CNC represents Computer Numerical Control and has been around since the earlier 1970’s. Ahead of this, it had been called NC, for Numerical Control. (In early 1970’s computers were brought to these controls, hence the name change.)
While people in most walks of life have never read about this term, CNC has touched almost 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 on a regular basis.
While there are actually exceptions to this statement, CNC machines typically replace (or work together with) some existing manufacturing process/es. Take one of several simplest manufacturing processes, drilling holes, by way of example.
A drill press can obviously be used to machine holes. (It’s likely that everyone has seen some type of drill press, although you may don’t work in manufacturing.) A person might place a drill inside the drill chuck that may be secured within the spindle from the drill press. They can then (manually) select the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull around the quill lever to drive the drill to the workpiece being machined.
That you can easily see, there is a lot of manual intervention required to utilize a drill press to drill holes. One is necessary to do something nearly every step as you go along! Although this manual intervention may be appropriate for manufacturing companies if but only a few holes or workpieces must be machined, as quantities grow, so does the likelihood for fatigue because of the tediousness from the operation. And do note that we’ve used one of several china CNC machining operations (drilling) for our example. There are many complicated machining operations that will demand a higher capability (and increase the potential for mistakes leading to scrap workpieces) of the person running the conventional machine tool. (We commonly talk about the style of machine that CNC is replacing as being the conventional machine.)
In comparison, the CNC equivalent for any drill press (possibly a CNC machining center or CNC drilling & tapping center) can be programmed to perform this operation in a far more automatic fashion. Exactly what the drill press operator was doing manually can be done by the CNC machine, including: placing the drill inside the spindle, activating the spindle, positioning the workpiece within the drill, machining the hole, and turning away from the spindle.
There is certainly another article incorporated into this web site called The Basics of CNC that explains how to program, setup, and operate CNC machines in greater detail. Additionally, we provide some products targeted at assisting you to discover ways to use CNC machines. Here we’re relating how CNC works in very general terms.
As you may curently have guessed, everything that 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 very straightforward to keep running. Actually CNC operators tend to get quite bored during lengthy production runs because there is so little to perform. With a few CNC machines, including the workpiece loading process continues to be automated. (We don’t mean to in excess of-simplify here. CNC operators are generally necessary to do other stuff related to the CNC operation like measuring workpieces and making changes 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 could 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. In most cases, the more axes, the better complex the equipment.
The axes of the CNC machine are essential just for causing the motions essential for the manufacturing process. From the drilling example, these (3) axis would position the tool across the hole to be machined (in two 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 can be a, B, and C.
A CNC machine wouldn’t be very useful if all it could possibly only move the workpiece in 2 or more axes. Almost all CNC machines are programmable in several other methods. The precise CNC machine type has a lot concerning its appropriate programmable accessories. Again, any required function will probably be programmable on cnc machining parts. Below are a few examples for one machine type.
Think of 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 combination 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 small grouping of CNC words form a command that look like a sentence.
For any given CNC machine type, there are only about 40-50 words used on a regular basis. When you compare finding out how to write CNC programs to learning a foreign 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 group of commands in sequential order. Mainly because it reads this program, the CNC control will activate the proper machine functions, cause axis motion, and then in general, follow the instructions given inside the program.
As well as interpreting the CNC program, the CNC control has 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 verify the correctness of the CNC program. The CNC control allows certain important operator inputs to be specified outside of this software, like tool length values. Generally speaking, the CNC control allows all functions in the machine to get manipulated.
For simple applications (like drilling holes), the CNC program could be developed manually. That is certainly, a programmer will take a moment to write this system armed only with pencil, paper, and calculator. Again, for simple applications, this might be the very best way to develop CNC programs.
As applications acquire more complicated, especially when new programs will be required consistently, writing programs manually becomes much more difficult. To simplify the programming process, a personal computer aided manufacturing (CAM) system can be used. A CAM product is a software program that runs using a personal computer (commonly a PC) that assists the CNC programmer with all the programming process. Generally, a CAM system is going to take the tediousness and drudgery out of programming.
In numerous companies the CAM system works with all the computer aided design (CAD) drawing created by the company’s design engineering department. This eliminates the necessity for redefining the workpiece configuration to the CAM system. The CNC programmer only will specify the machining operations to be performed and the CAM system can provide the CNC program (similar to the manual programmer would have written) automatically.
As soon as the program is developed (either manually or having a CAM system), it should be loaded in to the CNC control. Although the setup person could type this program directly into the control, this is like while using CNC machine being a very costly typewriter. When the CNC program is developed with the aid of a CAM system, then its already in the form of a text file . In case the program is written manually, it could be typed into any computer by using a common word processor (though most companies make use of a special CNC text editor for this purpose). In any case, this software is as a text file that could be transferred straight into the CNC machine. A distributive numerical control (DNC) product is used for this reason.
A DNC method is nothing more than a computer that is networked with several CNC machines. Until only recently, rather crude serial communications protocol (RS-232c) needed to be employed for transferring programs. Newer controls convey more current communications capabilities and will be networked in more conventional ways (Ethernet, etc.). Irrespective of methods, the CNC program must needless to say be loaded to the CNC machine prior to it being run.
Mentioned previously, CNC has touched almost every component of manufacturing. Many machining processes have been improved and enhanced through the use of CNC. Let’s take a look at several of the specific fields and place the increased exposure of the manufacturing processes enhanced by CNC machine usage.
Machining processes that have traditionally been done on conventional machine tools that are possible (and perhaps improved) with CNC machining centers include all types 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 done on CNC turning centers.
You will find all kinds 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 types like outside diameter (OD) grinding and internal diameter (ID) grinding are also being carried out on CNC grinders. CNC has even showed a whole new technology with regards to grinding. Contour grinding (grinding a contour in the similar fashion to turning), which was previously infeasible as a result of technology constraints is currently possible (almost commonplace) with CNC grinders.
In manufacturing terms, fabrication commonly identifies operations that are performed on relatively thin plates. Think of a metal filing cabinet. Each 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) 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 virtually every part of fabrication.
CNC back gages are typically used in combination with shearing machines to control the length of the plate being sheared. CNC lasers and CNC plasma cutters will also be used to bring plates for their final shapes. CNC turret punch presses is capable of holding a number of punch-and-die combinations and punch holes in all of the sizes and shapes through plates. CNC press brakes are employed to bend the plates to their final shapes.
Electrical discharge machining (EDM) is the method of removing metal through 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 usage of an electrode (commonly machined on a CNC machining center) which is in the model of the cavity to get machined in the workpiece. Picture the form of a 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 among the less popular CNC operations because it is so closely associated with making tooling used in combination with other manufacturing processes.
Like the metal removal industry, cnc milling parts are heavily found in woodworking shops. Operations include routing (much like milling) and drilling. Many woodworking machining centers are chinbecnnc that may hold several tools and perform several operations about the workpiece being machined.
Many forms of lettering and engraving systems use CNC technology. Waterjet machining relies on a high pressure water jet stream to slice through plates of material. CNC is even used in the manufacturing of several electrical components. As an example, you will find CNC coil winders, and CNC terminal location and soldering machines.
There is a reasonably shortage of skilled people to utilize CNC machines. And 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 reflected this shortage. Having said that, you could make an effective wage and create a rewarding career utilizing CNC machines. Here are one of the job titles of men and women working with CNC machine tools.