Quality assurance

Maximum quality for maximum success

Quality assurance

The top quality of our medical engineering products, precision springs, micro-turned parts, stamped-bent parts and plastic composite parts is the basis for the highest levels of customer satisfaction and our success. That’s what we work for, and that’s what we focus on in our organizational structures, our quality management system and our processes.

Create quality

  • We want more than satisfied customers – we want to inspire our customers
  • For us, quality is more than the product, quality is everything we do
  • Quality is the responsibility of all employees
  • Managers are role models for their employees
  • We plan quality from development of the product until the end of series production
  • You can find our quality certificates here

Customer orientation

  • Competent and friendly cooperation
  • Optimum customer service and short reaction times
  • Fast control loops for quality and costs (shopfloor management)
  • Zero-defect strategy for production and services (poka yoke)
  • Dependable schedules and commitments

Errors don’t have a chance

  • Corrective and preventive quality assurance (CAPA)
  • Stable and reliable processes (TPM / validation)
  • Hands-on culture of improvement
  • Training of the skills of all employees towards quality-oriented action
  • We analyze the risk (FMEA / risk management) and implement measures to avoid errors along the value chain (CAPA) in
  • order to ensure the highest levels of quality and product safety

  • Preventive maintenance (TPM)
  • Hands-on supplier management

Competitiveness and market leadership

  • Open-mindedness with regard to new processes and methods
  • Continuous research and development to maintain marketability
  • Development partnerships with customers, suppliers and research institutes
  • Uniform quality standards and systems in all companies within the KERN-LIEBERS group
  • In-company training of skilled personnel and continuous training of all employees
  • Sustainable use of resources
Quality policy
Quality policy
Quality policy

In most cases, the requirements for compression springs in applications such as automotive brake systems, medical engineering or complex electrical switches make it necessary to measure the properties and quality of the wire springs, strip springs and plastic assemblies in an integrated 100% inspection. We have special machines available to do this, integrated into the work process. Separate testing machines are responsible for a wide range of inspection tasks:

  • Acquisition of the force-displacement curve for the wire springs and strip springs
  • High-precision length measurement and force measurement system
  • Integrated geometry measurement using a camera system

We attach great importance to

  • A fully automatic test sequence
  • Process reliability in selection
  • High testing performance
Specialized wire spring & strip spring testing
Specialized wire spring & strip spring testing

Inspection of surface, shape, hardness and cleanliness in accredited laboratories, both internal and external

  • Traditional and computer-aided contour and hardness inspection
  • Roughness measurements
  • Microscopic surface examination
  • Particle inspection (residual dirt)
  • Surface tension / fat-free (test ink method)
  • Biocompatibility

Your products often have to meet a complex requirement profile.

Example of technical springs: In addition to the minimum requirements with respect to life cycles, the spring behavior must also be tested under conditions similar to the application for which it is intended. To do this, we develop dedicated testing systems for all spring variants in consultation with our customers,

which are mostly 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.

At the request of our customers, we can also carry out a range of other tests.

Examples include:

Testing for

  • Tightness
  • Force and tensile strength
  • Short circuit
  • Resistance
  • Residual moisture
  • Correct shape and position
  • Bonding area test using a camera system

In high-volume production, we guarantee the high quality of all products through continuous sampling.

Test and fatigue test facilities

In modern precision-engineered systems, fo example in medical engineering, measurement and control technology and watches, the avoidance of dirt and particles is extremely important. In these systems, the smallest movements can 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 actual and 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.

The test results are documented and assessed in accordance with VDA Volume 19 and other standards.

Another important element in our risk management system is the FMEA methodology, which plays an essential role at CARL HAAS. Early and systematic feasibility analyses are carried out during the tendering stage, on the basis of which potential sources of error can be identified and prevented. By linking the product and process FMEA, we can exclude virtually all potential problems with functions in high-volume production.

Creation is in accordance with the five-step method: structural analysis, functional analysis, failure analysis, risk assessment, optimization.

In the medical engineering sector, risk management is in accordance with DIN EN ISO 14971.

In addition, we also involve our customers and our tool and equipment suppliers in our risk management system at an early stage.

Our hardware and software specialists adapt the camera-based inspection systems to each particular application.

We use a range of different measurement processes for sampling, for inline process control or for 100 % final inspection.


  • Camera systems
  • Sensors
  • High-speed camera for process analysis

3D measurement processes, tests in goods receipt and issue

  • Optical, tactile and laser-based 2D and 3D measurement processes
  • In-process inspections, for the most part integrated into production lines and manufacturing cells
  • Fully-automatic measuring cells integrated into production and operator self-testing on separate 3D measuring instruments
  • Adapted measurement solutions for specific applications
3D measurement processes
3D measurement processes
3D measurement processes

Customer-specific resistance measurements are carried out for example on

  • Filaments for glow plugs
  • Contact springs
  • Wire
  • Strip
  • Plastic composite assemblies

Many of our customers’ demanding applications require leak testing of the plastic composite parts. These are carried out by us in-house, predominantly according to customer specifications.

The testing equipment for measuring the leak tightness of plastic composite parts can be provided either by you the customer or by our engineers.

The challenge with spiral springs, such as springs for measuring instruments, is measuring their torque – something done by many of our customers either with different instruments or even not done at all.

To avoid measuring differences and enable the measurement and documentation of the quality of CARL HAAS spiral springs, we have developed a special torque tester. This was initially only for our own use, but can now also be purchased by our customers.

Torque measurement

Industry applications


Building services engineering

Consumer goods

Electrical engineering

Mechanical engineering and equipment manufacturing

Medical technology

Precision engineering