[xupybd]

I work with commercial CNC machines. I think people are missing out on the second hand commercial market. One of our most reliable CNCs is an old pod and rail that cost $10k. It is much more than any hobby machine.

Please if you're getting into this look around at second hand machines. You'll be able to do really well if you want to setup an old 90s machine with new electronics. It's not as complex as building one from scratch and you get much better mechanical components.

[freeqaz]

How much would these machines have cost when they were new? Just trying to get an understanding of the price break vs the "risk" with older equipment. Time goes on and I imagine the motors + other mechanical components improve.

But maybe that's a bad assumption from working in tech for too long?

[xupybd]

They do wear out. But some of the things will last and last. The square frame will last forever unless it gets a really big impact. This is important because holding square is the only way you are going to get accuracy. I have no idea how people do this with a self assembled frame.

The main spindle might have issues with bearings but you should get a lot of life out of one. Ours run 16 hours a day and last 10 years plus. As a hobbyist even if you buy one with 95% of its spindle life left you are not likely to wear it out.

Keep the machine greased and it will last. A good machine will come with a service manual and tell you how often to grease each part. Most will have an auto greaser that will do most for you. Just have to keep it topped up.

All parts are easily replaced. Except the electronics and the computer but if you are wanting to build your own you're replacing them anyway so it's not an issue.

Vacuum pumps need regular servicing and replacement Blades every now and again but again hobbyist use they will last a long time just keep the filters clean. They are almost always 3 phase so that might be an issue.

They have AC servo controllers that you would have to interface with and normally have a can bus for all the peripherals I don't think it would be too much to get all of that going.

[freeqaz]

Thank you for the details! That's super neat to know about. Going to keep this in the back of my mind for the future. I just moved into a place with a garage :)

I'll have to search for a way to run 3 phase power out of residential. Not sure if that's even possible. I'm curious though!

[xupybd]

Oops just realised I didn't answer the price question. It's hard to give a price. Our pod and rail would have been $300k +- 50k new. A top end in that range could be up around $750k. The low end maybe $150k.

The type I work with are for wood working. Manufacturing cabinets and furniture. So very big (6m long work surface) but not capable of metal work. But there is a huge range out there.

[bluGill]

Most new industrial 3 phase equipment is running from a VFD which gives speed control. 20 years ago 3 phase was used because the power company would supply you 3 phase, and otherwise single phase was used. Today many home washing machines have 3 phase motors, since a VFD is cheap and 3 phase motors have some nice features.

[jacquesm]

And you can now get cheap single-phase to three phase inverters to drive that gear. You won't be running it at full power but a 240V socket will happily drive such an inverter/motor combo at rates that most hobbyists would be more than happy with.

[bluGill]

Single phase to 3 phase inverters are just a different name for VFD. Running a 3 phase VFD on single phase (tieing all 3 phases together) works if you derate the VFD/inverter. An inverter designed for this application should already be rated correctly.

There is no derating the motor when running on a 3 phase VFD/inverter if you have the correct specs for everything. If you are trying to run a bigger motor than any link in the chain it might work so long as you don't try to draw more power from the motor than the weakest link in the chain.

There is a static phase converter which does derate the motor. They are the cheapest way to run 3 phase from single phase, but otherwise don't have much to recommend them. They are NOT inverters.

[jpitz]

There are rotary converters and variable frequency drives - the latter are more flexible.

[yeuxardents]

Where does one look to search for second hand CNCs?

[xupybd]

https://www.ebay.com/itm/Biesse-Rover-18-CNC-Router/25435957...

They are on most auction sites but your best deals are going to be liquidation auctions. There will be auction houses that specialise in these in your part of the world.

[LeifCarrotson]

You can look for second-hand components and machines at surplus industrial suppliers and auction houses. When an old product is deprecated, it's often cheaper for a big manufacturer to get rid of the equipment and buy new for the new product line, find out where obsolete equipment is going. It's not worth paying $100/hr for an integrator to repurpose with no warranty, but at hobbyist $100/week budgets that scrapyard is full of treasure. Some manufacturers and integrators will have "boneyards" of old equipment that they'll purge on occasion.

The article said that Teknik Clearpath servos are considered a great value, and they are, but even their smallest fractional HP 24V motors cost more than some name brand Allen Bradley (unofficial slogan "you can get better but you can't pay more!") 3-phase servos at my local supplier: https://www.surplusindustrialsupply.com/motors-mot.html

These places are like a garage sale for industrial lego.

[mtreis86]

https://bidspotter.com

[oflannabhra]

Do you have a recommended process for accessing the second hand commercial market?

[HeyLaughingBoy]

Auctions. There are any number of online auctioneers selling off machine shop tooling (going out of business, upgrading and getting rid of old stuff, etc.).

I haven't bought CNC machinery that way, but I've gotten tooling, measuring equipment, etc. for pennies on the dollar buying from auctions.

And like jacquesm said, EBay.

[jacquesm]

Ebay, and specialized traders. Also: contact the sales people of new machinery for early access to trade-ins.