Replacing Manual Engine Lathes with Electronic or Teach type LathesAbout 15 years ago a new class of engine lathe was introduced, the Teach or Teach In lathe, also called an electronic lathe. These lathes combine many of the best attributes of a manual lathe, like hand wheels (actually manual pulse generators) and simple flat bed design, with those of a full-blown CNC lathe programmable speeds and feeds and numerous canned cycles. They are cost-effective when used for turning a single part, or for short production runs and any quantity in between. The cost of these lathes is considerably lower than a similar capacity CNC production lathe, plus they have the added benefit of practically eliminating the need for a trained programmer.
|
|
Because these lathes use electronic hand wheels and simple graphics conversational screens for data input with a true teach-in feature to create part programs, the operator is able to start using the machine with very little training. Early in the lathe operators learning of the new teach lathe, most work is done with the control in either the manual or the teach-in mode. These two modes make the transition from manual machining to CNC machining very simple for the operator. If a quantity of the same part is required, the operator machines the first part using a combination of graphic conversational screen prompts and handwheel movements. After the first part is completed, the teach-in processor automatically converts all the movements to G-codes and a part program is automatically created. The operator just loads in blank parts and presses the "PLAYBACK" pushbutton to get exact duplicates of the part. This teach-in functionality memorizes the machine movements and all other auxiliary functions that are pressed as well, such as spindle speeds, coolant, constant surface speeds, and so on. No editing of the part program is required to make subsequent parts, its all automatic.
A variety of cycles, including longitudinal and face turning, radius and taper turning, profiles, single and multiple threads, tapered threads, cut off, grooving, drilling and tapping are available as well as constant surface speed. These cycles are called up on an as-needed basis. CNC know-how is not required a user guide and graphic workpiece simulation is used to lead the operator through the programming process in a user-friendly manner. The control poses questions or offers menus of options the operator selects from. Hand wheels for both the X and Z axes let the operator input movements without having to punch in numbers. These hand wheels are especially handy when just one part needs to be turned.
One of the real beauties of these teach lathes is that they can function as manual lathes all day long without any concern about programming. Just turn on the machine set the control in the manual position, then set the spindle speed and use the electronic hand wheels just like a manual lathes hand wheels. The computer screen then displays absolute and relative location and functions as a digital readout. Nothing could be simpler.
The makes and models we generally see in the used market are Bridgeport EZ Paths with Bridgeports own PC Based control, Clausing-Colchesters, Harrisons, Nardinis and Romis with Fanuc 20 and 21 controls, Southwest Industries with Prototrak controls and a whole bunch or Taiwanese makes and models with various controls, mostly Fagor or Fanuc. They come in sizes from 10" swing all the way up to 40" and larger swing, but most are in the tool room lathe sizes of 14" to 30" swing by 40" to 120" center distance. Usually, they are not run hard and are still in very good condition when we get them, because most are not used in heavy production situations.
Prices for a good used CNC Teach lathe run 50% or less than the cost of a new machine, and, considering how lightly they are used, represent a very good value for the cost-conscious buyer. Actually, a new manual engine lathe often costs more than a really good 7 or 8 year old CNC teach lathe of equal size and capacity. It make you wonder why someone would choose a completely manual lathe over one of these, unless you knew youd never need to make two of the same part. The versatility, ease of use and relative low cost of these machines always makes them popular items in our inventory, and when we get them, theyre rarely available for long.
Of course, long production runs are best left to full-blown CNC turning centers made for that purpose. CNC lathes have higher horsepower, higher spindle speeds, faster feed rates and quicker tool change times than a teach lathe and can produce a lot more parts faster and more economically than a teach lathe.
As time goes on we will see fewer and fewer strictly manual engine lathes and more and more of these CNC electronic or teach lathes. As the price of the electronic parts, mainly the controls, comes down over time and the cost of machined parts, like gears and spline shafts goes up over time, its actually becoming cheaper to make an electronic lathe than a manual lathe. The electronic lathe eliminates most of those machined parts that are so costly to make in favor of computers, servo motors and electronic parts. In fact, if you think about it, most of the major manufacturers have given up making manual machines and are only making CNC machines today, for this very reason. The only companies left making manual machines are in the Far East, Eastern Europe and South America places where labor costs are low and most of them are gradually converting over their production to CNC. Eventually, there will be few, if any, manual lathes made.
|
|
|
