CNC Machines
What is a CNC Machine? CNC stands for Computer Numeric Control. Sounds complicated, but it isn’t. Years ago, it was just NC, or Numeric Control. Since, they’ve added computers to control the machine.
In the simplest of terms, think of a drill press. It’s a machine that drills holes. But before you can drill the hole, you have to loosen the chuck, install the correct drill bit, drill the hole in the correct place, turn off the drill, and remove the drill bit. Manually, this could be time consuming and cause fatigue over the course of numerous parts. This is a simple example, but throw in some lathe or milling machining and you have a greater chance for error.
With the CNC machine, all of this drilling can be done automatically instead of the manual process listed above. Machining has to be precise, and whether you use a CNC lathe or milling machine, you have to make sure the part is right. The computer takes a lot of the guesswork out of the machining of these parts. In fact, a CNC programmer can sometimes get bored watching the machine do all the work.
But there is more programming for the machine than you would think. The operator has to enter a set of instructions. The programming uses about 50 words and tells the machine how fast, how deep, and location for machining.
What can you do with a CNC machine? In manufacturing, you can use this tool for milling, drilling, reaming, boring and counter boring. You can also groove and thread parts in a CNC turning center. You may have several setups including CNC lathes, CNC drill and tap area, CNC milling, or even CNC grinding.
EDM (electrical discharge machining) can also take advantage of CNC operations. EDM can be either vertical or wire. A vertical EDM machine uses an electrode to make a cavity for a plastic injection-molding machine. A wire EDM machine uses a wire to cut metal for a tooling operation for fabrication. EDM is more closely related to making tooling for other machines, people often overlook the use of CNC with these machines.
CNC machines can also be used with routers in the wood industry. CNC can also be used with lettering and engraving.
I hope this gave you some basic information about what a CNC machine is and what they are used for.
Stuart Simpson
The 3 Options You Have in Obtaining Your Own CNC Router
Deciding on the purchase of CNC Router is not always the most attractive prospect. The upfront cost of a router can be a bit intimidating and cause a great deal of reluctance.
What I will do here is discuss the top 3 choices you will have in the acquisition of a CNC Router.
1. Buy Brand New
This is the most obvious prospect. There are some major benefits to purchasing a brand new CNC Router, the 1st of which is that you can rest easy knowing that your machine is brand new and most likely will not have any major mechanical difficulties for some time. The 2nd is that in 9 out of 10 cases you will receive some type of warranty from the company you purchase from; a benefit you will not receive from the other two options.
2. Buy Used
This is probably the most popular option of the 3. You can find plenty of resources online that sell used CNC Routers and I'm sure that you can receive an excellent bargain.
In my opinion, this option should only be resorted to if you absolutely cannot afford a new machine.
Why?
Because you have no idea what you are getting yourself into. Traditionally, you will not get any warranty with your CNC Router purchase or any assurance that the machine has not experienced major mechanical challenges in the past. However, if you can be sure that your source is reliable and trustworthy, then go for it! This option will save you about half the cost of a new CNC Router.
3. Build your own.
What!?
That's right, I said it. Build your own!
Now if you are anything like me, this is not a very inviting option. However, if you are the naturally crafty type this project may be a lot of fun and very rewarding. Again, you will easily find all of the necessary resources for this task online.
Well, there you have it! The top 3 options mixed in with a little bit of my opinion.
For more information on CNC Router or visit http://www.ez-router.com.
Important information about CNC Hot Wire Foam Cutting Machines
What is a hot wire cnc foam cutter used for?
Hot wire foam cutters will cut different types of foam, from insulation to fabrication, from logos, surfboards and signs to crown moldings and concrete molds
Hot wire foam cutters are designed to cut different types of foam
- EPS – expanded polystyrene
- XPS – extruded polystyrene
- EPP – expanded polypropylene
Not to be used for cutting polyurethane – will result in toxic fumes
What are the main components that a foam cutter is made of?
- The software is divided into two sections – design software to design the shapes to be cut, and the cutting software that controls the machine
- The hot wire tensioning mechanism
- Effective cutting sizes for the horizontal, vertical and the wire length
- Number of axis – a 4 axis machine will be able to cut tapered shapes (like a cone or a jet wing)
Here are some features to look for in a hot wire foam cutting machine:
For production of crown molding:
- Multiple wires – from 3 to 8 wires will increase the cutting capacity from 2 to 7 times
- 8 foot effective wire length – don’t settle for a 4’ machine
- If primary use of the machine is to cut logos and signs – a smaller machine will do the job
- Cutting speed – mostly material dependent – as a rule of thumb: the higher the foam density – the slower the cutting speed
Foam cutting machines have many applications. They can be used to cut architectural shapes, for packaging, building, construction, hobbies, RC Planes, sculptures, monuments, theme parks, props, aeronautics, aerospace and much more.
Hot Wire CNC Foam Cutter prices:
CNC foam cutters will range from $1500 to $50,000. The price is a factor of the machine size, the number of wires, the way the wires are kept under tension.
Other foam cutting machines:
Another way to cut foam is with a CNC router – this is mainly for machining the foam and not for cutting.
CNC routers for foam are mostly used for 3D shapes seen in Las Vegas, theme parts and even signs
Foam coating: EPS and XPS will melt if painted with oil-based paint. Painting is composed of two steps:
- Preparing the foam for coating – a primer should be used to prevent the coating material to penetrate the EPS beads
- Coating – Coating is usually Epoxy (usually brushed) or Polyurethane (brushed or sprayed)
Once the foam is coated – it can be painted with any type of paint.
Cutting EPS Foam:
Expanded polystyrene is very easily cut with a hot-wire foam cutter, which is easily made
by a heated and taut length of wire, usually nichrome due to nichrome's resistance to
oxidation at high temperatures and its suitable electrical conductivity. The hot wire
foam cutter works by heating the wire to the point where it can vaporize foam immediately
adjacent to it. The foam gets vaporized before actually touching the heated wire,
which yields exceptionally smooth cuts.
Polystyrene, shaped and cut with hot wire foam cutters, is used in architecture models,
actual signage, amusement parks, movie sets, airplane construction, and much more.
Such cutters may cost just a few dollars (for a completely manual cutter) to tens of
thousands of dollars for large CNC machines that can be used in high-volume industrial production.
Polystyrene can also be cut with a traditional cutter. In order to do this without ruining
the sides of the blade one must first dip the blade in water and cut with the blade at
an angle of about 30ยบ. The procedure has to be repeated multiple times for best results.
Polystyrene can also be cut on 3 and 5-axis CNC routers, enabling large-scale
prototyping and model-making. Special polystyrene cutters are available that
look more like large cylindrical rasps.
by: Tal Barnea
Cnc Windows Software
CNC is a technique whereby the movement of a router head is controlled by instructions from a computer. These instructions come from a computer program or list that the user keys into the CNC 860 console or into a computer as ISO standard commands called 'G' codes.As an example, the code G01 X100 Y100, instructs the head to move in a straight line to a point horizontally and vertically 100mm away from its starting position.
The CNC 860 The Trend CNC package is based around the Elu/DeWalt CNC 860 Machining Centre, which has a machining area of 860mm x 860mm x 90mm. These dimensions relate to the three axes, X,Y and Z (width, length and height). Each axis is served by a separate stepper motor, controlling the movement of the routing head. Two head options are offered: a modified portable router or a continuously rated, high cycle motor, that provides improved performance for intensive machining applications.
Programming directly in G-codes through the console can be time consuming. To assist the operator, a PC software application called CNCTalk is included with the machine. This is a basic computer aided design (CAD) application which runs under DOS, the original PC operating system before Windows. It is useful for intermediate applications like cutting out irregular shapes. However, to gain the maximum versatility from the CNC 860,Trend's Open Sign System Software for Windows is the most effective solution.
OSS consists of two separate software applications: OSS Draw which provides the drawing tools to create any shape or sign, and OSS Work which handles all the routing and tooling-related parameters like depth and offset. Graphical simulations are shown for all tool parameters enabling the user to perfect a design before routing any material.
Sign-writing As an example of how these products work together, the method of producing a simple sign is shown, incorporating two different lettering styles and a graphical logo. Having launched OSS Draw, the first step is to draw a box or boarder on the screen to indicate the overall area of the work. This can be either a simple rectangular boarder or a more decorative one. This border then needs to have a depth assigned to it. This is done by using colours to define the depth of each area.
The logo is then created using the drawing tools within OSS Draw. The words are keyed in using the text function. Again, colours are assigned to each area to produce a graphical representation of how the finished sign will look. The next task is to define the routing parameters. In the example, the red and blue areas of the logo and the lettering have been assigned a depth of 5mm and the green area assigned a depth of zero. The same dialogue box lets you specify whether a letter or object is engraved or routed through the material. The cutter profile that will be used can now be defined. With lettering, particularly serifed fonts, the cutter used needs to have a small diameter, perhaps 3mm. However, to achieve a 5mm cutting depth this will have to be routed in several passes.
A simulation of the cutting path is now drawn on screen. Having then created a G-code file of the sign ready for the CNC 860 to cut, the file is downloaded to the CNC 860. The design can now be routed, the material being held on the bed by an adaptable clamping mechanism. From the simulation, the path that the tool will take is known allowing a datum point to be set using the zero key on the console, and the program 8 INProfile is run using the start key. This type of routing operation takes around 20 minutes to complete and requires no further involvement by the machine operator. Other accessories Sign-writing is just one of the many complex and wide ranging routing operations that can be carried out using the OSS and CNC 860 package. OSS also has a range of tools for drawing component shapes and profiles directly or with an electronic sketchpad (graphics tablet). Vacuum Clamping To reduce the through-put time for this kind of operation, the CNC 860 can also be used with a vacuum bed. Trend offer a complete range of affordable vacuum pumps and jigmaking accessories to enable all CNC users to produce a highly automated production system to suit their own specific requirements.
Article Source: http://www.articlesnatch.com
About the Author:
Paul Disley is a woodworking expert at Trend Router
CNC Router Plans
The Top 5 Tool List: CNC Router Plans
With this you can cut straight lines and enormous curves. Setting a board along the head of 2 saw horses, can create a work area to hold wood being cut.
Next, for bigger wood working projects a table saw or radial arm saw is in line. Selecting one that rotates to different angles is significant if you intend to cut picture framing or crown mouldings for your house. The angles enable you to make the 45 degree mitre cuts for an ideal fit.
Third, the well- provided workshop has an electric sander. All of this work may be done by hand, but the electric belt sander gives each piece of wood a professionally finished look. It prepares long strips of moulding or the edges of table tops and other furniture for marking or painting. CNC Router Plans
This handy tool enables you make woodworking patterns and grooves that take a bit of furniture or moulding from that plain look of the Shaker style to the flamboyant French provincial elegance.
These will enable you to maintain blades and keep them cutting the small details and patterns that take your handicraft up a notch from amateur to professional.
Solid Brands for Solid Quality
There are some brands of tools that the name alone creates a picture of quality. The prices in these brands alter a little bit but with any of them you can count on a quality tool which will last decades.
Adding On: CNC Router Plans
Of course there are the smaller devices such as gluers and clamps that keep projects together while you're employed. But to that you are able to add electric nailers, dovetail jigs, jet tools and more to make life easier.
A well arranged workshop with all the basics is the most effective way to work. Maybe your first giant project can be building the workbench which will serve as your foundation for lots more projects to come.
Check out some great CNC Router Plans Info here!
Hans Bangor is a product researcher
CNC Turning Process - An Overview
CNC Turning process is a simple method of shaping a metal or wood on a lathe. It is a machine tool that spins or turns a block of material to achieve rotational symmetry in a machine shop. Turning can be done manually or using a CNC machining. The computer numerically controls CNC machine. A typical CNC machining center is designed to remove material using a rotating cutter that moves laterally to a work piece mounted onto a table or fixture. In the CNC turning process, a piece of material is rotated on the lathe and a cutting tool is traversed along two axis of motion, transverse or longitudinal. The process is done in a machine shop. The cutting tool is used until the required depth and dimension is achieved. Turning can be on both sides, inside or outside as per the needs and specifications. The rotation occurs at the turning center that enables control of tool motion through computer programs that use numeric data. Parts that are too large to balance and cause difficulty in rotating around one center point, can be worked on a machining center featuring a U axis. The turning length is about 1000mm between centers and has a drive power and speed range up to 46kW and 4,000 revolution/minute respectively. CNC turning process cuts the metal into various different shapes ranging from plain surface, taper ends, contour, and filter to radius profiles and threaded surfaces. These cut and turned metal pieces are used to create shafts, rods, hubs, bushes, pulleys and much more. Many industries also use it for fabricating parts and materials that have circular cross section. The process applies well to the most rigid materials that can be controlled exclusively with the software program tooling. The process does reduce the cost of production but on the other end, it limits the design flexibility. CNC turning machines are said to deliver components at a faster production rate with optimum manufacturing accuracy. The automation of the CNC turning process allows reaching tight dimensional tolerances in every piece. Other advantages are high level of parts consistency or uniformity, achievement of optimum cycle times for all components and faster execution of larger volume. As machines have brought a revolution in the industrial world, new technologies provided by emachineshop, boost the use of metal products. George is a well-known author who writes on the topics related with free CAD software, cnc machine shop and waterjet cutting for the site www.emachineshop.com. [Photo]
CNC Rotary Tables
1. Extreme Accuracy
A graduated dial and a vernier scale allow this rotary table to be positioned to a high degree of accuracy. The center of CNC milling equipment has hole that allows a morse taper center or fixture to be inserted. A tailstock is usually provided if the rotary table can be mounted from its end, so that the axis will be horizontal. The most common use of this CNC milling equipment is on it vertical axis that in this mode is on the same plane as the cutter when it is used on a milling machine.
2. Coaxial Design
If the CNC rotary table is mounted on a secondary table the work piece is adjusted in the center around the rotary tables axis, in this position the work piece is centered around the cutting tools axis; this make all three axis coaxial. Making a way for the secondary table to be offset in either the x or y plane so that the cutter is pitched at a distance from the work piece's center allowing a simultaneous operations on the work piece.
3. Specialized Or General?
There are literally hundreds of CNC milling equipments available on the market today with different specifications and different additional features. They come in all types of shapes and sizes. Some are designed for specific applications, while others are more of general purposes in nature. When looking for the right CNC rotary tables, try to talk to people who already using this kind of equipments from them you can learn how this things work. The good thing about talking to this people is that you will gain information not based on industrial propagandas but on experience and uses of there CNC milling equipments. You can also visit a shop in your area so that you will ly see on how CNC rotary tables work. You can eve try to use one CNC milling equipment to know how it feels. You can also attend CNC seminars to be able to gain professional views about his matters and also do not forget to check online information sites.
4. Setting Up Shop
When setting up your CNC rotary tables make sure that the platform is stable and your CNC milling machine secure. Setting up your CNC milling machines is a critical issue to early success, the less movement that occur the better. The right material to be used should also be thought about when using this kind of CNC milling machines. Determine the right thickness and sizes of your materials. Also look for proper fixtures for your CNC milling machines, for this will save time, money and frustration when using your CNC rotary tables.
Before going into production, make a plan to test the different variables you need to work with for a period of time. Getting familiar with your machine is also a critical issue for success. Try to make familiar with the different types of cut, type of materials to be cut, the table type, the depths of cut, the feed rates and the type and sizes of bits that you will be utilizing. Feel around the machine but not literally though for it may I injure you.
5. Satefy
Make sure to read your manuals and have a thorough understanding about the safety measures and the different features of your CNC milling machines. Have a good idea on how this things works. On what it can do to make your business prosper and also on how it can harm your employees.
Article Source: http://www.articlenorth.com
For more great cnc rotary table related articles and resources check out www.onlyrotary.com
CNC Milling Machine Buying Tips
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!
Article Source: http://www.articlenorth.com
For more great cnc milling machine related articles and resources check out www.cnc-advisor.com
About CNC Controllers
Industrial communications options for CNC controllers include ARCNet, CANBus, ControlNET, Data Highway Plus, DeviceNet, Ethernet 10/100 Base-T, parallel, PROFIBUS, SERCOS, Universal Serial Bus (USB), serial (RS232, RS422, RS485), and web-enabled. Communications language choices include bitmap, conversational, DXF file, G/M codes, Hewlett Packard graphics language, and ladder logic. A bit map (often spelled "bitmap") defines a display space and the color for each pixel or "bit" in the display space. Conversational language is a higher level, easy to learn programming tool. It performs the same functions as the standard G-code commands. Drawing eXchange Format (DXF) file that was created as a standard to freely exchange 2 and 3 dimensional drawings between different CAD programs. It basically represents a shape as a wire frame mesh of x, y, z coordinates. G-code is the programming language for the Computer Numerically Controlled (CNC) machine tools that can be downloaded to the controller to operate the machine. M-code is the standard machine tool codes that are normally used to switch on the spindle, coolant or auxiliary devices. Hewlett Packard Graphical Language (HPGL) was originally created to send 2 dimensional drawing information to pen plotters, but has since become a good standard for the exchange of 2 dimensional drawing information between CAD programs. Ladder logic is a programming language used to program programmable logic controllers (PLC). This graphical language closely resembles electrical relay logic diagrams.
CNC controllers have several choices for operation. These include polar coordinate command, cutter compensation, linear and circular interpolation, stored pitch error, helical interpolation, canned cycles, rigid tapping, and auto-scaling. Polar coordinate command is a numerical control system in which all the coordinates are referred to a certain pole. The position is defined by the polar radius and polar angle. Cutter compensation is the distance you want the CNC control to offset for the tool radius away from the programmed path. Linear and circular interpolation is the programmed path of the machine, which appears to be straight or curved, but is actually a series of very small steps along that path. Machine precision can be remarkably improved through such features as stored pitch error compensation, which corrects for lead screw pitch error and other mechanical positioning errors. Helical interpolation is a technique used to make large diameter holes in workpieces. It allows for high metal removal rates with a minimum of tool wear. There are machine routines like drilling, deep drilling, reaming, tapping, boring, etc. that involve a series of machine operations but are specified by a single G-code with appropriate parameters. Rigid tapping is a CNC tapping feature where the tap is fed into the work piece at the precise rate needed for a perfect tapped hole. It also needs to retract at the same precise rate otherwise it will shave the hole and create an out of spec tapped hole. Auto scaling translates the parameters of the CNC program to fit the work piece.
Features common to CNC controllers include alarm and event monitoring, behind tape reader, diskette floppy storage, tape storage, zip disk storage, multi-program storage, self diagnostics, simultaneous control, tape reader, and teach mode.
http://www.cnc-academy.com/cnc-programming-articles/cnc-programming-articles.htm
For all your CNC machining and plumbing needs
CNC Programming Tips the Professional Way
The fairest and reasonable answer to those questions would basically when a part has been machined under the most optimized working conditions. Therefore the Programmer’s responsibility does not end after he or she finishes the program. We could say that the program at this stage is still very much in the development process, because most of the programming considerations were based on certain assumptions and there are a lot of external factors that may affect the outcome of the product.
Every Computer Numerical Control programmer should have an effort to be in the touch with the actual production. In the field of software development, Constant communication with your colleagues as well as actual machine operators of the CNC will help you to improve your own program. Because most of the time the CNC machine operators are a good source of constructive ideas, improvements and suggestions.
A good CNC programmer should talk, ask questions to them and most importantly listen to what they have to say. Programmers who never put their foot in the actual machining process and think they are always right are all on the wrong track. Exchanging ideas with CNC machine operators, asking questions and seeking answers is the only way to be fully aware of what is going on in the machine.
Whenever you start a Computer Numerical Control Program the first time it is important to check its Program Integrity. A new and unproved program is a potential source of problems. During Manual Programming in CNC, mistakes are more common than when the program is made in a CAM program.
A good way to look at a new program is through the machine operator’s perspective. Experienced Machine Operators take a direct approach when running a program for the first time. That means that they wont take any chances of mistakes with the actual running of a program therefore a good programmer must take note of any comments that the Machine operator will say about the program.
What does an experienced Machine Operator look for in a new part of a program? Most of the Machine operators would say that the first and most important thing to be checked on a Computer Numerical Control Program is its consistency. Therefore a machine operator looks at how a CNC programmer does its own programming, is the way you create your own algorithms the same as the other ones. Machine Operators take note with this kind of Information.
Upgrading your CNC Program
Whenever you upgrade your own program, it means that you are strengthening or enriching it, therefore making it better than it was before. Upgrading would be based on this standard, It is to decrease the production cost without compromising the quality of the part being manufactured or the safety of the Computer Numerical Control Machine Operator.
One of the Most Common forms of Program Optimization is doing some minor changes to the spindle as well as the feed rates of the machines. This process is called cycle time optimization, slightly increasing the spindle speed and feed rates of these machines will decrease the time it takes to finish the part.
And when we compare it to mass production, saving one second for each part in a batch of 3600 pieces would mean an hour saved. Efficiency in the rate of production is a very important aspect in Mass Production.
Practical Applications of CNC
Computer Numerical Control or more commonly called as CNC’s are the new trend in machine shop manufacturing and practice. Any manufacturing environment owns one or is basically acquainted to this kind of device because of its capability to increase productivity as well as consistency on the products being produced.
Benchmarked from Numerical Control (NC) during the late 50’s, Computer Numerical Control incorporate the functionality of a Programmable Logic Controller (PLC), meaning you could program it to execute different functions depending on the type of manufacturing that the industry needs.
Given this kind of quality what does the Computer Numerical Control do in the practical application concept? CNC can do a variety of things depending on how the machine operator would program the system. The more acquainted the machine operator is to the CNC machine the more complex applications as well as programming can be made. Practical applications of CNC range from drilling, lathes, multi-axis spindles, milling machines, laser cutting machines, and wire electrical discharge machines.
Let’s discuss some of these common applications further. In Metal fabrication, Computer Numerical controlled Lathe’s are used to fabricate metal sheet by shearing, flame or plasma cutting, punching, laser cutting, forming and welding. Most CNC Lathe’s are used for designing modern carbide tooling. The design could be created with the Computer Aided Manufacturing (CAM) process, and when done, the CNC could start creating the product automatically with little supervision from the machine operator.
Electrical discharge machining (EDM) is the process of removing metal with the use of electrical sparks to take away the metal. These Electrical Discharge Machine has two types, the vertical EDM and wire EDM. Vertical EDM uses an electrode that is the shape of the cavity to be machined into a work piece. Wire EDM is used to create punch and die combinations in the fabrication industry. Computer Numerical Control EDM’s are not usually known because it is mostly incorporated to other CNC process.
Drilling is the most common machine process. Computer Numerical Controlled Drilling is used to create precise right circular cylinders over a certain material, the CNC could be programmed to create holes on different standards, most of the time this is the gaps between these holes. Drilling is commonly used in wood working manufacturing process in which other process is also involved such as milling, turning and grinding.
Several tools for creating holes with CNC’s involve varied hole sizes as well as drill press for creating different depths on its holes. CNC drills are equipped depending on the type of hole that the machine operator is drilling.
Applications stated above are just a few examples on what the Computer Numerical Control could execute. Depending on how you want it to perform, more complex designs can be made and a lot of things can be made in a shorter period of time, therefore the key concept for the proper use of CNC’s is that the machine operator must know what he or she wants to do.
This makes the CNC an indispensable tool for the Manufacturing Industry nowadays.
Understanding CNC
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.
The CNC Family
Let’s start with a brief introduction. CNC stands for Computer Numerical Control and it has been around since the early 1970’s. Before it was christened CNC, it was called NC, for Numerical Control. When computers were introduced during 1070’s, the name changed. It has stroked almost all manufacturing forms in almost all stages of production. CNC machines either substitute some existing manufacturing processes or combine work with them.
A CNC program is just any other set of instructions. It’s written like a sentence and the order of operation is chronological. The machine will then execute that set of instructions step-by-step. A special series of CNC words/codes are used to relay what the machine is supposed to do. CNC codes begin with letter addresses (like S for spindle speed, and X, Y & Z for common linear axis motions).
When certain codes are arranged together in a coherent method, this group of CNC codes create a “command” that is like a sentence. A common CNC machine will only be needing around 40-50 words/codes to program different commands. See, it’s not very difficult to learn.
Although CNC sounds very independent and do-it-all, there are a few words that you need to know to fully understand CNC operations.
THE CAM
CAM stands for Computer Aided Manufacturing. It simplifies the programming processes which are new, and added to the CNC program regularly. Of course, the easy applications can be programmed with only the simplest machines around: the pen, paper and calculator. However, more complex programs are vital regularly. It is when composing these programs become much more tricky and (worse) tedious.
The CAM is a program that runs on a computer that aids the CNC programmer with the programming. It also works hand-in-hand with the CAD (Computer Aided Design) design drawing (those designs engineers compose/nurture). With the CAM helping, redefinition of the work-piece configuration is not needed. What the CNC programmer is left to do is just to specify the machine operations to be executed and the CAM system will compose the CNC program automatically. Thanks to CAM, programming tediousness will not be a problem to the CNC programmer again.
THE DNC SYSTEM
DNC stands for Distributive Numerical Control. It is a computer that is connected with one or more CNC machines, forming a network. When a program is manually composed and ready to be loaded to the CNC control, it is being typed right into the control. However, this is like using the CNC machine as a luxurious keyboard.
Moreover, if the CNC program is achieved with the help of CAM, it is already in text form and ready to be loaded to the CNC control. The DNC simply distributes the CNC program to more than one CNC machine. Lately, the newest controls are more advanced in terms of networking capabilities and can be networked with, say, the Ethernet.
If it’s your first time to read and learn about the CNC, it may sound so mighty and ubiquitous. It’s about time you learn they also need help from some programming friends such as the CAM and the DNC. No man is an island; but hey, neither are CNC machines.
Programming 101: CNC
HOW TO PROGRAM A CNC MACHINE
CNC programming uses a code similar in structure to BASIC. So, if you know how to construct a simple counting program, chances are, you already know what a G-Code looks like. However, there a few other things you have to consider before you start encoding instructions.
The first thing that you have to do is to assign values for each of the variables. These variables include the programmable motion directions (axes), and the reference point for the axes. The values that you assign to these variables dictate the movement of the machine.
The next thing that you have to do is to take into account the accessories of the machine. Many machines have accessories that are designed to enhance the capabilities of the basic device. However, using these accessories requires you to include them in the coding system. This means that if you want a more efficient machine, you will have to know the machine inside out.
READING CODES
After those steps, you have to create a subprogram that will deal with the math. This step will then allow your machine to compute the necessary variables and effectively operate without stopping to ask the operator what the limitations are.
To show you what these codes look like, here’s an example from Wikipedia:
#100=3 (bolt circle radius)
#101=10 (how many holes)
#102=0 (x position of ctr of bolthole)
#103=0 (y position of ctr of bolthole)
#104=0 (angle of first hole
Tool call,
spindle speed,and offset pickup,etc
G43 in some cases (tool length pickup)
G81(drill cycle)
call sub program
N50
G80
M30
Subprogram
N100
#105=((COS#104)*#100) (x location)
#106=((SIN#104)*#100) (y location)
x#105 y#106 (remember your G81 code is modal)
If #100 GT 360 goto N50
#100=(#100+(360/#101))
Goto 100
In the code above, the machine is a drill. The operator utilized a loop in order to keep the machine from stopping. The subprogram then governs the cycle of the machine. This code is still quite a simple code. Other machines require the inclusion of the maximum RPM in the coding.
An easier way of programming CNC machines would be the use of Computer Aided Manufacturing (CAM). This system takes on the brunt of programming so that it doesn’t seem so tedious and frustrating. It is still similar to BASIC.
Another programming enhancement that was developed was the parametric programs or the logical commands. These programs were designed to shorten lengthy codes in order to make them user friendly. However, these codes do not always use the same language with every machine. The language and sequence often varies depending on the typ of machine you will be working on.
The operator has to know what the machine can do or what it was made to do before attempting to program it. You should be able to visualize the machine doing what you want it to do.
But, you don’t have to be a math wizard or a programming genius. You just have to know what your machine does and what you want it to do.
