A coordinate measuring machine (CMM) is a device that measures the geometry of physical objects by sensing discrete points on the surface of the object with a probe. Various types of probes are used in CMMs, including mechanical, optical, laser, and white light. Depending on the machine, the probe position may be manually controlled by an operator or it may be computer controlled. CMMs typically specify a probe's position in terms of its displacement from a reference position in a three-dimensional Cartesian coordinate system (i.e., with XYZ axes). In addition to moving the probe along the X, Y, and Z axes, many machines also allow the probe angle to be controlled to allow measurement of surfaces that would otherwise be unreachable.
Derby (About this soundlisten) DAR-bee) is a city and unitary authority area in Derbyshire, England. It lies on the banks of the River Derwent in the south of Derbyshire, of which it was traditionally the county town. Derby gained city status in 1977, and by the 2011 census its population was 248,700.
Derby was settled by Romans – who established the town of Derventio – Saxons and Vikings, who made Derby one of the Five Boroughs of the Danelaw. Initially a market town, Derby grew rapidly in the industrial era. Home to Lombe's Mill, an early British factory, Derby has a claim to be one of the birthplaces of the Industrial Revolution. It contains the southern part of the Derwent Valley Mills World Heritage Site. With the arrival of the railways in the 19th century, Derby became a centre of the British rail industry.
Derby is a centre for advanced transport manufacturing, being home to the world's second largest aero-engine manufacturer: Rolls-Royce. Bombardier Transportation are based at the Derby Litchurch Lane Works and were for many years the UK's only train manufacturers. Toyota Manufacturing UK's automobile headquarters is southwest of the city at Burnaston. To the east lies Nottingham, separated by the M1 motorway.