Are You Ready for CNC?Comments (0)
This article is from Issue 91 of Woodcraft Magazine.
Three woodworkers share their experiences in bringing computer-controlled woodworking into their shops
By Ken Burton
I started using CNC (Computer-Numeric-Controlled) machines about 12 years ago when I purchased a small Shopbot model for the Tech Ed program in the high school where I teach. It didn’t take long for me to see how I could take advantage of the technology in my own shop and I haven’t regretted getting my own.
Today getting started with CNC is much less expensive than you might think. You can buy a small CNC router kit for under $800 or about double that if you want one that is ready to go right out of the box. This will get you a machine capable of cutting a piece of material about 12" square. The price jumps to about $2400 for a 12 × 24" model and to about $6000 for a 24 × 48" version. If you’re interested in using the machine for furniture making, this is about as small as I’d consider. Machines capable of cutting a full 4 × 8' sheet of plywood start at about $12,000.
For the money, you get the router along with the software necessary to run it and design basic shapes and toolpaths. This software is usually specific to the machine you buy, although most CNC software will accept files from more sophisticated CAD (Computer-Assisted Drawing) programs such as SketchUp or Autocad.
To give you some idea as to how a CNC machine might fit into your shop, I spent time with three woodworkers who have taken advantage of this technology. Their observations and advice can help you answer the question at the top of this page.
Campbell-Strasser Cabinetry and Architectural Millwork
4 × 8' Shopbot
Software: Shopbot Partworks (a form of Aspire)
Favorite bit: 3⁄4"-dia. × 45° V bit for chamfering inside frames.
WM: How did you get started with CNC?
JS: At that point I had been designing on the computer with AutoCad for four or five years so it wasn’t too big a stretch to move to a machine that actually cut along the lines I was drawing instead of simply printing them.
WM: What do you use your machine for?
JS: The question might be better phrased as: “What don’t I use it for? It’s like having and extra guy in the shop. Anytime it’s not a straight line, I think about how I can get the router to do it. It makes incredibly accurate templates, so curved work becomes a lot more affordable. Plus we do some ecclesiastic millwork, so we use it for floral carvings, fleur-de-lis, and inscriptions—work that I’m not sure how I would do without the router.
WM: What advice would you offer someone getting started with CNC?
JS: Get comfortable with the software—particularly on the drawing side. If you’re comfortable with drawing on the computer, the transition to CNC work is a lot easier. Take the time to make sure your machine is set up right and check this every few months to confirm that nothing has changed. To do so, cut a few squares and check the diagonals to make sure they are actually square. If you use a spoil board, use the router to cut its surface level so your Z cuts are truly consistent.
WM: What did you find most challenging about learning to do CNC work?
JS: As with any tool, you have to learn what it is capable of. The weak point is often the bit. You’ll probably break a few before you are comfortable with how hard you can push them. Also, it took me some time to learn how to sequence the cuts I was making. You’ll want to think through the whole series of cuts, so you don’t cut away support for a subsequent operation.
For example, if you have several interior cuts to make on a board, do them first before doing the overall cutout.
Three Gryphons Carving Studio
Shop Sabre 48 × 96"
Software: Aspire & Enroute
Best bits: 1⁄8"-dia. ball nose for carving; 1⁄2" compression bit for clean through cuts.
WM: What made you decide to buy a CNC machine?
NP: I worked as a cabinetmaker for about fourteen years before branching off into woodcarving. After a couple of years as a professional carver, I found I just couldn’t keep up with the demand working by hand. To build my business, I had to find a more efficient way of working. CNC seemed to be just the ticket. I was glad I took the plunge because when the recession hit, the CNC part of my business kept me going.
WM: What kind of challenges did you find as you got up and running?
NP: The first year was insane. Getting the machine to work was pretty easy. It was the design part that was tricky—especially setting up to cut 3D shapes. These days, some of that fussy design work has gotten easier. You can actually purchase 3D files online. There are even places that will generate 3D files to your specifications—for a price, of course. You’ll pay quite a bit more if you want exclusive use of those files. You can defray some of the cost if you allow the designer to resell the files to other users.
WM: Do you think using a computer takes away from the craft?
NP: I’ve changed my mind about that. The artistry is still there. You still have to visualize and design your work. But you’re adding to your capabilities by developing a different set of skills. Even if someone wants something “hand-carved,” I may rough the piece out on the CNC machine and then finish it by hand. To those woodworkers who consider that cheating, I ask: “Do you hand-plane all off your lumber, or use a jointer and planer to save a little of the grunt work?” It really is the same thing.
WM: What advice would you offer to someone getting started with CNC?
NP: Incorporate CNC into your workflow with realistic expectations. The software isn’t perfect, and it will take time to fully explore the possibilities that exist with CNC. Like any other aspect of woodworking, it takes practice—and more than a few mistakes—to improve your skills. If you’re having trouble, you can be sure that there are other CNC users who have already figured out what you’re trying to do. So take advantage of the on-line community of users and tap into their collective knowledge.
Laguna IQ HHC (24 × 36")
Favorite bits: 1⁄8"-dia. ball nose for carving; 1⁄2" straight bit for cutting parts to size.
WM: What prompted you to get a CNC machine?
TH: I got started with woodworking by making pens on a small lathe. With several dozen pens under my belt, I started thinking it would be cool if I could add some graphics to them, which led to the purchase of a small laser engraver. From there it wasn’t that big a step to a CNC router which could cut things out as well as engrave them. I’ve been at it for about two years now.
WM: How did you learn how to run the machine?
TH: I’m pretty much self-taught. There are tons of online resources available, including plenty of instructional clips on YouTube. I also belong to a CNC users club, which is a great source for advice and new ideas. One of the things I like about being a part of the CNC community is how collaborative everyone is. It is so different from the pharmaceutical industry where I make my living. There, everyone seems to be trying to take advantage of everyone else.
WM: Are you happy with the capabilities of your machine?
TH: I upgraded my machine almost immediately, replacing the stock router with a water-cooled spindle. I paid about $700 for this extra, but I’ve since seen them online for about $400. I really like the new spindle. It runs quieter, does a better job of controlling dust, and can handle extended run times with no problem. Some of the carving files I’ve run can take as long as 12 hours to cut.
WM: What kind of things do you like to make?
TH: Signs, boxes, plaques...lots of wedding presents. I’ll stop along the street when I see something I like and just stare at it, trying to figure out how to make it. Nine times out of ten, I just give away the things I make. I hung a sign I’d made up in my office and a lot of people saw it and wanted one. I could probably start a business making things like that.
WM: What advice would you offer to someone getting started with CNC?
TH: Remember the machine will only do what you tell it to do. Take your time and think through each process. You can usually figure out where your mistakes are going to happen, especially if you watch the on-screen simulations carefully. These video previews will show you exactly what your toolpaths look like. Until you become confident in your abilities, run them in slow motion so you can really watch what’s going to happen.
Item 161354Model 10011
Item 167551Model 10024
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