Detailed explanation of the working principle of electric fusion welding machine: How to achieve seamless connection of PE pipes

1. What is an electric fusion welding machine?

Electric fusion welding machine is a welding device specially used for connecting PE (polyethylene) pipes and fittings. It is often used in municipal gas, water supply, power communication and other fields. It does not require open flames or excessive temperatures. It only applies current to the metal heating coil embedded in the pipe fitting to make it heat up, thereby melting the surrounding PE material to achieve a firm, sealed and seamless connection.

This welding method has the following characteristics:

High degree of automation and easy operation;

Suitable for narrow space or underground operations;

Stable connection quality and standardized pipe network construction.

2. Equipment composition

A standard electric fusion welding machine usually includes the following structural components:

Control host

Provides setting and output of welding voltage and welding time;

Display screen (LCD or digital tube) is used to display welding parameters, progress and fault prompts;

Built-in or external control chip system can realize automatic parameter adjustment or data recording.

Cable output terminal

A pair of output lines connected to electric fusion pipe fittings usually have spring plugs or alligator clips for power heating;

The output voltage is generally 8~48V, which is set according to the size and brand of the welded parts.

Barcode/QR code scanner (some models)
There will be a barcode on the electrofusion pipe fittings, which contains information such as recommended voltage and welding time;
By scanning, the correct parameters can be automatically set to avoid human input errors.
Cooling/protection system
The equipment has a built-in fan or thermal protection function to prevent overheating due to long-term operation.
Data recording interface (high-end models)
Construction records can be exported via USB or SD card to meet the needs of engineering audits and quality management.

3. Detailed explanation of the principle of electrofusion welding
1. Structure of electrofusion pipe fittings
Electrofusion pipe fittings are PE accessories specially designed for electrofusion welding. They are pre-buried with spiral resistance heating coils, and the outer layer is still PE plastic, which is compatible with ordinary PE pipes. They are of various types, the most common ones are:
Electrofusion straight-through
Electrofusion elbow
Electrofusion tee
Electrofusion flange seat
Electrofusion plug

2. Heating and welding process
After power is turned on, the metal resistance wire is quickly heated to above 200°C;
The surrounding PE material softens or melts immediately;
At the same time, the outer wall of the inserted PE pipe is also heated and softened;
Under a certain pressure and molten state, the two gradually merge into one;
After welding is completed, the current is cut off and the cooling stage begins;
During the cooling process, the molecules are cross-linked and fixed to form a welded joint with high strength and strong sealing.
The molten layers are "homogeneous fusion", and their physical structure is the same as that of the parent material, and the strength is often higher than that of the pipe body.

IV. Standard process of electrofusion welding

1. Surface treatment (very critical)
Use a special scraper to scrape off the oxide layer on the outer surface of the PE pipe by about 0.1~0.2mm;
If there is oil stain, wipe it clean with industrial alcohol;
The surface must be dry, clean and dust-free.

2. Insertion and alignment
When inserting the PE pipe into the electric fusion pipe fitting, it must be inserted to the bottom;
Use the centering fixture to fix it to ensure the axial direction and insertion depth are standard;
Prevent misalignment or warping during welding.

3. Parameter setting
Use the welding machine to scan the pipe fitting barcode to automatically read the parameters (recommended method);
If there is no code scanning function, manually set the welding time and voltage according to the manufacturer's instructions;
The common parameter range is 39V/45 seconds to 48V/180 seconds, which varies depending on the size.

4. Welding execution
Press the "Start" button and the equipment will automatically start heating;
It is forbidden to move the pipe and pipe fittings during welding;
Generally, the welding time ranges from tens of seconds to several minutes.

5. Natural cooling
After welding is completed, do not move or pressurize immediately;
Stand and cool for 5 to 20 minutes until the pipe fitting cools and shrinks to shape;
The cooling time is related to the ambient temperature and pipe diameter.