As a follow on to the last post, I have been investigating the cost of manufacturing equipment. The classic machine tool is the most widely used piece of equipment for fabricating just about anything made out of metal. The machine tool has been quietly undergoing it’s own revolution since it’s inception in the 1950’s.
The traditional metal cutting machine tool has been around since the 1800’s and was entirely manually operated. Since the machines were manually operated, the dexterity of the operator became a major factor in accuracy and repeatability of part manufacturing. Because of the skill required, we still have the term “master machinist” in circulation, even though most machining today is automated.
During the Second World War, the Air Force was confronting the difficulty of manufacturing airplane parts. Through the work of John Parsons and MIT, the first “punch card” controlled machine tool was built. Parsons’ company was using early punch card computers to generate a larger number of points along the curve of a wing brace. The numerical information was then used directly by machinists as a look up table for manually positioning a milling tool. Parsons realized that if they could motorized the manual process, it could greatly increase the speed of the machining process, lowering costs dramatically and increasing accuracy at the same time.
Gordon Brown’s Servomechanisms group at MIT has recently been working on early forms of closed loop dc motor control for the gun turret on B-29 bombers. By combining these recent technologies to numerical punch card calculation approach the first Computer Numerical Controlled Machine Tool was demonstrated.
The rest, as they say, is history. The lessons learned in computer numerical control have been instrumental in every major field of manufacturing. Cars, electronics, robotics, would not be feasible or cost effective without the underlying control technology of CNC.
Which brings me to a 2 major points as we contemplate the next generation of manufacturing.
Additive manufacturing is maturing rapidly with a wide range of materials, steels and titanium are now available, and precision is improving at the same time. The surface finish requirements for a large number of parts cannot be achieved with a strictly additive process. The new wave of additive manufacturing requires a complementary subtractive technology at complementary prices.
Secondly, while there are an increasing number of machine tools at low cost, they are not CNC. This will likely be the next “breakout” technology. There are a number of technical hurdles that have to be addressed in terms of reducing the cost to a level comparable with the Makerbot. With the current generation of dedicated motion controller chips, lower cost step motors and low cost feedback technology, this should be a slam dunk.
Get your pencils out and get after it! There’s some serious money to be made here.