CNC means Computer Numerical Control and has been around since the early 1970’s. Just before this, it was called NC, for Numerical Control. (During the early 1970’s computers were brought to these controls, hence the name change.)
While folks most walks of life have never heard about this term, CNC has touched almost every form of manufacturing process in one way or another. If you’ll be working in manufacturing, it’s likely that you’ll be dealing with CNC frequently.
While there are actually exceptions to the statement, CNC machines typically replace (or work jointly with) some existing manufacturing process/es. Take one of many simplest manufacturing processes, drilling holes, for example.
A drill press can of course be employed to machine holes. (It’s likely that almost everyone has seen some kind of drill press, even when you don’t work in manufacturing.) A person can place a drill within the drill chuck that is certainly secured within the spindle of your drill press. They may then (manually) pick the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Chances are they manually pull on the quill lever to drive the drill in the workpiece being machined.
Since you can easily see, there is a lot of manual intervention required to utilize a drill press to drill holes. A person is needed to make a move nearly every step as you go along! Although this manual intervention might be acceptable for manufacturing companies if but a small amount of holes or workpieces must be machined, as quantities grow, so does the likelihood for fatigue as a result of tediousness of your operation. And do remember that we’ve used among the china machining parts operations (drilling) for your example. There are many complicated machining operations that could call for a much higher capability (and increase the chance of mistakes contributing to scrap workpieces) of the person running the typical machine tool. (We commonly talk about the design of machine that CNC is replacing as being the conventional machine.)
In contrast, the CNC equivalent for the drill press (possibly a CNC machining center or CNC drilling & tapping center) can be developed to perform this operation in a much more automatic fashion. Precisely what the drill press operator was doing manually will now be carried out 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 away from the spindle.
There is certainly another article a part of this web site known as the Basics of CNC that explains the best way to program, setup, and operate CNC machines in greater detail. Additionally, we provide you with several products aimed at helping you learn how to use CNC machines. Here we’re relating how CNC works in very general terms.
As you might already have guessed, everything that 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 fairly straightforward to keep running. In fact CNC operators often get quite bored during lengthy production runs as there is so little to complete. With many CNC machines, even workpiece loading process is automated. (We don’t mean to over-simplify here. CNC operators are typically 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: They all have several programmable directions of motion called axes. An axis of motion may 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 just how many axes it offers. Generally, the greater axes, the better complex the appliance.
The axes of the CNC machine will be required just for resulting in the motions required for the manufacturing process. Within the drilling example, these (3) axis would position the tool over the hole to become machined (in just two axes) and machine the hole (together 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 beneficial if all it might only move the workpiece in two or more axes. Nearly all CNC machines are programmable in several other methods. The precise CNC machine type offers quite a bit to do with its appropriate programmable accessories. Again, any required function will probably be programmable on cnc machining parts. Below are a few examples first machine type.
Think about giving any number of step-by-step instructions. A CNC program is nothing more than another form of instruction set. It’s written in sentence-like format as well as the control will execute it in sequential order, step-by-step.
A special group of CNC words are used to communicate precisely what the machine is intended to do. CNC words start out 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 team of CNC words comprise a command that resemble a sentence.
For just about any given CNC machine type, there will only be about 40-50 words used frequently. So when you compare learning how 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 series of commands in sequential order. As it reads this program, the CNC control will activate the proper machine functions, cause axis motion, and also in general, follow the instructions given within the program.
Together with interpreting the CNC program, the CNC control has a number of other purposes. All current model CNC controls allow programs to become modified (edited) if mistakes are normally found. The CNC control allows special verification functions (like dry run) to verify the correctness of your CNC program. The CNC control allows certain important operator inputs being specified apart from this system, like tool length values. In general, the CNC control allows all functions in the machine being manipulated.
For easy applications (like drilling holes), the CNC program might be developed manually. That is, a programmer will take a moment to write down this program armed simply with pencil, paper, and calculator. Again, for easy applications, this may be the very best way to develop CNC programs.
As applications get more complicated, and particularly when new programs are needed frequently, writing programs manually becomes far more difficult. To simplify the programming process, a pc aided manufacturing (CAM) system can be utilized. A CAM system is an application program that runs on a pc (commonly a PC) that helps the CNC programmer with all the programming process. Most of the time, a CAM system can take the tediousness and drudgery from programming.
In many companies the CAM system will work together with the computer aided design (CAD) drawing produced by the company’s design engineering department. This eliminates the requirement for redefining the workpiece configuration for the CAM system. The CNC programmer will simply specify the machining operations to become performed as well as the CAM system can create the CNC program (much like the manual programmer would have written) automatically.
After 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 software directly into the control, this could be like using the CNC machine as a very costly typewriter. In case the CNC program is developed with the help of a CAM system, then its already in the form of a text file . In case the program is written manually, it can be typed into any computer using a common word processor (though most companies use a special CNC text editor for this purpose). In any case, this software is as a text file which can be transferred straight into the CNC machine. A distributive numerical control (DNC) technique is used for this reason.
A DNC method is nothing more than a computer that is networked with a number of 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 may be networked in additional conventional ways (Ethernet, etc.). Regardless of methods, the CNC program must obviously be loaded to the CNC machine prior to it being run.
As stated, CNC has touched just about every element of manufacturing. Many machining processes have already been improved and enhanced with the use of CNC. Let’s take a look at a few of the specific fields and set the increased exposure of the manufacturing processes enhanced by CNC machine usage.
Machining processes who have traditionally been done on conventional machine tools which can be 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, all kinds of turning operations like facing, boring, turning, grooving, knurling, and threading are carried out on CNC turning centers.
There are a myriad 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 kinds like outside diameter (OD) grinding and internal diameter (ID) grinding are also being done on CNC grinders. CNC has even opened a whole new technology when it comes to grinding. Contour grinding (grinding a contour inside a similar fashion to turning), that has been previously infeasible as a result of technology constraints has become possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly refers to operations that are performed on relatively thin plates. Think of a metal filing cabinet. Each of 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) 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 in nearly every facet of fabrication.
CNC back gages are normally used in combination with shearing machines to regulate the length of the plate being sheared. CNC lasers and CNC plasma cutters are also employed to bring plates on their final shapes. CNC turret punch presses can take many different punch-and-die combinations and punch holes in all of the styles and sizes through plates. CNC press brakes are widely used to bend the plates inside 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 using an electrode (commonly machined on a CNC machining center) that is certainly from the form of the cavity to get machined to the workpiece. Picture the contour of the plastic bottle that must be machined in a mold. Wire EDM is typically utilized to make punch and die combinations for dies sets utilized in the fabrication industry. EDM is amongst the lesser known CNC operations because it is so closely linked to making tooling combined with other manufacturing processes.
As with the metal removal industry, cnc milling parts are heavily utilized in woodworking shops. Operations include routing (similar to milling) and drilling. Many woodworking machining centers are chinbecnnc that could hold several tools and perform several operations on the workpiece being machined.
Great shape of lettering and engraving systems use CNC technology. Waterjet machining utilizes a high-pressure water jet stream to slice through plates of material. CNC is even found in the manufacturing of many electrical components. By way of example, you will find 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 that they can cannot find skilled people. Unfortunately, it has also been my experience that pay scales have not really reflected this shortage. However, you may make an effective wage and develop a rewarding career utilizing CNC machines. Here are some of the job titles of people working together with CNC machine tools.