1. Calculate the single batch mixing amount and the actual formula based on the capacity of the internal mixer mixing chamber and a suitable filling factor (0.6～0.7).
2. According to the actual formula, accurately weigh the amount of each raw material in the formula. Place the raw rubber, small materials (ZnO, SA, accelerator, antioxidant, solid softener, etc.), reinforcing agent or filler, liquid softener, and sulfur separately and arrange them in order on the shelf.
3. Turn on the power switch and heating switch of the internal mixer for preheating. Simultaneously, check whether the air pressure, water pressure, and voltage meet the process requirements. Check whether the temperature measurement system, timing device, power system indication, and recording are normal.
4. After the internal mixer is preheated, stabilize it for a period of time and prepare for rubber mixing.
5. Lift the upper top plug, put the raw rubber that has been cut into small pieces into the internal mixer through the feeding port, lower the upper top plug, and mix the rubber for 1 minute.
6. Lift the upper top plug, add small materials, lower the upper top plug, and mix for 1.5 minutes.
7. Lift the upper top plug, add carbon black or filler, lower the upper top plug, and mix for 3 minutes.
8. Lift the upper top plug, add liquid softener, lower the upper top plug, and mix for 1.5 minutes.
9. Discharge the rubber, measure the temperature of the rubber with a thermocouple thermometer, and record the initial temperature of the mixing chamber, the temperature of the mixing chamber at the end of mixing, the discharge temperature, the maximum power, and the speed of the rotor.
10. Adjust the roll gap of the internal mixer to 3.8 mm, turn on the power switch to start the open mill, open the circulating water valve, then put the rubber discharged from the internal mixer onto the open mill to wrap the roll. After the rubber temperature drops to below 110℃, add sulfur, cut the rubber twice on both sides, wait until the sulfur is completely absorbed, the surface of the rubber is relatively smooth, and then cut off the rubber.
11. Adjust the roll gap of the internal mixer to 0.5 mm, put in the rubber for thin rolling, make a triangular package, thin roll 5 times, adjust the roll gap to about 2.4 mm, put in the rubber to wrap the roll, wait until the surface is smooth and bubble-free, remove the sheet, weigh the total mass of the rubber, place it on a flat, clean metal surface, cool to room temperature, paste a label indicating the rubber formula number and mixing date, and set aside for later use.