Hot melt welding is a common plastic joining process, and servo hot melt welders replace conventional pneumatic cylinders with servo motors for pressure and displacement control — taking this traditional process to a new level of precision.
How it works
Hot melt welding has three steps: first a hot plate or hot melt head heats the plastic faying surfaces to a molten state; then the heating element retracts quickly and the two molten surfaces are pressed together; finally they cool under holding pressure as the molten plastic resolidifies into one piece. In servo models, pressing pressure, speed and displacement are all precisely servo-controlled.
Advantages over conventional pneumatic hot melt machines
Programmable pressure: different pressures can be set for each stage — e.g., light pressure during fusing to avoid squeezing out too much material, then higher pressure during hold for bond strength.
Precise displacement control: melt depth (collapse distance) is set directly and executed by the servo system, giving excellent dimensional consistency.
No air supply needed: no compressed air required, so installation isn't limited by air lines and pressure never fluctuates with the air supply.
Typical applications
Welding large plastic parts such as automotive intake manifolds, fuel tanks and tail lamps; structural parts in medical and home appliance industries demanding both strength and appearance. Hot melt welding deserves consideration wherever weld areas are large and strength requirements high.
Usage tips
Temperature control is the key: too low gives incomplete fusion, too high degrades the material and causes severe stringing. Validate the temperature window for each material to find the best combination of heating temperature, heating time and holding pressure.