About Ultrasonic Welding
Ultrasonic Technology
If your business involves the sealing packaging, welding plastic moulded parts, punching out components or cutting textiles or food products, then ultrasound could be the perfect addition to your production process. Ultrasonic technology is fast, very energy-efficient and economical with materials, guaranteeing speed, precision and efficiency.
We will explain how ultrasonic technology works, how our machines are designed and what you can do with them – all in a way that’s easy to understand. We may just have the solution you need to optimise your production processes.
Which plastics can be welded with ultrasound and which materials can be combined ?
Ultrasound can be used to create reliable, sealed joins in moulded parts and to weld or seal films and technical textiles. The components to be joined should be made primarily of thermoplastics, which may be semi-crystalline or amorphous. Semi-crystalline thermoplastics include POM, CA, LCP, PEEK, PA, PBT, PE, PPS, PP and PTFE. Amorphous plastics include ABS, MABS, PMMA, PC, PET, PS and PVC. The best results are achieved when welding two components made from the same material, but you can also weld compatible pairings of different materials.
A list of compatible plastics can be found here.
Moulded parts must be designed for ultrasound compatibility – moulded part design
In order to weld two moulded parts together quickly and achieve a reproducible, high-strength result, one of the two components must be designed with integrated pointed elements.
These pointed elements, also known as energy directors or pinch seams, direct the ultrasonic oscillation into the second moulded part. This ensures that both moulded parts melt simultaneously along the seam to create a permanent join.
If there is no energy director or pinch seam, the surfaces will be welded together instead of a seam being formed. This type of welded join is not as strong; it also takes significantly longer to achieve and there is a risk of damage to the components.
Let’s take a closer look at the two most common join zone geometries:
Energy directors
Energy directors direct the energy into the material with a high degree of precision. They are usually triangular or have a V-shaped profile and they are primarily used with amorphous thermoplastics. When the ultrasound source is applied, the energy directors melt and excess material is forced out of the sides of the join. The design of the moulded part determines where the material flows out.
Pinch seam (Shear joint)
Due to their design, pinch seams are also known as stepped seams. This type of seam is ideal for seal welding and semi-crystalline plastics. This join zone geometry can also be used to create very attractive seams.
In addition to the two aforementioned join zone geometries, there are a number of other, less common forms of weld seam. Stud welding is one of the options.
Stud welding
If you need to permanently join two moulded parts but there is no need for the join to be sealed, stud welding is another option. This type of welding is suitable for hard amorphous and semi-crystalline plastics.
The design of the moulded parts has an enormous impact on the seal, strength and look of the welding result. This is why it is very important to consult with RINCO ULTRASONICS right from the start of your project. We will be happy to advise you.
Benefits of ultrasonic welding
Economical
Ultrasonic welding is a very economical technology. Compared to thermal welding, ultrasonic welding requires
- No warm-up time
- No cooling phase for the application
- Less material
Efficient
The welding cycle usually takes just a few tenths of a second. The weld seam also hardens in a fraction of a second.
And because the seams can be very narrow, you can also reduce material consumption.
Perfect weld seams
The weld seams can be designed to meet your exact requirements. Whether your goal is hermetically sealed seams or perfect visual results, your weld seams will always be strong and precise.
No additional materials
Ultrasonic welding is highly economical, as no additional materials are required to join the components. This also makes the materials easy to separate for recycling.
Welding without additional materials such as screws or adhesives also helps to make products safer – ideal if you manufacture children’s toys, for example.
Three-dimensional weld seams
The sonotrode – the actual welding tool – is designed and manufactured specifically to suit the customer’s requirements. As this design process is tailored to your needs, you can also opt for three-dimensional weld seams.
