Shopping for a CNC Router
Solid generic advice on getting the right machine for what you do at the right price. July 13, 2010
Question
I am going to be purchasing a new or used 5' x 10' CNC router for panel work and machining solid wood. What are some features to look for or steer away from? Ball screw versus rack and pinion, moving table versus gantry, spindles, etc. And what should I watch out for in a used machine?
Forum Responses
(CNC Forum)
From contributor P:
If you will be machining solid wood, I would consider including a C axis unit on the machine. You will probably find the need to use aggregate heads down the road and the presence of a C axis will make a huge difference on the versatility that these heads can offer.
From contributor B:
When purchasing used I think the greater issue is condition versus type of drive. If it is a rack and pinion machine I'd want the moving gantry to wrap around the side of the table so that you don't have long axis rails to reach over when setting sheets. Most newer machines in the medium duty range are designed like this. I have the CNT 900 machine (with side rails to reach over) and would love to upgrade to the CNT 950, which is a comparable machine but designed without high side rails.
If you purchase new the amount of money and size/weight of the machine will pretty much dictate the type of drive. Rack and pinion is often on the long axis of light to medium cost machines, while ball screw design is used on the short table axis and the z (spindle) axis. Heavier, more expensive machines typically have ball screw systems on all 3 axis. I don't know for a fact, but I think this is because that will stand up better to the heavier weight being moved back and forth.
Your major issues are table size, hold down, horse power, speed and tool changers. You need to examine all these and decide where it leads you price wise. For most shops, medium duty machines are more than adequate. Lots of folks opt for the heavy iron, which is usually more expensive, because they feel they will give better long term repeatability and durability. Personally I think you can do just as well in this area with a medium duty/weight machine.
From contributor J:
In my opinion the first parameter is establishing a budget. Not only consider the price of the machine, but add in rigging cost to load (used machines), shipping cost based on size and weight and where it's coming from. Setup and training costs, software, vacuum pump and dust collection as well as tooling (tool holders, collets, wrenches). Also, some manufacturers now charge a fee for access to tech support for used machine buyers. We sell new and used machines. The used ones are refurbished and sold with a warranty as well as on site setup and training. No rigging costs or DOA equipment. In the long run ball screw driven machines are better than rack and pinion. They are found on light and medium duty lower end machines. And there are all grades of rack OEMs use. Some use HIWiN, which I would suggest staying away from.
From contributor A:
Find two big iron CNC companies and two mid-weight CNC companies, and ask them for a list of clients who have machines in their shops. Go see them. People who are successful with the implementation of CNC really like them and do not mind showing them off. Look for what your shop will need as an end result in product, budget, and implementation. I would write a list of everything you think you would like to do with your router (cabinet nesting, 3d carving, signage, etc.).
I started with a used 4x8 single head router. It was a great learning machine and taught me to think about what I would ultimately need. My next step was a three head 5x8 new that has done everything I expected and more at a budget that kept us in business through this recession. I also have a 4x4 for smaller carvings and parts. My larger machine has a lathe, as I incorporate custom parts into my work.
In the end, it will be up to you to sell yourself a machine. CNC machine company salesmen are very experienced in machines, but I have yet to meet many who I would trust with my shop.
From the original questioner:
Thanks for all the input. I suppose I should have mentioned that I have some CNC time. At my old job we had a MultiCAM MG 103, 4 x 8 table, 12" Z, 10HP Columbo and a 4 head aggregate that we bought in 1999. A good machine that served our purpose. We made high end cherry furniture. I should say they still do, and the machine is still hammering away. The only problem we had was the servo drivers started to go bad and we discovered that they were no longer available. After years of buying used ones we finally had to start getting them repaired and ultimately wound up spending $12,000 to switch over to new drivers and servo motors. Other than that, no complaints.
My new job is going to be pretty much the same kind of work. There's a lot of new technology out there, even in a used machine, and I'm trying to get a grip on it.
From contributor A:
I hope you will look first at USA built machines. There are some good ones! DMS, CNT, Onsrud, Multicam would be a good start.
From the original questioner:
So with regards to buying a used machine, I suppose the question comes down to; is it better to start traveling to look at machines myself or find a dealer/broker with whom I feel comfortable? I'm tucked way up in northern NH.
From contributor B:
Purchasing locally is always nice if you feel comfortable that you have the ability to check out a machine from top to bottom yourself. If not, then you need to get some help, even for a local purchase.
Try online, even EBay, to see if there is anything close by. I bought my first machine used at a good enough price that even if I had some problems, or it didn't work out as well as I hoped for our business, I could have come out okay when reselling. I was lucky in that I got it from a dealer who was very trustworthy.
Learn as much as you can about the mechanics of what you are looking at and proceed on your own if you have the time and understanding. This is easier to do on the medium duty machines than the big iron, though.
From contributor H:
I would never buy a used machine unless it was from and certified by the company who makes and/or sells it. Your inquiry shows that you personally don't have the knowledge to inspect a used machine.
If you buy a used one, make sure it has the current generation of software, or at least only one generation older. And be sure it's still supported by the manufacturer or distributor. Call their parts and/or service department and discuss with them parts and service availability for the machine you choose. You can also get a feel for their attitude toward you before you buy one of their used machines elsewhere.
From contributor C:
Be extremely careful who you buy from. In April 2008, we visited a local (75 miles away) CNC manufacturer and loved everything we saw. Small company but people who seemed to know what they were doing. Put our $5800.00 deposit with a leasing company to get the ball rolling. Many phone calls and promised upgrades all summer long, then Sept. 2008, we get a Chapter 11 letter from this company. By December it was downgraded to a Chapter 7. Leasing company won't refund my money, said I made the deal and no machine.
My point? Buy from a well known company. Before we went into this deal, the company gave us a list of 10 customers, and through email correspondence, most were happy, 1 or 2 were not so happy, but I know it's not a perfect world, so we went with them.
The real kicker is they opened up under another name, new logos, etc. I guess they can operate for another 7 years under the bankruptcy laws in this country.
From contributor K:
When you are looking at purchasing a CNC router the first step is to establish the expected workload for a machine. There is a hefty price to pay for adding speed and accuracy to a machine. Medium duty moving gantry machines like the Multicam or similar products - AXYZ, CNT Motion, Flexicam, and others - are ideal for most applications that don't place a premium on speed and high tolerance. Most nested based woodworking applications fall into this category. Those types of systems generally sell new between $60,000 and $85,000 depending on options packages.
If the application requires more precision or speed, you can take a step up to a moving table system or beefed up moving gantry system such as the Komo, Thermwood, Northwood and CR Onsrud products. These machines generally come in higher price points between $90,000 to $200,000.
If budget is an issue one can always consider used equipment. In today's market late model used machines sell for between 50-60% of new. Many of these systems are between 1-4 years old and can be a great way to keep some dollars in your pocket. A major key to purchasing used machinery correctly is working with a machinery broker you feel comfortable with.
