The machine capability is a key figure for the quality of the machine and describes the quality, related to the required specification of the machine. The machine capability study, MFU for short, is a short-term study as an instrument of quality assurance and evaluates the process variable “machine”. This can be used to detect probable machine-related process errors.
In the course of a machine capability study, it is examined how the machine behaves with regard to the realization of specified characteristics and quality requirements.
The indices are called cm (machine controllability) and cmk (machine capability).
The cm value reflects the ability to manufacture in a given tolerance zone, whereas the cmk value represents the position in the tolerance zone.
The ability of machines to manufacture products within required specifications is referred to as capability. A constant result is achieved when external influences or/and regularly occurring disturbing influences are identified and eliminated.
A machine capability test is usually carried out when a new machine is purchased, and also, if necessary, before it is put into operation at the customer’s premises. Machines that are already running are checked at specific intervals to ensure that the required quality is produced.
As a rule, a fixed sample of workpieces is produced under constant general conditions. The critical quantities are then measured. Influences such as man, material, measuring method, machine temperature and production method must not change or must change only slightly. The aim is to record and evaluate exclusively machine-related influences on the manufacturing process.