Thermoplastic welding technology is usually used to weld HDPE (high-density polyethylene) sheets together. The main methods are as follows:
Common welding methods
Method 1: Hot Air Welding
Principle:
Use a hot air welding gun to heat and soften the surface of the HDPE sheet and the welding rod at the same time, and fuse them by applying pressure.
Equipment:
Hot air plastic welding gun (such as Leister brand)
HDPE welding rod (round or triangular)
Pressure roller
Operation steps:
Clean the sheet joint area to remove oil and dust;
Set the welding gun temperature: 230°C–280°C (depending on the environment and material);
Put the welding rod in the intersection of the welding nozzle and the sheet;
Heat the weld area with hot air, and apply pressure to melt the welding rod;
Let it cool naturally after welding is completed.
Applicable conditions:
Thin plates (≤10mm)
Point or local repairs
Easy manual operation
Method 2: Extrusion Welding
Principle:
Use an extrusion welding gun to directly extrude the HDPE molten welding wire through the screw under pressure, and fill it into the weld to achieve a firm connection.
Equipment:
Extrusion welding machine
Heating and preheating nozzle
HDPE welding rod (granules or welding wire)
Operation steps:
Slot or pretreat the joints of the plate;
Preheat the plate with a hot air nozzle;
Start the extrusion gun and press the molten HDPE material into the weld;
Move the welding gun evenly to ensure that the weld is full;
Natural cooling and molding.
Applicable conditions:
Thick plates (＞6mm, especially 10mm~50mm)
High-strength welding requirements (such as water tanks, chemical containers)
Industrial welding site
Method 3: Hot plate butt welding (Butt Fusion Welding)
Principle:
After the edges of the two HDPE plates are heated and softened, they are butt-fused under pressure.
Equipment:
Hot plate butt welding machine (generally used for HDPE pipes)
Flat plate pressure fixture
Temperature-controlled hot plate
Operation process:
Clamp the plate;
Heat the contact surface of the plate until softened (about 200~220°C);
Immediately press the two plates together after removing the heating plate;
Cool under pressure until solidified (generally 5~10 minutes);
Check the uniformity of the weld.
Applicable situations:
Factory-scale batch welding
Large-area splicing or assembly projects
Precautions
Project Description
Cleaning treatment must be thoroughly cleaned before welding, otherwise the weld is prone to fall off
Preheating temperature Control at 200–280°C, overheating will cause burning, and overcooling will not stick firmly
Welding angle The angle between the welding nozzle and the weld is about 45°, which is conducive to uniform welding
Welding rod consistency Use HDPE welding rods of the same grade and color as the plate
Cooling time Cool naturally after welding to avoid stress fracture caused by forced cooling