In this post we will cover CNC 101. Providing some of the most important things you needs to know about CNC machining. These will include the following:

What is CNC

Why do we use CNC

Types of CNC machines

CNC Turning

CNC Milling

CNC machining materials

Working with Prototype Finder on your CNC project

Do you want to know how Prototype Finder works with your CNC machined parts? Check out our page here all about it. Or continue reading on, so that we can understand what exactly CNC is.

What is CNC

What is CNC and what does it stand for? CNC is an acronym for the words Computer Numerical Control (CNC). CNC can be considered applying modern technology to established manufacturing processes to simplify complex tasks for the user. We program Computers that send Numerical signals and inputs to Control machines. These signals and inputs can make machines perform extremely complex tasks in a seemingly effortless way.

Parts that are manufactured with CNC are now designed on a computer using Computer Aided Design (CAD) Software. This software allows us to build complex models that can be thought of as a numerical 3-dimensional block of information. Computer Aided Manufacturing (CAM) uses this the 3D CAD model to convert the 3D model into a physical object. The 3D model can be created on a computer by a designer that has the appropriate software and the ability to manipulate the software. The 3D Model is then sent digitally to the workshop. A programmer will then create a computer program using CAM software. The program is exported to the CNC machine tool. The machine tool performs a series of tasks that are dictated by the CNC program. The tasks performed are digital signals that are converted into a complex and highly coordinated series of physical movements of the machine.

Imagine a 3 axis CNC Milling machine. This machine as the description implies can move in three axis, just like an old school conventional milling machine. A three axis machine can move in three directions which are designated as X,Y And Z axis. Each axis has a stepper motor on it and the program commands that motor to turn at a given time by a given amount. Sounds simple enough right? The three motors can be programmed to move together to form complex 3 dimensional forms.  This is just one example, of which there are many more.

CNC, or Computer Numerical Control, is the process of controlling computers to work with machines. These machines then preform extremely complex tasks in simple ways.

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Why we use CNC

CNC machining is often chosen over manual control, but why we may ask? Manual machines are cheaper to buy, and for small quantities they are often a cheaper option. Manual machining involves skilled operators performing laborious and complex tasks, it is also costly. Manual machining can produce only a fraction of the complexity and accuracy of the CNC machine. CNC is preferred for many reasons but as in all business it boils down to cost, this is the driving force. CNC machines are faster than manual machines, much faster. CNC machines are far more accurate and capable of producing parts in high volume with a very low margin of error. CNC machines are becoming ever easier to program and operate as the software develops and machines become smarter with the use of sensors and innovative design. The CNC process has overhauled the way we manufacture things over the last 50 years. This has resulted in a broader selection of products available to the consumer, at a lower price than ever before. A great example of how this technology has influenced an industry is the automotive industry. CNC machines are used to make every part of a new car model from the body panels to the smallest electronic components. This is why we have so many new car models entering the market. 40 years ago, a new car model would be a big deal and there would be a big fanfare, today it is an everyday occurrence. Thanks, CNC, for all you do for us!

So, what exactly does a CNC machine do? In simple terms, a CNC machine does exactly what it is “told “to do very accurately repeatedly until we say stop. A robot arm is CNC controlled and will work 24/7 and only needs power to keep going. A robot arm can be programmed to load and unload a CNC machining center to further reduce costs. Here is a CNC machine which is using the milling process.

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Types of CNC Machines

There are many types of machines with CNC controls. These include CNC Milling machines, CNC turning machines, CNC Gun drilling machines, CNC grinding machines, CNC Punching machines, CNC bending machines, CNC injection molding machines and practically every kind of machine that is on the market these days. We not only have CNC machines that cut and bend material, but we also have CNC machines that build things for us. Take for example a Printed Circuit Board Assembly, we have all seen one at some stage. How do you think this was built? Of course, CNC machines or SMT in this case which means Surface Mount Technology.  An SMT machine can build a PCBA at speeds so fast it is hard to even see what is happening.

Most machines that are available come with a CNC controller because it makes the machine more economically viable in a production environment. With some basic training an operator can quickly become able to set up a CNC machine to produce high quality parts at the lowest possible cost for the company. CNC technology is used in the manufacture of practically every consumer product from medical products to biscuits. The device you are reading this blog on would not be possible to produce if it were not for CNC technology. We at Prototype Finder focus on CNC Milling and CNC turning and we will explain about these processes in a little more depth.  

CNC Turning

Turning is a common machining process and can be performed on a manual or a CNC lathe. Turning is a subtractive process. Turning cuts away excess material which results in your final product. In the turning process the workpiece or stock material is clamped in a chuck or other work holding mechanism. The stock material rotates and the cutting tool which is fixed in a tool post is fed into the workpiece in a controlled manner. The computer sends information which controls the spindle speed and feed speed and direction of the cutting tool. In the turning process it is the material that turns.

On a manual lathe, the machine is controlled by the technician via handwheels and levers. A manual lathe requires a highly skilled technician to produce a complex part. On both manual and CNC machines we hold the part in a rotating spindle, clamped into place with collets or in a 3 or 4 jaw chuck, this can be manual clamping or using hydraulics. Since the material is spinning, the shape ends up with a revolved profile. So, a sphere, taper, cylinder, or thread for example is possible to machine on a lathe. We control this machine with a computer which results in a complex precision turned component. It is possible to turn complex thread forms with great accuracy, very quickly compared to the manual process used in years gone by.

CNC turning involves a piece of material placed into a CNC turning machine – called a CNC lathe – and spun in a rotating spindle. While a cutting tool, cuts away at the workpiece to achieve its desired shape. These revolved creations can be very complex with a high degree of accuracy.

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Working with Prototype Finder on your CNC Project

If you are considering having your product CNC machined, please get in touch with us and we will review your design to check for any potential trouble areas before starting. The best time to change a design is before you start cutting the first part. We are a company with many years’ experience working with CNC Machining and CNC Machined Parts. In order to get a quote for CNC machining you will need a number of things which include.

A CAD drawing of your part in either IGES or Step file format (stl files are only possible to use for 3d printing).

A 2D drawing of your part which shows where the threads are and what type of threads.

A 2D drawing which tells us what tolerances we need to achieve for you. The threads and tolerances can be on the same drawing.

A material selection. If you need help with that let us know.

Surface finish and surface treatment, again we can help you decide what is best for you, do you need parts anodized? What color?

Quantity, how many do you need, minimum quantity is one

Once you have all these, drop us an email and we will get back to you, normally within 12 hours. We can produce both low and high-volume production parts for you today! Simply contact us or request a quote our team is happy to help.

CNC Milling

So, what is milling? CNC milling has many different machine combinations and configurations, but they are often classified as either Vertical milling or Horizontal Milling. A vertical machining center has a spindle that holds the tool with the axis of the spindle being in the Vertical position. The horizontal machine is…. You guessed it ! In general think of milling as a block of material carved into a desired shape by a series of rotating cutting tools. The tools are programmed to work away at the workpiece one by one, each tool producing features, drills make holes for example, taps cut threads, slot drills cut slots and so on. We hold down the part onto the machine bed in a vice, using clamps or dedicated tooling fixtures.

The cutting tools are like drills which rotate at very high speeds but differ in the way they cut. Drills feed along their rotational axis to create a round hole. Milling cutters cut on the end to create flat surfaces or on the outside diameter to create flat or contoured surfaces. Milling cutters come in many shapes and sizes and can create a broad range of shapes. Imagine a sculptor carving a statue from a marble block, a multi axis CNC Milling machine can produce a similar shape much faster. Of course, the milling machine differs in that it uses a rotating cutting action rather than a chisel cutting action. Now you get the idea and can understand what milled components are. Milling machines can work with a variety of materials. From wood, metal, composites, and many others, and if set up properly can produce accurate identical parts in the most cost-effective way.

CNC milling involves a stationary or semi stationary block of material. This gets carved away by a rotating cutting tool, to the untrained eye it looks like a drill. These tools can produce flat or sculptured surfaces and parts and are used only on milling machines.

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CNC 101: Machining Materials

CNC Milling and CNC turning machines can work with a wide variety of materials. These materials include Aluminium, Steel, Copper, Bronze and many others. Additionally, plastics and composites are often used to machine prototypes and production series parts. We have manufactured carbon fibre parts for drone frames for example, this material was used because of its light weight and stiffness.

The important part when it comes to material selection is ensuring it works in the designated environment. It must have the requisite structural integrity and be able to withstand the chemicals and temperatures it will be exposed to.

Aluminium is a very popular choice when it comes to CNC manufacturing for several reasons. Aluminium is a low-cost material that is easy to machine, it has a good strength to weight ratio and can be anodized in a broad range of colours. Anodizing provides a very durable and attractive protective coating to aluminium products at a low cost. If you are unsure which is the best material for your next part, you can always contact us and we will assist you.

Another form of CNC cutting is with water jet cutters. They utilize high-pressured water, mixed with other materials to cut even the hardest of metals. Many factory parts are often built by way of this process.

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CNC 101: Conclusion

In this article, we have covered CNC 101.  We have given you an overview of some things you need to know about this machining process. We hope we have given you a better understanding of CNC. Our founder has been working with CNC technology for almost 40 years and he just loves it. His experience in CNC machining spans defence, automotive, oil and gas, aerospace, and many other exciting areas, but the most exciting project, is always the next one.

Does your next part require CNC milling or turning? Unsure which process you will need or even the material you will require? Simply ask and we will do our utmost to assist you.

If you enjoyed this article, make sure you check out our other ones. In which we cover a wide array of topics. How about looking at our Blow Molding vs Injection Molding to see which is the best process? Or try China Metal Sheet Fabrication to see how we fabricate sheet metal. Learn more about PTFE (Teflon) to find out about this incredible material. These and many more are featured on our Blog.