Release time:2017-04-27 | Source:Dongguan Xiehe Ultrasonic Equipment Co., Ltd, | Hits:80
Ultrasonics This process works through the translation of AC current into mechanical vibrations using piezo-electric ceramics. The vibrations are then passed through the part to the joint at which point they cause stress and strain in the contact area between the two parts which leads to localized heating and melting of the polymer. Ultrasonic welding typically has weld times from one-tenth to two seconds and our ultrasonic welding equipment can handle parts from approximately one-eighth inch diameter at high frequencies up to twelve inches square at low frequencies.
Step 1 - Parts in fixture The two thermoplastic parts to be assembled are placed together, one on top of the other, in a supportive nest called a fixture.
Step 2 - Horn contact A titanium or aluminum component called a horn is brought into contact with the upper plastic part.
Step 3 - Pressure applied A controlled pressure is applied to the parts, clamping them together against the fixture.
Step 4 - Weld time
The horn is vibrated vertically 20,000 (20 kHz) or 40,000 (40 kHz) times per second, at distances measured in thousandths of an inch (microns), for a predetermined amount of time called weld time. Through careful part design, this vibratory mechanical energy is directed to limited points of contact between the two parts. The mechanical vibrations are transmitted through the thermoplastic materials to the joint interface to create frictional heat. When the temperature at the joint interface reaches the melting point, plastic melts and flows, and the vibration is stopped. This allows the melted plastic to begin cooling.
Step 5 - Hold time The clamping force is maintained for a predetermined amount of time to allow the parts to fuse as the melted plastic cools and solidifies. This is known as hold time. (Note: Improved joint strength and hermeticity may be achieved by applying a higher force during the hold time. This is accomplished using dual pressure.)
Step 6 - Horn retracts Once the melted plastic has solidified, the clamping force is removed and the horn is retracted. The two plastic parts are now joined as if molded together and are removed from the fixture as one part. Plastics assembly is a fast, clean, efficient, and repeatable process that consumes very little energy. No solvents, adhesives, mechanical fasteners, or other consumables are required, and finished assemblies are strong and clean.