Used Ultrasonic Welders for Sale

An ultrasonic welder joins two thermoplastic parts by pressing a tuned metal horn on the joint while the horn vibrates at one fixed frequency. The acoustic stack is a converter, a booster and a horn. A generator drives that stack from ordinary plant power, commonly 120 to 240 volts. Friction at a small energy director melts a thin layer of resin. The slide then holds the parts together while that melt freezes. Leave the hold out and the joint can look closed and still peel. A hand-held probe is enough for a short run or a repair. A vertical press repeats the cycle all day behind a guard.

Frequency decides the horn, and it is not a quality ranking. Twenty kilohertz moves more amplitude through a larger horn, which suits bigger housings, softer resins and joints with more area. Forty kilohertz uses a smaller horn and a shorter stroke, which suits thin walls and show surfaces that mark when the amplitude is high. A horn is machined for one frequency and will not tune on a generator built for another. Booster gain changes amplitude without a new horn. A 2:1 booster doubles what the converter delivers. A 0.5:1 booster cuts it in half. Output on these systems runs from about 200 watts on a small stack to about 5,000 watts when the horn and the joint are large. Glass-filled resin usually wants more amplitude than an unfilled grade of the same polymer.

The controller ends the cycle by time, by energy or by collapse distance. Time is the simple choice when the director is sharp and the parts repeat. Energy, measured in joules, lets the weld run a little longer or shorter when the wall varies. Collapse stops the vibration after the horn has traveled a set distance, which keeps a joint at a finished height. Trigger force starts the vibration only after the horn is already loaded. A cracked horn often screams or draws more power than the last good setup, and keeping it in service can break the ceramics in the converter.

The station sits after the molding press. An operator or a robot sets the part in a nest, and a two-hand control or a light curtain releases the slide. Shop air and the generator supply are the utilities. Vibration will not form a retaining head on a molded stud. That job is heat staking, with a heated tip and a dwell. It will not lay a silicone or epoxy gasket either. That job is a meter mix dispenser. Match the horn face to the director before you compare frames.

Fire a used ultrasonic welder into a coupon, not an empty stroke. Listen for a rattle at the stack studs, which means amplitude is leaking out as heat. Read the frequency and the watts on the plate and confirm they match the horn you intend to run. A loose stud between converter, booster and horn is a common fault on a machine that still looks clean.

Meadoworks moves these presses out of molding-cell closures, consignments and auctions. Look at the horn face, the studs and the generator before the unit is skidded, and send the nest with the press when the cell travels together. A dead generator is cheaper to find on the floor than after the pallet is opened at the dock.