Introduction to rubber processing and safety issues - HSE

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Where this is not possible a safe system of work is essential. Operate the haul-off at reduced speed, via a hold-to-run control, which should be under the direct control of the operator. BS EN 1114. Part 3 permits a maximum feeding speed of 200mm/second under these circumstances and gives details of more guarding options. Ram extruders Here, a roll of rubber compound or 'pig' is placed into the extruder barrel with the die swung out of position; the die is then closed, either manually or under power, and the rubber is forced through the die by the forward action of a powered ram. The most common type is the Barwell extruder. Because the extruder is loaded with individual batches of rubber, these machines cannot produce continuous profiles but produce a strip or pellet for further processing. Where pellets or slugs are produced, the die may have a rotating knife (die face cutter). The main mechanical hazard is the trap between the closing die and the barrel on machines where there is power assisted die closure. Accidents have occurred when a second member of the extrusion team has attempted to assist die closure by trimming back the rubber during closure. Die closure should be under two hand control and safe systems of work adopted to exclude third parties. Interlock movement of the ram with the die, so that ram movement is not possible with the die swung out of position. Rotating knives of die face cutters should have an interlocking guard with appropriate time delay to account for run down.
Calendering Introduction A calender is a machine with a number of horizontal rolls (sometimes called bowls), heated or unheated, through which material and/or rubber is passed under pressure. They can create either a rubber sheet of a required thickness, or apply a thin layer of rubber onto a cloth liner. This is known as frictioning or combining. Cushion calender Calenders can have two, three or four, rolls of various sizes and configurations. The diagram shows a 4-roll calender and the material circuits for bilateral coating either textile of metallic fabric or cords. Mechanical hazards The main mechanical hazards at calenders are caused by nips between the rolls, for both the rubber and fabric feed. This is a particular problem during threading up, cleaning and maintenance. There is also a running nip at the take-off or wind-up devices. Depending on the design, there may be other mechanical hazards caused by : auxiliary rollers for embossing or tensioning; cooling drums; cutting devices; stock guides
Page 1 and 2: Introduction to rubber processing a
Page 3 and 4: For larger machines, during mainten
Page 5 and 6: Main mechanical hazards Feeding ing
Page 7 and 8: For further information see safe in
Page 9 and 10: External or open mill mixing (two r
Page 11: Mechanical hazards Screw (or scroll
Page 15 and 16: Adding the fabric liner backing she
Page 17 and 18: Fabrication (including tank lining,
Page 19 and 20: Vulcanisation (including presses, a
Page 22 and 23: Frequent access so rise and fall in
Page 24 and 25: an explosive reaction, involving ge
Page 26 and 27: Polyurethanes (including PU foam pr
Page 28 and 29: PU foam off-cuts can be reconstitut
Page 31 and 32: Horizontal slitters: These machines
Page 33 and 34: Pre-polymers Isocyanate pre-polymer
Page 35 and 36: The tyre manufacturing process Text
Page 37 and 38: tread is added as a single strip, b
Page 39 and 40: means of protecting the operator. T
Page 41 and 42: Tyre retreading Introduction Tyre r
Page 43 and 44: tread to the casing. Curing may tak
Page 45: Other hazards Noise Tyre buffing ma

Introduction to rubber processing and safety issues - HSE

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