Buying Used CNC Equipment- What do you look for?

Napkin Artist · Jan 11, 2015

I am curious to get some opinions on buying used CNC equipment. I realize that some questions are specific to the brand, initial cost, and type of equipment. But speaking in generalities for VMCs on the used market, what do you look for? What are red flags that keep you away from equipment you look at? Specifically:

1. What do you consider "low hours" on a machine?
2. If you see paint removed in specific spots, as if the machine ran the same part for it's whole life, is that really bad?
3. What is the oldest piece of equipment would you still consider useful? Was there a technology leap around a certain year that I should stay above?
4. What equipment can you still get good service and parts for here in the U.S.?
5. What brand/machine seems to hold it's value/usefulness the best?
6. What other stuff do you look for?

Thanks for your input!

reedeprintice · Jan 11, 2015

Are you looking for a mill ? Lathe ? What are you trying to get into what do you need ? I think I would be more interested right now in what you can afford and what your trying to do .

Krovvax · Jan 11, 2015

reedeprintice said:
Are you looking for a mill ? Lathe ? What are you trying to get into what do you need ? I think I would be more interested right now in what you can afford and what your trying to do .

He mention he was looking for a VMC

sneebot · Jan 11, 2015

How much memory does the control have-- is it sufficient for your application(s).
How easy is it to transfer programs to the machine from a PC.

RC Mech · Jan 11, 2015

If the machine has run the same part it's whole life, that's not really a problem. If the wear on any ballscrew is excessive, you can change the backlash compensation for specific points on the screw. IME Tree 1040/1050VMC's w/Dynapath controllers are able to do this.

Anything less than 5k hours is low IMO. On some controls (Haas comes to mind) you can see the difference between idle hours (control 'on') and spindle hours. 5k spindle isn't a big deal.

Things to check: spindle noise @ highest spindle speed, spindle housing temperature after running @ speed for 5-10 minutes. If the machine has spindle ranges, check the gears work, whether manually or M-code actuated. Axis noise, particularly X axis noise in certain spots. Does the machine home properly, hit the soft limits, do a tool change. If the machine is connected to a PC and it's verified that programs can be transferred, try to get the PC thrown into the deal. This is important for older machines that are finicky to communicate with modern hardware.

I wouldn't buy a 1980 Mazak VMC w/Mazatrol for anything near 5 figures, even if it had the oh-so-sweet 60 tool magazine. *What* do you have in mind?

Vancbiker · Jan 11, 2015

If it does not come with the the electrical schematics and hardcopy of the ladder diagram, I'd move on. Those are almost impossible to get for a used machine and are crucial to keeping it running.

Not having the manuals from the builder (operation, parts, maintenance) would be a big minus, but I'd still consider a deal if the price was good. Again, almost impossible to get for a used machine, but not as crucial to have to keep it running.

The manuals for the control are usually available by various methods. If you have to buy them they are sometimes expensive. Some builders have them for free as downloads.

ewlsey · Jan 11, 2015

Personally, I look for a few things:

Find something newer than say 1988 or so when AC servos became popular (mid 90s for the low end machines like Haas and Fadal). DC servos are fine, but you need to keep an eye on the brushes and they are significantly slower.

Stick to the major brands. You can get Haas and Fadal parts almost anywhere. Mori Seiki, Okuma, Mazak, Nakamura, Makino, Hardinge, Brother, etc are all well supported. I'd stay away from the lesser Taiwanese/Korean/Eastern European machines unless they are a great deal.

Stay with the major controls. Who is going to help you with your goofy Centroid, Seicos, or Anilam control when you can't figure it out?

Buy a machine with the options you want. You will have a really hard time upgrading an old machine. If your Mazak doesn't take EIA or your lathe doesn't have a bar puller, you might be SOL if you need them.

You can check backlash. You can check the spindle. You can't predict electrical failures.

Bobw · Jan 11, 2015

#1 consideration on a used machine... Can I still get parts and support.

#2 can I still get parts and support at a reasonable cost and in a reasonable time frame.

Everything else is negotiable.

Napkin Artist · Jan 12, 2015

RC Mech said:
I wouldn't buy a 1980 Mazak VMC w/Mazatrol for anything near 5 figures, even if it had the oh-so-sweet 60 tool magazine. *What* do you have in mind?

I love the idea of some of the smaller machines because of the size parts I make. Specifically, the Fanuc Robodrills and Brother D/T machines. However, the Haas machines seem more readily available on the secondhand market. There is a beat looking Super MiniMill at my local secondhand dealer that has been sitting outside but under cover for about a year. It probably isn't worth the trouble. I was cutting off the age at around the mid 2000's but don't really have a good reason for it. I would love to get it functionally running with all needed tooling for around $50k (preferably under). I also need to consider transport costs if the machine needs to be moved here. I see deals on the West Coast but I assume it would be costly to get it to Virginia! Is that reasonable?

swarf_rat · Jan 12, 2015

The answer also depends a great deal on who is going to fix it. Are you going to learn to fix it? (Do you have the skills to fix it?) Or is a factory or independent technician going to fix it?

Napkin Artist · Jan 12, 2015

swarf_rat said:
The answer also depends a great deal on who is going to fix it. Are you going to learn to fix it? (Do you have the skills to fix it?) Or is a factory or independent technician going to fix it?

That depends... I am sure I "can" fix just about anything. However, if I need a $10k specialty tool or electronics interface to reset or diagnose it then the answer is no. I will pay someone to fix it before buying expensive tools.

Gizmo Machine · Dec 20, 2020

Hello! I know this post is extremely late, but just in case any new people are still trying to figure out what to look for in a CNC Machine hopefully this helps.

I actually created a Buyers guide for anyone looking to purchase their first CNC Machine
Here is the link to the guide: https://gizmo-mt.ca/blog/used-cnc-machine/

Some tips I'd recommend right off the bat include the following:

Buy Used: Since you are just a hobbyist don't invest a significant amount of money in buying something completely new or out of your budget. There are alot of very solid used machines you can get that work just as well at a fraction of the cost.

Always ask your supplier for a demonstration of the machine: Since you are on a budget the last thing you want happening to you is that you buy a machine that doesn't have the quality you are looking for. With that being said ALWAYS ask for a demonstration of the machine before buying. If in-person is not possible, ask the company to send you a video demonstrating the CNC router you are looking to buy.

Do your research about specifications: Every CNC machine has a specification sheet containing all the information you need to know. Id recommend making an excel file spreadsheet and taking the time to come up with a criteria where you look at all of the potential CNC routers and machines in terms of their specifications and price. This helps keep everything organized and helps you make an informed decision.

As mentioned before, be sure to check out the guide as its a lot more in depth but I really hope and wish you the best of luck in regards to finding your desired CNC machine.

DDoug · Dec 20, 2020

Gizmo Machine said:
Hello! I know this post is extremely late, but just in case any new people are still trying to figure out what to look for in a CNC Machine hopefully this helps.

I actually created a Buyers guide for anyone looking to purchase their first CNC Machine
Here is the link to the guide: https://spammers.ca/blog/spamming for the stain/

Some tips I'd recommend right off the bat include the following:

Buy Used: Since you are just a spammer don't invest a significant amount of reading time in spamming something completely new or out of your budget. There are alot of very solid used machines you can get that work just as well at a fraction of the cost.

Always ask your supplier for a demonstration of the machine: Since you are on a budget the last thing you want happening to you is that you buy a machine that doesn't have the quality you are looking for. With that being said ALWAYS ask for a demonstration of the machine before buying. If in-person is not possible, ask the company to send you a video demonstrating the CNC router you are looking to buy.

Do your research about specifications: Every CNC machine has a specification sheet containing all the information you need to know. Id recommend making an excel file spreadsheet and taking the time to come up with a criteria where you look at all of the potential CNC routers and machines in terms of their specifications and price. This helps keep everything organized and helps you make an informed decision.

As mentioned before, be sure to check out the guide as its a lot more in depth but I really hope and wish you the best of luck in regards to finding your desired CNC machine.

Spam is best served cold....hence the "just before winter solstice" dredge post....

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Buying Used CNC Equipment- What do you look for?

Napkin Artist

Plastic

reedeprintice

Stainless

Krovvax

Hot Rolled

sneebot

Stainless

RC Mech

Stainless

Vancbiker

Diamond

ewlsey

Diamond

Bobw

Diamond

Napkin Artist

Plastic

swarf_rat

Titanium

Napkin Artist

Plastic

Gizmo Machine

Plastic

DDoug

Diamond

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