The most important rotation
When you have access to the manufacturing procedure of your company’s products you are among the lucky people that can enter the premises where dark green and grey machines stand, heavy and repetitive thuds fill the space, the metal work stands its ground.
You walk along to greet the powerful CNC units which focus on operating according to some numerical orders resulting to the transformation of brass rods to numerous, identical components. Right behind, at the corner of this room, the floor is occupied by the ancestor of this young machine, a turret lathe, the one that assists the hand to create all the samples for the new products.
A lathe is a machine that rotates the workpiece about an axis and with the use of various machine tools performs actions as cutting, sanding, knurling, drilling, facing and other. Lathes are widely used in woodturing, machining of metal parts, metal spinning and exceptionally in glass- turning and the shapping of pottery. The methodology of this tool comes from ancient times since rotary lathes are known to be used in ancient Egypt, Assyria and Greece. The earliest illustrations of the first machines show that the operation required two persons working together with the one turning the work piece and the other using a sharp tool to make different shapes on the surface. During the Roman times a turning bow was added and it was not until the Middle Ages when a pedal replaced the hand-operated turning of the workpiece.
From the Industrial Revolution and onwards the lathe was finally recognised as the ‘mother of machine tools’ because it has lead to the invention of many other machine tools since. Given that from classical times man has harnessed wind and water to operate heavy machinery, to relieve him of hard physical labour and to speed up production the next step of evolution comes along with the power being generated by water wheels or steam engines. In the beginning of the 20th century electric motors were applied to each lathe steadilly resulting to automated machines.
The Computer Numerical Controlled lathes (CNC) are rapidly replacing the older production machines due to their advantage over settings, accuracy and operation. The final workpiece shall be designed, the tool paths programmed with CAD/CAM process or manually by the programmer, the information will be uploaded to the machine and once tested the machine will repeatidly produce parts under the occasional supervision of an operator. The facts say that the earliest numerical control was developed after the second World War for the accurate production of aircraft parts. It is John Parsons the one to aknowledge for the methodology. By using an IBM multiplier to calculate airfoil coordinates, and inputting this data to a Swiss jig boring machine, it was possible to produce templates from data on punched cards. Parsons’ work lead to numerous Air Force research projects at the Massachusetts Institute of Technology (MIT) starting in 1949. Though the early CNC systems were rudimentary by today’s standards, they do share much in common with modern CNC equipment. All automated motion control machines require a command function, a drive/motion system, and a feedback system.
Our knowledge allows us to describe the metal working lathes, the ones responsible for long production runs of identical components. The automatic screw machines, invented by Joseph R. Brown ( Brown and Sharpe), operate upon the basic idea of a turret lathe, modified in order to make the same movements repeatidly and produce quantities of a specific part. For the large majority of us today all that is required to run a lathe is to push a button and the magic of electricity does the rest. Even though manually controlled and CNC lathes coexist in the manufacturing industries there is a big difference in the type of knowledge that is required for the operation of the two systems.
The methods we follow tend to establish the use of our fingertips rather than our whole body, leaving us defenseless when it comes to setting up a machine that counts centuries of evolution. Few people are confident nowadays to profile or sharpen the cutters and knives.