CNC turning and milling are two of the most common processed used to create custom parts and components on a lathe.  These areas of precision engineering are the state of the art versions of very ancient forms of machinery – the lathe – which was used back as far as the Ancient Egyptians.  Today’s equipment is very different from those historic versions and works in different ways.  So how do you know when CNC turning is needed for a project versus CNC milling?

If you aren’t doing the work yourself, then the precision engineering firm you are working with will understand these processes and know which one is right.  But it never hurts to understand the basics, what the differences are, and which might be the right one for the job.

CNC turning versus CNC milling

Both of these processes allow users to create patterns as well as add details to metals that simply cannot be done by hand.  With CNC milling, codes are programmed into a computer and the mill then drills and turn along the axes to cut the materials to match the designs entered into the computer.  Programs allow for the most precision cuts while users can also adjust things manually to speed up or slow down the process as needed.

CNC turning uses computer-controlled machines to make the final product.  It has a single-point cutting tool that inserts parallel to the material and makes cuts.  The material is rotated at different speeds to allow the cutting tool to make cylinder shaped cuts to very precise measurements.  It is ideal for circular or tube-shaped parts from larger pieces.  While it is mostly automated, speeds can be adjusted manually.

Benefits of CNC turning and milling

Both of these systems have a few core benefits that make them ideal for a range of projects, ahead of manual or traditional methods of turning and milling.

High precision levels

For starters, CNC machining allows the highest precision possible for any project.  There’s just no way that a human can match the precision of a computer and this opens up many possibilities in terms of what can be made and the size it can be made.  CNC machining can produce hundreds of identical parts down to 0.01mm and sometimes less.

Large quantities

Often a project needs a lot of a certain part and creating these by hand simply isn’t practical.  That’s where CNC machining comes in – it is simple to create large numbers of parts that are all identical and often in a short time frame.  For some parts, a machine can create 30 or more parts per hour – this would take at least three for manual machining.

Speed of manufacture

It is worth mentioning the speed of manufacture again as the benefit of CNC turning or milling.  It can take around an hour to set up the machine then some parts can be created in as little as two minutes while the same piece made manually would take at least twenty minutes.  Even if there is only a need for a few pieces for a prototype, the speed of creation means it can be ready and tested in a very short time, allowing the project to move ahead.

When is CNC turning needed?

Now we have established the difference between these two main types of CNC machining and the benefits they bring, it is worth looking at some examples of when CNC turning is needed as opposed to milling.

In simplest terms, if something is round, you will turn it.  There are plenty of examples of this including things like washers, ball bearings, casters and even chess pieces.  Turning works on rounded pieces and therefore if you need something round, this is the system that will be used.

In the majority of cases, the smaller the batch of parts needed, the more likely that turning is the right choice.  CNC turning is perfect for short run volumes and prototypes that are less than 60-65mm in size.  Anything larger than this and each part will need to be to checked individually when turning is used, which can impact the cost of the production and the time involved.

When is CNC milling needed?

For anything that isn’t round (and a few things that are), CNC milling is a common choice.  It can be used to fabricate a part from start to finish but can also work as a secondary process for something already made.  So, it might be that you have an item that has been created with CNC turning and then milling is used to make further alterations to it to complete the design.

Whatever the project, CNC machining experts will know what process to use – or if more than one is required.  This means you always get the right quality piece for your needs.