What Is CNC Machining
CNC machining is a manufacturing technique that computer software guides factory equipment through its motions. A wide variety of sophisticated tools, such as lathes, grinders, mills, and CNC routers, can be operated with this method.
CNC machining allows for simultaneous cutting in three dimensions at the push of a button.
Compared to manual control, where human operators are required to prompt and lead the commands of milling tools via levers, buttons, and wheels, the advantages of the CNC process become clear. While the hardware of a computer numerical control (CNC) system is similar to that of a standard computer, the software and control panels used in CNC machining set it apart.
Below is a video, which can help you to have a general idea for CNC Machining & it’s working process.
Types of CNC Machining Operations
The CNC machining operations incorporate a variety of computer-controlled machining processes that include electrical, thermal, mechanical, and chemical operations to remove remove excess material from the workpiece to create the desired part or product. In this section, we’ll talk about some of the most widely used mechanical CNC machining tasks, such as:
CNC Milling Machine
Milling is a type of machining in which a workpiece is machined by rotating a set of cutting tools. In computer numerical control (CNC) milling, the workpiece is fed to the cutting tool in the same direction as the rotation of the cutting tool, whereas in manual milling, the workpiece is fed to the cutting tool in the opposite direction. The milling process’s operational capabilities include:
- Face milling allows for the creation of shallow, flat-bottomed, and flat surface cavities in the workpiece.
- Peripheral milling allows for the creation of deep cavities like threads and slots.
CNC Turning Machine
Single-point cutting tools are used in conjunction with a revolving workpiece to perform machining operations, such as turning. CNC turning lets you make cylindrical parts with slots, taper, and threads on the outside and inside. The machine (usually a CNC lathe) moves the cutting tool in a straight line along the surface of the rotating workpiece. It removes material around the circumference until the desired diameter is achieved.
Thread cutting, boring, and facing are just a few of the many turning operations available. With its revolving cutting tools, CNC milling is preferable to lathe cutting for more intricate components. But lathes, which have workpieces that can rotate and stationary cutting tools, are ideal for quickly and precisely making cylindrical components.
CNC Drilling Machine
In drilling, a multi-point drill bit is used to create a cylinder in the material being machined. Holes with sizes identical to the drill bit’s diameter are produced via computer numerical control (CNC) drilling, in which the CNC machine feeds the revolving drill bit perpendicular to the plane of the workpiece’s surface. However, with the right setup and work-holding tools, angular drilling operations can be carried out on various machines. Counterboring, countersinking, reaming, and tapping are all drill-process operations.
CNC Grinding Machine
A CNC grinding machine takes material off by a spinning wheel. The goal is to give a metal part a high-precision finish. The surface quality that can be made is very good. So, it is not used to make the final piece from raw materials but rather as a finishing step.
CNC Router Machine
It looks like CNC routers are the same as CNC milling machines. Again, the piece that turns is the cutting head. The main difference is in the kinds of things that can be cut. Routers are great for cutting through soft materials (not metals) that don’t need to be cut very precisely. Because of how much less power it puts out. In addition, routers are faster. Because of this, they can make the parts in less time
CNC Plasma Cutting Machine
Plasma-cutting CNC machines are used for the same purposes as milling CNC machines. In contrast to their milling counterparts, they use a plasma torch to do this process. The term “plasma cutting machine” refers to a device that uses an accelerated stream of hot plasma to cut through electrically conducting materials. To work with tough materials like metal, these CNC machines typically come equipped with a powerful torch.
CNC Lathe Machine
This CNC machine operation features CNC machines that can turn materials while operating. These milling machines are more compact than their CNC counterparts due to a reduction in the number of axes they use.
Computer numerical control (CNC) lathe machines have a central lathe that handles and moves material by computer programming. Because of its quick and precise function, it is currently commonly utilized as a lathe.
Once set up, even a semi-skilled person will have no trouble using it. The lathe is employed in mass production, just like the turret and capstan. There isn’t, however, a system that automatically feeds information.
CNC Laser Cutting Machine
Laser-cutting CNC machines are similar to plasma-cutting CNC machines because they both employ lasers to make precise cuts in hard materials. Although lasers are accurate, they are not as powerful as plasma torches.
CNC machines that perform laser cutting typically use either a carbon dioxide (CO2), yttrium-aluminum-garnet (YAG), or neodymium (Nd) laser.
CNC Electrical Discharge Machine
This operation is also referred to as a spark. A subset of CNC machines uses electric sparks to guide materials into the desired form.
Due to its temporary nature, electrical discharge can compromise the materials it is applied to—electron flow to reshape materials. CNC machines take advantage of this by constructing controlled sparks.
The computer then calculates the amount of electrical discharge generated by the electrodes by considering the materials sandwiched between the electrode’s upper and lower surfaces.
CNC Machine with Automatic Tool Changes
Switching Tools Mechanically, CNC technology increases the machine’s tool capacity and output rate. And it’s used to improve the machine’s versatility in terms of its tools. For broken or worn tools, operators of this sort of CNC machine can easily and rapidly replace them.
One of the primary benefits of this CNC machine is a decrease in downtime. The CNC machine with an automatic tool changer is an excellent first step on the road to full mechanization.
5-Axis CNC Machine
There are a total of five axes on the 5-Axis CNC machine. Cutting with any tool has traditionally occurred along three axes (X, Y, and Z), but adding two more axes (A and B) brings the total to five. Sculptures are made with this machine
3-D Printer
It is a CNC machine that prints part one layer at a time. The CAD and CAM process is used to make the design and drawing. The 3D printer is then used to make the design come to life. A 3D printer is a CNC machine that prints buildings and other structures.
Pick and Place Machine
This is another kind of machine that uses CNC. People in business use it. The pick-and-place CNC machine has many nozzles that lift and place electrical parts for electronic equipment in the right place. Most of the time, they are used to make computers, cell phones, tablets, etc.
How Do CNC Machines Work?
Modern CNC machines are fully automated. They all need digital files that tell them how to cut and what tools to use. To make a part, you need many designs or machining tools. Machinists can make digital tool libraries that work with the actual machine. These machines can automatically switch tools based on digital instructions, making them real workhorses in manufacturing.
Parts Are Designed in CAD Software
The parts are first made in CAD software, which is the first step in CNC machining. The 3D model tells us how big and what properties the final part needs to have.
Some of these programs are part of CAD-CAM packages, so you can keep working on the same program. If not, the CAD models are put into CAM software. If both CAM and CAD are from the same family of products, there is no need to translate the files. If not, the CAD files will have to be imported.
Preparation of the Model Using CAM Software
CAM software (computer-aided manufacturing) prepares the model for the fabrication process. First, it looks for mistakes in the model. The computer then makes a CNC program to make the part.
In manufacturing, the program functions essentially as a collection of coordinates that direct the movement of the cutting head.
Choosing Right Parameters
Step three is to choose the right parameters. The parameters include the cutter’s RPMs, voltage, and RPMs, among others. The geometry of the part and the available equipment and tools are primary considerations in determining the layout.
Determining the Nesting
After all other factors are considered, the program decides the nesting. When pieces are nested, they are oriented and positioned concerning the raw material. The objective is to make as much productive use as possible of the available resources.
The information gathered was then converted into machine-readable formats like M-code and G-code.
G-Code vs. M-Code
It’s often assumed that G-code is unnecessary for actually performing machining operations. This is not the case with G-Code and M-code. To instruct a machine’s motion, humans utilize a language called G-code. It’s the same thing as the geometric code, essentially. The positioning and velocity of the cutter heads are controlled using G-code.
A machine controller, which is just a computer used in manufacturing, receives the instructions. This then determines how the motors should move. The motors, of course, decide the course that must be taken.
Contrarily, the M-code provides all the data that the G-code leaves out. For this reason, it is sometimes called assembly language or machine code. The use of coolant, tool changing, program stops, and other similar topics are all addressed in M-code.
In other words, both are crucial, but they serve different purposes.
Machine Preparation
After the operator has obtained a readable file, they will be able to configure the computer itself. In order for the program to function appropriately, they will attach the necessary workpieces and tooling in place.
Process Execution
The CNC operator can now carry out the final step now that the machine and the data have been prepared. They initiate the software, which directs the machine through the entirety of the process after it has begun.
Materials for CNC Machining
In choosing the right materials for CNC machining, you need to consider several factors such as:
- How will you use the part to be produced?
- Will the part to be produced is for indoors or outdoors
- Material’s stress load
- Material’s dimension tolerance
- Fastening requirements
- Operating temperatures
- Weight and stress capacity
- Total project cost
After giving the considerations above their due, you should be able to settle on the most appropriate material for your task. It could take some fiddling and trying out several options before finding the best one. The following is a brief summary of some of the common materials for CNC-machined parts:
Metals
Metals with the right mechanical qualities for machining include those that are strong, flexible, and hard. There is a wide range of machinability among metals and alloys due to their differences in characteristics.
While there are many elements to consider when deciding which metal to use (which we shall discuss in more detail below), it is safe to say that the higher the cost, the harder it is to process the metal. This is because more time will be needed for the machining process. The price of raw materials is another factor that might affect the final cost of a component. Some commonly used metals for CNC machining are brass, steel, and aluminum.
Rigid Foam
Rigid foam provides the best insulation since it blocks conduction better than any other foam. It works well between -100 and 200 degrees Fahrenheit. Because of its high R-value, rigid foam is widely considered the material of choice for use in waterproofing floors, walls, and other structural components
Plastics
Some of the many applications for which plastics are manufactured include bearings, bushings, and electrical insulation. However, demand does exist for the more common polymers. Numerous sectors can profit from plastic’s versatility, including the aviation, automotive, healthcare, and electronics industries.
Plastics are indispensable in the current industrial sector because of their accessibility, low cost, and suitability for common techniques, including injection molding, 3D printing, and computer numerical control machining.
Some of the common plastics available today used for CNC machining are as follows:
- ABS (Acrylonitrile Butadiene Styrene)
- Nylon 66
- PEEK (Polyetheretherketone)
- POM (Polyacetal polyoxymethylene)
- PC (Polycarbonate)
- PTFE (Polytetrafluoroethylene)
- HDPE (High-density polyethylene plastics)
- UHMW (Ultra-high molecular weight polyethylene)
- PMMA (Polymethyl methacrylate)
- PP (Polypropylene)
Carving Foam
You can make almost anything out of foam if you carve it. Due to carving foam’s malleability, it is commonly used as a mold pattern, but it also has other applications, such as gaskets and seals. Dense and heat-resistant polyisocyanurate is used to make carving foam.
Phenolics
Phenolics can be made to conform to strict military standards like MIL-I-24768. CE, LE, G10, G10/FR4, G9, G11, and G7 are just some options available to you. Each one excels in different ways. For instance, the phenolic linen fine weave results in superior mechanical qualities, dimensional stability, and polish for machined components compared to CE material. But phenolic linen is not recommended for use as principal insulation in electrical systems. Both LE and CE phenolics comply with Mil-I-24768/13 FBE and Mil-I-24768/14 FBG.
The Benefits for CNC Machining
CNC machines improve efficiency and precision while decreasing the likelihood of human mistakes by automating several tasks that were previously performed by hand.
Here are some of the benefits of CNC machining:
Produces Less to No Waste
CNC machines use software programs that are optimized over and over again to find the most efficient way to turn a part. Simulations can also be used to test how well the governing program will work before it is put into action.
So, the final CAD-CAM model will produce results and deliver value from the first cycle instead of improving the design by trying things out and seeing what works and what doesn’t.
Plus, since all precision milling machines run on repeatable software programs that use fixed tools along fixed paths, they make good use of their raw materials. Because of this, most of the very advanced CNC machines can help manufacturers eliminate waste.
Minimal to No Defects and Better Accuracy
Precision turning machines work on their own and don’t need any help from a person. This means that human mistakes can’t get into the manufacturing process and cause problems. With codes and software programs running the whole process from start to finish, the machines can work more accurately and without any mistakes.
Also, these inputs don’t change much during the whole production process, cycle after cycle, unless they are changed on purpose. This keeps the final products consistent. Also, the machines can work for a long time without stopping, and the quality of their work doesn’t change.
Efficient and Faster Production
Milling machines can be set to their fastest speed to meet growing needs. Also, as was already said, these machines can work 24 hours a day, seven days a week, without getting tired, taking breaks, or giving up anything.
These features, along with the fact that the machine will still be very accurate and won’t waste any materials, make it one of the best ways to make production fast, efficient, and scalable without incurring any extra costs.
Easy to Assemble
By moving people down the assembly line, manufacturing units can be made more efficient by separating the amount of work they can do from the number of workers they need. People know that manual assembly lines work better in high-production settings, and when putting together, the product is so complicated that it requires specialized skills that machines can’t do.
Also, the high-precision turning of parts makes it possible for them to fit together smoothly, so the assembly line can keep going without stopping.
Improved Safety Condition for Personnel
CNC machines keep people away from machines and reduce the risk that would otherwise happen.
These machines can work without a person running them. This reduces the chance of accidents and the risk to life and limb. Modern CNC machines are very powerful, and they can even change their tools on their own. Even if the design changes, it can be implemented by changing the software, which doesn’t require the person or machine to be there.
So, human involvement is limited to a supervisory role, where they can watch the software programs run from a distance and do preventive or reactive maintenance to keep things from breaking down. This reduces the need for people to get involved and makes the workplace safer.
Less Energy Consumption
It is common knowledge that energy-intensive industries incur significant losses in the production process, especially in oil and natural gas, aerospace, petrochemicals, automotive, etc. Nonetheless, with the help of CNC machines, they can continue to expand in size and accuracy without excessively consuming scarce resources like power and human labor.
In addition to introducing sustainability, they work to minimize energy loss as a result of carelessness or incompetence in planning.
Less Production Costs
Given these benefits, it stands to reason that using CNC machines for the precision turning of parts can drastically reduce production costs. The first benefit is that it reduces material waste while simultaneously increasing production and assembly efficiency.
In a similar vein, it lessens the need for electricity, hence cutting down on ongoing maintenance expenditures. Also, it removes the burden of financial responsibility for unexpected events like accidents. It’s one of the best methods to save money across the board without lowering standards or cutting corners.
CNC Machining Manufacturer
I think you already have a general idea of CNC Machining through detailed introduction above. If you want to order a bulk of accurate mechanical parts quickly for prototyping or production, find a reputable & reliable manufacturer is very important.
- First you can have the most professional suggestions
- Second, you can get a more competitve & accurate quotations.
Leisheng Machinery is a professional CNC Machining Manufacturer, founded in 1991, located in Ningbo China. Over 20 years experience help them to be the leading CNC Machining Sevices supplier. If there is any requirements, please feel free to get in touch with us & get a quotation.
