We are shopping for a CNC router (first time) and have been looking at some used machines as well as new. I was told by a rep that I need to be careful of abuse to a used machine. I know of wear and tear on moving parts, but what constitutes "abuse"?
From contributor B:
I have purchased used and new and both have their advantages and similarities. Whether purchasing used or new, you need to make sure you can get local support. As you know, these are complex machines and your ability to adjust and/or repair will be limited by your ability and time.
As to used specifically, I'd say the simpler the machine design and the greater your electrical/mechanical skills, the better off you will be. If you are looking at a higher end machine, you need to give greater consideration to having support available.
The key to a used machine is to consider you're buying something that will need lots of tweaking, and pay accordingly. Our first machine was a 1987 Thermwood C50 with 2 15 hp Perske and an ancient controller. The mechanics were in good shape, and we paid 2K for the machine and about as much to rig it. Luckily, all the mechanics were in great shape except for a paint job, cleaning, and a few small items. We ripped the controller out of it, and rewired a brand new controller with aftermarket software. We did have to replace an amplifier, but it was not too bad. It did take about $15,000 worth of my time, and the coding was hell. We retained an application engineer who consulted in the shop for a day and over the phone and net for about eight months. It was painful. However, the machine is great - solid, precise, we know it like the back of our hands, and repairs are a breeze. We now have a Thermwood hybrid with full hand held controller, full G code, M code, everything tailored to our needs, and can go from a dxf file to machining in minutes with the front end PC. Total cost about 18 K plus about 15 K of my time (at $ 30.00/hr).
We do not have a tool changer, but even added a desouter air drill, and can bore panels in the Z all day long. Frankly, even with my labor included, I don't think we could buy a 5x10 beast like that for the money, and we would still be at the mercy of the techs.
The second machine was a 1994 Rover 20 PTP with NC 410 controller. Purchase 12K, rigging 2K. About 2K of parts in it. Rover parts are outrageously priced. The experience on the first machine proved invaluable. We bought it early August, and we are running it daily. It's great. We did not change the controller and decided to deal with Biesse's horrible interface.
Total hard cash cost for both machines about 34 K and maybe 20 K of my time. I find it worth the investment. I'm the only guy in town with both flavors. The first one is already paid for, and no expensive tech to repair the machines. Bottom line, it can be dangerous and costly, but if you have time, I find it well worth it. The guy down the street has to run his Weeke nonstop to make his lease and tech support. I can run my machines a few hours a week and be ahead.
One tip, though - do not count on too much help from the manufacturer. You're on your own. Thermwood was okay, and considering we were not upgrading with their 91000 controller, can't complain. Wish we could have gotten machine blue print from them, though. Biesse, frankly terrible, despite about 2 K of replacement parts, as well as 4 K for a burnt amplifier (not counted in cost - it was an insurance claim due to electrical problem with the building). They did take our money, but were not very helpful.
I honestly believe that it does not matter whether you buy a new machine. The backup service will be generally crap (unless you get it direct from the manufacturer), because the selling dealers don't know or don't care to know about how to fix the problems. So perhaps the way I have gone was of great value, as there is not much I don't know about this machine and so far have been able to fix all of the problems. Some decent manuals would have helped.
I think another lesson here is do not buy a second hand machine unless the seller can give you all of the original programming manuals and electrical /mechanical diagrams. I was lucky - I got a lot of information, but would have liked the rest.
It incidentally has a NUM control on it, and they have been fantastic in assisting from France and USA. Anyway, in closing, I now have a solid, high end machine that would set me back $170k if I were to have bought it new, and as the previous post said, it's paid for, so if it sits for some of the weeks, it really does not matter. I don't have the bank calling about the payments.
Would I do it again? Yes, absolutely. I would buy second hand. I will certainly know where to look for drama.
In the best case scenario, you could find a late model used machine with very low hours for close to half the price of a new one. On a 100k machine, that savings is significant. As for service, the high end companies like Thermwood and Komo will service their used machines on the same priority that they take care of the new ones.