The History Of Precision CNC Machining
Early Numerically Controlled (NC) machines were servomotor controlled tools that were able to machine precise shapes by following sets of instructions fed into them on magnetic or paper tape or punch cards. These instructions took the form of a series of points through which the controls would move, with the result that geometric forms could be machined far more precisely than if the machines were operated by hand.At first the geometric calculations to generate the points required to generate different shapes had to be worked out by hand by hand, which was a time-consuming process.However, the mid 1950s brought the advent of computer-generated punch tapes, and the era of computer numerical control had arrived.Computers were so much quicker and more efficient in performing the calculations required that in 1956 the US Air Force commissioned Douglas T. Ross’ proposal to develop a programming language, based on points and lines, for numerical machine control. This language was developed into the Automatically Programmed Tools (APT) programming language, which was used to program CNC machines until the 1970s. In 1957 MIT began developing a fully computerized numerical control system using the APT language.In 1959 they unveiled the fruit of their labours – a machined aluminium ashtray, the first product ever produced using computer-aided design and manufacturing.
The falling price and size of computing power in the 1960s meant that it became cost-effective to replace the dedicated servo systems controlling CNC machines with minicomputers.The development of microprocessors in the 1970s led to the widespread adoption of microprocessor control in CNC machines, and today almost all CNC machines are microprocessor-controlled. Modern media like USB drives, floppy disks and local area networks have replaced punch tapes to some extent in modern CNC systems.
Modern CNC precision engineering has diversified from the spindle and cutting tool processes for which it was originally developed, and today CNC can be used for any processes that can be carried on machine tool motion platforms. CNC industrial processes common today include lasing, welding, flame cutting, bending, spinning, pinning, gluing, fabric cutting, sewing, routing, and sawing.
Tags: Precision Machining, precision cnc machining, Engineering, Precision Engineering
