How Glass Insulators Composite & Porcelain Insulators are Manufactured?

Glass Insulator Manufacturing Process :

Batching: This involves uniformly mixing different raw materials according to a specific recipe. Currently, forced vertical shaft mixers are commonly used. The key point is ensuring the uniformity of the mixture.
Melting & Fining: Melting refers to heating the batch at high temperatures to form homogeneous glass melt. Fining refers to the de-gassing process applied to the molten material.
Pressing: The molten glass from the melting/fining stage enters the pressing stage via a feeding system. This involves pressing the glass melt into the shape of the glass insulator shell, typically using fully automatic hydraulic presses. The shape is controlled by the mold, and the precise amount of glass used for each shell is controlled to ensure product consistency.
Tempering: The glass shell then undergoes tempering, a controlled cooling process that imparts permanent surface compressive stress. Equipment involved includes homogenizing furnaces and tempering machines.
Thermal Shock Testing: Tempered shells undergo thermal shock testing. Special nickel sulphide treatment furnaces and specific nickel sulphide elimination processes are used for homogenization. The effectiveness of the nickel sulphide removal process directly impacts a key operational performance indicator – the self-explosion rate.
Cementing Assembly: An assembly machine, equipped with steel pin positioning aids, is used to assemble the glass shell, steel pin, and steel cap using cement. Ensuring the coaxiality of the pin, shell, and cap is critical, as poor alignment can also lead to a high self-explosion rate.
Testing: Each assembled glass insulator undergoes individual testing, including a 50% tensile load test and structural height measurement, to ensure compliance with standards.

The production of composite insulators resembles a precise art, divided into three main parts: epoxy glass fiber reinforced polymer (GFRP) rod production, rubber compounding, and assembly.

Epoxy GFRP Rod:
Glass fibers are impregnated with epoxy resin.
Vacuum-assisted injection ensures thorough impregnation.
Continuous pultrusion shapes the rod.
High-temperature curing solidifies the rod, ensuring perfect fusion of fiber and resin. Each step requires precise control.

Rubber Compounding:
Silicone raw rubber is precisely mixed with additives like silica and aluminum hydroxide.
The mixture undergoes compounding and sulfurization/re-milling to form homogeneous synthetic rubber, ensuring stable material properties.

Assembly Process:
Metal Fitting Preparation: Fittings are polished and sandblasted to ensure clean contact surfaces and increase friction.
Core Rod Preparation: The GFRP rod is polished, cleaned, and dried to remove impurities and ensure bonding quality.
Primer Application: A coupling agent is applied to enhance the chemical bond between the silicone rubber and the core rod.
Molding & Vulcanization: Silicone rubber is injection molded over the core rod and vulcanized (cured) to form the sealed and durable weathersheds (sheds/housing).
Rigorous Final Testing: After all steps, the insulators undergo final tests according to the GB 19519-2014 (Chinese National Standard), including mechanical failing load and steep-front impulse voltage tests, ensuring each product meets the highest industry quality standards.
Every process, every detail, is dedicated to ensuring the exceptional performance of composite long rod insulators, providing a solid guarantee for the safe operation of power systems. This is the technological story behind them, a precise journey from raw material to finished product.
Porcelain Insulator Manufacturing Process

The production process for porcelain insulators mainly includes the following steps:

Raw Material Preparation: Raw materials like pottery stone, feldspar, clay, and alumina are ground finely and purified through steps including ball milling, sieving, and filter pressing (de-watering to form pug).

Forming:
Vacuum Pugging: A vacuum pug mill removes air bubbles from the pug, forming a solid clay column.
Shaping: Molds are used to press the clay column into the shape of the insulator body (green body).
Trimming: The green body is trimmed to ensure it meets the required shape.
Drying: The green body, still containing significant moisture, is dried to reduce water content to around 1%.

Glazing & Sand Coating:
Glazing: Glaze is applied using techniques like dipping or spraying.
Sand Coating (Gritting): Sand particles are applied to the porcelain body's head (the area where metal fittings will be assembled). This increases the contact area and friction between the porcelain and the cement, enhancing the bond strength.
Firing: The glazed and gritted bodies are fired in kilns. Subsequently, they are screened through visual inspection and internal hydraulic pressure tests to ensure quality.
Assembly: After firing, the steel cap and steel pin are assembled to the porcelain body using cement.
Testing: Each assembled insulator undergoes individual testing, including mechanical tensile tests and electrical tests.