554,025 active members*
3,034 visitors online*
Register for free
Login
Page 1 of 2 12
Results 1 to 20 of 27
  1. #1

    Join Date
    Jun 2021
    Posts
    14

    Buying my first CNC from China

    Hey CNCZone,

    Thank you in advance for taking the time to look at this thread - and I apologize if I didn't post it in the right place, assistance from a moderator would be greatly appreciated.

    I'm purchasing a 6090 primarily for aluminum and a little bit of steel. I've reached out to about 30-40 vendors on Alibaba and have narrowed down CNCs to around $1,900-$2,000 FOB. My primary consideration for the unit are:

    * 25mm TBI (or similar) ball screws on all axis
    * HIWIN (or similar) 20mm square guide rails
    * I want a cast iron bed, gantry and Y-axis (non-welded)
    * With a cabinet and a water tray/table/sink
    * Z travel of 200mm

    I don't care that much about electronics because I want to install my own steppers, drivers, controller (600oz.in. steppers from Vince, corvetteguy50, paired with a G540 and an ethernet smoothstepper) and I will source a VFD / spindle locally. I want them to do the wiring so that I can just plug and play my own electric components and I am asking them to wire it just like they would for a ncstudio controller.

    The machines in question generally look like this: https://s.alicdn.com/@sc04/kf/A2f619...pg_960x960.jpg

    Since this is my first CNC machine, I would really appreciate your input if you've gone through this process before - any answers to the following questions would be SUPER appreciated:

    1. What else should I look into when purchasing?
    2. Are there any additional useful accessories I could source from China given that I'm already going to pay somewhere around $1,000 for shipping?
    3. What other considerations should I care about from a machine construction/feature perspective?
    4. Is it going to be a pain to go through the customs process?
    5. I'm close to the port of Detroit - should I go pick it up myself? Should I get a local freight company for last mile delivery?
    6. It might be overkill to go for a 2510 ball screw on the Z axis... but will it detract from accuracy? My understanding is that I will just be able to get more speed out of Z by going with a larger diameter ball screw.

    Any other tips/tricks/advice that comes to mind?

    Thanks in advance, sorry for the long-winded post, but it's a large investment for me and your collective knowledge might help me from making a mistake along the way.

  2. #2
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    For ''aluminum and a little bit of steel'' I would be looking for a used metal working VMC with a dead control. You can pick them up for scrap price or less, and they will already have heavy ball screws. For metal working, any router is marginal at best.
    Jim Dawson
    Sandy, Oregon, USA

  3. #3

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Quote Originally Posted by Jim Dawson View Post
    For ''aluminum and a little bit of steel'' I would be looking for a used metal working VMC with a dead control. You can pick them up for scrap price or less, and they will already have heavy ball screws. For metal working, any router is marginal at best.
    Thank you for your suggestion, can you tell me how one would go about finding a VMC with a dead control? I've been looking at Bridgeports on bidspotter.com for example. For the $3-4k I would spend on this machine, I'm sure I could get one of those and automate it - another avenue I've considered.

  4. #4
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    Here is one example near Detroit https://detroit.craigslist.org/okl/t...495630824.html

    I use Search Tempest for searching Craigslist https://www.searchtempest.com/

    Then have a look at eBay. There are a lot of machine tools available in the upper mid-west and northeast
    Jim Dawson
    Sandy, Oregon, USA

  5. #5
    Member
    Join Date
    Apr 2004
    Posts
    5538

    Re: Buying my first CNC from China

    Look at physical industrial auctions in your area. Old manual Bridgeports shouldn't cost that much - half that is about what to expect at an auction. But it's a lot easier to convert something that was originally a CNC machine. You could try contacting local machine shops - often they've got something that's just taking up space, which they'd like to use for something else.
    Andrew Werby
    Website

  6. #6

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Quote Originally Posted by Jim Dawson View Post
    Here is one example near Detroit https://detroit.craigslist.org/okl/t...495630824.html

    I use Search Tempest for searching Craigslist https://www.searchtempest.com/

    Then have a look at eBay. There are a lot of machine tools available in the upper mid-west and northeast
    Quote Originally Posted by awerby View Post
    Look at physical industrial auctions in your area. Old manual Bridgeports shouldn't cost that much - half that is about what to expect at an auction. But it's a lot easier to convert something that was originally a CNC machine. You could try contacting local machine shops - often they've got something that's just taking up space, which they'd like to use for something else.
    I feel like a 6090 would be an acceptable size compromise for volume (that the machine takes) and fun to learn (as a first CNC router with no prior machining knowledge). You guys are in a different place in your journey as machinists (maybe do this professionally?) but my wife would, for a lack of a better term, "remove my manhood" if I brought something like this home that would take up a whole slot in our garage. Maybe I'm miscalculating the size but this seems like it might be the next evolutionary step from what I'm currently going for.

  7. #7
    Member
    Join Date
    Apr 2004
    Posts
    5538

    Re: Buying my first CNC from China

    Like Jim was trying to tell you, you're setting yourself up for disappointment if you think a cheap Chinese router is going to be able to make acceptable parts in steel. Aluminum is going to be a stretch. These machines (despite what the sellers might claim) are designed for cutting wood and plastics. And to do that effectively, you'll need to set up dust collection - if they make nothing else, they certainly make lots of dust and chips. A shop-vac is not going to work; you'll need a system that takes up a lot more space than that.

    If metal parts are really what you want to make, look at the Taig mills I sell. You can get one with ball screws that's CNC-ready, so you can power it with your own steppers and a G-540 as planned, for about what you're talking about spending. The spindle is more suited to cutting metal - those bolt-on 2.2 kw spindles go too fast. And it's small enough to keep you out of trouble with your wife.
    Andrew Werby
    Website

  8. #8

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    That's fair, thank you for the advice. Is there anything preventing us from mounting the type of spindle that you use on your Taigs (which I looked at by the way, and they look great), on something like a Chinese 6090?

  9. #9
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    Quote Originally Posted by IonutZu View Post
    That's fair, thank you for the advice. Is there anything preventing us from mounting the type of spindle that you use on your Taigs (which I looked at by the way, and they look great), on something like a Chinese 6090?
    Of course you could mount a Taig spindle, or any other spindle that you want, on a 6090. That still won't make it a metal cutting machine. The problem is that the machine frame is not rigid enough for metal cutting. A customer of mine does use his router slotting aluminum angles for bolts, but his router weighs over 6000 lbs, and takes up the footprint of a midsize car. It is not a lightweight ''table top'' size machine.

    I'm not trying to beat you up here, I am just offering advice based on over 50 years experience working with machine tools, including routers from desktop size to huge. You wondered about if we do this professionally, and yes we do. I do have a commercial machine shop, and the largest machine in my shop has a 39x14 travel. Sometimes we could use larger, just to run more parts at a time, not because we need a larger work envelope for our parts. Most everything we make could be made on a table top milling machine, and we have one of those also. I think it's about 8x5 travel, about a 450 lb machine.

    If you can get by with a Bridgeport sized machine for work envelope, then there are a lot of BP and clone CNC machines out there for sale, and you don't need to buy a huge VMC. To get into the 600x900 (23x35) work envelope range, requires a pretty big machine. My BP clone CNC is a 10x54 table with 32x13 travel, and it's just a little larger than a standard BP with a 9x42 table.
    Jim Dawson
    Sandy, Oregon, USA

  10. #10

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Got it, thank you for all the advice Jim - not knocking it or feeling beat up lol. It's just that a Bridgeport seems slightly more daunting from a mechanical standpoint (I understand all the components of the CNC router really well) - I'm afraid that if I spend say $2,000 on a Bridgeport that then breaks on me, I would be forced to spend more money to fix it rather than what seems to be a more simplistic design of a CNC router (given that this would be my first machine ever). But maybe you can suggest some material that might break it down so that it is more digestible for someone brand new like me? I'm not afraid of getting my hands dirty, I just don't know where to start with such a machine if that makes sense. I also wouldn't know what to look for in a BP type machine when purchasing it, so I'd be more at the mercy of the seller - if that makes sense.

  11. #11
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    In general, CNC machines that would normally be found in the home shop come in a couple of flavors for the X/Y movement: A metalworking machine, where the tool is in a fixed location and has a moving table, or the case of a router where the tool moves and the table is in a fixed location. By having a fixed tool, the supporting structure can be made much more rigid. Also mass is your friend when doing any kind of machining, wood or metal. From a mechanical drive perspective there is really no difference between a router and any metalworking milling machine. Both normally use ball screws driven by servos or steppers, the mechanics are virtually identical. Pretty much all of the machines have a ball screw drive for the Z axis.

    There are two common types of CNC metalworking milling machines, the knee mill, like a Bridgeport, and the bed mill. Bed mills come in sizes from table top to huge industrial machines. Bed mills are generally more rigid than a knee mill in a given weight class. The Taig is a bed mill, as are a number of other small machines. Here is another example of a small bed mill, that is larger than the Taig https://www.precisionmatthews.com/sh...recision-mill/ There are many other veriations of machines like this. Vertical knee mills are capable of doing some serious work also, but I think were originally designed for tool room work, rather than production. I have two of each type in my shop. If you were closer to me, I would send you home with a really nice CNC knee mill that is taking up space in my shop.

    Buying a used machine does require a bit of a trained eye. The most important thing is the wear on the ways. Machines that have not been cared for with proper lubrication can show a lot of wear, not good. And some are just beat to death. On the other hand, I have found 30 year old machines that are mechanically near perfect, just depends on the owner. As far as machines breaking, that just pretty much doesn't happen unless the operator does something really stupid, they are built to run. Parts do wear over time, but mostly maintenance items like bearings and ball screws, and both are good for thousands of hours. When equipped, the variable speed spindle drive in the BP and clones is a wear item, but again are good for thousands of hours, there is a bushing in there that wears, and of course the belt needs to be replaced every few years. In the home shop, a well cared for machine will last pretty much forever with normal maintenance and lubrication without any parts replacement.

    If you want a CNC machine, then I would start out buying a used machine that is already a CNC. That way all of the hard work is done, the drives and controls are the easy and inexpensive part.

    Maybe something like this https://www.ebay.com/itm/29481202862...kAAOSwHZNiCV4m

    Or this https://grandrapids.craigslist.org/t...494596690.html This is almost identical to mine, can be used either manual or CNC. If I had only one mill in my shop, one similar to this is what I would have.

    I'll try to help guide you through the mill swamp.
    Jim Dawson
    Sandy, Oregon, USA

  12. #12

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    What kind of machine is it? Maybe I can pay for the freight Might be less than what I would pay from China or from the local CNC graveyard (that I just visited) - SO MUCH COOL STUFF, VMCs and crazy mills and lathes...

    Thanks for the breakdown - I can definitely sacrifice some bed area for stability/quality of output. I guess looking at all of these knee mill videos, I was getting scared by the complexity of the milling head where you have functionality like autofeeding and a gearbox for low/high/neutral that seemed to me like additional complications when something breaks - but I'll take your word for it that they're designed to last - they seem a lot less daunting now, so thank you for that.

    Thanks again for the words of encouragement and the guidance, this is really helpful!

  13. #13
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    It's a Shizuoka AN-S, might be a little big for your garage About 5000 lbs of machine, about 2X the footprint of a BP and about 9 ft tall. A fresh controls retrofit on it.



    You have a local CNC graveyard? OMG, I would never get out of there, I'd have to bring a large truck with me. What fun

    In most cases the auto down feed hardware is removed for CNC use, no reason to have it any longer. The Z axis provides the quill downfeed if needed. The high/neutral/low system is so simple it almost can't fail. I've never seen one fail in 50 years, I'm sure they have, but I've never seen it. The weak link in that system is the timing belt, which would fail before anything else could, and I have never seen one of those fail either. About a $10 part.

    So go find a machine, and get lots of pictures. Then we can help you with a decision on a purchase. If that machine in the Craigslist link I posted above was local to me, I would have it sitting in my shop right now. I have all the hardware in stock to get it powered up and running again, like I really need another project. :tired:
    Jim Dawson
    Sandy, Oregon, USA

  14. #14

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Damn that's cool... seems just outside of wife approval size haha, but I'd love to own something like that.

    I'm assuming the guy who owns the CNC graveyard buys them at auction. I'm waiting to hear the price on the Bridgeport. He wants $5900 for the Chevalier. Took a couple of pictures of some Fadals that seem to have the footprint of a machine that I could see myself owning eventually. Pics were too big so uploaded them here instead: https://imgur.com/a/aZ57F7k - the Chevalier he offered for $5900 is in the one before last picture - he had a couple. This is out of my budget, but I see a couple of BPs going up for auction near me - might go see them and bring some pics.

    I just bought a Warp9 ethernet Smoothstepper and the G540. I don't think I'd use a screen like that attached to the machine - I would probably just run the software on my laptop. That ATC is really cool, is that an addon you built for it? Or do all Shizuokas come with that?

  15. #15
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    That Chevalier is a nice machine. Looks to be a 2 axis machine, with a R-8 spindle and power draw bar. Nothing wrong with that, mine started out as a 2 axis, virtually identical to mine. Has the square Y axis ways, better than the Y axis V-ways, more stable. I can't see the knee ways to tell if they are square or V So it is either a 4VK or 5VK frame.

    Running from a laptop is fine. Just keep the chips out of the keyboard Actually the Shizuoka is running on a laptop, it's just stuffed in the cabinet. I normally use mini computers now, about $150 on Amazon.

    The tool changer is an aftermarket unit, but it came with the machine. I extensively modified it so it actually works like it should, the original system was a bit of a hash job IMHO. In reality the thing is useless, tool changers and knee mills are not a good combination. They work great on bed mills where you have a lot of Z travel available. I did the upgrade on this machine a few years ago for a friend, then he bought a couple of Fadals and he doesn't have room in his shop for it. So I'm stuck with it for now.
    Jim Dawson
    Sandy, Oregon, USA

  16. #16

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    The mini computer idea is actually smart - I could have it in the cabinet and just remote into it... running with a UPS so that it doesn't lose power - I considered a heavy duty UPS for the machine @ 240v - is that something that's done? Maybe linked to a relay that pauses the operation once power is switched so that you don't lose state.

    I found these 2 BPs that are close to me:
    https://www.bidspotter.com/en-us/auc...f-aeca01098c4b
    https://www.bidspotter.com/en-us/auc...a-aeca01098c4b

    How do we feel about them? one has a bed that was nicely drilled into lol... but I feel like I could maybe grab one of these at a relatively decent price? I don't think the auction would go past $3,000 (although I may be wrong, I see them for sale @ $9,500). What would be a "fair" price / deal price?

  17. #17
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    It really doesn't matter what you do on a power fail or even just a blip. Something is going to get screwed up, so just let it go down and stay down until you can recover and reset the system. Never allow a machine to just restart itself after a power fail, require an operator action, like a button press, when restarting. A standard 3 wire E-stop/control power relay circuit is normally the way this is done.

    You're not going to lose your 0/0 because you already have a known point to set 0 from, you would set this point when you set up your part. You did set a reference point for recovery, right? That point could be a feature on the work, like a corner, or could be a point on the vise or table.

    Both of those machines look pretty good in the pictures. They look pretty clean and not beat up. Seem to be standard 9x49 tables, 2 axis CNC with manual quill, R-8 spindle. I can't see the ways so no opinion there. ''Stupid marks'' in the table are somewhat common in used machines, and unless are really outrageous, don't normally hurt the machine. But from a buyer perspective it can be a negotiating point for a lower price. If possible, I would go look at those machines before bidding.

    Going back to that CNC graveyard and having a chat with somebody there about what to look for in a used machine would be really helpful to you. Most used machine tool salesmen will be honest and give you some good advice, consider that they buy stuff all the time. Just make sure they understand that you will be doing a controls upgrade and don't care about the computers and electronics, only the mechanical condition. The more machines that you look at the more knowledgeable you will become just by picking up the clues from the machines.

    If I wanted one of those machines that you linked to, bidding up to your max budget would be safe. I don't know the market in your area, but around here those machines could go as high as $4500 or so.

    Again, this machine would be worth looking at also https://grandrapids.craigslist.org/t...494596690.html

    I have never bought a machine without looking at it first. A road trip might save you money in the long run. When we bought our Haas, my son jumped on an airplane and flew down to Florida to look at it, and I drove down to Texas to inspect our CNC lathe before we bought it. I towed a trailer down there ready to pick it up, but would have walked away if the machine didn't look good. In that case I had two other machines on my list to look at if that one was not acceptable.
    Jim Dawson
    Sandy, Oregon, USA

  18. #18

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Quote Originally Posted by Jim Dawson View Post
    It really doesn't matter what you do on a power fail or even just a blip. Something is going to get screwed up, so just let it go down and stay down until you can recover and reset the system. Never allow a machine to just restart itself after a power fail, require an operator action, like a button press, when restarting. A standard 3 wire E-stop/control power relay circuit is normally the way this is done.

    You're not going to lose your 0/0 because you already have a known point to set 0 from, you would set this point when you set up your part. You did set a reference point for recovery, right? That point could be a feature on the work, like a corner, or could be a point on the vise or table.
    Fair enough!

    So I have some new developments... my neighbor works for a shop and they have a Series 1 BP they're willing to let go for $200... they said they would only get $150 if they scrapped it lol. It looks like it's seen some wear... the scraping is slightly visible on the Y ways - couldn't see them anywhere else.

    Pictures are here: https://imgur.com/a/yGixrcw

    If I got this, I would likely do the following:
    * new motor 4-5HP + VFD $500-1000
    * ball screws on all axis $1000-1500
    * motors + drivers + controller for all axis $500-800
    * 1 ton shop crane $80 - already negotiated on Craigslist

    I guess my question then becomes, is it worth doing this? Or am I better off spending $3000-$4000 on one of these EZ-TRAKs assuming I can get one for that price?
    https://www.bidspotter.com/en-us/auc...a-aeca01098c4b

  19. #19
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013
    Posts
    5598

    Re: Buying my first CNC from China

    Why are you posting here? You should be over there loading it up right now

    It looks like it has hard chrome ways, an option on some machines. This is a good thing. The fact that you can see scraping on the ways means very little wear.

    Those machines came with a 1, 1.5, or 2 HP motor. 3 HP is about as big as you would want to go on that machine. I would not change the motor unless that one is broken.

    That machine weighs about 2100 lbs, a 1 ton crane might be a bit light unless you remove the turret. The table comes off pretty easy also, about 300 lbs.

    However this is my preferred method of moving them That fork lift cost less than the shop crane you are looking at, it just showed up on my door step one day.

    Jim Dawson
    Sandy, Oregon, USA

  20. #20

    Join Date
    Jun 2021
    Posts
    14

    Re: Buying my first CNC from China

    Hahaha you have friends in high places Jim Dawson. Thank you - so worth it over the EZ-TRAK??? I definitely plan on taking apart all the axis so that I can replace the leadscrews... should make it easier to move around. Already watched a video on how to do this... now it's pure will power at this point lol.

Page 1 of 2 12

Similar Threads

  1. Replies: 9
    Last Post: 11-22-2021, 02:28 AM
  2. Tips for buying CNC Router from China
    By Roctech-Cathy in forum Roctech CNC Routers
    Replies: 0
    Last Post: 03-25-2015, 06:38 AM
  3. Replies: 2
    Last Post: 05-17-2014, 06:29 AM
  4. Im buying a CNC & Laser from China
    By maxydog in forum Chinese Machines
    Replies: 17
    Last Post: 05-15-2013, 09:11 AM
  5. Buying X1/X2/X3 from China
    By Jfwiet in forum X3/SX3/G0619/G0463
    Replies: 3
    Last Post: 09-02-2011, 08:32 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •