Glossary
This glossary defines the most important technical terms regarding the production of high-precision drive elements and describes how these technologies are applied within the Christ & Heiri Group.
A
Assembly
The process-reliable joining of individual parts into a functional, higher-level unit (gear stage). The Christ & Heiri Group offers not only pure parts manufacturing, but also assembles complete components (such as gear stages for medical dosing pumps or automotive seat adjustments) for its customers. State-of-the-art procedures are used for this.
B
Bevel Gears
Gears in the shape of a truncated cone, the axes of which mostly intersect at a 90-degree angle, are used for precise power and motion transmission around corners (bevel gears). Christ & Heiri manufactures these products with workpiece diameters from 0.2 mm to 80 mm, which are used, among other things, in high-speed dental drills and surgical instruments.
Burnishing
A non-cutting, forming fine-machining process for metallic surfaces, in which micro-roughness is plastically levelled by rolling tools. The result is an extremely smooth surface with increased surface layer strength. Christ & Heiri offers burnishing as a finishing process (see Technology).
C
Climate Neutrality
The state in which a company’s activities have no net impact on the climate (through avoidance, reduction and compensation of CO2 emissions). Christ & Heiri produces climate-neutrally at its sites in Switzerland (Selzach) and Germany (Löffingen).
H
Hobbing
A continuous, highly productive machining process for the production of gears (such as spur gears or worm gears). The tool (hob) and the workpiece rotate in a precisely coordinated relationship. At Christ & Heiri, we use this technology on the most modern CNC machines to produce our geared products (such as drive pinions and worm shafts) in the highest accuracy classes for segments such as the automotive industry, medical technology, watchmaking industry, aviation and robotics (see Technology).
I
IATF 16949
The world’s leading quality management standard for the automotive industry requires continuous improvement, defect prevention and the reduction of variation and waste in the supply chain. Since a large part of Christ & Heiri‘s volume flows into automotive segments, the plants in Germany, Mexico and Switzerland produce certified to this standard.
ISO 9001
The internationally best-known and most widely used standard for quality management systems (QMS). It forms the basis for continuous improvement processes. All locations of the Christ & Heiri Group are certified to ISO 9001 in order to guarantee absolute reliability in all processes and the manufacture of our products (gears, worm gears, turned parts, assemblies).
ISO 13485
An international standard that defines the requirements for a comprehensive quality management system for the design and manufacture of medical devices (focus on patient safety). For customers from the medical technology sector – one of our most demanding segments – the site in Selzach (Switzerland) is certified to produce biocompatible drive elements, for example for surgical hand instruments or dental drills.
ISO 14001
The globally accepted standard for environmental management systems, which supports companies in improving their environmental performance and systematically reducing emissions. The Christ & Heiri headquarters in Selzach is certified according to ISO 14001, which proves our claim to environmentally friendly technology and sustainable manufacturing processes for all geared parts. Grieshaber Feinmechanik expects certification according to ISO 14001 in the summer of 2026.
M
Micro-Gearing
The production of extremely small and high-precision gears, often at the limits of mechanical feasibility, requires special machines and measuring tools. At our Swiss group headquarters in Selzach (Canton of Solothurn), Christ & Heiri specialises in micro-gearing starting from an extremely fine module of 0.02. Such products are primarily required for mechanical watch movements, sensors and medical implants.
Module
The module (m) is the most important reference dimension in gear technology and defines the ratio of the pitch of a gear to the number Pi. Only gears with the same module can mesh with each other. In the manufacture of our products, Christ & Heiri covers a technological bandwidth from the extreme micro-module 0.02 up to a maximum module of 2.5 (in steel) respectively module 3.5 (in NF metals) using state-of-the-art technology.
N
NFM (Non-Ferrous Metals)
A collective term for all metals and alloys in which iron is not the main component (e.g. brass, bronze, aluminium, titanium). They offer specific advantages such as corrosion resistance, low weight or biocompatibility. Christ & Heiri machines NF metals using state-of-the-art technology into high-precision products (gearings up to module 3.5).
NVH (Noise, Vibration, Harshness)
A term from the automotive industry that describes the audible and tactile vibrations in a vehicle. Especially in noiseless modern cars, gear noises are immediately noticeable and disruptive. Through our technology, our worm gears and pinions (see products) meet strict NVH requirements of the automotive industry.
P
Pinion
In a gear pair, the smaller of the two gears is usually referred to as the pinion, while the larger one is called the wheel. It often drives the larger wheel or is driven by it. Christ & Heiri manufactures these custom-made products for maximum running smoothness with diameters from 0.2 mm to 100 mm for complex applications in our segments such as robotics, drone technology, medical technology and haute horlogerie (Swiss watchmaking industry).
S
Spur Gears
The most frequently used and best-known type of gear has a cylindrical shape where the teeth are arranged on the outside circumference (straight or helical). These are among the most frequently requested versions of our products. Christ & Heiri hobs and shapes straight and helical spur gears for a wide variety of segments such as aviation, robotics, the automotive industry, medical technology and sensor technology with tolerances in the single-digit micrometre range.
T
Thread Chasing
A high-precision machining process that is primarily used to produce the finest threads or special worm profiles by having a multi-cutting tool (chaser) travel along the contour multiple times. Christ & Heiri uses thread chasing to achieve extremely high profile accuracy and surface quality for certain products (such as micro-worms for medical technology) (see Technology).
Turned Parts
Rotationally symmetrical components manufactured by machining (turning) on CNC machines. In Swiss-type turning, the material is pushed through a guide bush: in short turning, the material is firmly clamped. In our group’s plants in Löffingen (Grieshaber) and Selzach, Christ & Heiri produces high-precision turned parts in runs of millions, which often serve as the basis for downstream technology processes (such as the gear cutting of motor shafts or medical instruments).
W
Worm Gear
A spirally toothed drive element that resembles a screw in form and function and, in combination with a worm wheel, forms a worm gear that enables extreme gear ratios in the smallest of spaces. Worm gears are one of the most important products of Christ & Heiri for the automotive industry. We manufacture single- and multi-start worm gears, for example, for seat adjustments, electric windows, tailgates or steering systems.
Worm Milling
A specific machining process for producing the spiral thread profile on a worm shaft. Christ & Heiri masters this technology to perfection in order to manufacture high-precision worm shafts for servomotors, wiper systems and comfort drives in a highly efficient manner (see Technology).