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BS ISO 6502-3:2018 pdf free

BS ISO 6502-3:2018 pdf free.Rubber – Measurement of vulcanization characteristics using curemeters
Test pieces with appropriate thickness should be cut from a rubber sheet. The sheet shall be homogeneous and, as far as possible, free from trapped air.
The test piece should be circular with a diameter slightly smaller than the die cavity. The volume of test piece shall be slightly larger than the die cavity volume (typically 130 % to 150 % larger) so that a small amount of material is extruded between all edges of the dies when they are closed. Typical volume of test piece is between 3 cm3 and 6 cm3 for a biconical cavity, and approximately 5 cm3 for a flat plate cavity. The pertinent volume shall be determined by preliminary tests, and test pieces of equal volume should be used to obtain reproducible results. The use of an appropriate device which ensures the production of test pieces of constant volume is recommended
NOTE Undersized test pieces can cause low cavity pressure and low torque readings. Oversize test pieces might cool the cavity excessively during the early part of the test cycle.
The loading of the test piece and the closure of the dies shall be carried out as quickly as possible. The dies shall be closed immediately after insertion of the test piece. The whole cycle, from opening to closure, shall not exceed 20 s.
The vulcanization time shall be counted from the instant the dies are fully closed. Oscillation of the movable die shall be started before or at the instant of die closure.
After removal of the cured tested piece, a further test piece may be inserted immediately if the temperature of the dies remains within ± 0,3 °C of the set value. If not, the dies shall be closed and the temperature be allowed to recover to the set value.
For low viscosity or sticky materials, a piece of protective film may be inserted between the test piece and the die surface for prevention of contamination and easy removal after the test. For biconical-die roterless curemeters of the sealed-cavity type, the use of protective film is strongly recommended.
If film layers are not used, a deposit of material from the rubber compound can build up on the dies which might affect the final torque values. It is suggested that reference compounds be tested daily to detect this occurrence. If such contamination develops, it can be removed by very light blasting with a mild abrasive, ultrasonic cleaning or non-corrosive cleaning fluids. Great care should be taken with cleaning, and the manufacturer’s advice followed. If fluids are used, the first two tests after cleaning shall be rejected. Running a natural rubber gum compound can be used to remove debris.BS ISO 6502-3 pdf download.

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