Question: What is a CNC Machine?
Answer: A CNC machine is a computer controlled machine.
Ok, I know what you are saying! Tim, you cannot define a word by using the same word in the definition. You are right. If you are like me, it drives me crazy when people define a term by using that very term in the definition. Let’s take a deeper look at the questions “What is a CNC machine?” for a better understanding.
A more complete definition
A CNC machine at the most basic level is nothing more than a computer controlled machine. CNC is an acronym for Computer Numerical Control. You can read more about Numerical Control here. Typically when people talk about CNC machines they are referring to machines used in the industrial manufacturing world. These machines build the things we use everyday. Examples include, mills, drills, lathes, routers, plasma & water jet cutters and many more. Almost any machine used to manufacture a part that is controlled by a computer qualifies as a CNC machine. Naturally, all of these machines come in a variety of shapes and sizes. Many of the high end CNC machines cost hundreds of thousands of dollars & weight many tons. However, as technology improves the component cost is reduced. In turn, the cost to build a CNC machine comes down. We are at a price point now where the technology is accessible to the weekend hobbyist and maker. Granted, these DIY machines are not as fast or as powerful as the expensive industrial version. However, they open the door to really exiting home manufacturing opportunities.
An industrial CNC machine also called a VMC – Vertical Machining Center
Why would someone need or want a CNC machine?
The marriage of computers and machinery allows us to make a large quantity of the same part quickly. Yet maintain the flexibility to make a bunch of different parts all on the same machine. Essentially a CNC machine can perform most of the tasks a manual machine could in addition to those that only a CNC machine could.
A real world example…
Say you wanted to make a cutting board. The traditional method is to saw the raw lumber on a table saw and glue all the pieces together forming a cutting board blank. Once the glue is dry you cutout the shape. If you want a square or rectangular cutting board, this is no problem with manual woodworking tools. But what if you wanted your cutting board to have the outline of the state where you live? You would need to find an outline of your state, transfer the shape onto the cutting board blank and then manually cut on the line using a jig saw, scroll saw or coping saw. This is completely doable if you are only making one or two. What happens when your friend sees the cutting board and wants their own? You start the entire process again from the beginning. If however, you owned a CNC router, you could use it to cutout the shape of the state from the cutting board blank.
The same cutting board made with a CNC router.
The process would look something like this. Instead of copying the outline of your state onto the cutting board, you upload the outline into your CNC machine. We will talk more about uploading files to a CNC machine in detail later. You make the blank as described above but once complete, you install the blank on the cnc machine. Hit “cycle start” on the CNC router and the machine will automatically cutout the shape. This is where the real time and effort is saved. No tracing or sawing. Just sit back and sip a tasty beverage while the machine does the work. Then when your next friend wants a cutting board of their own, all you have to do is make another blank, setup the CNC router and hit “cycle start” again.
CNC Machines are great! I could and have watched hours of machines doing their work. However, there are limits. The machines must be programmed and will only do what an operator tells them to do. The applications where artistry and craftsmanship are required are less adaptable to CNC Machines. Often, CNC machines can do the repetitive work for a craftsman to allow them to concentrate on the artistry of their work.
Final Thoughts
How could a CNC machine help you? Let me know in the comments below. Note sure if a CNC Machine is a good fit for your application, I would love to hear about that too.
Thanks for reading. Until next time…
Tim
Wow i had no idea that machines I use in my workshop had come this far. So many times I’ve wanted a very specific or precise task done and brushed it off thinking it impossible. I’m definitely going to tell my mates about this. Thank you for the information!
I really like the idea of using a CNC machine. Like you said, the benefits of combining computers and machine has allowed for making large quantities of the same part. The other great thing is that the are precise and consistent from part to part. I think that is a really big deal. Customer want to have consistency, and be able to rely on the part fitting every time.
Bob, Thank you for the comment. I agree. There is a certain peace of mind from knowing the 1st part will fit like the 100th.
I think CNC machines are so interesting. Just the fact that you can have a computer control a machine to make it act with tight precision. I love to see how technology allows us to function precisely. Thanks for sharing!
Braden, thank you for the comment. I agree it’s pretty amazing especially considering how the cost keeps coming down making the technology even more accessible.
I think that CNC machining is really cool and I would love to see it in person. It seems to have a great advantage because it is very precise compared to conventional methods. I can see why more and more companies are using CNC machines. Thank you for the great article!
It seems there are a lot of benefits to using a CNC machine for manufacturing. I like the idea that it can save so much time and money by automatically cut out a shape rather than using a table saw. Not to mention the precision that it brings as well as the large quantity of cutting that it can do.
CNC machining is so useful these days. From what I have heard, there are a lot of items that we get because of machining. It definitely has made mass production a reality and made it a lot earlier to make things more available. I know that now we don’t have to worry about running out of products because of how fast we produce them.
Charles – Good insight. The high end production CNC machines can really make parts very quickly. Way faster than my Harbor Freight Mini Mill.
I don’t think that CNC machines are used just because they can do a job quickly and without needing to start from the beginning every time. I think it is also a matter of accuracy. CNC machines are often used to make the parts in airplanes, parts that have to be extremely precise. A regular worker might be able to do this, but not nearly as well as the computer can.
James – You are right. There are any number of good reasons to use a CNC machine. Thanks for the comment.
I appreciated the real world example that was used to show how a CNC router could be used. People talk about how nice it is to have. However, it’s hard to relate unless a real world example is used in their explanation.
Thank you so much for this article. I’ve been hearing about CNC machines for months now, but have had no idea what they are. It seems to me that their function differs from machine to machine, but their main purpose is just to create something (usually intricate metal parts). I think every time I come across a computer chip or strange piece of metal, I will remember this article and how the object was created! Thanks again for clearing things up for me.
Thank you for great article.
Ibrahim – You are welcome. I appreciate the feedback.
Thanks Tim for the helpful writeup on CNC machines. I recently lost access to my old router and I’m currently looking at getting a new one – as I’m sure you know, they can be crazy expensive. In looking for options that are a bit cheaper, I came across this page, which talks about a program that supposedly teaches you how to make your own CNC machine at home for under $1000. I’m a bit skeptical and I was hoping to get your thoughts on it. If you prefer not to comment, no problem, but I thought I’d mention it anyway. Thanks again for the article.
Jim – Sorry to hear you lost access to a CNC machine. Were you a casualty of the TechShop debacle? I would never buy the plans/videos offered on that site! Where are the pictures of the finished machine? Where are the testimonials from people who have actually built one? You don’t have to take my word for it… Check out the reviews on Amazon If you are interested in buying some plans, send me an email at Tim@DIYMachining.com and we can talk about what plans might be right for you. Just so you know, I don’t have any to sell you.