Engineered Rubber Products - Materials, Product Design Principles and Fundamentals of Processing
Date:
- June 2-3, 2010
Time: 8:30 a.m. - 4:30 p.m.
Cost: $915 USD
CEU's: 1.5
Instructors: John G. Sommer and Dr. T.J. Dudek
Location: Akron Polymer Training Center, Akron, OH 44325-5404
Course Overview: This two day course will familiarize technologists with the unique capabilities of rubber materials (thermoset and thermoplastic rubbers). Key rubber compounding principles and test methods will be reviewed. This will be followed by a presentation of design principles for rubber products. The important processes used in the manufacture of rubber products (mixing, milling, extrusion, compression and injection molding, and calendering) will be presented. Additional product design information will be discussed followed by a review of different types of elastomer products. Course includes newly published book by John G. Sommer, "Engineered Rubber Products".
Textbook Information:
Engineered Rubber Products
Price US: $99.95
ISBN 13: 9781569904336
Author: J. Sommer
Hanser Gardner Publications: https://www.hanserpublications.com/product.php?ISBN=3-446-41731-1
Course Outline:
Day 1 (morning):
Elastomer Materials
1. Introduction to Polymers and Elastomer Materials - Basic Concepts
- Glass transition temperature
- Molecular mass, molecular size distribution.
- Molecular properties important in processing (viscosity and die swell)
- General purpose and specialty thermosetting elastomer types
- NR, BR, SBR, CR, NBR, IIR (butyl rubber), EPDM, CPE (CM), Vamac (ethylene acrylate)
- Crystallizing elastomers and effect on properties
2. Rubber Technology - Thermoset Elastomers
- Compounding ingredients
- Polymer, fillers, antidegradants, cure systems (activators, accelerators, sulfur, peroxide), plasticizers, tackifiers
- Mixing
- Vulcanization
- Curemeter (cure rate/time/temperature)
- Scorch (premature vulcanization)
- Effect of vulcanization (crosslinking) on physical properties
- Examples of typical rubber compounds and property comparisons among selected rubber materials.
3. Thermoplastic Elastomers (TPE’s) Technology
- TPE, TPO, TPV Types
4. Flow Properties of Elastomers and Rubber Compounds
Day 1 (afternoon):
Product Design
1. Introduction to Design
- Communication
- Cost
- Definitions
- Stress-strain behavior
- Steel
- Rubber
2. Modulus vs. stiffness
- Factors
- For steel
3. Creep
4. Friction
5. Fatigue
6. Adhesion
- Important factors
- Peel test
- Effect of test temperature
7. Rubber properties
- Young’s modulus
- Shear modulus
- Single lap shear
- Quadruple lap shear
- Bulk modulus
- Poisson’s ratio
8. Typical properties for steel and rubber
9. Shape Factor
- Effect over wide range
- Various products
- Effect of very high loads
10. Dynamic properties
- Rebound resilience
- G’ as function of strain and temperature
- Equation for
- Free vibration
- Transmissibility
- Figure
- Demonstration
11. Stress-strain factors
- Test specimen
- Tear
- Effect of flaws
- Compressive stress
- Boundary effect
- As function of shape factor
- Poisson’s ratio
- Definition
- Effect of rubber type and carbon black
12. Permeability
- General
- Tennis balls
- Silicone membrane
- Swelling rate
13. Finite element
- Tensile specimen
- Successful application
- Tires
- Air ducts
- Belting
- Bearings
- Mounts
Day 2 (morning):
Fundamentals of Rubber Processing
1. Mixing: Internal Mixers and Mills
2. Rubber Extrusion Technology
- General Description and Purpose of Single Screw Extruder Components
- Extruder Barrel, Screw Design, Feed Hopper, Die, Heating and Cooling Elements, Instrumentation and Control Systems, Screens and Screen Changers
- Extrusion Flow Rate
- Dependence on screw speed, screw design, die dimensions and barrel, screw, and die temperature settings
- Rheological and thermophysical properties of the rubber compound
- Vulcanization of Extrudates
- Power Consumption and Extruder Scaling Relations
- Troubleshooting possible sources of variation in extrusion
- Profile extrusion processes
- Die design for single material extrudates
- Coextrusion and triplex dies
- Automotive weather seal applications
3. Compression and Transfer Molding
4. Rubber Injection Molding Technology
- General Description and Functions of Injection Molding Machine Components
- Reciprocating screw injection unit, Mold (sprue/runner/gate system), Clamping unit
- Mold Design (rheological, thermal, mechanical)
- Moldflow simulation programs
- Phases of the Injection Molding Cycle
- Pressure/flow rate vs. time
- Factors that determine mold filling
- Setting the Process Parameters
- Mold/cure temperature, Injection unit (barrel and nozzle temperatures, screw speed, back pressure)
- Shot size (stroke), Injection speed/pressure, Holding pressure/cure time,
- Clamping (speed, pressure)
- Rubber Compound Temperature Changes During the Molding Cycle
- Effect of nozzle diameter on injection time and temperature (shear heating)
- Temperature increase versus nozzle diameter as a function of injection pressure
- Moldability Window (determined largely by scorch properties)
- Troubleshooting Rubber Injection Molding Defects
- Scorch related defects; Distorted or rough surface appearance; Blisters; Microporosity; Cavities not completely filled; Backrinding; Size variation of parts; Flash; Surface contamination
Day 2 (afternoon):
Products
1. Compound effect on product performance
2. Process effect on product performance
3. Product examples
- Roofing membrane
- Temperature effect on
- O-rings
- Fuel cells
- Hood stops
- Bridge bearings
- Toilet tank ball
- Compound
- Example
- Constant velocity joint boots
- Fuel cells
- Tennis ball
- Gasket
- Truck bed hold down
- Tennis shoes
- Brake pedal pad
- Rubber in solid rockets
- Insulation
- Insulation adhesion
- Nozzle bearing compound
- Nozzle bearing
- Triaxial tension
- Automotive weather strip
- Molded corner
- Extruded corner