CNC is short for Computer Numerical Control and has been around since the early 1970’s. Prior to this, it absolutely was called NC, for Numerical Control. (In the early 1970’s computers were unveiled in these controls, hence the name change.)
While people most walks of life have never heard of this term, CNC has touched virtually every kind of manufacturing process in one method or another. If you’ll work in manufacturing, it’s likely that you’ll be coping with CNC consistently.
While there are actually exceptions to this particular statement, CNC machines typically replace (or work in conjunction with) some existing manufacturing process/es. Take one of several simplest manufacturing processes, drilling holes, as an example.
A drill press can of course be utilized to machine holes. (It’s likely that almost everyone has seen some kind of drill press, although you may don’t work in manufacturing.) An individual may place a drill within the drill chuck that is secured in the spindle of the drill press. They could then (manually) select the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull on the quill lever to get the drill in the workpiece being machined.
Since you can easily see, there is lots of manual intervention required to use a drill press to drill holes. An individual is required to do something virtually every step in the process! Even if this manual intervention could be acceptable for manufacturing companies if but a small number of holes or workpieces should be machined, as quantities grow, so does the chance for fatigue because of the tediousness of your operation. And do keep in mind that we’ve used one of several china machining service operations (drilling) for our own example. There are far more complicated machining operations that could require a much higher ability (and increase the potential for mistakes leading to scrap workpieces) of the individual running the traditional machine tool. (We commonly reference the style of machine that CNC is replacing because 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 far more automatic fashion. Anything that the drill press operator was doing manually will be carried out by the CNC machine, including: placing the drill within the spindle, activating the spindle, positioning the workpiece under the drill, machining the hole, and turning from the spindle.
There is certainly another article a part of this website referred to as the Basics of CNC that explains the best way to program, setup, and operate CNC machines in greater detail. Additionally, we offer some products targeted at helping you discover ways to use CNC machines. Here we’re relating how CNC works in very general terms.
As you may already have guessed, everything that an operator would be asked to use conventional machine tools is programmable with CNC machines. Once the machine is setup and running, a CNC machine is quite simple to keep running. Actually CNC operators often get quite bored during lengthy production runs since there is so little to do. With many CNC machines, including the workpiece loading process has been automated. (We don’t mean to over-simplify here. CNC operators are generally necessary to do other stuff associated with the CNC operation like measuring workpieces and making alterations in keep your CNC machine running good workpieces.)
All CNC machine types share this commonality: Every one has several programmable directions of motion called axes. An axis of motion can be linear (along a straight line) or rotary (along a circular path). One of the primary specifications that implies a CNC machine’s complexity is when many axes they have. Generally, the greater number of axes, the greater complex the device.
The axes associated with a CNC machine are essential for the purpose of resulting in the motions necessary for the manufacturing process. In the drilling example, these (3) axis would position the tool within the hole being machined (in 2 axes) and machine the hole (with 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 may only move the workpiece in two or more axes. Virtually all CNC machines are programmable in many other methods. The specific CNC machine type has a lot to do with its appropriate programmable accessories. Again, any required function is going to be programmable on cnc machining parts. Here are a few examples for starters machine type.
Consider giving any group of step-by-step instructions. A CNC program is simply another type of instruction set. It’s developed in sentence-like format as well as the control will execute it in sequential order, comprehensive.
A special series of CNC words are utilized to communicate what the machine is designed to do. CNC words begin with letter addresses (like F for feedrate, S for spindle speed, and X, Y & Z for axis motion). When placed together inside a logical method, a group of CNC words make up a command that look like a sentence.
For any given CNC machine type, there will only be about 40-50 words used frequently. When you compare learning to write CNC programs to learning a foreign 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 group of commands in sequential order. As it reads this program, the CNC control will activate the appropriate machine functions, cause axis motion, and then in general, refer to the instructions given inside the program.
Along with interpreting the CNC program, the CNC control has a few other purposes. All current model CNC controls allow programs to be modified (edited) if mistakes are located. The CNC control allows special verification functions (like dry run) to confirm the correctness from the CNC program. The CNC control allows certain important operator inputs to become specified apart from this system, like tool length values. On the whole, the CNC control allows all functions in the machine to become manipulated.
For easy applications (like drilling holes), the CNC program might be developed manually. Which is, a programmer will sit back to publish this system armed only with pencil, paper, and calculator. Again, for simple applications, this can be the top method to develop CNC programs.
As applications have more complicated, and especially when new programs are needed consistently, writing programs manually becomes a lot more difficult. To simplify the programming process, a 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 using the programming process. In most cases, a CAM system will take the tediousness and drudgery out from programming.
In many companies the CAM system work using the computer aided design (CAD) drawing designed by the company’s design engineering department. This eliminates the demand for redefining the workpiece configuration to the CAM system. The CNC programmer will simply specify the machining operations being performed along with the CAM system will provide the CNC program (just like the manual programmer will have written) automatically.
When the program is developed (either manually or having a CAM system), it should be loaded in the CNC control. Even though the setup person could type this software directly into the control, this may be like while using CNC machine as a expensive typewriter. In case the CNC program is developed with the help of a CAM system, then its already as a text file . When the program is written manually, it could be typed into any computer by using a common word processor (though most companies work with a special CNC text editor for this function). In any event, this program is as a text file that could be transferred directly into the CNC machine. A distributive numerical control (DNC) method is used for this function.
A DNC system is simply a personal computer which is networked with several CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) would have to be utilized for transferring programs. Newer controls have more current communications capabilities and will be networked in conventional ways (Ethernet, etc.). Regardless of methods, the CNC program must obviously be loaded into the CNC machine prior to it being run.
As mentioned, CNC has touched almost every part of manufacturing. Many machining processes have been improved and enhanced by using CNC. Let’s take a look at several of the specific fields and put the emphasis on the manufacturing processes enhanced by CNC machine usage.
Machining processes who have traditionally been done on conventional machine tools that are possible (and perhaps improved) with CNC machining centers include all kinds 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 completed 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 sorts like outside diameter (OD) grinding and internal diameter (ID) grinding may also be being done on CNC grinders. CNC has even opened a fresh technology in relation to grinding. Contour grinding (grinding a contour in the similar fashion to turning), that was previously infeasible as a result of technology constraints is already possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly means operations which can be performed on relatively thin plates. Visualize a metal filing cabinet. All the primary components are constructed with steel sheets. These sheets are sheared to size, holes are punched in appropriate places, and also the sheets are bent (formed) for 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 in nearly every part of fabrication.
CNC back gages are generally used in combination with shearing machines to control the size of the plate being sheared. CNC lasers and CNC plasma cutters are also used to bring plates on their final shapes. CNC turret punch presses can take a number of punch-and-die combinations and punch holes in all of the styles and sizes through plates. CNC press brakes are utilized to bend the plates into their final shapes.
Electrical discharge machining (EDM) is the process of removing metal by using electrical sparks which burn away the metal. CNC EDM comes in two forms, vertical EDM and Wire EDM. Vertical EDM requires the use of an electrode (commonly machined with a CNC machining center) that may be of your model of the cavity to get machined in the workpiece. Picture the shape of the plastic bottle that must definitely be machined in to a mold. Wire EDM is normally employed to make punch and die combinations for dies sets employed in the fabrication industry. EDM is probably the lesser known CNC operations as it is so closely linked to making tooling used in combination with other manufacturing processes.
Like the metal removal industry, cnc turning parts are heavily found in woodworking shops. Operations include routing (comparable to milling) and drilling. Many woodworking machining centers are chinbecnnc that will hold several tools and perform several operations on the workpiece being machined.
Various forms of lettering and engraving systems use CNC technology. Waterjet machining uses a high-pressure water jet stream to slice through plates of material. CNC is even utilized in the manufacturing of countless electrical components. By way of example, you will find CNC coil winders, and CNC terminal location and soldering machines.
There is a reasonably shortage of skilled men and women to utilize CNC machines. As well as the shortage is increasing. 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 even reflected this shortage. However, you could make a good wage and develop a rewarding career working with CNC machines. Here are one of the job titles of men and women working with CNC machine tools.