Jobs
Deburr
There are many deburring processes, but the most common are mass-finishing, spindle finishing, media blasting, sanding, grinding, wire brushing, abrasive flow machining, electrochemical deburring, electropolishing, thermal energy method, machining, water jet deburring, and manual deburring.[5]
Manual
Manual deburring is the most common deburring process because it is the most flexible process. It also only requires low cost tools and allows for instant inspection.[6] Manual deburring is either done with tools like scrapers, files, sandpaper, stones and reamers or with handheld power tools that use abrasive points, sandpaper, or cutters similar to those used to deburr during machining.
Electrochemical
Electrochemical deburring is the use of electrochemical machining to deburr precision work pieces and edges that are hard-to-reach, such as intersecting holes. The process uses a salt or glycol solution and electricity to dissolve the burr. The electric current is applied with a specialized tool to reach the burr location. Burrs are removed in 5 to 10 seconds, while the rest of the work piece is unaffected.[6]
Thermal
Thermal energy method (TEM), also known as thermal deburring, is a deburring process used to remove hard-to-reach burrs or burrs from multiple surfaces at the same time. The process uses an explosive gas mixture to provide thermal energy to burn off the burrs. It is the fastest burr removal process, requiring only 20 milliseconds to remove a burr.[7]
The process starts by loading the workpiece into an explosion-proof chamber, which is then sealed and clamped with approximately 220 metric tons (240 short tons). The chamber is then evacuated of air and filled with an oxygen and fuel mix; this mixture is pressurized to 0.5 to 1.9 MPa (73 to 276 psi). An electrical igniter then ignites the mixture, which burns for approximately 20 milliseconds, causing all of the sharp corners and burrs to burn away. The peak temperature reaches 3,000 °C (5,430 °F).[7]
London is the capital and largest city of England and the United Kingdom. It stands on the River Thames in south-east England at the head of a 50-mile (80 km) estuary down to the North Sea, and has been a major settlement for two millennia.[9] The City of London, its ancient core and financial centre, was founded by the Romans as Londinium and retains boundaries close to its medieval ones.[note 1][10] Since the 19th century,[11] "London" has also referred to the metropolis around this core, historically split between the counties of Middlesex, Essex, Surrey, Kent, and Hertfordshire,[12] which largely comprises Greater London,[13] governed by the Greater London Authority.[note 2][14] The City of Westminster, to the west of the City of London, has for centuries held the national government and parliament.
London, as one of the world's global cities,[15] exerts strong influence on its arts, commerce, education, entertainment, fashion, finance, health care, media, tourism, and communications,[16] and therefore has sometimes been called the capital of the world.[17][18][19] Its GDP (€801.66 billion in 2017) makes it the biggest urban economy in Europe,[20] and it is one of the major financial centres in the world. In 2019 it had the second-highest number of ultra high-net-worth individuals in Europe after Paris[21] and the second-highest number of billionaires of any city in Europe after Moscow.[22] With Europe's largest concentration of higher education institutions,[23] it includes Imperial College London in natural and applied sciences, the London School of Economics in social sciences, and the comprehensive University College London.[24] The city is home to the most 5-star hotels of any city in the world.[25] In 2012, London became the first city to host three Summer Olympic Games.[26]
London's diverse cultures mean over 300 languages are spoken.[27] The mid-2018 population of Greater London of about 9 million[5] made it Europe's third-most populous city.[28] It accounts for 13.4 per cent of the UK population.[29] Greater London Built-up Area is the fourth-most populous in Europe, after Istanbul, Moscow and Paris, with 9,787,426 inhabitants at the 2011 census.[30][31] The London metropolitan area is the third-most populous in Europe after Istanbul's and Moscow's, with 14,040,163 inhabitants in 2016.[note 3][4][32]
London has four World Heritage Sites: the Tower of London; Kew Gardens; the combined Palace of Westminster, Westminster Abbey, and St Margaret's Church; and also the historic settlement in Greenwich, where the Royal Observatory, Greenwich defines the Prime Meridian (0° longitude) and Greenwich Mean Time.[33] Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge and Trafalgar Square. It has numerous museums, galleries, libraries and sporting venues, including the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres.[34] The London Underground is the oldest rapid transit system in the world.
