A semi-automatic strapping machine is a device that wraps and tightens items using plastic strapping (commonly known as "strapping") and makes them secure through hot melt welding. Its core features are: manual threading, automatic tightening, welding, and cutting by machines.
1、 Core workflow (one cycle)
Step 1: Preparation and Straightening (Manual)
The operator places the objects that need to be bundled on the packaging table.
Pull out the tie from the scroll and manually wrap it around the object underneath.
Insert the front end of the strap into the "belt path" of the machine until it triggers a micro switch or sensor, and the machine senses that the strap is in place.
Step 2: Tighten (automatic)
The operator presses the 'tighten' button or directly presses the only operating handle (integrated design).
The conveyor wheel inside the machine will rotate forward, forcefully pulling the free end of the strapping to tightly wrap it around the object.
A device called a stop skateboard will act like a ratchet to prevent the strap from slipping back and ensure tension is maintained.
When the tightening force reaches the preset value (controlled by mechanical springs or electronic sensors), the tightening action stops.
Step 3: Hot melt welding and tape cutting (automatic)
After tightening is completed, the machine will automatically move on to the next step.
Welding device starts working:
A heating element (heating element) will quickly descend and be inserted between the overlapping packaging tapes (upper and lower layers).
At the same time, the upper and lower pressure plates will close together, tightly pressing the two layers of packaging tape on both sides of the electric heating element.
The high-temperature electric heating element will melt the contact surface of the packaging tape (usually made of polypropylene PP material), causing the plastic on its surface to melt.
After a very short heating time (about 0.5-1.5 seconds), the electric heating element quickly exits.
The upper and lower pressure plates continue to maintain pressure, allowing the two layers of molten plastic surface to cool and solidify under pressure, forming a firm welding point.
At the same time or after welding, a cutting knife will move to cut the strapping from the reel. In this way, a complete bundle is completed.
Step 4: Reset (Automatic)
All moving parts (pressure plate, cutter, etc.) are reset to their initial positions.
The machine emits a warning sound or changes the indicator light, indicating readiness to start the next bundling cycle.