Engineering

The requirements for compression, tension and torsion springs in applications such as automotive fuel injection systems or complex electrical

switches sometimes makes it necessary to measure the properties of the springs with 100% inspection. We have special machines available to do this,

sometimes integrated into the work process. Separate spring setting and testing machines can take care of a wide range of testing procedures as

required:

• Acquisition of force-displacement characteristics
• High-precision length measurement and force measurement system
• Integrated geometry measurement using a camera system
• Fully automatic test sequence
• Reliable selection
• High testing performance

High-performance dynamic fatigue test systems are available for testing the service life of wire springs and the fatigue strength of spring

wires.

• High-speed test machines for testing service life
• Simultaneous testing of multiple springs
• Variable test frequency
• Different amplitudes (lift height)

Leakage is not acceptable, especially in fuel injection technology. Leak tests are therefore essential for critical components. The leak test

used by KERN-LIEBERS independently detects even the smallest leaks, assuring the quality and function of the injection components.

The demand for ever lower fuel consumption and the environmental requirements for ever lower exhaust emissions make it necessary to implement

100% inspection of critical components such as valve seats and microhole products with flow rates. The measuring equipment developed by KERN-LIEBERS

is so fast and reliable that the flow value for every component is precisely measured.

If required, the values for specific parts can be stored and marked with a data matrix code.

In completely automated systems, it is possible to integrate a 100% inspection of parts into the production process. This already takes place

in many applications at the KERN-LIEBERS group, as is the case for example in the manufacture of complex plastic composite parts.

Here, the finished parts are mechanically removed from the mold and transferred to a 100% test track, where every component is subjected to a

serial cycle of various tests, including for example:

• Electrical tests

  • Short circuit
  • High voltage
  • Continuity
  • Pin in place

• Visual tests (camera)

  • Done by the customer for further processing of critical areas
  • Interfaces
  • Other critical areas
  • Pin positions
  • Critical areas of visible parts

• Identification of OK components

• Automated packaging (stored in trays)

Machine parameters are monitored and logged during the manufacturing process, leading to the automatic discharge of reject parts in the event

of deviations.

Testing of the surface, shape, hardness and microstructure

• Traditional and computer-aided contour and hardness tests
• Testing of microstructure and texture
• High and very high resolutions and accuracies down to the nanometer range

In-process surface tests, including for example

• 3D surface test methods
• Interferometry
• Tactile measuring systems
• Thermography
• Ultrasound sensors
• Image processing

Strip often have to fulfill a complex requirement profile. In addition to the minimum requirements with respect to service life, some of which

are statutory, the spring behavior must also be tested to ensure that it complies with standards and the application for which it is intended. To do

this, we develop dedicated testing systems in consultation with our customers, which are often designed to determine the number of load cycles until

failure of the spring or to demonstrate that a guaranteed minimum number of cycles can be met. These practical tests are supported by the latest

statistical methods (e.g the Weibull method).

In serial testing, we ensure high levels of quality through continuous sampling
and control.

KERN-LIEBERS has a consistent approach to quality, from product development through to final inspection and shipping. Modern methods of quality

planning, such as FEM, APQP, FMEA and so on, are used extensively to support the planning process. Test planning is integrated into the planning

process during the product development phase. The in-process tests for products are derived from the control plan. Our machine and test equipment

engineers can meet complex testing requirements. At the end of the manufacturing process, our high quality levels are documented in the final

inspection to ensure their traceability.

We design our production workplaces in accordance with ergonomic principles, and ensure that the most important product features are tested

during the production process.

Our first-class supplier ratings testify to the success of our quality assurance strategy.

• Certificates

KERN-LIEBERS has a consistent approach to quality, from product development through to testing during production and shipping. Modern methods

of quality planning, such as FEM, APQP, FMEA and so on, are used extensively to support the planning process. Test planning is integrated into

product development. The in-process tests for products are derived from the control plan. Our machine and test equipment engineers can meet the

specific testing requirements for every workpiece, including poka-yoke solutions where appropriate. The quality data is archived in the CAQ system

and available for tracing when required.

We design our production workplaces in accordance with ergonomic principles, and ensure that the most important product features are tested

during the production process.

To monitor the processes, we use the relevant test methods specified in AIAG CQI-9 for heat treatment and VDA 19 and ISO DIS 16232 for

technical cleanliness.

Our first-class supplier ratings testify to the success of our quality assurance strategy.

• Certificates

In modern precision mechanical systems, the avoidance of dirt and particles is of great importance. In these systems, the smallest movements could

potentially be blocked, lead to failure of the system. Given that these systems are closed and designed for lifetime use, subsequent cleaning is no

longer possible.
The residual dirt analysis serves two purposes: to detect and eliminate potential causes of dirt, and to provide evidence to

the customer that the shipped components are clean.

There are a wide range of testing requirements, both national and international. We adapt to customer-specific test variants. We can carry out

some tests in our own laboratory. Where this is not possible, we work with external specialists.

The test results are documented and assessed in accordance with specified criteria such as VDA Volume 19.

At KERN-LIEBERS, FMEA plays an important role. A early and systematic feasibility analysis is carried out during the tendering phase. The use

of FMEA is designed to identify and avoid potential sources of error at an early stage. By linking the product and process FMEA, we can exclude

virtually all potential problems with functions in subsequent high volume production.

Fast-response quality control loops in production, technical planning and quality management at all locations allow us to successfully

implement a global zero-defect strategy.

Our in-house special purpose machine engineering department specializes in the development of product-specific visual-tactile testing machines.

Our hardware and software specialists adapt geometry and surface control by high-resolution vision systems with specific lighting systems to each

particular application.

Our in-line process monitoring or 100% final inspection has a cycle time-neutral repeat measurement accuracy of a few microns, and surface

defects can also be detected.

We use laser-based measurement processes for sampling, for in-line process control or for 100% final inspection.

Examples:

• Laser interferometry
• Laser triangulation
• Light-section processes

3D measurement processes, tests in goods receipt and issue, production line

• Visual, tactile and laser-based 2D and 3D measurement processes,
  measuring range up to 800 mm
• Tests in air-conditioned measuring rooms or in special measuring cells
• In-process tests integrated into the production line (operator, automatic testing), some fully automatic measuring cells integrated into production
• Adapted measurement solutions for specific applications