WoodEzine:

Thinking
About
CNC?

(Click here for our guide to CNC terms)

 

“We believe that everyone can learn to use CNC tools, and the increased productivity and capability these tools offer will pay for your efforts many times over. It’s not hard, but it does take time.” ShopBot Tools

You have nothing to fear…
Fortunately, you’re not the first person to think about doing this.
Ted Hall, the president of ShopBot Tools Inc. has a little test on his site that you might want to take. It’s called the CNC 101 readiness test, and he uses it to figure out how long it will take a potential customer to learn how to run one of the company's machines. The questions have nothing whatsoever to do with woodworking: they are about how comfortable you are with computers.

And that's the point. Adding a CNC is not about working wood: it is about working a computer. The challenge with CNC is not making the machine do what you want. It’s learning what the machine is capable of, and then working within those limitations. The learning curve is actually quite short. Yes, it takes a bit of effort and time to learn the basics, but once there, you’ll fly. It’s a bit like teaching a new employee how to run standard equipment. Once he/she spends a day on a table saw and learns how to avoid kickback and use a fence, they're up and running.

 

Shown above is The ShopBot Desktop MAX
Once you figure out how to use CNC software to make the parts for your first cabinet, it’s a whole lot easier to make the next one. Yes, the table saw is scary when somebody has never run one, but if they follow a few simple rules they can make it sing. Yes, a CNC router is scary when you’ve never run one, but follow a few simple rules and you can make it sing, too. That’s a pretty healthy attitude to have when approaching new technology. Concentrate on the fact that you’re going to have to spend some time learning this, and not on the fact that you don’t know anything yet. If you’re smart enough to be in the position where you’re considering the purchase, then you’re certainly smart enough to run it.

Shown above is the Thermwood Cut Center
  So, here’s the process.
First, turn off the CNC, because that’s not where the journey begins. You won’t be machining anything for a while yet. Before you do, you'll need to learn how to run some software. That involves two things: figuring out how to draw something, and then figuring out how the machine can cut the parts for what you drew. The first of those, the drawing program, is called CAD (computer aided design). It’s actually kind of fun, and nowadays there are so many libraries (collections of drawings in the form of computer files) that you’re hardly ever starting at scratch. In fact, a company in Indiana called Thermwood builds a machine called the Cut Center (at left) that can start cutting furniture or cabinet parts with no custom programming, no computer and no software. Just turn on the touch screen, select a project from the library, plug in your custom sizes and start feeding material to the machine. This CNC is so intuitive, any employee can run it. The screen asks a few questions in plain English (no computer-speak), and then goes to work. If you need to build standard cabinets, that is a great way to go. But if you want to be more creative, you’ll need to learn how to draw.
CAD is more of a skill than an art. It doesn’t require innate talent: it can be learned. One of the best ways to tackle the learning curve is to start exploring software before you choose a machine. There are countless night classes and weekend seminars out there – just call the local community college or have a look on our Schools page. There are also numerous online courses, where you sit at your own computer and create things. A good example is Carbide 3D's free Crash Course in CNC. To get yours, click on this link and then scroll almost all the way down the page. Most software packages have tutorials and support groups. And many of the CNC manufacturers will let you play in their showrooms or classrooms until you get up enough speed to start looking at machine options.

Once you learn how to draw, the next step is to tell the machine how to translate your drawings into actual parts. That’s called CAM (computer aided manufacturing). Here, the key is toolpaths. First, you figure out where and how to attach the raw material to the machine (clamps, nails, screws or vacuum). Next, you determine the router bit’s starting point in three axes (left/right, back/forward, and up/down). With the workpiece locked down and the starting point established, the cutter can now follow what is known as a toolpath. This tells it how far to travel, how fast to move across the work, how fast to rotate on its axis, and how deep to cut.

For a list of available software programs (and most have both CAD and CAM), click on our CNC page. There you'll find more than two dozen companies that publish programs. And even though it will confuse the living heck out of you at this point, it is still a good idea to click through them briefly and just see what they're about. The more you expose your mind to the concepts, the more things will begin to fall into place. It's an ancient theory of learning: if you throw enough mud at the wall, some will eventually stick...

 



If you have the time and the means, a day or two at George Vondriska's shop in Wisconsin is a wonderful way to learn the basics of smaller machines. George has been teaching for a long time, and his very affordable courses cover topics such as designing in VCarve Pro software (common to many CNC machines), how material is secured to the work surface of the CNC, zeroing of the X,Y, and Z axes, bit changes, and how cuts are made on the CNC machine.



For woodshops looking at medium to large machines, most manufacturers will go out of their way to show you what's available. For example, CNC Factory in California invites serious shoppers to spend a day at the facility looking at every aspect of their machines, and they'll even pick up your travel expenses in many cases.

  Laguna Tools has a really focused page on its website asking the question: "Why should I invest in a CNC?" The company points out that a CNC will reduce waste, reduce costly errors and increase productivity. You'll also be able to cut down on the number of machines in your shop. And if you have questions about a specific process, you can send the company a rendering and they will test it (within limits) on the machine you are considering, and then send the piece back to you. At left is a photo from one of Laguna's customers, Camp-Inn, which is based in Necedah, Wisconsin. Co-owner Cary Winch says that the heart of their production centers on a SmartShop II router that's equipped with a two-pump vacuum pump (for holding work in place), an eight-tool tool changer, and a dust collector. The tool-changer means that he can load several tools on the machine and as each one is needed the CNC selects it automatically, so there's no downtime while Cary looks for wrenches. "It’s like having an employee who works for free," he says.
When you're shopping for a CNC, think about how it can be expanded over time. For example, many machines will accommodate a device called an aggregate head, which essentially adds another axis to its abilities. It can hold more than one tool, and can twist and bend in ways that let you get at the work from angles that a standard spindle doesn't offer. The bottom line here is that a woodshop needs to do some homework before going shopping. The more educated you are, the better purchase you will make.

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