We all know the basic rules of ultrasonic welding，high-frequency electric energy turned into high-frequency mechanical energy，this repeated vibration transfers to the thermal plastic or metal, generates friction and energy between the plastic to plastic, plastic to metal or metal to metal.
 
In the process of ultrasonic welding，the heat that generated by friction melts the two plastic surface into each other. In the process of ultrasonic riveting welding, the tip controls the flow direction of the melted plastic，forms, and then presses. in the process of ultrasonic nut imbedding，the welding tip injects the nut into the plastic.

 
Various ultrasonic system configurations could be chosen with different frequencies(15kHz-50kHz) and power (600W-4800W)，or different control methods ，such as pneumatic ultrasonic welder，servo ultrasonic welder or different applications like handheld welder，non-standard ultrasonic welder，metal welder etc.
 
Many factors affect the result of the ultrasonic welding: Mold (upper horn plus lower fixture)，frequency，material，welding line design，welding parameter and spare parts injection etc.





Welding system frequency
 
Typical welding frequency includes 15kHz，20kHz，30kHz，35kHz，and 40kHz. Appropriate welding frequencies could be chosen per the product sizes, inner electric components types, welding strength, welding result etc. Basically, the following principles could be referred:


For small and high-precision electronic products (containing PCB board and microelectronic component inside) housing welding, a 40kHz ultrasonic welder is often used. It has a smaller amplitude with smaller welding pressure to avoid damaging the inner electronic components.


1. For the small products with demanding requirements on the look, a 40kHz ultrasonic welder could be applied. Smaller amplitude and pressure help to weld a better looking.


2. For the plastic welding with medium or large size, 15kHz or 20kHz are usually applied.


3. For the relatively soft material such as PP, or the material with thin poor stiffness, low frequency and big amplitude, a 15kHz welder is normally applied.


4. For far-field welding-the welding horn is far away from the welding line, for instance, if this distance is bigger than 12mm, on this occasion a 15kHz ultrasonic welder could be used.


5. 20kHz welder is applicable to most small or medium-sized plastic welding, which is also the most widely used frequency in ultrasonic applications.



Material


1. For ultrasonic plastic welding，it only applies to thermoplastic welding for the thermoplastic could melt in a specific range of temperature. For the thermosetting plastics, it degrades while heating so it could not be welded by the ultrasonic.


2. The weldability of the thermoplastic depends on the stiffness, elasticity modulus, density, friction coefficient, heat conductivity coefficient, specific heat capacity，glass transition temperature(TG) or melting temperature(TM).


3. Generally,  a material with good stiffness has excellent far-field welding ability for it easily transmits the vibration energy, soft material with low elasticity modulus would be hard to weld for it decreases the ultrasonic vibration. On the contrary, for rivet or spot welding, the softer the material, the easier the welding.


4. Normally, plastics are divided into two types-amorphous and crystalline. The ultrasonic energy can transmit easily in the amorphous material so it is easy to weld. However, it is not very easy for the ultrasonic energy to transmit in the crystalline material so it takes a larger amplitude and energy for the ultrasonic welder to weld crystalline material, the welding line should also be designed carefully.


5. The weldability could further be affected by the factors such as water content, releasing agent, lubricant, plasticizer, filler reinforcers, pigments, flame retardants, and other additives, and actual resin grades. In addition, attention should also be paid to the degree of compatibility between different materials. There is a certain degree of compatibility between certain grades of some materials and not others.


It should be considered whether the welding is near-field or far-field welding. The distance between the welding tip contacting the plastic part and the welding line is less than 6mm is called near-field welding, if the distance is larger than 6mm, it is then called far-field welding. The longer the distance, the greater vibration attenuation，the harder the welding. 





Tooling & welding head
 
Generally, customers will choose the same brand tooling and welding head. In fact, as long as the frequency is the same as the equipment, other brands could also be chosen.
 
The welding horn material could be aluminum, titanium, or hard alloy steel. The tooling material could be aluminum, stainless steel, and resin mold. The material chosen normally depends on the material type, the material fiberglass content, connector structure and size, welding strength, and service life. For instance, to lengthen the service life of the welding horn, hard alloy steel could be a choice.




The ultrasonic welding horn could be designed and optimized by FEA (finite element analysis), which allows the engineer to evaluate the welding head vibration and pressure before actual manufacturing. An optimal welding horn design is one with uniform output amplitude and minimum stress. In the picture above, the left picture is the welding horn design before optimization, the right one is the horn design after optimization.
 
In the process of welding horn design and manufacturing, the horn symmetry is of vital importance, asymmetric horn leads to non-axial vibration which increases the horn stress and causes the horn invalidity.
 
A good tooling design is also important, the tolling has two main functions: align the parts below the welding horn and rigid support welding area. The rigid support help reflects the ultrasonic energy to the welding line, which is why the tooling is usually made of metal working pieces.
 
In order to increase the durability of the welding horn and prolong its service life, the welding horn surface could be dealt  with tungsten carbide treatment or chromium plating treatment. The tooling could be designed in sections to better match the products.




Welding parameters
 
Welding parameters affect the welding result in the welding process. These parameters include amplitude, welding pressure, trigger pressure, welding distance, and energy.
 
Different plastic material requires different amplitude, the amplitude is usually adjusted in the software percentage setting, or adjusted by changing the booster with different ratio. Welding pressure could be adjusted by the rotary button or the software setting. The pressure trigger is when the pressure reaches the setting value after a certain amount of pressure on the plastic parts, the ultrasound starts, the value is adjusted by the rotary button or the software setting.
 
Several control modes in the welding process:
Times mode
Energy mode
Distance/position welding mode
 
Different plastic uses different welding modes. For instance, the thin plastic material usually adopts energy mode, products with large dimensional tolerances are welded in distance mode, Products with high tolerance requirements are welded in position mode.
 
In addition, you could monitor all the parameters in the welding process, also you could set the parameter qualification range to avoid malfunctioning workpieces.
 
Plastic welding is special processing, in the early stage of product development, one should work closely with the ultrasonic equipment manufacturer, using their experience, to evaluate the product structure and welding line design and test the sample product to greatly improve the qualification rate in the later mass production process.



For more plastic welder, refer to below link: 


plastic welding machine click here

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Are you in the market for ultrasonic welding equipment and want to make sure you make the best purchase for your needs? Look no further! Our comprehensive buyer's guide covers everything you need to know about ultrasonic welding equipment, from understanding the technology to determining the best equipment for your specific application. Whether you're a seasoned professional or a newcomer to the world of ultrasonic welding, this guide has all the information you need to make an informed decision. Keep reading to learn more about ultrasonic welding equipment and how to choose the right one for your business.
Ultrasonic Welding Equipment: A Comprehensive Buyer’s Guide

Ultrasonic welding is a widely used method for joining thermoplastic materials by using high-frequency ultrasonic vibrations. This process is fast, efficient, and produces strong and reliable welds. If you are in the market for ultrasonic welding equipment, it is important to understand the different factors to consider before making a purchase. In this comprehensive buyer’s guide, we will explore everything you need to know about ultrasonic welding equipment, including its benefits, applications, key features, and how to choose the right one for your needs.

Benefits of Ultrasonic Welding Equipment

Ultrasonic welding offers numerous benefits, making it an attractive choice for various industries. Some of the key advantages of using ultrasonic welding equipment include:

- Fast and efficient process

- Strong and reliable welds

- No need for additional adhesives, solvents, or fasteners

- Produces clean and precise welds

- Suitable for a wide range of thermoplastic materials

- Environmentally friendly process

Applications of Ultrasonic Welding Equipment

Ultrasonic welding equipment is used in a variety of industries for different applications. Some common uses of ultrasonic welding equipment include:

- Automotive industry for assembling components such as dashboards, door panels, and headlights

- Electronics industry for bonding wires, connectors, and sensors

- Medical industry for producing medical devices and equipment

- Packaging industry for sealing and cutting plastic films and containers

- Consumer goods industry for manufacturing toys, appliances, and household products

Key Features to Consider

When shopping for ultrasonic welding equipment, there are several key features to consider to ensure you are getting the right machine for your needs. Some of the essential features to look for include:

- Power output: Choose a machine with the appropriate power output for the materials and applications you will be working with.

- Frequency: Different materials require different frequencies for optimal welding results. Make sure the machine offers a suitable frequency range.

- Welding horn: Look for a machine with a high-quality welding horn that is designed for durability and precision.

- Control system: Consider the control system and user interface to ensure ease of operation and customization options.

- Safety features: Check for safety features such as emergency stop buttons, overload protection, and interlocking systems to protect operators and the equipment.

Choosing the Right Ultrasonic Welding Equipment

When selecting ultrasonic welding equipment for your specific needs, it is important to consider the following factors:

- Materials: Determine the types of materials you will be welding and ensure the machine is compatible with those materials.

- Production volume: Consider the volume of production and choose a machine that can meet your production requirements.

- Budget: Set a budget for your ultrasonic welding equipment and compare options within your price range.

- Support and training: Look for a supplier that offers technical support, training, and after-sales service to help you get the most out of your equipment.

Ultrasonic welding equipment is a versatile and efficient method for joining thermoplastic materials, offering numerous benefits for a wide range of industries. By understanding the key features and factors to consider, you can make an informed decision when choosing the right ultrasonic welding equipment for your specific needs. Whether you are in the automotive, electronics, medical, packaging, or consumer goods industry, investing in high-quality ultrasonic welding equipment can greatly improve your production processes and product quality.

ConclusionIn conclusion, ultrasonic welding equipment is a crucial investment for companies looking to improve their manufacturing processes and product quality. With the comprehensive buyer's guide we have provided, businesses can make informed decisions when selecting the right equipment for their specific needs. Whether it's for automotive, medical, packaging, or electronics applications, ultrasonic welding equipment offers a wide range of benefits. As a company with 9 years of experience in the industry, we understand the importance of choosing the right equipment and are dedicated to helping businesses find the best solutions for their ultrasonic welding needs. With the right equipment, companies can enhance their production efficiency, reduce costs, and ultimately achieve greater success in their respective industries. We hope this buyer's guide has provided valuable insights and guidance for those considering investing in ultrasonic welding equipment.