CNC stands for Computer Numerical Control and has been available since the early 1970’s. Ahead of this, it was called NC, for Numerical Control. (In early 1970’s computers were unveiled in these controls, hence the name change.)
While individuals most parts of society have never heard about this term, CNC has touched virtually every type of manufacturing process in one method or another. If you’ll work in manufacturing, it’s likely that you’ll be handling CNC regularly.
While there are exceptions for this statement, CNC machines typically replace (or work in conjunction with) some existing manufacturing process/es. Take among the simplest manufacturing processes, drilling holes, as an example.
A drill press can naturally be used to machine holes. (It’s likely that almost everyone has seen some type of drill press, even when you don’t work in manufacturing.) An individual may place a drill in the drill chuck which is secured within the spindle of the drill press. They can then (manually) pick the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull on the quill lever to operate the drill in the workpiece being machined.
That you can easily see, there is lots of manual intervention required to utilize a drill press to drill holes. A person is required to do something virtually every step along the way! Even though this manual intervention can be appropriate for manufacturing companies if but only a few holes or workpieces should be machined, as quantities grow, so does the likelihood for fatigue as a result of tediousness from the operation. And do remember that we’ve used one of the china CNC machining operations (drilling) for our example. There are other complicated machining operations that might require a better level of skill (and increase the opportunity of mistakes contributing to scrap workpieces) of the individual running the traditional machine tool. (We commonly refer to the design of machine that CNC is replacing because the conventional machine.)
In contrast, the CNC equivalent for any drill press (possibly a CNC machining center or CNC drilling & tapping center) may be developed to perform this operation in an infinitely more automatic fashion. Anything that the drill press operator was doing manually will be carried out by the CNC machine, including: placing the drill in the spindle, activating the spindle, positioning the workpiece underneath the drill, machining the hole, and turning off the spindle.
There may be another article a part of this website referred to as Basics of CNC that explains how to program, setup, and operate CNC machines in greater detail. Additionally, this site offers several products targeted at assisting you figure out how to use CNC machines. Here we’re relating how CNC works in very general terms.
As you may curently have guessed, precisely what an operator would be required to do with conventional machine tools is programmable with CNC machines. After the machine is setup and running, a CNC machine is fairly easy to keep running. In fact CNC operators usually get quite bored during lengthy production runs because there is so little to accomplish. With a few CNC machines, the workpiece loading process is automated. (We don’t mean to over-simplify here. CNC operators are commonly needed to do other activities linked to the CNC operation like measuring workpieces and making changes in keep the CNC machine running good workpieces.)
All CNC machine types share this commonality: They all have two or more programmable directions of motion called axes. An axis of motion might be linear (along a straight line) or rotary (along a circular path). Among the first specifications that implies a CNC machine’s complexity is when many axes it offers. In most cases, the greater axes, the greater number of complex the machine.
The axes for any CNC machine will be required with regards to inducing the motions necessary for the manufacturing process. From the drilling example, these (3) axis would position the tool on the hole to get machined (by two axes) and machine the hole (using the third axis). Axes are named with letters. Common linear axis names are X, Y, and Z. Common rotary axis names are A, B, and C.
A CNC machine wouldn’t be very helpful if all it could only move the workpiece in two or more axes. Almost all CNC machines are programmable in a number of different ways. The particular CNC machine type offers quite a bit to do with its appropriate programmable accessories. Again, any required function will likely be programmable on cnc machining parts. Here are some examples for one machine type.
Think about giving any combination of step-by-step instructions. A CNC program is nothing more than another form of instruction set. It’s printed in sentence-like format as well as the control will execute it in sequential order, comprehensive.
An exclusive series of CNC words are employed to communicate precisely what the machine is supposed to do. CNC words start with letter addresses (like F for feedrate, S for spindle speed, and X, Y & Z for axis motion). When placed together within a logical method, a group of CNC words make up a command that resemble a sentence.
For virtually any given CNC machine type, there will only be about 40-50 words used regularly. So when you compare learning to write CNC programs to learning an overseas language having only 50 words, it shouldn’t seem overly tough to learn CNC programming.
The CNC control will interpret a CNC program and activate the combination of commands in sequential order. Mainly because it reads this system, the CNC control will activate the correct machine functions, cause axis motion, and then in general, refer to the instructions given from the program.
Along with interpreting the CNC program, the CNC control has a number of other purposes. All current model CNC controls allow programs being modified (edited) if mistakes are found. The CNC control allows special verification functions (like dry run) to ensure the correctness of the CNC program. The CNC control allows certain important operator inputs being specified separate from this program, like tool length values. Generally speaking, the CNC control allows all functions of the machine to become manipulated.
For easy applications (like drilling holes), the CNC program may be developed manually. That is certainly, a programmer will sit back to write down the program armed only with pencil, paper, and calculator. Again, for simple applications, this can be the top approach to develop CNC programs.
As applications have more complicated, especially when new programs are needed on a regular basis, writing programs manually becomes far more difficult. To simplify the programming process, a computer aided manufacturing (CAM) system can be used. A CAM method is a software program that operates on a pc (commonly a PC) that can help the CNC programmer with the programming process. Most of the time, a CAM system will take the tediousness and drudgery from programming.
In several companies the CAM system work using the computer aided design (CAD) drawing developed by the company’s design engineering department. This eliminates the requirement for redefining the workpiece configuration on the CAM system. The CNC programmer will just specify the machining operations to get performed along with the CAM system can provide the CNC program (just like the manual programmer will have written) automatically.
Once the program is developed (either manually or with a CAM system), it should be loaded to the CNC control. Though the setup person could type this software straight into the control, this is like using the CNC machine like a very expensive typewriter. If the CNC program is developed with the aid of a CAM system, then it is already by means of a text file . In the event the program is written manually, it might be typed into any computer employing a common word processor (though some companies utilize a special CNC text editor for this specific purpose). In either case, this system is in the form of a text file which can be transferred directly into the CNC machine. A distributive numerical control (DNC) technique is used for this purpose.
A DNC technique is nothing but your personal computer that is networked with more than one CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) needed to be useful for transferring programs. Newer controls convey more current communications capabilities and can be networked in conventional ways (Ethernet, etc.). No matter methods, the CNC program must of course be loaded to the CNC machine prior to it being run.
As mentioned, CNC has touched almost every facet of manufacturing. Many machining processes are already improved and enhanced with the use of CNC. Let’s look at a number of the specific fields and put the concentrate on the manufacturing processes enhanced by CNC machine usage.
Machining processes that have traditionally been done on conventional machine tools that happen to be possible (and perhaps improved) with CNC machining centers include all sorts of milling (face milling, contour milling, slot milling, etc.), drilling, tapping, reaming, boring, and counter boring.
In similar fashion, all kinds of turning operations like facing, boring, turning, grooving, knurling, and threading are completed on CNC turning centers.
There are all kinds of special “off-shoots” of the two machine types including CNC milling machines, CNC drill and tap centers, and CNC lathes.
Grinding operations of all sorts like outside diameter (OD) grinding and internal diameter (ID) grinding are also being done on CNC grinders. CNC has even opened a brand new technology when it comes to grinding. Contour grinding (grinding a contour within a similar fashion to turning), which had been previously infeasible on account of technology constraints is now possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly identifies operations which can be performed on relatively thin plates. Visualize a metal filing cabinet. All of the primary components are created from steel sheets. These sheets are sheared to size, holes are punched in appropriate places, and the sheets are bent (formed) on their final shapes. Again, operations commonly referred to as fabrication operations include shearing, flame or plasma cutting, punching, laser cutting, forming, and welding. Truly, CNC is heavily involved with nearly every part of fabrication.
CNC back gages are commonly combined with shearing machines to manipulate the duration of the plate being sheared. CNC lasers and CNC plasma cutters may also be accustomed to bring plates with their final shapes. CNC turret punch presses is capable of holding a variety of punch-and-die combinations and punch holes in every shapes and forms through plates. CNC press brakes are utilized to bend the plates to their final shapes.
Electrical discharge machining (EDM) is the method of removing metal with the use of electrical sparks which burn away the metal. CNC EDM will come in two forms, vertical EDM and Wire EDM. Vertical EDM requires the use of an electrode (commonly machined on a CNC machining center) which is from the model of the cavity to be machined in to the workpiece. Picture the contour of any plastic bottle that really must be machined in a mold. Wire EDM is commonly accustomed to make punch and die combinations for dies sets utilized in the fabrication industry. EDM is amongst the less popular CNC operations as it is so closely relevant to making tooling combined with other manufacturing processes.
Like the metal removal industry, cnc turning parts are heavily employed in woodworking shops. Operations include routing (similar to milling) and drilling. Many woodworking machining centers are chinbecnnc that may hold several tools and perform several operations about the workpiece being machined.
Various forms of lettering and engraving systems use CNC technology. Waterjet machining utilizes a high pressure water jet stream to cut through plates of material. CNC is even used in the manufacturing of countless electrical components. By way of example, there are CNC coil winders, and CNC terminal location and soldering machines.
There is quite a shortage of skilled individuals to utilize CNC machines. And also the shortage keeps growing. Everywhere I go I hear manufacturing people claiming they cannot find skilled people. Unfortunately, it has been specifically my experience that pay scales have not really reflected this shortage. Even so, you could make an excellent wage and develop a rewarding career dealing with CNC machines. Here are some of the job titles of people dealing with CNC machine tools.