Ultrasonic Welding

Frequently Asked Questions

• What is Ultrasonic Welding?

  Ultrasonic welding is a process that uses high frequency vibrations to join two materials together and maintain a consistent weld quality. It works by converting electrical energy into mechanical vibrations that are applied to the materials being joined. Here are some key points about ultrasonic welding:

  • It utilizes high frequency vibrations, typically between 15-40 kHz, which are above the range of human hearing (higher than audible sound).

  • The vibrations are generated by converting electrical energy into mechanical motion using a transducer. The transducer contains piezoelectric material that expands and contracts when electricity is applied.

  • The materials to be joined are held together under pressure and the ultrasonic vibrations are directed to the interface between them.

  • The ultrasonic energy & ultrasonic vibrations create friction and heat at the contact point between the materials, causing their polymer chains to mix and entangle together. This creates a strong, solid-state bond.

  • It is commonly used to weld thermoplastic materials like plastics and composites. Metals can also be ultrasonically welded.

  • Benefits include quick joining times, low heat generation, precise localization of bonding, and suitability for automation.

  • Applications include joining plastic parts, wire bonding in electronics, manufacturing medical devices, and packaging.

  So in summary, ultrasonic welding uses high frequency vibrations to create bonds between materials under pressure. It is a quick, versatile joining technique used widely for plastics and other materials.

• What are Ultrasonic Welder systems?

  An ultrasonic welder is the machine or device used to perform ultrasonic welding. It consists of the following main components:

  • Power supply – Provides electrical energy to drive the transducer. It converts the standard electrical supply to a high frequency electrical signal.

  • Ultrasonic transducer – Contains piezoelectric materials that convert the high frequency electrical signal into mechanical vibrations. It is the source of the ultrasonic vibrations.

  • Booster – Amplifies the vibrations coming from the transducer. It is used to increase the amplitude of the vibrations.

  • Horn – Applies the ultrasonic vibrations directly to the materials being welded. Different horn designs are used for different applications.

  • Anvil – The part of the welder that supports the materials being joined. It provides the counterforce to the horn.

  • Controller – Controls and sets parameters like amplitude, frequency, time, and pressure.

  During the welding process, the materials to be joined are clamped between the horn and anvil under applied pressure. The transducer generator converts electrical power input into high frequency mechanical vibrations which get transmitted through the booster and horn to the contact area between the materials. The vibrations cause local melting and joining.

  Key process parameters that can be set and controlled include vibration frequency, amplitude, force, time, and temperature. The machine allows for automated and repeatable welding. Ultrasonic welding systems are commonly used for plastics but also metals, ceramics and other materials.

• Overview of the Ultrasonic Welding Process

  Ultrasonic welding is a process where two materials, commonly thermoplastics, are held together under pressure and subjected to high frequency vibrations typically in the 15-40 kHz range. An ultrasonic welder converts electrical energy into these mechanical ultrasonic vibrations through a transducer and applies them directly to the materials using a horn. The vibrations create frictional heat and motion at the contact point between the materials which causes their polymer chains to mix and fuse together forming a weld. The combination of pressure, ultrasonic vibration energy, and generated heat at the interface results in a strong solid-state bond between the materials in a rapid and localized manner.

  Ultrasonic welding is an efficient alternative to gluing  plastics or bonding plastic using adhesive.

• Ultrasonic & Plastic Welding

  Ultrasonic welding is commonly used for joining and welding thermoplastic materials. Some key reasons why using ultrasonic welding that is a preferred method for plastics welding include: welding technique

  • It works well for many common thermoplastics such as polypropylene, polyethylene, polystyrene, nylon, and acrylic. The polymer chains in thermoplastics allow for the frictional heating and mixing necessary.

  • The localized heat generation allows plastic parts to be welded without melting or deforming the whole part. This gives more precision and control.

  • Bonding occurs rapidly, in less than a few seconds, increasing throughput in manufacturing.

  • No need for consumables like adhesives or fasteners that add cost and time.

  • Minimal flash or splashing compared to other welding processes. Gives cleaner welds.

  • Ability to automate the process for high volume production.

  • Consistent, repeatable, and strong welds achieved. Strength is often greater than the base materials.

  • Low capital investment compared to alternatives like hot plate or spin welding.

  • Environmentally friendly process with no chemicals or solvents involved.

  So in summary, the friction, heat, pressure and melt mixing created in ultrasonic welding makes it highly suitable and widely used for welding and joining a wide range of plastic parts and products. It is a fast, clean, and adaptable process.

• Where can I buy Ultrasonic Welding Equipment?

  Sabre Plastics Tooling sell Rinco ultrasonic welding machines and also offer Purchase and Leasing options.

  With in-house manufacturing of welding horns, jigs, and fixtures.

  Ideal for Electronics, the Medical industry, Aerospace Industry, Manufacturing Industries.

  Contact us for more information today. 

• Types of Ultrasonic Welding Processes

  Here are some of the main types and names of ultrasonic welding processes:

  • Stake welding – The most common type. The materials are clamped between a sonotrode (horn) and anvil. The central stake transmits vibrations. Used for welding overlapping parts.

  • Contoured welding – The sonotrode has a contoured or patterned face to focus energy. Used for applications like wire bonding.

  • Spot welding – Intermittent welds are created at specific spots or nodes. Often used for fastening or tacking parts.

  • Seam welding – A continuous seam weld is created by traversing or rolling the horn along a path. Useful for leak-proof seals.

  • Swing welding – The transducer swings in a pendulum motion to create a series of spot welds. Used for applications requiring welds at many points.

  • Laser assisted – Laser heating is combined with ultrasonic welding to weld challenging materials using the heat generated.

  • Rotary welding – The horn rotates against the part to create a circular weld. Used to seal tubular parts.

  • Torsion welding – The horn moves in an orbital path under torsional forces to create a circular weld.

  • Wire welding – Ultrasonic energy used to weld fine gauge wires and terminals to circuit boards.

  So in summary, the main variants utilize different horn geometries, motions, and techniques to deliver the ultrasonic vibrations based on the particular application and desired weld type, shape or pattern. But all rely on high frequency vibration and ultrasonic energy to create fusion between materials.