CNC Basics - What You Need To Get Started

- Oh, (beep). (drill whirring) If you are unsure about purchasing a CNC router, this is the video for you. Let's take a look at the main workflow used to run a hobbyist CNC router. This video will focus on three-axis CNC milling machines, which are the most popular among hobbyists. This includes LongMill, Shapeoko, and X-Carve, to name a few. Notice that they all have three axes. X, Y and Z. The basic workflow required to execute these can be divided into three main sections. First, you come up with a really clever design on the computer. Second, you take the design and create instructions that describe how to carve it.

This process is called CAM, we will talk about that later. Third, we must deliver these instructions to the machine. This is usually done with a digital interface. Then we can press the start button and the machine will cut out the design. Of course, each of the three sections has many different subsets. Let's delve into each section. The first step of the process is often called CAD, which stands for computer-aided design. It simply means that we are using computer software to create the design. This is where most beginners start to sweat. But I promise you it's not as difficult as it seems.

For starter projects, you can use simple 2D graphics programs like Inkscape or Illustrator. The other end of the spectrum are professional-level CAD programs like SolidWorks or Fusion 360. In the middle, there are programs created specifically for hobbyist CNC machines like CAMLab, Carbide Create, and Easel. The software you choose will also depend on the type of cut you are trying to create. Most CNC projects use one of three different cutting strategies. First, we have 2D slices. This is when we simply have the machine trace an object and cut it out. Things like letters and basic shapes. Secondly, we have three-dimensional cuts, where the machine uses all three axes at the same time.

This method is used for more complex projects. Between these two, we have 2.5D. This is when we simply follow simple shapes, like normal 2D cuts, but tell the machine to cut deeper into a certain area. It's not a true 3D slice because the Z axis never moves at the same time as the Y or 3D to make it easier to see

what

we are cutting. Comment below which of the three cutting strategies you think this design requires. Once we have created the design, we

need

to create the instructions for the machine. This second step uses CAM or computer-aided manufacturing.

That means we are using a computer to control a machine that can make things. Remember, CAD is design and CAM is manufacturing. Fusion 360 is my preferred software because it does CAD and CAM in the same software. It's also free for fans. You can also learn Fusion 360 right here on my YouTube channel. The first step when creating our CAM instructions is to define our material. I'm going to cut the ice cream emoji out of a piece of wood, so I'll enter the dimensions into Fusion 360. Second, we

need

to choose our cutting tool. The cutting tools will have to be in a separate video, but the number one takeaway is that our cutting tool should be smaller than the objects we want to cut.

A 1/4 inch end mill physically cannot drill a 1/8 inch hole. Then we need to tell the software

what

tool we are using to make sure it will work with our form. We can also define the speeds and advances. This concept often intimidates newbies, but it's much simpler than most think. Cutting speed is defined as how fast the cutting tool moves relative to the material. You can think of this as the speed limit. Feed rate is defined as the distance the tool travels during one revolution of the tool. Most hobby projects are for common materials like MDF, plywood, or hardwoods.

Therefore, we can simply copy and paste the ideal numbers from online cheat sheets. You don't need a degree in mathematics or engineering. These cheat sheets are a great starting point when you're just starting out and you'll eventually learn what speeds and feeds work best for you. Once we have defined our material and bit info, we must write the body of the instructions. This is where we tell the software which shapes to crop. We refer to these as trajectories, or the path through space that our cutting tool follows. How to achieve this will vary from software to software.

But as you can see, this is pretty easy in Fusion 360. I've set up a tool path for the interior design and a 2D outline tool path for the exterior shape. The biggest advantage of CAM software is that we can simulate our cut before sending it to the machine. This helps us detect any potential problems before we destroy our material or, worse yet, break the machine. Beginners often get frustrated when the machine doesn't follow instructions. But the problem is that the machine follows all the instructions. When something goes wrong it is because we gave an instruction that was not our intention.

We finish creating our instructions once our configuration and tool paths are complete. At this point, we must hand them over to the machine. At this moment the instructions are on our computer and the machine does not know them. To send the instructions to the machine, we will need to export them in a language that the machine can understand. Most machines read something called G code. The "G" stands for Geometric. The best thing about G code is that you never need to learn how to write it, since the software does everything for us. However, as you delve deeper into the world of CNC machines, you will find that having a basic understanding of G-code will help you avoid unwanted problems.

Simply put, G-code is written to tell the machine where to travel. Remember that our machine has three axes. For now, let's forget about the up and down Z axis. Our machine now only moves in the X and Y directions. This is similar to a graph where the points are plotted on a Cartesian plane. G-code includes lines of code that map out each shape of the design. Remember our toolpaths? They dictate what the software includes in the G code. Now, there's a little more to it than that, but hopefully that gives you a basic idea of ​​what's going on.

Once we have our G code, we have to find a way to get it to the machine. Hobbyist machines typically have a control box that includes a microcontroller, such as an Arduino. That means we will need to use our computer to communicate with him. Depending on the machine, this can be done directly from Fusion 360 using a plugin, or we can use GRBL, which is an open source CNC controller. This allows us to open the G code generated by our CAM software. First, we need to secure our material. We can simply screw the material, fix it with clamps, use double-sided tape or a vacuum table that sucks the material.

We also need to place the appropriate drill bit in the collet. Remember that this has to be the same as what we defined in the CAM software. Next, we must place the machine in its initial position. With most hobby machines, we will have to do this manually. Most hobby machines also require us to manually adjust the speed of the router and turn it on. Then we can simply press the Run or Play button and the machine starts cutting. We keep our fingers crossed that our instructions only include what we want. Remember, if the machine travels where we don't want it to, then it's because we told it to do something we shouldn't have done.

Most errors are due to unknowingly including features or settings. Thank you for staying until the end of this video. You can help me by pressing the Like button. And let's see if we can get 5000 likes in the first week. If you're ready to dive into the world of CNC machines, be sure to subscribe. I will have many Fusion 360 CAM tutorials and CNC projects coming soon. If you're ready to learn Fusion 360, click on that playlist in the bottom right corner.