How the Industrial Rubber Products Are Manufactured
Rubber is known to have the unique properties of “elongation enables rubber to stretch well”, “recovery enables rubber to recover the original shape” and “elasticity enables rubber to bounce well”. However, the raw rubber does not have these properties even though it has potentiality to have them. Only after compounding the raw rubber with very many different types of chemical ingredient, and only after the complex manufacturing processing, the rubber having these properties can be created.
Very many different types of rubber are manufactured by compounding the ingredients having the characteristics suited to the desired application.
Material Acceptance Department
Raw materials and parts necessary for manufacturing our products arrive at the truck yards.
The materials are then stored in the warehouses and delivered as required.
The raw rubber and compounding ingredients are selected in compliance with the final product application and required performances. Numerous types of the industrial rubber products are developed and the operating conditions under which the products are subjected also vary.
Based on our accumulated experiences for long years and our well accepted deliveries to our customers in the past 80 years, the ratio of the various compounding ingredients (vulcanizing agent, accelerator, antidegradant, stiffener, softener, plasticizer, flame retardant and others) is determined that is unique to Hokusei Rubber Industry.
The raw rubber is compounded with the compounding ingredients, which are processed under the specified temperature control unique to the respective ingredients and under the strict quality control, in accordance with the formulation uniquely designed by our company. Then, they are kneaded. It is general practice today to compound more than 10 different types of ingredients in a single product. The technology of kneading them to disperse these ingredients uniformly and ideally over the entire amount of the raw material is indispensable.
We have developed unique mixers (mixer, rolls) with which the ingredients are finely dispersed so that the ingredients are blended into a homogeneous substance. The compounded rubber is sent to the shearing stage where the rubber is sheared into the desired size according the customer’s specification, and is sent to the next stage.
The kneaded rubber is extruded by the extruder machine in accordance with the specification drawing.
After extrusion, the rubber compound is sent to a vulcanizer. The vulcanization process is a chemical process by which the physical properties of rubber are made. In this process, heat is applied to the rubber compound so that the chemical reaction between the rubber and sulfur occurs which gives the desired physical properties to the final rubber product.
The rubber compound before the vulcanization process is simply a clay. Sulfur gives rubber the required characteristics. During the vulcanization process, the rubber compound changes from viscous solid to an elastic solid.
The vulcanized rubber compound is cooled, and then sent to either the shearing process to cut the rubber to length, or rolled up on a spool, or the flash removing process depending on the product for final processing.
A rubber tube is inserted into a core metal called mandrel, which is molded according to the shape of the product, and then heated.
The sizes and the processing accuracy of every product are inspected carefully with human hands and eyes. The performance test of the finished product is also executed.
Automatic winding process
In some cases, double-sided tape is used to join pieces of rubber. With our unique processing technologies, we have the capability to work with various shapes and materials.
Sealer Punching Process
A thin sheet of rubber is punched out using a special punching die. Sheets can come in different materials, colors, and thicknesses based on their application. They are available in thousands of shapes and their qualities are strictly controlled.
Production of Dies
A die that will ensure that the final product has taken the desired shape is made according to the characteristics of the material.