Important Terms
from our Industry


Assembly technology

Assembly technology refers to the technical devices that are needed in order to join together various parts. These devices can be operated manually or be fully automated, and are incorporated into the production process.


Automation refers to technical systems or resources that perform intended activities through independent actions, with or without partial human involvement, and thereby make production processes more effective. Its goal is full automation for autonomous production with no involvement of human workers.


Back pressure testing

Procedures in flow testing/Flowtest, where the air flows through a bore hole, opening or a channel at a predetermined pressure. The back pressure resulting from the inflow into the area is measured and compared with reference values. In this way, it is possible to determine whether the necessary continuity is provided.


Clamping force

The force that is needed in order to bind the sealing element to the component in a way that is reliable for the process. Since the clamping force acts directly on the component, care must be taken that no plastic deformation of the component is caused.

Cycle time

This describes the mean time in which a quantity unit is completed in the production process. Cycle time determines to a large extent the required degree of automation and therefore the costs of an entire system as well.

Component quality

Component quality represents the quality of a component produced in relation to a particular characteristic. For example, the usability of the tested component may be determined by its degree of impermeability.

Control unit

A system composed of a programmable logic controller (PLC) and a human machine interface (HMI) for control of the machine components.


Electrical cabinet

The heart of every machine - the main components for electronic control are housed in this element. Paul Köster GmbH primarily installs electrical cabinets made by RITTAL.



The leak test fixture is the part of the leak testing machine that is individually customized to the component. With the modular construction of the machine, multiple fixtures can be used in alternating operation in a single base machine.


Testing procedures with air, in which openings, bore holes and channels are tested for continuity. In the direct procedure, flow volume is measured and compared to reference values; in the indirect procedure, the back pressure at the entry into the area to be tested is evaluated.


Helium accumulation test

This measurement procedure using gas in leak testing presents a more precise alternative to measurement procedures with air. It detects the increase in helium concentration in the test space environment and through this determines the overall leakage rate.

Hydraulic power unit

A central unit for supplying hydraulic pressure, consisting of a storage tank, pumping unit, filter, valve mechanism, sensor system, and necessary control components.


Leak localization

Procedure in leak testing that is used not only to establish the leakage of a component, but also to locate the position of a leak at the same time. Here, the test object is filled with air and positioned in a transparent water tank. Bubbles occur at the leaking positions.

Leak sniffer

An aid for the detection of leaks in the form of helium concentrations in gas testing procedures.

Leakage rate

A key figure for the permissible degree of leakage for a component. A differentiation is made between air and fluid leakage rates here. A leakage rate of 0 is impossible in principle, since no component is sealed up to 100%.

Leak testing

Procedures by which the components and assemblies are tested for impermeability. In this case, common testing procedures can be broken down into two categories: Testing procedures using air and testing procedures using gas.

Linear servo axes

In the area of automation, linear servo axes make it possible to move components using various drive systems on a linear guide.


Mass flow procedures

Testing procedures using air for leak testing, where the air escaping into the test cavity is measured. If air escapes during the measurement, there is a leak.



Original Equipment Manufacturers, called Erstausrüster in German, are suppliers in the engineering and automotive industries that do not sell their products directly to end customers.


Pressure difference procedures

Testing procedures with air, where it is not the escaping air that is measured, but the effects on the prevailing pressure in the test cavity. If the pressure drops during the measurement, there is a leak.

Pressure difference transmitter

A sensor within a measurement mechanism that converts the pressure difference between two areas into an electronic signal.

Prototype testing

Components that are prepared for trials prior to mass production must frequently be leak-tested prior to finalization. Since it is not financially worthwhile to construct an individual testing machine matched to the prototype, in rare cases prototype testing is offered on site at the premises of the mechanical manufacturer.



Redundancy refers to the protection of system availability in the event of the stoppage of an individual machine. This provides the opportunity to perform maintenance on individual stations without fully interrupting production.

Rotary adhesive wetting

An automatic system for the wetting of bore holes with sealant. Systems from the manufacturer LOCTITE are frequently used at Paul Köster GmbH.


Sealant application

Automated sealant application is necessary for assembly technology, in order to caulk and seal engine and housing parts. This is frequently left to robots for maximum flexibility. In these cases, for example, systems from the manufacturer Dreibond are used.

Sealing concept

This is a detailed description of the individual sealing points on the component being tested and defines the sealing elements used. These are based on predetermined testing parameters and other influencing factors, such as the clamping forces that occur. The sealing concept represents the basis for the detailed construction of the clamping and sealing device.

special mechanical engineering

Custom machines are those that are tailor-made to the customer’s requirements. In general, these machines are uniquely produced, and differ from standard machines through a high degree of innovation and complexity.


Test Cavity

The test cavity is a closed area in a component that must be separately tested. A component may have multiple test cavities, which are usually defined by subsequent function.

Turnkey solutions

A turnkey solution describes complex offerings from a manufacturer that the customer buys and can immediately put to use without having to make additional expenditures. In this way, responsibility lies with the supplier, and the customer does not need to coordinate interfaces.


Vacuum testing

Testing procedure using air for leak testing, where a vacuum is generated in the test cavity. If the pressure increases during the measurement, there is a leak.