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Bubble phenomenon and analysis of rubber products (1)

Update:08-05-2020
Summary:

1. Factors of semi-finished products 1. Cause analysis […]

1. Factors of semi-finished products
1. Cause analysis
(1) The additives in the mixing rubber are not uniformly dispersed during mixing.
(2) The mixing temperature is low and the water is not volatilized. When the temperature is high, the sulfur is easily melted when the sulfur is added to the open mixer, or scorch occurs.
(3) Insufficient parking time of rubber compound or production without parking.
(4) The rubber compound is unevenly heated, and the surface is not smooth when it is molded
(5) When the rubber compound is heated on the open mixer, the surface is covered with air, and the molded rubber compound has the phenomenon of air.
2. Solutions
(1) Optimize the production formula, select easily dispersible additives to replace the currently used additives, increase the application of processing aids such as dispersant and leveling agent, and improve the dispersion performance of various additives.
(2) The compounded rubber is produced by two-stage process of the internal mixer. The temperature is raised during the first stage of mixing to fully evaporate the moisture and volatiles in the raw materials. After the compound is parked, the two-stage mixing is performed. Within the temperature range of the accelerator, avoid short scorch time or scorch.
(3) Smelting, one-stage mixing, two-stage mixing, and release processes strictly control the parking time of semi-finished products. Let all kinds of additives fully diffuse, improve the uniformity of the rubber, and at the same time help to restore the stress and strain under mechanical action.
(4) The rubber compound should be hot-melted evenly, and the rubber compound can be mixed evenly through the operations of cutting knife, dropping plate and tamping. Adopting the operation method of hot-smelting glue supply and separation, to improve the smoothness of the surface of the molding compound.
(5) The extrusion process is used to extrude the rubber compound, and there is no longer any air entrapment on the surface of the rubber compound.
Second, equipment and mold
1. Cause analysis
(1) The deviation of the temperature control system of the flat vulcanizing machine is large. When the temperature control is high, the mold temperature is high, which reduces the die flow time of the rubber.
(2) The surface of the mold is damaged, and the unevenness affects the fluidity of the compound.
(3) The surface of the mold is prone to fouling, which affects the fluidity of the rubber and easily causes scars on the body.
(4) The distribution of the mold exhaust line and the exhaust line holes is unreasonable, the exhaust line is thin, and the diameter of the exhaust hole is small, which affects the exhaust effect.
(5) The design of the groove and lead angle of the side iron teeth on the mold is unreasonable, so that the rubber will have a layer when it enters, and it cannot be discharged after the gas is included. The rubber is easy to produce vortex, turbulence and overlap when the mold is exhausted.
2. Solutions
(1) Improve the temperature measurement point and temperature control sensor system of the flat vulcanizing agent to make the temperature in the mold cavity coincide with the temperature displayed by the instrument.
(2) Repair the damaged parts on the surface of the mold in time. The manufacturer takes measures to protect and prevent damage to the surface of the mold to avoid damage to the surface of the mold.
(3) The surface of the mold is regularly cleaned and polished to ensure the smoothness of the surface of the mold.
(4) Improve the layout of the exhaust line of the mold and the exhaust holes, which are horizontal and vertical, and the distribution tends to be reasonable. The exhaust lines are thickened appropriately, the diameter of the exhaust holes is increased, and the exhaust effect is enhanced.
(5) Optimize the design of the side grooves and guide angles of the mold to reduce the eddy current and overlap phenomenon of the rubber material here.
Through the analysis of the causes of bubbles generated by rubber vulcanization, formulate rectification plans to solve the problem, strengthen the use and management of raw materials, standardize the compounding and processing of rubber compounds, improve the process operation, and optimize the implementation of measures such as mold design. , The air bubbles are generated on the pattern and in the middle of the steel cord, and the quality defects of the open scar are significantly reduced, which improves the appearance quality of the product.
Auto-maintenance equipment rubber product

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