CNC stands for Computer Numerical Control and has been around since the early 1970’s. Before this, it was called NC, for Numerical Control. (In early 1970’s computers were exposed to these controls, hence the name change.)
While people most walks of life have never heard about this term, CNC has touched nearly every method of manufacturing process in one way or another. If you’ll work in manufacturing, it’s likely that you’ll be working with CNC consistently.
While you can find exceptions to the statement, CNC machines typically replace (or work along with) some existing manufacturing process/es. Take one of the simplest manufacturing processes, drilling holes, for example.
A drill press can obviously be employed to machine holes. (It’s likely that almost everyone has seen some sort of drill press, even when you don’t operate in manufacturing.) An individual may place a drill from the drill chuck which is secured in the spindle of your drill press. They are able to then (manually) choose the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Chances are they manually pull in the quill lever to get the drill in the workpiece being machined.
That you can easily see, there is a lot of manual intervention required to use a drill press to drill holes. One is needed to take action nearly every step on the way! While this manual intervention can be suitable for manufacturing companies if but a small amount of holes or workpieces must be machined, as quantities grow, so does the chance for fatigue due to tediousness of your operation. And do keep in mind that we’ve used one of many china machining parts operations (drilling) for the example. There are many complicated machining operations that could require a better ability (and increase the potential for mistakes leading to scrap workpieces) of the person running the traditional machine tool. (We commonly talk about the design of machine that CNC is replacing as the conventional machine.)
In comparison, the CNC equivalent for the drill press (possibly a CNC machining center or CNC drilling & tapping center) could be programmed to perform this operation in a much more automatic fashion. Precisely what the drill press operator was doing manually will be performed by the CNC machine, including: placing the drill in the spindle, activating the spindle, positioning the workpiece beneath the drill, machining the hole, and turning from the spindle.
There is certainly another article a part of this website referred to as Basics of CNC that explains how you can program, setup, and operate CNC machines in greater detail. Additionally, we provide a series of products directed at helping you to figure out how to use CNC machines. Here we’re relating how CNC works in very general terms.
As you may curently have guessed, exactly what an operator would be asked to use conventional machine tools is programmable with CNC machines. After the machine is setup and running, a CNC machine is very very easy to keep running. In fact CNC operators have a tendency to get quite bored during lengthy production runs as there is so little to complete. With some CNC machines, even the workpiece loading process is automated. (We don’t mean to in excess of-simplify here. CNC operators are typically expected to do other items associated with the CNC operation like measuring workpieces and making alterations in maintain the CNC machine running good workpieces.)
All CNC machine types share this commonality: Every one has a couple of programmable directions of motion called axes. An axis of motion can be linear (along a straight line) or rotary (along a circular path). Among the first specifications that implies a CNC machine’s complexity is how many axes it has. Generally speaking, the greater number of axes, the greater number of complex the machine.
The axes of the CNC machine are needed for the purpose of causing the motions needed for the manufacturing process. Within the drilling example, these (3) axis would position the tool across the hole to be machined (in just two axes) and machine the hole (with all the third axis). Axes are named with letters. Common linear axis names are X, Y, and Z. Common rotary axis names can be a, B, and C.
A CNC machine wouldn’t be very beneficial if all it could possibly only move the workpiece in a couple of axes. Nearly all CNC machines are programmable in numerous alternative methods. The precise CNC machine type offers quite a bit to do with its appropriate programmable accessories. Again, any required function will be programmable on cnc machining service. Here are several examples first machine type.
Think of giving any number of step-by-step instructions. A CNC program is nothing more than another type of instruction set. It’s printed in sentence-like format and the control will execute it in sequential order, step-by-step.
A unique combination of CNC words are widely used to communicate exactly what the machine is designed to do. CNC words get started with letter addresses (like F for feedrate, S for spindle speed, and X, Y & Z for axis motion). When placed together in the logical method, a team of CNC words comprise a command that look like a sentence.
For any given CNC machine type, there are only about 40-50 words used frequently. So if you compare understanding how to write CNC programs to learning an overseas language having only 50 words, it shouldn’t seem overly challenging to learn CNC programming.
The CNC control will interpret a CNC program and activate the series of commands in sequential order. As it reads this system, the CNC control will activate the appropriate machine functions, cause axis motion, as well as in general, refer to the instructions given in the program.
In addition to interpreting the CNC program, the CNC control has other purposes. All current model CNC controls allow programs to be modified (edited) if mistakes are found. The CNC control allows special verification functions (like dry run) to verify the correctness from the CNC program. The CNC control allows certain important operator inputs to get specified outside of this software, like tool length values. Generally, the CNC control allows all functions from the machine to become manipulated.
For simple applications (like drilling holes), the CNC program can be developed manually. That may be, a programmer will sit down to write down the program armed simply with pencil, paper, and calculator. Again, for easy applications, this might be the top way to develop CNC programs.
As applications find more complicated, and particularly when new programs are needed frequently, writing programs manually becomes far more difficult. To simplify the programming process, a personal computer aided manufacturing (CAM) system may be used. A CAM technique is a software program that runs on a computer (commonly a PC) that assists the CNC programmer with all the programming process. Most of the time, a CAM system will take the tediousness and drudgery from programming.
In many companies the CAM system works with all the computer aided design (CAD) drawing designed 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 being performed and also the CAM system can provide the CNC program (just like the manual programmer would have written) automatically.
As soon as the program is developed (either manually or with a CAM system), it should be loaded in the CNC control. Even though the setup person could type this system directly into the control, this could be like utilizing the CNC machine like a very expensive typewriter. In the event the CNC program is developed with the aid of a CAM system, then it is already in the form of a text file . In case the program is written manually, it may be typed into any computer utilizing a common word processor (though a lot of companies make use of a special CNC text editor for this function). Either way, the program is by means of a text file that could be transferred directly into the CNC machine. A distributive numerical control (DNC) system is used for this function.
A DNC method is merely your personal computer which is networked with more than one CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) had to be utilized for transferring programs. Newer controls acquire more current communications capabilities and might be networked in conventional ways (Ethernet, etc.). No matter what methods, the CNC program must of course be loaded in the CNC machine prior to it being run.
Mentioned previously, CNC has touched nearly every part of manufacturing. Many machining processes have been improved and enhanced through the use of CNC. Let’s take a look at a few 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 in many cases 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, a myriad of turning operations like facing, boring, turning, grooving, knurling, and threading are performed on CNC turning centers.
You can find all sorts 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 types like outside diameter (OD) grinding and internal diameter (ID) grinding can also be being done on CNC grinders. CNC has even opened a whole new technology in terms of grinding. Contour grinding (grinding a contour in a similar fashion to turning), that was previously infeasible because of technology constraints is already possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly identifies operations which are performed on relatively thin plates. Visualize a metal filing cabinet. All the primary components are created from steel sheets. These sheets are sheared to size, holes are punched in appropriate places, along with the sheets are bent (formed) for their final shapes. Again, operations commonly known as fabrication operations include shearing, flame or plasma cutting, punching, laser cutting, forming, and welding. Truly, CNC is heavily involved in just about every component of fabrication.
CNC back gages are typically used in combination with shearing machines to manage the size of the plate being sheared. CNC lasers and CNC plasma cutters are also used to bring plates for their final shapes. CNC turret punch presses is capable of holding many different punch-and-die combinations and punch holes in all styles and sizes through plates. CNC press brakes are widely used to bend the plates within their final shapes.
Electrical discharge machining (EDM) is the process of removing metal with the use of electrical sparks which burn away the metal. CNC EDM can be purchased in two forms, vertical EDM and Wire EDM. Vertical EDM requires the use of an electrode (commonly machined with a CNC machining center) which is of the form of the cavity being machined in the workpiece. Picture the contour of the plastic bottle that really must be machined right into a mold. Wire EDM is often accustomed to make punch and die combinations for dies sets used in the fabrication industry. EDM is amongst the less popular CNC operations as it is so closely associated with making tooling combined with other manufacturing processes.
As in the metal removal industry, cnc milling parts are heavily utilized in woodworking shops. Operations include routing (just like milling) and drilling. Many woodworking machining centers are chinbecnnc that can hold several tools and perform several operations on the workpiece being machined.
Great shape of lettering and engraving systems use CNC technology. Waterjet machining works with a high-pressure water jet stream to cut through plates of material. CNC is even found in the manufacturing of several electrical components. For example, there are actually CNC coil winders, and CNC terminal location and soldering machines.
There is quite a shortage of skilled individuals to utilize CNC machines. And the shortage is growing. Everywhere I go I hear manufacturing people claiming that they cannot find skilled people. Unfortunately, it has also been my experience that pay scales have not really reflected this shortage. Nevertheless, you possibly can make a great wage and develop a rewarding career utilizing CNC machines. Here are the job titles of people dealing with CNC machine tools.