What Is a CNC Machine?
CNC stands for Computer Numerical Control, and it just means machines whose cutting is controlled via computer.
What’s Different about Wood CNC machines?
Nothing has to be different about a Wood CNC Machine. There are plenty of companies that use “regular” CNC Machining Centers to cut wood. But, it’s a lot more common to see a CNC Router being used for cnc woodworking. They have a large work area suitable for large flat projects, such as things made with plywood. And, various other characteristics are traded off on a CNC Router versus a traditional CNC Vertical Machining Center (VMC).
For example, wood cnc routers will be a little less rigid and therefore can’t hold as tight tolerances as a VMC. For most woodworking, less precision doesn’t matter and tolerances are plenty good enough on a cnc router. CNC routers typically have less z axis travel than most general purpose VMC’s as well. Again, that may not matter as most wooden boards don’t require much z axis travel.
Another wood cnc machine is a laser engraver. These machines use a laser beam to engrave or cut wood by burning through it. It’s also possible to buy a laser module that changes your own cnc router into a laser engraver.
What to Look for When Buying a CNC Machine for Woodworking
It’s all about the trade-off between the various features and your budget. If you’re starting a business, my suggestion is to shoot for good enough but no better. You may find that buying “too much” cnc router leaves you short on budget that is needed for other things–such as advertising to help acquire customers.
CNC Router Kits or even DIY CNC Routers can provide considerable savings while still being functional enough to build a business around.
Software for CNC Woodworking
Here’s the basic software suite for cnc woodworking:
- CAD Software: Use it to design the parts you want to make with your router.
- CAM Software: Feed it the CAD model of the part and CAM software will produce a g-code program your CNC Router can run to make the part.
- Feeds and Speeds Software: Every cutting tool, material, and situation demands a different recipe for feeds (how fast the cutter is fed into the material) and speeds (what rpm the spindle is running). Make sure your Feeds & Speeds software is setup for CNC Routers. You can’t use just any old Feeds and Speeds program because routers have different needs.
You will want to cover all three bases.
A good software package may incorporate the CAD and CAM into the same package. For example, Aspire and Autodesk Fusion 360 are that type.
Laser Engravers use their own forms of software for the most part, much like 3D Printers do as well.
Sample the software before buying
A major point is any cnc machine software you get into should have a free trial. By all means, exhaust that free trial by really using the software before you spend a dime on it.
There are different kinds of axis on a cnc machine.
CNC Machines have at least 3 Axes (ok, lathes use only 2, but lets save those for another time!). Some applications require a 4Axis CNC Router.
An axis consists of some kind of sliding “ways” and a drive system that motorizes the axis under computer control.
There are several kinds of sliding ways commonly used for a CNC Router:
V-Grooves involve using ball bearings with wheels that often have a V-shaped groove in them. These wheels ride on the edge of a rail of some kind. V-Grooves are the most inexpensive way to suspend an axis, but they’re also the lowest performance.
Round shafts use ball bearings and can be quite a bit better performers than V-Grooves. The highest performance are linear slides, which have a prismatic shape and trucks that ride on ball bearings. They’re standard equipment for the best cnc machines, especially if the machine is capable of working on metal too.
For more on Axes, see our full article on CNC Router Parts.
Axis Motors and Drive System
The CNC Router’s Axis Drive converts rotary motion from a motor of some kind to linear motion to drive the axis on its sliding ways.
There are several common Axis Drive in use for these machines:
When choosing your drive system, a number of factors must be considered:
- Conversion of the motor’s torque to rapid movement speed at the rpm where the motor’s torque peaks.
- Elimination of backlash or lost motion, which can reduce the accuracy of cutting as well as lead to other problems.
- More specialized issues such as ballscrew whipping on long axes.
Some machines use different drive systems on different axes. My Shapeoko Pro has belt drive on the x axis and y axis and a ball screw on the z axis.
Also part of the drive system are the motors, and any drive connecting the motors to the rest of the drive. The most common type of motor used are stepper motors, but servos are a higher performance option.
Stepper motors perform well in all but the highest speeds and tightest tolerance cnc woodworking machines, so don’t be afraid to consider a stepper motor equipped cnc machine.
Some say the Spindle is the heart of any CNC Machine, including a cnc router. It certainly plays a major role in setting the performance potential of the cnc machine.
At the low end, a CNC Router will often use a regular hand held router or even Dremel-style tools as spindles. A step up from that is a spindle with a VFD. At the top of the heap are spindles set up for ATC–Automatic Tool Changers.
BTW, there are special CNC Router Bits that are largely about reducing splintering in wood.
Table Size and Bed
Bigger cnc machines have greater capacity for doing work. You can put an entire 4×8 sheet of plywood on such a cnc machine, for example. That lets the machine get more work done automatically before you need to take off the parts and load more wood as well as allowing it to take on larger projects. That’s why the best machines are a larger machine with an extended table that can accept a large workpiece.
OTOH, a big cnc machine costs more money, and if they are to maintain rigidity and decent tolerances, they will weigh more too.
You can get a lot of work done on a mini router or compact router.
Controller and Electronics
Your cnc machines controller is the gizmo that goes between your computer and the cnc machines motors. You usually plug into a usb port to connect the two.
Often, the controller consists of a single all-in-one control board.
Be sure your cnc machine includes limit switches or home switches.
Dust Collection System
Dust collection may seem optional, but you’ll sound find it isn’t. Without one, dust gets in everywhere and will eventually jam up the operation of your cnc router. Do yourself a favor and start with a dust shoe at least. It can help make for easy maintenance of your machine.
Community and Support
This is going to be very important unless you are already an experienced cnc router user. You need to find a community, and the maker of your cnc router needs to give good support for the machine. CNC Woodworking can be a lot of fun, but you need to get the right help and mentors.
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Recently updated on August 17th, 2023 at 03:02 pm
Bob is responsible for the development and implementation of the popular G-Wizard CNC Software. Bob is also the founder of CNCCookbook, the largest CNC-related blog on the Internet.