Computer Numerical Control

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CNC Milling Machine Buying Tips

CNC stand for Computer Numerical Control, and refers specifically to the computer control of machine tools. The main purpose of CNC Milling Machines is to repeatedly manufacture complex parts in metal as well as other materials, using a specially coded program. This specially coded program that is used by CNC Milling machines is written in a notation called G-code. G-codes represent specific CNC Milling functions in alphanumeric format. CNC Milling was developed in the late 1940's and early 1950's by the MIT Servomechanism Laboratory.

1. About CNC

- Computer Numerical Control (CNC) Milling is the most common form of CNC - CNC mills can perform the functions of drilling and often turning - CNC Milling machines are classified according to the number of axes that they possess - Axes are labeled as x and y for horizontal movement, and z for vertical movement - The evolution of CNC milling machines drastically changed the manufacturing industry - Curves are as easy to cut as straight lines, complex 3-D structures are relatively easy to produce, and the number of machining steps that required human action is way down.

2. The Fabrication Process

With the use of CNC milling machine the fabrication process of the materials have been trimmed down to just a couple of steps. CNC Milling machines now days are driven directly from computer softwares crated by CAD software packages. With the use CNC Milling machines the assembly of parts can go from brief designs without any intermediate paper drawing works being required. In one sense, with the use of CNC milling machines industrials tasks are done must easier and much faster and the production cost of the company is also lessening out. CNC machines may be said to represent special industrial robot systems, as they are programmable to perform any kind of machining operation, within certain physical limits, like other robotic systems.

3. Buying Tips

Before buying a CNC milling machine it is a must that you should have knowledge about the CNC milling machines basic parts. A CNC milling machine is basically composed of a Safety shield that is usually a clear plastic cover that cover and protects the cutting area. The Tool bit, this part of the CNC milling machines is the one that do the cutting. Spindle Shaft, is the part that holds the tool bit. Spindle Motor, is the part of the CNC milling machine that drives the cutter. The Vertical Column, the part that holds the spindle and all of its part. The Cross Side, a moveable support where the work piece is being cut. The axis motors, which moves the cross side into different axis and the Controller box.

When purchasing your milling machine make sure to check that you have all of this part intact on your CNC milling machine, for if one of this parts is not there it will not surely work or will produce an undesirable end product. Also see to it to check out for safety features, never buy a CNC milling machine without an emergency stop button, this button automatically stops machining when it is pressed. Human, hardware or software errors could mean big losses if the CNC cannot be stopped quickly enough to correct the problem. Also check out the control panel part, it is advisable to buy one with a big control guide sticker so you can clearly see it.

Also check out the screws and tools with long overhangs and adapters, be more observant about cracks and breaks on this CNC milling tools. Make sure that the plastic shield that you are purchasing with your CNC milling machine is made up of high impact polycarbonate plastic. An insert break loose from a 35 mm diameter CNC milling cutter at a spindle speed of 45,000 rpm will be thrown out at a speed of 90 meters per second - equivalent to a bullet that is being shot out of a pistol!

For more great cnc milling machine related articles and resources check out http://www.cnc-advisor.com

How CNC Helps Companies

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The advent of Computers lessened the need for human intervention in almost all aspects of our daily lives. This is especially true in the industrial sector now that production is virtually automated.

Precision and accuracy

Computer numerical control has been able to help companies in terms of precision. With the need for more complex designs and more complex operations, human workers could not cope with the required precision that comes with advancement. CNC machines were able to alter that idea by allowing increased precision and lesser error ratios with regards to production.

Another important improvement that CNC has brought with it is the increased accuracy. The dimensions of components have to be very accurate. And since an increase in production speed also increases the error ratio, CNC has helped lower that ratio by the increased level of automation and the error detection capabilities that computers have.

Speed

In the industrial sector, speed is of the essence. With CNC technology, the normal production capacity has been increased exponentially. This means that effective and accurate production methods have been developed. Mass production requires more scrutiny for errors and mistakes. However, anomalies can also be corrected. The programming structures of CNC machines can be altered in a fast way. This means that mistakes do not have as serious an impact as they had before CNC was improved to this level.

Machine versatility

CNC machines have become very versatile with regards to the tools that they use. They can easily be assigned to different tasks and thus can be very productive. Tools and networks can be switched without compromising the speed of the production. Aside from this, one machine can do more than one task at a time. This exceeds the normal human capacities as it allows more tasks to be accomplished at a faster rate than before.

Furthermore, when one machine tool breaks down, it can easily be pulled off the grid to prevent it from affecting the whole production cycle. It can then be replaced or repaired on the spot.

Lesser human intervention

Since component production is a very tedious and repetitive operation, human error skyrockets as time passes. This is due to fatigue and other factors. Furthermore, the ability of a person degrades due to psychological and emotional factors. This means that if a person works on the same job for a certain amount of time, the person may eventually get bored or tired or both. This increases the possibility for the human to commit an error and thus causes a drop in the efficiency rating of that person. A machine, however, does not get tired or bored. A machine does not have any concern at all.

Therefore, a machine increases efficiency ratings by speeding up production and eliminating or reducing factors that threaten efficiency. In this case, one must simply program the machine to start a cycle. Furthermore, humans have to be fed, paid, and rested. Machines only have to be rested when failures occur to often and they do not need to be paid or fed.

This brings us to the conclusion that companies will be able to save a lot in the long run. While investing in CNC machines is not cheap, maintenance will only cost a fraction of what will be paid to manual laborers.

Computer Numerical Controlled Machines Automate the Sheet Metal Fabrication Industry

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Manufacturers, which produce various steel products, require punching of sheet metal to meet design requirements. Technology has entered the scene of this once manually operated process. This not only increases the speed of production but it gives a new meaning to the term "accuracy" in the positioning of the specific operations. This has been accomplished with the introduction of CNC or computer numerically controlled machining centers.

Punching of sheet metals is a steel fabrication process utilizing 'tools and dies'. A punch press is the machine which performs the work of shaping and cutting. A turret houses a set of various tools on the machine, depending on the type of punching required.

The punch press, a type of fabricating machine, presses sheet metal against a die with extreme pressure and at very rapid speed of positioning. Sheet metal, now pushed into the die, assumes the shape and design of the specific dye. Cut away, is any excess metal from the newly shaped piece of sheet metal.

Punch presses use hydraulic, pneumatic, or electrical power in their operation. This power exerts immense pressure to press the shape into and perform the cutting of the metal. A piece of sheet metal receives its new form from the taking away of material. Less sheet metal makes a new form. The excess taken away becomes scrap metal for other uses.

A CNC operated punch press typically performs this manipulation process. CNC stands for computer numerical controlled. In the case of a punch press, it utilizes a computer in its operations. The computer directs the action of this press, which contains the tools and their respective dies.

This machine receives different punching instructions from a program written and installed in the computer for a particular application. This enables the machine to go through a complete machining cycle, using various tools and automatically positioning the sheet metal over the appropriate die, at very rapid speeds and with little operator intervention. The accuracy of this process is measured in thousandths of an inch.

A manually operated punch press, for simple punching, with one tool and die set, are still in use today. Large operations with multiple dies and unique specifications rely on the CNC application.

The die portion of a punch press is of very fine tolerances. These are tolerances of thousands of an inch. Pressing sheet metal into a die with a punch means the die does the actual cutting of the metal. The punch, attached to a ram, is a removable piece, as is the die portion.

The die set for sheet metal punching consists of a male punch and a female die. When brought together, with the application of intense pressure, the result is a sheet metal piece as per the specified design.

Punch presses using CNC technology have meant greater volumes of sheet metal production. This process spells efficiency for a company, which means greater profits. This edge is necessary in the competitive steel fabrication companies worldwide find themselves.

Today, there are turret punch presses, CNC types, which perform faster because of technological advances. They can operate unattended and have sheet metal sorting capabilities. New technology constantly raises the mark for performance. Wise steel fabrication companies invest in these applications if it means streamlining of their operations for maximum profit.

Today's CNC controlled machines can even alert workers who are off-site if something goes wrong in a sheet metal punching process. This allows for unattended "lights out" production capabilities for manufacturers. Telecommunications technology embedded in these computer systems links to users' phone devices. In essence, CNC technology provides a constant watch over machining of steel.

The use of robotic applications in steel fabrication, including punching, receives continued research and application. Advanced, state-of-the-art CNC technology is the solid future of most fabrication industries.

Billy Kite is a researcher writing on behalf of premium steel sales. A company that sells more than just hrpo - hot rolled pickled and oiled steel products.
Article Source: http://www.articlesbase.com/technology-articles/computer-numerical-controlled-machines-automate-the-sheet-metal-fabrication-industry-390530.html

Understanding CNC

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Have you ever asked yourself how machines in a factory know exactly when to stop making the parts they’re supposed to make? Well, this is all because of Computer Numerical Control (CNC). But to understand CNC, you have to know what Numerical Control (NC) is.

HISTORY

NC machines were first introduced after the 2nd world war as mass production became the trend. These machines were given a set of instructions in punched cards. However, these machines were hard-wired and their parameters were difficult to change.

These NC machines still required a great deal of human intervention. To illustrate this point, try to take a look at a drill press. A lot of actions have to be taken in order to manufacture a product. The process is actually so complicated that a person has to do something almost every step of the production process. This created an avenue for errors to take place as the likelihood of fatigue increased with the quantity growth.

CNC then came into the picture when computers were introduced. Punched cards were replaced by floppy disks, cables, and other software transfer media. This made it easier to manage and edit data.

Production and manufacturing were revolutionized by the increased automation of CNC machines. These machines allowed a degree of added control over the quality and consistency of the components that were manufactured without any additional strain on the operators. This reduced the frequency of errors and allowed the operators time to perform additional tasks. Furthermore, this automation allowed a greater degree of flexibility in the way components are held in the manufacturing process.

With the advent of Computer Aided Manufacturing (CAM), even programming CNC machines is a snap. These programs actually take the bulk of the programming process to make the operation less tedious. However, to be an effective programmer of CNC machines, you have to know what the machine you’re working on will be doing. That is why machinists are often the best people for the job.

The ease that the machines provide is hinged heavily on the quality of the machine. Low-cost CNC machines oftentimes have many functions that have to be manually activated. High-cost machines, however, are almost fully automated. The operator only has to load or unload workpieces. Once the cycle has been initiated, the operator just has to sit back and watch for any malfunctions. The stress on the operator is so low that some even complain of boredom in the middle of a cycle.

CODING

The programming language that CNC uses is called a G-Code. These codes actually position the parts and do the work. To be able to have a machine work properly, you have to input the correct variables such as axes, reference points, the machine accessories, and whatnot. Every machine has a different set of variables so you have to be careful to take note of the differences.

Aside from the G-Code, logical commands or parametric programming can be used to make the process more time-efficient. This type of programming language shortens lengthy programs with incremental passes. A loop can also be programmed thereby removing the need for coding repetitions.

Because of these features, parametric programming is more efficient than CAM. It allows users to directly and efficiently make performance adjustments. It also allows extensions to the functionality of the machine it is running on.

And that makes CNC.