All About CNC Machining: Types, Errors & Steps To Program [Guide]

Computer Numerical Control, also known as CNC machining, is a type of manufacturing technology that is used to produce parts and components that require a high level of accuracy. It is a method that makes use of computer programmes to control the motions of various cutting tools and other pieces of machinery. The Computer Numerical Control (CNC) machining process is widely utilised in a variety of industries, including the aerospace, automotive, medical, and electronic product manufacturing sectors. In this blog, we will go over the CNC machine basic information, various forms of machining that can be performed by a CNC machine, the types of mistakes that are most frequently made during the process, and the actions that are required to programme a CNC machine.

What is CNC System?

Let’s explore about CNC machine. CNC stands for Computer Numerical Control. A CNC system is a type of manufacturing technology that uses computers to control machine tools and other manufacturing equipment. A computer programme is used in a CNC system to control the movement and operation of machine tools such as lathes, mills, routers, and grinders.

The CNC system enables precise and automated manufacturing process control, resulting in high accuracy and repeatability. The computer programme instructs the machine tool to move along specific paths and perform specific operations like drilling, cutting, and shaping. The programme can be altered or customised to create various parts and products.

CNC systems are widely used in the aerospace, automotive, electronics, and medical device industries. They have transformed manufacturing by increasing efficiency, reducing waste, and improving quality. With advances in technology, CNC systems continue to evolve, becoming more capable and adaptable to different manufacturing processes and requirements.

Different Types of CNC Machines

Different Types of CNC Machines

The term “CNC machining” refers to a variety of distinct processes, each of which has its own set of benefits and drawbacks. The most common types of CNC machining are milling, turning, drilling, and grinding.

1) Milling

Milling is a precise and efficient manufacturing process that involves the use of Computer Numerical Control (CNC) machines. These machines use specialised software and tools to control the movement of the cutting tools and the workpiece. This allows for highly accurate and repeatable machining, which is essential for the production of complex parts and components.

The milling process involves the use of cutting tools that are mounted on a rotating spindle. The spindle is able to move in three or more dimensions, allowing the cutting tools to remove material from the workpiece in a controlled manner. The cutting tools can be made from a variety of materials, including high-speed steel, carbide, and diamond.

One of the key advantages of milling is its versatility. By using a variety of different tools and techniques, milling can be used to produce a wide range of parts and components. For example, simple shapes like squares and circles can be easily machined using standard end mills, while complex geometries like gears and turbine blades require specialized tools and techniques.

Milling can also be used to produce parts from a variety of materials, including metals, plastics, and composites. This makes it an ideal process for a wide range of industries, from aerospace and automotive to medical devices and consumer products.

Overall, milling is a highly versatile and precise machining process that is essential for the production of complex parts and components. With advances in CNC technology and tooling, milling continues to evolve and become even more efficient and capable of producing highly intricate shapes and geometries.

2) Turning

CNC turning is a type of machining in which a non-rotating cutting tool is used to remove material from a workpiece that is rotated. Creating cylindrical shapes and contours is made possible thanks to the fact that the cutting tool is held in a tool turret that can move along the length of the workpiece. Turning is commonly used to produce parts such as shafts, pins, and other cylindrical components.

3) Drilling

The process of creating holes in a workpiece through the use of a rotating cutting tool is referred to as drilling and falls under the category of CNC machining. When making holes with complex geometries, the cutting tool can be held in a stationary position or it can move along multiple axes at the same time. The production of holes in materials such as metal, plastic, and other types of materials frequently requires the use of drilling.

4) Grinding

The fine removal of material from a workpiece can be accomplished through the use of abrasive cutting wheelsin the form of grinding, which is a type of CNC machining. The grinding wheel that rotates at a high speed while the workpiece moves either rotationally or in a linear motion as required.. Grinding is a process that is frequently utilised in order to produce parts that have precise tolerances and surface finishes such as a polished finish.

Errors That Frequently Occur in CNC Machining

Errors That Frequently Occur in CNC Machining

Errors are still possible during the manufacturing process when using CNC machining, despite the high level of precision and accuracy it provides. Some of the most common errors in CNC machining include:

1) Tool Wear

Over time, cutting tools can become dull and worn, which can result in inaccurate cuts and unsatisfactory surface finishes. When cutting tools are properly maintained and replaced at regular intervals, tool wear can be reduced.

2) Vibration in the Machine

During the manufacturing process, inaccuracies in the final product can be caused by vibration in the CNC machine, which can cause parts to shift or move. Proper maintenance and calibration of the machine can help reduce vibration and improve accuracy.

3) Material Deformation

Some materials, such as plastics, can deform or warp during the manufacturing process, leading to inaccuracies in the final product. Material deformation can be kept to a minimum by selecting the materials to be used and the processing parameters with care.

4) Programming Errors

Programming errors can occur at any point in the CNC machining process. Issues can arise from creating the CAD model to writing the CAM programme. And as a result, the CNC machine develops parts or components that do not meet the required specifications. It can even be completely unusable.

The incorrect programming of the cutting tool path is a common cause of programming errors. If the tool path is programmed incorrectly, the CNC machine may cut too deep or too shallow, resulting in a part that is out of tolerance. Another source of programming errors is incorrect cutting parameter selection, such as cutting speed, feed rate, and depth of cut. If these parameters are set too high or too low, the part of the cutting tool may be damaged.

It is critical to test and debug the programming code before running the CAM programme on the CNC machine to avoid programming errors. This can involve simulating the machining process using CAM software to identify any errors or issues. The programming code should also be thoroughly checked for errors, using programming tools such as syntax checkers or code analyzers.

Using standardised programming practises and guidelines is another way to avoid programming errors. Following some basic guidelines can help reduce the risk of programming errors and ensure that parts are produced to specifications.

Steps to Program CNC Machines

Steps to Program CNC Machines

The programming of a CNC machine involves a number of steps, each of which needs to be carefully carried out to guarantee that the manufacturing process along with the product design & development solutions will be successful. The following are the basic steps involved in programming a CNC machine:

Step 1: Create a CAD Model

The development of a CAD (Computer-Aided Design) model of the component or part that is going to be manufactured is the initial step in the process of programming a CNC machine. The CAD model is a 3D digital representation that is a part of the 3D modelling service of the component, which can be created using software such as SolidWorks, AutoCAD, or Creo.

Step 2: Convert the CAD Model to CAM

After the Computer-Aided Design (CAD) model has been created, it needs to be imported into a CAM (Computer-Aided Manufacturing) programme. Software packages like Mastercam, EdgeCAM, and GibbsCAM are utilised in the development of the CAM program. The CAM programme serves as a repository for the instructions that are followed by the CNC machine in the process of fabricating the part or component. The CAM programme will determine the cutting speeds and feeds, as well as the cutting paths that need to be followed. It will also specify the cutting tools that will be used.

Step 3: Configure the CNC machine

The next step in the manufacturing process is to configure the CNC machine for its intended use. This includes loading the workpiece, installing the cutting tools, and configuring the machine’s parameters. The machine’s cutting speeds, feeds, and coolant flow rates are all included in the list of parameters.

Step 4: Load the CAM Program

After the CNC machine has been prepared, the CAM programme can be uploaded into the computer system that is connected to the machine. The programme will provide the machine with the instructions that it needs to manufacture the part or component according to its specifications.

Step 5: Start the Application

We can begin using the CNC machine once the CAM programme has been loaded. The machine will follow the instructions in the programme to create the part or component. The machine operator must monitor the progress that the machine is making throughout the manufacturing process and make any necessary adjustments to the cutting parameters.

Step 6: Inspect the Finished Product

When the manufacturing process has been concluded, the finished product must be inspected to validate that it complies with the prerequisite criteria. Measurement instruments such as micrometres, callipers, and coordinate measuring machines might be utilised at some point during the inspection process.

Wrapping Up

Machining by Computer Numerical Control (CNC) is a manufacturing process that is extremely precise and efficient. It is used in a wide variety of industries to produce precision parts and components. Milling, turning, drilling, and grinding are some of the many subcategories that fall under the general category of CNC machining. Despite its precision, CNC machining can experience errors during the manufacturing process, such as tool wear, machine vibration, material deformation, and programming errors. The programming of a CNC machine requires a number of steps to be completed, including the creation of a CAD model, its subsequent conversion into a CAM program, the setting up of the CNC machine, the loading of the CAM program, the execution of the program, and the inspection of the finished product. By following these steps, manufacturers can produce high-quality parts and components that meet the required specifications.