Nylon 46 gives circuit breaker thermal stability without brittleness

Nylon 46 gives circuit breaker thermal stability without brittleness

International Survey Nylon 46 gives ©lrcuit breaker thermal stability without brittleness G e r m a n c o m p a n y ABL S u r s u m (Lauf/Pegnitz) has...

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International Survey Nylon 46 gives ©lrcuit breaker thermal stability without brittleness G e r m a n c o m p a n y ABL S u r s u m (Lauf/Pegnitz) has recently started using nylon 4 6 in three parts of its circuit breakers for d o m e s t i c use. In view of the high currents that m a y o c c u r during an overload or short circuit, the main functional elements of a circuit breaker must be able to withstand a temperature of 150°C for extended periods of time. Stanyl from DSM was chosen because of

its m e c h a n i c a l p r o p e r t i e s a n d chemical stability at high temperatures. The electromagnetic release mechanism includes a coil with a soft iron core. Should a short circuit occur, the resulting high current through the coil causes the core to push against a plunger and the circuit is opened. Both the bobbin on which the coil

is wound a n d the plunger are m a d e of a 3 0 % glass reinforced grade. T h e t h e r m o s e t previously u s e d for this application resulted in parts of variable quality and in b r e a k a g e during a u t o m a t i c assembly, due to its brittleness. Further information: DSM, PO Box 6 5 0 0 , NL-6401 J H Heerlen, Netherlands. Tel: +31 4 5 7 8 2 4 2 2

Self.aligning die for ooextruded film O n e of the major p r o b l e m s that producers of coextruded film face is t h a t of i n t e r f e r e n c e fit with adjustable film die bodies: in m o s t c a s e s , die b o d i e s m u s t b e assembled hot. C o n c e n t r i c i t y b e t w e e n the die b o d y and the mandrel is d e t e r m i n e d o n c e a die is a s s e m b l e d and into production. Now, a taper-lock die technology has been introduced by B r a m p t o n Engineering that ensures that their film dies are self-aligning, elimin-

ating labour a n d s c r a p during start-up. T h e a p p r o a c h introduces a taper along the b a s e of the mandrel. Individual mandrels are pre-stressed and treated, so that w h e n the die is put t o g e t h e r for the first time or the lOOth time, the b o d y and mandrel will align with perfect concentricity, requiring no further body adjustment. In coextrusion dies, concentric t a p e r s a r e m a c h i n e d on o n e

c o m m o n mandrel, eliminating the mechanical interference fits a s s o c i a t e d with multiple spiral mandrels. A n o t h e r feature of the Taper-Lock t e c h n o l o g y is that it permits easier disassembly of the die for cleaning, b e c a u s e it can be d i s a s s e m b l e d hot and a s s e m b l e d cold. Further information: Canadian Plastics Institute, 1 2 6 2 Don Mills Road, Don Mills, Toronto, Ontario, Canada M3B 2W7.

POLYTECHNIC SOUTH WEST P1.YMOUTH • EXETER • EXMOUTH • NEWTON ABBOT

COMPOSITES E D U C A T I O N A N D TRAINING ACMC runs regular Short Courses and discussion meetings on the design, manufacture and testing of fibrereinforced plastics, aimed at engineers and technicians at all levels. The Centre is also active in R & D and Consuhancy in composites and other engineering materials. GRP B O A T B U I L D I N G - 2 1 - 2 3 O C T O B E R 1991 An informal discussion meeting exploring the ways in which the GRP moulder can respond to the twin challenges of a wider European market together with tougher legislation on health and safety and product liability. PHENOLIC

COMPOSITES

- 26-28 NOVEMBER

1991

A short course to introduce the properties, applications and manufacturing options for these increasingly important materials. The course will be relevant for designers, specifiers and manufacturers, particularly in building, transport and offshore industries. RESIN CURE MONITORING

AND PROCESS CONTROL

- 9-11 D E C E M B E R 1991

This course explores the current alternatives for monitoring the cure of thermosetting polymer systems, with emphasis on ways in which the technology can be applied to the control of manufacture. Topics for 1992 will include: Manufacture of Thermoplastic Composites - Sandwich Structures Vacuum Bag, Autoclave and Compression Moulding • Resin Transfer Moulding • Composite Tooling Further details and information from: Denise Home, A CMC, Polytechnic South West, Plymouth PL4 8AA Phone 0752 232653

MATERIALS & DESIGN Vol. 12 No. 5 OCTOBER 1991

b~x: 0752 232638

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