
Microcellular
Injection Molding
2000 ‘10
Focused Research
Microcellular
Foaming
MuCell® INJECTION MOLDING
“The most significant plastic processing innovation in the last 20 Years”
MuCell Process developed at Massachusetts
Institute of Technology. (M.I.T.) Exclusively
licensed to Trexel Inc. in mid 90’s.
Trexel over the last 15 years commercialized, industrialized MuCell
Technology. Today, Trexel owns over 50 global patents covering
article and methods in producing microcellular foam. Support leading
OEMs globally from HQ in Boston and through subsidiaries in Japan,
Germany, Hong Kong and China.
Patented, closed loop processing solution
creating predictable and repeatable
homogeneous microcellular material structure
with average cell size <100 microns.
What is MuCell®
• MuCell is a foaming technology
 Putting small cells into a thin wall plastic part
• Primarily using nitrogen as the foaming agent
MuCell ® Commercial Applications
Business Equipment
Automotive
Industrial & Electrical
MuCell® process animation
The MuCell Process
• Benefits of the MuCell process come from two key
process effects:
– Dissolving an SCF (Supercritical Fluid) into a polymer reduces
the material viscosity
• typical range : 10 to 15%
– Cell growth provides final packing of the part
• Reduces cavity pressure
• Equal cavity pressure through the mold cavity
• Cycle time reduction due to shorter pack/hold and increase
mold contact
Plasticizing effect – improved flow
Solid at 30 °C Tool Temp.
MuCell® at 30 °C Tool Temp.
 Mould was cooled such that
solid parts were no longer
filling the mould
 With same parameters and
MuCell® on, the parts could
easily fill
Material: Valox 420 SEO (PBT GF30)
Material: Valox 420 SEO (PBT GF30)
Microcellular Foam Properties
 Without foam
DSC - Curve: PBT GF 30 with
mould temp. 80°C
Melting temperature : 225,4°C
Heat of Fusion (H): 40,67 J/g
 10% physical foam
DSC - Curve: PBT GF30 with
mould temp. 30°C
Melting temperature: 225,0°C
Heat of Fusion (H): 41,93 J/g
Crystallinity Level is identical
Cycle Time Reduction
Start of Injection
30 sec
Solid
Molding
3 sec
Injection
2.5 sec
4 sec
17 sec
Pack &Hold
0.5 sec
6 sec
Cooling
15 sec
6 sec
Mucell
24 sec
Typical Cycle Time Reduction: 15-30%
Motions
Clamp Tonnage
Cavity Pressure
Tranfer Pointold
End of Hold Time
300
Pressure, Bar
250
200
M5 Gate
150
Solid Gate
100
50
0
0
2
4
6
8
10
Tim e, sec
Peak Cavity pressure (bar)
Solid
250
M5
25
Clamp Tonnage = Cavity Pressure * Projected surface area
10/3/2014
Improved Dimensions
• Typical MuCell process pressure curves
Cavity Pressure
80
70
Transfer Point – Injection
to hold
Pressure, Bar
60
50
M5 Vent
40
M5 Gate
30
20
10
0
0
2
4
6
Time, sec
8
10
STRATEGIC IMPLEMENTATION of MuCell®
TECHNOLOGY Cost Reduction Strategy
+ Material / Weight Savings 6-8%
- Limited tooling changes
- Must use existing presses
- Tools already qualified
- Product at/near end of life
Design Process
Cost-down
Initiatives
Designing for Function
Part
Design
Tooling
Pre-production
Validation
Production
Release
+Material / Weight Savings
20-30%
Problem Solving Strategy
+ Significantly reduced # Mold
Iterations
+ Optimal Gating
+ Optimized Press-sizes
+ Reduced time to production
+ Material / Weight Savings 8-12%
+ Reduced # Mold Iterations
+ Additional Tooling options
- Press sizes already determined
- Non-optimal tooling
Volume
Production
Limitations of Solid Molding
• Solid molding is constrained by:
 Need to push plastic from gate to end of fill without
freezing off
• Need to pack the part along the entire flow length…
 To reduce shrinkage for dimensional stability
 To reduce sink marks and vacuum voids
These processing limitations impose design restrictions
that affect the ability to reduce wall thickness
The MuCell Process removes these restrictions!
Differences in Wall Thicknesses
 Filling from “thin to thick“
Preferred injection
with MuCell®
Injection in solid
(with MuCell® still possible
but with limited density reduction)
 Wall to rib ratio 1:1 possible
Conventional design
MuCell® design
LIGHTWEIGHTING APPLICATION
Interior Trim Volkswagen Touran
Design Drivers:
 Energy absorption on impact
 No visible sink marks
through PVC layer
 Deletion of “plug-in-module“
Conventional Design:
 Base thickness:
Plug in module:
MuCell-Design:
4.4 mm
 Base thickness:
2.2 mm
65 g
 Rib thickness:
2.2 mm
Comparison of MuCell Design vs. Conventional Design
 Equivalent or better energy absorption
 Approx. 40 % reduction in part weight
 20 % through wall thickness reduction
 14 % through deletion of “plug-in-module“
 6 % through density reduction
Lightweighting Application
Fan Shroud
Fixing Points
Fixing Points
Functional Design
Conventionell:
MuCell Design:
2,0 mm
2,0 mm
1,0 mm
 2,0 mm overall thickness
 1,0 mm basis thickness
 2 Injection Points
 2,0 mm in selected areas
 Part weight = 880 g
 4 Injection Points
 MuCell Part Weight = 670 g
 Additional Costs Hotrunner (tool+maschine) = ca. 25.000,- €
 But: Material Savings > 80.000,- € per Year
(based on 60.000 parts/y - 2,40 €/kg Material Cost)
= Injection Gate
Lightweighting Synergies Between
3M™ Glass Bubbles and MuCell®
MuCell® Equipment T series
•
•
•
•
•
fully integrated or stand aside
Interface Kit eliminated
lower energy consumption
less maintainance
easy to operate :
indicate shotweight and
%SCF only
MuCell® - on the market
Trexel inc.
 Examples
MuCell® Fan Shroud
Shroud + hinge
combined in one
mould
MuCell® Benefits:
 8 % weight reduction
 20 % cycle time reduction
 30 % smaller machine size
 Fatigue-to-failure improved by 400 %
Material:
PA 6 GF15 MN25
MuCell® Climatic Control Housing
MuCell® Benefits
• Shorter cycle times due to quality improvement
• Clamp force reduction
• Easier to assemble
Mercedes Benz : Project MFA (B Class …)
Pressure
• weight saving by design + density
• reduced warpage, easy assembly
2 parts out of 11
High Gloss Frame with MuCell®
Screen DVD player
Mercedes Benz – W246
Head Lamp Housing
• Clamp Force reduced by 50%
• more design freedom
• reduced warpage
IP Carrier Golf VII
• 500g weight reduction per part !
MuCell in Packaging
MuCell® - Positive Impact on
Project
Trexel inc.
contact :
Martin Jacobi
m.jacobi@trexel.com