A complete service, from analysis to manufacturing.

Connection technologies

Innovative connection technologies – with a wide range of different processes, we offer the optimum connection solution for creating your highly complex assemblies.

Clinching is a cost-effective joining technology – a permanent connection of at least two elements with two-sided accessibility of the joint without auxiliary parts (rivet etc.).
The connection is form-locked and friction-locked, and an adhesive bond may occur under certain conditions.

Clinching is used as a semi-automatic and fully automatic joining technology for sheet metal parts with high fatigue strength. It also enables the connection of sheet metal to other malleable materials such as plastic.

KERN-LIEBERS uses radial point riveting mainly for the production of joint connections.

In this process, the rivet is fixed to one part of the joint, and the second part rotates around the rivet. In the axial direction, the stop is ensured by a collar on the rivet.

Given the relatively low forming forces at the rivet head, radial point riveting is suitable for the manufacture of very precise riveted joints with narrow shoulder widths. These small shoulder widths allow a large riveting cross section with good strength and small bearing diameters with low frictional torque. With the negligible deformation of the rivet on the bearing diameter, a virtually play-free design of the bearing point is perfectly possible.

Unlike compression riveting or wobble riveting, there is virtually no structural change or hardening at the rivet head. The rivet material is formed outwards from the center by the rosette-shaped, hypocycloid loop path of the rivet stamp, giving these riveted joints excellent static and dynamic load capacities.

Caulking is a very cost-effective and easy way to join two workpieces together.
The plastic deformation it produces is based on a form-locked and friction-locked connection.

Caulking is suitable for all materials that can be deformed plastically, such as plastics and metals. These properties mean that different materials can be joined together.

Depending on the application, KERN-LIEBERS can incorporate threaded pins, bushings and nuts into your products as part of the completion process for the assembly. Force is generally monitored during the introduction of these fasteners, which can be fully integrated into production equipment and tools or carried out at separate workstations.

Depending on the specific component requirements, the design and selection of components is either flush with the surface of the component, for the transmission of high torques, traction or ejection forces, or to save space and weight.

In conjunction with special testing systems, our automated processes guarantee 100% quality of the connection.

The benefit to you is a versatile, robust, constructive and universally applicable way to integrate fittings or fasteners cost-effectively into components.

At KERN-LIEBERS, processing with laser beams is a favored method. Laser welding has been used for many years as a joining process in high volume production with low heat input and high levels of precision. Depending on the product requirements and material properties, both pulsed and continuous wave lasers are used. Used in conjunction with specially developed inspection systems, these highly automated processes guarantee perfect component quality, even under extreme conditions.

For fuel inflammation, we manufacture filaments for glow plugs in a range of different designs to customer specifications. For filaments made of several components, the components are joined using laser welding.

Resistance welding can be used to join two electrically conductive materials together without the addition of any other material. In this process, large currents are passed by two electrodes for a short period to the components to be connected. The transfer resistance at the contact zone leads to heating, further increasing the resistance, which then leads to the melting of the contact zone and the welding of the components.

The power source used can be both direct current (DC) and alternating current (AC) or the discharge from a capacitor (CD).

Capacitor pulse welding in particular can achieve very large currents (500 kA) in very short exposure times. This results in very low heat input and distortion. In resistance welding with DC or AC current, the welding current is supplied by a transformer.

The small contact zone is produced by the electrodes during spot and seam welding.

In projection welding, the contact zone is on the component itself.
With this technology, KERN-LIEBERS is able to join parts made of different materials and with different thicknesses with virtually no distortion in highly productive automated facilities.

Ultrasonic welding is generally used to join at least two thermoplastic materials by means of internal friction in the joint zone.

The ultrasonic welding process is particularly useful when fast process times and a high level of process reliability are required, or if no other additives may be used. Ultrasonic welding is also characterized by the quality, strength and exact reproducibility of the welded joint.

Electrical oscillations from the generator are converted into high-frequency mechanical vibrations in what is known as the resonant unit, consisting of a converter, amplitude transformer and sonotrode.

In ultrasonic welding, these longitudinal vibrations cause molecular and boundary friction in the joint zone, producing the heat required for welding and plasticizing the material. After the ultrasound exposure, short cooling periods in which the joining pressure is maintained produce a homogeneous hardening of the joint zone. In addition, the the welding result is also affected by both the geometry of the sonotrode and the anvil, and by the design of the energy director in the joint zone itself.

In contrast to cold riveting, hot riveting forms the rivet head at high temperatures. The rivet is brought to red heat and then deformed.

On cooling, the rivet contracts, pressing the riveted parts together. This produces a frictionally engaged connection in which the rivet should not absorb any shear forces.

The heating of the rivet can be done in various ways. The rivet can be positioned while cold and then heated by a high current flow. At the same time, the water-cooled electrodes also take care of the deformation work.

Fully automatic assembly systems with in-line process control at
high cycle frequencies.

Examples of current assembly applications

  • Laser welding
  • Pressing
  • Ultrasonic welding
  • Riveting
  • Screwing
  • Bonding

Packaging systems to customer requirements such as

  • One-way packaging and returnables e.g. customer blister
  • Bulk goods in PE bags
  • Magazines

Industry applications


Electrical engineering

Building services engineering

Consumer goods

Mechanical engineering and equipment manufacturing

Medical technology