Getting educated on CNC's

[John Loftis]

Hi folks,

I'm trying to get educated on CNC's for woodworking (cabinetry + cutting some smaller hardwood parts). The big industrial machines I saw at AWFS and IWF are incredible, but not realistic for us right now. So when you start dropping down in price, there are inevitable compromises in quality, size, speed, etc. Since I've never run a CNC, it's really difficult to know how to prioritize those features, which features to insist on and which to treat as 'nice to have,' etc.

It also seems like we have a decision between used and new, where we could get a more robust tool with some years on it or a newer machine with less. My gut says that unlike most big power tools, 'old iron' is a very risky proposition in a CNC... but I don't know that for sure. I would guess that CNC's are more susceptible to abuse than other machines, plus the computer controlled aspects of them could become antiquated/irreparable. I have this image of sticking a punch card in a slot on a 1979 machine...

Can anyone recommend a resource to help me get better informed? I know there are dozens of manufacturers of machines in the category I'm looking at (4X8, ATC, small professional shop), and my thought is once I have a prioritized list of features, then it becomes easier to compare one maker's machine to another's.

[Jesse Busenitz]

Never ran CNC, but I'm basically in the same boat you are, and was looking at Camasters and Shopbots as they seemed to both be a good starting machine but as was stated, no experience here.
Hopefully some one who knows more can help you.

[Keith Outten]

Both ShopBot and CAMaster are reliable machines. ShopBot paved the way for small shops to be able to add CNC machines and I believe ShopBot is the current leader in the number of machines shipped today. CAMaster has designed their machines from the ground up based on welded frames that are rock solid and their company continues to grow in the marketplace.

Its difficult to start with a lesser machine than these two companies provide, due to cost and other factors buying smaller machines with the expectation of trading up at a later time is an expensive ordeal. Its best to start with a proven machine, often there will not be a need to move upward as your knowledge and quality of work increases.

If either of these two companies could develop a less expensive machine that was reliable they would be selling them right now. Experience has proven that the lower limit of component quality can never be reduced if a machine is to be reliable and robust enough to be productive.

My 2 cents.....based on owning both a ShopBot and a CAMaster and many years of listening to others here.
.

[Ken Fitzgerald]

Though I have worked with computers, computer-assisted equipment and some very sophisticated electronics since the late 60's, I had never encountered CNCs in any form until last Thursday. My wife and I are having a kitchen bump out built on our home, new lighting, cabinets, etc. We are going with granite countertops. We were looking at some very beautiful Brazilian granite that had a stunning pattern that varied dramatically from one end to the other of the 10' by 6' slab. The young man assisting us proceeded to explain how they would move the granite "slice" to a work table and photograph it. Then they would take the template that they had made of our new cabinets and measure it. They made multiple patterns from the template and transferred them temporarily to the photo of the granite. To match the intricate pattern in the stone as the traversed the room, they may have to cut from more than one consecutive granite "slice" thus the more expensive cost of that particular granite. When they are finally satisfied they can make a seamless counter top even if they have to cut from more than one slice, they transfer the patterns to a CNC, position the granite slice/slices on the work table and calibrate the CNC to the granite slice. The CNC then directs a water jet to cut the stone. I was impressed!

[Bruce Page]

Both ShopBot and Camaster are American made and have excellent support forums. I spent weeks reading these and asking questions to acclimate myself before purchasing my Camaster Stinger.

If you want to PM me an email address I can send you a PDF, "Understanding CNC Routers" that I found very helpful. It's file size (3.8mb) is too large to post here.

[Erik Loza]

John, is this for a hobby shop or production use? And if production, what kind of volume are we talking about?

I don't sell CNC's but know a bit about them from SCM's various lines.

Erik

[John Loftis]

Bruce, I PM'd you. Eric, I have a 2 man shop. I'd love to tell you I'm doing a kitchen a day, but I'm not. I do more furniture than cabinetry, but a CNC could allow me to ramp up production on cabinetry significantly. I was recently contacted by a guy who would need a fairly steady amount of CNC work done, and that has created new motivation to see if I can make this happen.

I've glanced at Laguna's Smart Shop 2, Camaster's Cobra, and have messaged a company that rebuilds old big boy machines. And I've drooled over Biesse, Thermwood, and the other machines I flatly can't afford.

I'm also concerned about the 'all in' price, since I know that accessories such as vacuum pumps, software, etc. can be huge with CNC's.

[William Adams]

Has anyone ever written (or found) a good article comparing /discussing the various classes of machines, their tradeoffs, similarities and differences?

In particular, which machines cross over, or come closest to performing out of their weight class?

For bonus points, the article would consider affordable and innovative new technological developments and potential programming and sensor development which would allow a lightweight, hobby level machine to know where it is and thus not miss steps? A good example of the latter is the LoboCNC which uses commercial encoding technology to determine its position — there was a more affordable control board for a while which used a PS3 processor to do this, at a lower price point than the stock setup (I think it also took advantage of a brief availability of encoding strips?).

Other examples would include Grbl and Makerslide making the recent wave of hobby-level machines easier, or Mach3 and the development and open sourcing of Enhanced Machine Controller (EMC) which brought prices down out of the stratosphere.

[Erik Loza]

...I'm also concerned about the 'all in' price, since I know that accessories such as vacuum pumps, software, etc. can be huge with CNC's.

That's basically what I was going to say: It's the cost software the vacuum pump that seem to drive most "small" shops away from the CNC option. Of course, for the big money, you get a much higher production rate.

Again, I don't sell CNC's and don't have much hands-on experience with them but do have a lot of shops that use them have had a number of guys who got one, then sub out as much work for other builders as they do for themselves, to keep the revenue stream flowing. Quite common, in fact.

Erik

[ed vitanovec]

There is a company East of you in Mineola TX, EZ Router

http://www.ez-router.com/

[Art Mann]

. . . the LoboCNC which uses commercial encoding technology to determine its position

Servo motors and closed loop feedback is commonplace on the more expensive CNC routers. It isn't usually included on the less expensive models because it is an unnecessary expense. Steppeer motors in a well designed system are perfectly adequate and seldom to never skip steps.