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Rubber extrusion examined. (Meetings).

An integrated technological course titled "Rubber extrusion technology" will be held at the University of Wisconsin-Milwaukee's University Outreach in Milwaukee, WI, February 20-22.

Applicable basic information on all aspects of the rubber extrusion process will be provided during the course. The course will encompass products ranging from intricate profile extrusions to tires and having compositions ranging from a single thermoplastic elastomer to multiple dense and cellular compounds coextruded with carriers and reinforcements.

To achieve this course objective, the immense variety of products, equipment and processing conditions within the rubber extrusion industry is unified by considering such common operations as compound selection, evaluation and processing; equipment needed for pumping, shaping (including die design), curing and monitoring; operating procedures to insure high production rates and quality; and analysis and control of process variation.

A section on new technologies will explain how to make extrudates with variable cross-section and composition along their length, to form curved sections and to control screw speed for individual extruders forming laminate structures. The course will conclude with a troubleshooting guide giving problems, causes and corrective actions.

This course will benefit materials and process engineers, die designers, quality control personnel, supervisors and managers responsible for these functions. It will benefit those responsible for specifying equipment purchases and particularly individuals new to the rubber extrusion industry. Companies will receive an added advantage by sending teams of these personnel since their working together is crucial to efficient design and manufacturing programs, according to the sponsor.

Conference speakers will include James F. Stevenson of Honeywell International and John S. Dick of Alpha Technologies.

Elastomer properties will be examined, including chemical structure, molecular weight/distribution, morphology and crystallinity, viscosity (flow), including shear rate, temperature and slip, elasticity (swell), including shear stress and die L/D, and scorch.

Laboratory tests for extrudability will be discussed, including Mooney viscosity, processability testers such as the capillary rheometer and the rubber process analyzer, standard dies (Garvey) and state of cure tests.

Compound ingredients examined will include elastomers, fillers, plasticizers and process aids, and cure systems/nitrosamines.

Processing and compounding will be discussed, including EPDM, polychloroprene, SBR/BR, nitrile rubber, chlorosulfonated polyethylene, silicone rubber, fluoroelastomers and thermoplastic elastomers.

Pumping equipment will also be highlighted during the course. Types of hot/cold feed screw extruders will be examined, along with barrels (construction and materials), screws (construction and materials), screw types (moving wall pumps, hot feed, barrier screws, superimposed flights, Transfer-mix, pin barrel, pin convert and gear extruder), two-stage screws, continuous mixers/twin screw extruders and feed devices.

The ram (preform) extruder will be discussed, as well as such auxiliary devices as shear head, cavity transfer mixer and gear pump. Drives and transmissions will be highlighted during the course, along with temperature control (heater/cooler geometry and controllers).

Shaping equipment examined during the course will include heads (inline, crosshead - wire and hose, coextrusion - profile and tire, breaker plates and screen changers), and dies (types and design criteria, flow - viscosity, pressure-flow relations and swell, drawdown, sheet dies - calendering, single roller die, double roller die and tire belt die, profile dies - product design, die design, die operation, coextrusion dies, coating dies and orientation control, design computations such as die face dimensions, internal die dimensions and die with carrier, die relief strategies - straight cut, back relief and face relief, and finite element simulation - vehicle seal dies and carrier dies).

Downstream equipment will be examined, including low pressure continuous vulcanization (liquid curing media, hot air, microwave, infrared, fluidized bed and comparison), and reinforcement (braiding).

Instrumentation will be highlighted, including an instrumented extrusion line, temperature sensors (thermocouples - fixed and mobile, resistance devices and infrared probes), pressure sensors (strain gauge and Piezoelectric), dimension sensors (lasers - profile, shadow and oblique line, electromechanical, diode array, length and coating thickness), and weigh and area sensors (scales and radiation).

Extruder dynamics discussed will include flow in screw pumps, output rate (screw speed, temperature set points and die resistance), operating curves, heat transfer, extrudate temperature (screw speed, temperature set points and die resistance), conveyor operation, extrudate contraction and extrudate curvature (flow, swell, relaxation and wind-up).

Productivity and quality will be examined during the conference, including optimum conditions (quality measurement, screw speed, barrel temperature and screw temperature), feed strip geometry, feed mill operation, adjustments on the pin barrels, stability testing, screw and barrel wear (causes of wear, characteristics of wear, when to change, measurement and maintenance) and starved operation (causes, evidence and remedies).

Process variation and control will be discussed, including sources of variation, process capability, statistical process control, diagnosis by crosscorrelation, feedback control, size control (line speed and screw speed), shape control (die temperature, stock temperature and adjustable dies), guides for online measurement and commercial systems.

Such advanced technologies as changing extrudate shape, switching feed streams, directed flow technology (curved extrusion, takeaways, rapid die change and dimensional control), multicomponent process control and low resistance dies will also be discussed during the course.

An introduction to troubleshooting will be provided, including product geometry (surface defects, lumps, porosity and dimensional variability), extruder operation (safety, output rate, temperature, vent plugging and wear) and material.

The registration fee for "Rubber extrusion technology" is $1,090. The fee includes program materials, breakfasts, breaks and lunches. Participants completing the course will receive 1.8 Continuing Education Units. Further information is available from Murali Vedula (414) 227-3121.
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Title Annotation:"Rubber extrusion technology" at University of Wisconsin-Milwaukee's University Outreach in Milwaukee
Comment:Rubber extrusion examined. (Meetings).("Rubber extrusion technology" at University of Wisconsin-Milwaukee's University Outreach in Milwaukee)
Publication:Rubber World
Geographic Code:1U3WI
Date:Dec 1, 2001
Previous Article:Post cure thermo-oxidative effects on HNBR.
Next Article:Plastics technology colloquium held. (Meetings).

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