Welding polyethylene sheets (especially HDPE sheets or UHMWPE sheets) is a common way to achieve sealing, structural connection or large-scale structural forming. According to the type and thickness of polyethylene, the main welding methods are as follows:
Common polyethylene sheet welding methods
- Hot air welding
Applicable to: HDPE sheets with a thickness of ≤ 10mm (not suitable for UHMWPE)
Tools: hot air welding gun + plastic welding rod (same material)
Temperature control: 260℃–280℃
Operation method:
Grind and clean the butt surface;
Heat the edge of the sheet and the welding rod at the same time;
Press the welding rod into the gap with pressure to form a molten connection;
After cooling, a continuous weld is formed.
Note: The welding rod must be made of the same polyethylene material (HDPE to HDPE) to avoid brittle cracking. - Extrusion Welding
Applicable to: large HDPE sheet structures with a thickness of ≥ 6mm
Tools: extrusion welding gun (extrusion welding machine)
Operation method:
Open a V-shaped or U-shaped groove at the weld;
Use an extrusion welding machine to heat and squeeze the molten polyethylene into the weld;
Pressure is applied to form the weld at the same time;
After cooling, a high-strength weld is formed.
Extrusion welding can be used to manufacture large water tanks, troughs, pools and other structures. - Butt Fusion Welding
Applicable to: thick plates or whole plates (thickness ≥ 10mm)
Process flow:
Two plates are aligned and fixed;
The middle heating plate heats the surfaces of both ends at the same time;
Immediately press after removing the heating plate;
Maintain pressure and wait for it to cool and weld.
Advantages: High weld strength, up to 80%-100% of the parent material.
Special note: UHMWPE sheets cannot be welded by traditional methods
Ultra-high molecular weight polyethylene (UHMWPE) is not suitable for hot air welding or butt welding due to its high molecular weight and extremely low melt fluidity. If you want to connect UHMWPE sheets, you usually use:
Mechanical connection (screws, rivets, mortise and tenon)
Embedded structure fixation
Or use low-temperature plasma pretreatment + special adhesive (but not recommended for load-bearing)