CNC represents Computer Numerical Control and has been available since the earlier 1970’s. Before this, it absolutely was called NC, for Numerical Control. (During the early 1970’s computers were brought to these controls, hence the name change.)
While people in most avenues of life have never heard about this term, CNC has touched just about every type of manufacturing process in one method or another. If you’ll work in manufacturing, it’s likely that you’ll be dealing with CNC on a regular basis.
While there are actually exceptions to this particular statement, CNC machines typically replace (or work together with) some existing manufacturing process/es. Take one of many simplest manufacturing processes, drilling holes, for example.
A drill press can of course be utilized to machine holes. (It’s likely that just about everyone has seen some sort of drill press, even when you don’t work in manufacturing.) An individual can place a drill from the drill chuck which is secured in the spindle in the drill press. They can then (manually) find the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. They then manually pull about the quill lever to get the drill in to the workpiece being machined.
Since you can easily see, there is a lot of manual intervention required to employ a drill press to drill holes. One is necessary to make a move nearly every step in the process! Even though this manual intervention may be acceptable for manufacturing companies if but a small number of holes or workpieces needs to be machined, as quantities grow, so does the likelihood for fatigue because of the tediousness in the operation. And do be aware that we’ve used one of the china CNC machining operations (drilling) for our example. There are far more complicated machining operations that will call for a much higher ability (and increase the chance of mistakes leading to scrap workpieces) of the individual running the standard machine tool. (We commonly refer to the fashion of machine that CNC is replacing as being the conventional machine.)
By comparison, the CNC equivalent for a drill press (possibly a CNC machining center or CNC drilling & tapping center) may be developed to perform this operation in a far more automatic fashion. Everything that the drill press operator was doing manually will be carried out by the CNC machine, including: placing the drill inside the spindle, activating the spindle, positioning the workpiece beneath the drill, machining the hole, and turning from the spindle.
There may be another article a part of this site called The Basics of CNC that explains how to program, setup, and operate CNC machines in greater detail. Additionally, we provide you with a number of products targeted at assisting you learn to use CNC machines. Here we’re relating how CNC works in very general terms.
As you might have guessed, exactly what an operator would be required to use conventional machine tools is programmable with CNC machines. Once the machine is setup and running, a CNC machine is pretty simple to keep running. The truth is CNC operators have a tendency to get quite bored during lengthy production runs because there is so little to do. With a few CNC machines, even the workpiece loading process is automated. (We don’t mean to over-simplify here. CNC operators are normally needed to do other things associated with the CNC operation like measuring workpieces and making modifications to keep 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 could be linear (along a straight line) or rotary (along a circular path). One of the first specifications that implies a CNC machine’s complexity is just how many axes it provides. In most cases, the better axes, the greater complex the appliance.
The axes of any CNC machine will be required when it comes to inducing the motions essential for the manufacturing process. Inside the drilling example, these (3) axis would position the tool over the hole being machined (in 2 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 can be a, B, and C.
A CNC machine wouldn’t be beneficial if all it may only move the workpiece in a couple of axes. Almost all CNC machines are programmable in several different ways. The specific CNC machine type has a lot related to its appropriate programmable accessories. Again, any required function is going to be programmable on cnc machining parts. Here are a few examples for one machine type.
Consider giving any combination of step-by-step instructions. A CNC program is simply another kind of instruction set. It’s written in sentence-like format and the control will execute it in sequential order, in depth.
A particular series of CNC words are utilized to communicate precisely what the machine is intended 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 virtually any given CNC machine type, there are only about 40-50 words used frequently. So if you compare finding out how to write CNC programs to learning an overseas language having only 50 words, it shouldn’t seem overly difficult to learn CNC programming.
The CNC control will interpret a CNC program and activate the series of commands in sequential order. Mainly because it reads this system, the CNC control will activate the proper machine functions, cause axis motion, and in general, refer to the instructions given within the program.
In addition to 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 can be 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 to become specified separate from this software, like tool length values. On the whole, the CNC control allows all functions of the machine to be manipulated.
For simple applications (like drilling holes), the CNC program could be developed manually. Which is, a programmer will sit down to create this software armed only with pencil, paper, and calculator. Again, for easy applications, this could be the most beneficial method to develop CNC programs.
As applications find more complicated, especially when new programs are needed frequently, writing programs manually becomes a lot more difficult. To simplify the programming process, a personal computer aided manufacturing (CAM) system may be used. A CAM product is a software program that runs using a pc (commonly a PC) that helps the CNC programmer using the programming process. Generally speaking, a CAM system is going to take the tediousness and drudgery away from programming.
In many companies the CAM system will continue to work with all the computer aided design (CAD) drawing developed by the company’s design engineering department. This eliminates the requirement for redefining the workpiece configuration to the CAM system. The CNC programmer will surely specify the machining operations being performed as well as the CAM system will create the CNC program (just like the manual programmer would have written) automatically.
Once the program is developed (either manually or using a CAM system), it ought to be loaded in the CNC control. Even though the setup person could type the program directly into the control, this may be like making use of the CNC machine like a extremely expensive typewriter. In case the CNC program is developed by using a CAM system, then its already in the form of a text file . If the program is written manually, it can be typed into any computer employing a common word processor (though many businesses make use of a special CNC text editor for this purpose). In either case, this program is such as a text file which can be transferred straight into the CNC machine. A distributive numerical control (DNC) product is used for this function.
A DNC system is nothing but your personal computer that is networked with one or more CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) must be used for transferring programs. Newer controls convey more current communications capabilities and will be networked in additional conventional ways (Ethernet, etc.). No matter what methods, the CNC program must obviously be loaded to the CNC machine before it can be run.
As stated, CNC has touched nearly every element 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 place the concentrate on the manufacturing processes enhanced by CNC machine usage.
Machining processes that have traditionally been done on conventional machine tools which are possible (and in some cases 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 types of turning operations like facing, boring, turning, grooving, knurling, and threading are done on CNC turning centers.
You can find all sorts of special “off-shoots” of those 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 can also be being carried out on CNC grinders. CNC has even opened a fresh technology in relation to grinding. Contour grinding (grinding a contour inside a similar fashion to turning), which had been previously infeasible because of technology constraints is now possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly refers to operations that happen to be performed on relatively thin plates. Consider a metal filing cabinet. All of the primary components are made 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 identified as fabrication operations include shearing, flame or plasma cutting, punching, laser cutting, forming, and welding. Truly, CNC is heavily involved with nearly every component of fabrication.
CNC back gages are commonly combined with shearing machines to control the duration of the plate being sheared. CNC lasers and CNC plasma cutters will also be employed to bring plates with their final shapes. CNC turret punch presses can take a variety of punch-and-die combinations and punch holes in all styles and sizes through plates. CNC press brakes are utilized to bend the plates to their final shapes.
Electrical discharge machining (EDM) is the process of removing metal by using electrical sparks which burn away the metal. CNC EDM is available in two forms, vertical EDM and Wire EDM. Vertical EDM requires using an electrode (commonly machined on a CNC machining center) that may be of your shape of the cavity being machined in to the workpiece. Picture the design of a plastic bottle that must be machined in a mold. Wire EDM is typically utilized to make punch and die combinations for dies sets used in the fabrication industry. EDM is among the less popular CNC operations as it is so closely linked to making tooling used with other manufacturing processes.
As with the metal removal industry, cnc turning parts are heavily used in woodworking shops. Operations include routing (comparable to milling) and drilling. Many woodworking machining centers are chinbecnnc that may hold several tools and perform several operations around the workpiece being machined.
Great shape of lettering and engraving systems use CNC technology. Waterjet machining utilizes a high-pressure water jet stream to reduce through plates of material. CNC is even found in the manufacturing of numerous electrical components. By way of example, there are CNC coil winders, and CNC terminal location and soldering machines.
There is a reasonably shortage of skilled customers to utilize CNC machines. Along with 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 yet reflected this shortage. Having said that, you may make an effective wage and establish a rewarding career working together with CNC machines. Here are some of the job titles of people dealing with CNC machine tools.