CNC means computer numerical control. CNC machines are widely integrated in the manufacturing industry as they play important roles. A computer controls the activities of these machines; therefore, they offer a level of consistency, efficiency, and accuracy. All this can’t be achieved via a manual process.
CNC machines are completely different from “old-school” devices that are controlled manually by levers, or hand wheels. Today’s CNC machines understand the CNC machining language and function based on this. The CNC machining language is known as G-code. This language informs the machine about the precise measurements for production, such as coordination, speed, and feed rate.
In the 1940s and 1950s, the first CNC machines were developed. These machines depended on a common telecommunication data storage technology known as “perforated paper tape” or “punched tape.” However, punched tape technology has become obsolete as the data medium transformed to analog and digital computer processing. CNC machines kept improving their performance and efficiency as new technologies were introduced.
What is CNC Machining?
CNC machining defines a process in manufacturing in which computer software controls the movement of machinery and factory tools. Also, this process can control several complex machinery, from lathes to grinders and CNC routers and mills. CNC machining helps in achieving three-dimensional cutting tasks in just a single set of prompts.
Therefore, this enables manufacturers to produce parts within a short time, minimize waste and get rid of the risk of human error. CNC is a computerized manufacturing process.
The CNC process functions in contrast to manual process and as such overcomes its limitations. In manual control process, live operators prompt and guide the machining tools through wheels, levers, and buttons. To a layman, a CNC system might look like computer components. However, CNC machining works differently from other forms of computation. This can be attributed to its integration of consoles and software programs.
How Does the CNC Machining Process Work?
Machining integrates a controlled material removal process to transform a piece of material like a block of plastic into a finished product. This process is very similar to a prototype development technology, FDM (3D printing. CNC functions based on digital instructions from a Computer-Aided Design (CAD) file such as Solidworks 3D. The CAD file offers the roadmap required for the CNC to create the design. The CNC machine then interprets these designs as instructions for cutting parts of a prototype.
CNC machining enhanced productivity by automating labor-intensive and highly technical processes through its ability to control machine tools through programming. Also, automated cuts enhance both the accuracy and the speed to create prototype parts, particularly for critical materials like polypropylene.
Machining processes usually integrate multiple tools to achieve the desired cuts. CNC machines combine tools into common cells or units from which the machine can make a drawing. Automated cuts are usually more accurate than cuts from manual inputs. When you activate a CNC system, the software programs the desired cuts and dictates corresponding machinery and tools which then perform the dimensional tasks as defined, just like a robot.
The code generator in CNC programming will often assume the mechanisms are without errors despite the possibility of errors. These errors may be more when you direct a CNC machine to cut in more than one direction at the same time. A series of input outlines how a tool is placed in a numerical control system.
Types of CNC Machines
The first CNC machines were developed in the 1940s. At this period, machine producers integrated motors to regulate pre-existing tools’ movement. However, these mechanisms enhanced as technologies advanced from analog computers to digital computers. Below are the most commonly used machines in CNC systems.
Lathe machines integrate indexable tools to cut pieces in a circular direction. The introduction of CNC technology made it possible for lathes to make cut with high velocity and precision. Also, CNC lathes are widely integrated in producing complex designs that are impossible with manual machines. In general, lathes share similar control functions with CNC-run mills.
Lathes can make use of different tools to make precise cuts. Also, unique proprietary code or G-code can direct lathes. However, the majority of CNC lathes comprise two axes which are X and Z. CNC lathes offer more precision than manual lathes.
CNC plasma cutter
Plasma cutter integrates a plasma torch to cut a material. Also, plasma cutting is a common method employed to cut heavy materials like steel. A CNC plasma cutter blows gas at a high speed from a nozzle. While doing this, the gas discharging from the nozzle to the surface that is being cut forms an electrical arc.
Therefore, some of the gas converts into plasma. Therefore, the temperature of the plasma ranges from about 10,000-50,000 degrees. In this case, the plasma becomes very hot and can melt whatever material that needs to be cut. After this, it blows away molten metal from the cut.
CNC cutters have a similar appearance with CNC routers as regards size and shape. Also, CNC plasma cutters work only with two-dimensional shapes.
CNC milling machine
The CNC milling machine is one of the most commonly used CNC machines. This mill cuts different materials by integrating computer controls. Also, a CNC milling machine is capable of translating particular programs of letters and numbers to move the spindle in different ways. Most mills integrated a programming language called G-code.
Furthermore, a CNC milling machine can serve several purposes like shoulder milling, turning, face milling, and tapping. The majority of CNC mills are available in three to six-axis configurations.
Electric discharge machine
This machine uses electrical discharges to create a particular shape within a specific material. The electrical discharge machine removes the material from a particular work piece by several recurring electrical discharges between two electrodes. A dielectric fluid separates these two electrodes. This fluid receives an electric voltage.
The electric discharge machine places the material between two electrodes and then it calculates the amount of electrical discharge needed to be produces by each electrode. The electric field is more intense when there is a smaller space between the electrodes.
Water Jet cutter
This CNC machine can cut hard materials like metal and granite. It makes use of high-pressure from water. Sometimes, the water mixes with strong abrasive substance like sand. Manufacturing companies shape parts of factory machine with water jet cutter.
Water jets are usually integrated as a cooler option for materials that can’t endure the heat-intensive processes of some CNC machines. Also, water jets are widely employed in mining and aerospace industries since they have cooler nature.
What is CNC Programming?
CNC machines integrate programming languages. Programming in CNC machines involves developing code for a computer to operate CNC tools and machines. The computer sends instructions to machines to carry out their tasks.
CNC programming enables manufacturers to automatically create parts while regulating the process manually. Also, CNC machines can convert raw materials into finished goods in large batches. Also, these machines offer great precision while doing this. Mass production can be more cost-efficient and more consistent with repeatable machine movements. This production process is better and faster than products made manually.
CNC machines can make products safer and stronger. Also, CNC machines can make it much easier to produce parts with 3D geometrics as computers are capable of handling the measurements and mathematical calculations.
Methods of CNC machine programming
There are three primary CNC machine programming methods. These are conversational, CAM, and manual system programming. When it comes to manual programming, the code is manually input. This process can be time-consuming and can require some efforts. Also, it requires having an intensive knowledge of the programming language. Manual programming is a foundational skill for operators. Also, it is a good way to carry out quick modifications to CAM outputs and as well optimize code.
The CAM system programming works in a similar way with the conversational method. However, it is more advanced. The software offers an advanced GUI in a CAM system. This helps the operator generate and prepare the program, thereby, getting rid of the need for manual programming.
All these methods of CNC machine programming involve M-code and G-code. The programming language that tells the CNC machine what to perform is the G-code. Also, this code enhances repeatable and accurate parts. On the other hand, M-code takes control over all of the miscellaneous CNC machine functions. Also, these codes are customizable and they vary based on the type of CNC machine. Therefore, programmers and programmers must be sure they are inputting the right functions before machining begins.
Types of Codes Integrated for CNC Programming
There are several codes used for CNC programming. Each of these codes has its specific function. Different letters are used to identify these codes. CNC programming codes instruct the machine on how, where and when to remove material from the stock. The most common types of CNC code includes:
This code is the tool offset of the CNC machine. It can be the distance the tool sticks out from the tool holder.
This means “Geometry” code. G-code tells the machine where, how, and when to move between two points.
N-code is a block of machine code or identify line. This line labels some parts which helps the programmer to follow written CNC code.
This code is ideal for use when machining a particular feature on the workpiece.
This code describes the various speeds at which the machine should move while cutting. The F-code is a feed rate code.
How Do You Write CNC Codes?
It is very easy to write CNC codes if you follow the necessary steps. However, you need to be familiar with some principles of CNC machining. Having a good understanding of the functions and features of CNC tools is important to optimizing the best speed settings. Below are steps on how to write CNC codes:
Export 3D model
You can export the CAD model in the CAM software first. However, you might not need to export since some CAD systems have CAM capabilities.
Create tool paths
You can transform the CAD model into tool paths manually or by allowing the CAM software produce the tool paths.
Verify tool paths
You need to confirm that the tool paths are accurate. You can do this by simulating the tool paths or manually.
Download code to CNC machine
You need to input the G-code in the machine. A portable storage device can help you achieve this process. Alternatively, you can download the code to the machine.
Tips for CNC Machine Programming
Revisit the basics
CNC programmers and machinists should master the basics before beginning any project. Conversational and manual programmers need to cross-check their mathematical calculation to be sure the right specifications are being programmed in the CNC machine. Also, it is important that programmers know that CNC software is fallible.
Simplify CNC machine programming
For the majority of CNC machining programs, G-codes are the standard programming code. But, it can take a lot of time to program operations. Therefore, CNC machine operators can use canned cycles to reduce the programming of hole-machining operations.
Canned cycles only need a block for each hole, irrespective of the machining style. Operator can machine extra holes by programming the hole’s coordinates again once he inputs a canned cycle. Codes such as G83 minimize errors, make programming easier, and save time.
Customize CNC machine feed rates
Operators usually spend time to dial a program to be certain that it runs consistently and smoothly. Immediately they accomplish this and they lock the program, they can “set it and forget it.” Operators can optimize manufacturing by simply customizing particular parts of CNC machining.
Understand types of CNC machine compensation
Compensation is CNC machine programming enables and accounts for the occurrence of unpredictable variations. Also, it is possible for an operator to input CNC programming codes or calculate the values that should produce the perfect part. However, they can only confirm the precision and accuracy of programming until they have completed machining.
The CNC process functions in contrast to manual process and as such overcomes its limitations. In the manual control process, live operators prompt and guide the machining tools through wheels, levers, and buttons.