CNC Mill Conversion Questions.

Thanks Gary,

I am now leaning towards using a closed loop stepper system, with rotary encoders on the steppers. This seems to be the newest approach and offers the best attributes of steppers and servos. The linear encoder approach seems too costly for now, as the only dual-encoder input controller/driver, I could find, is north of $2,000 USD...
 
Thanks for this. Will bear in mind what you say when I get started. 2000 bucks is too much...!
 
I'm kinda in the middle of a conversion (4 odd years collecting bits and money). Anyways I sent a email off Friday night to a China based ebay dealer for some ballscrews with end machining to suit my application. Within 10 minutes I had a reply and the order was completed later that night.
There's a lot of happy campers that have used Chinese ballscrews for their conversions. As long as you realise that they are what they are you should be happy. Like many have mentioned on cnczone without Chinese ballscrews many of us would still be using stock leadscrews in our conversions.
Just remember try not to chase accuracy from your ballscrews that your hobby mill can't reach. Don't discount one of the G0704/BF20 mills, I'm really happy with mine.
Once I get my screws I could let you know what I think of them if you like.

Rob.
 
Eddyde said:
Thanks Gary,

I am now leaning towards using a closed loop stepper system, with rotary encoders on the steppers. This seems to be the newest approach and offers the best attributes of steppers and servos. ..
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This would be a good goal. Might i suggest you walk before you run and just get the plane Jane stepper system running first. Then do an upgrade.

BTW, I'd also suggest you spend time lurking (or even posting) on CNCzone.com. maybe not quite as helpful folks as here, but CNC is all they do and there's a LOT of knowledge there.

Karl
 
bladehunter said:
I'm kinda in the middle of a conversion (4 odd years collecting bits and money). Anyways I sent a email off Friday night to a China based ebay dealer for some ballscrews with end machining to suit my application. Within 10 minutes I had a reply and the order was completed later that night.
There's a lot of happy campers that have used Chinese ballscrews for their conversions. As long as you realise that they are what they are you should be happy. Like many have mentioned on cnczone without Chinese ballscrews many of us would still be using stock leadscrews in our conversions.
Just remember try not to chase accuracy from your ballscrews that your hobby mill can't reach. Don't discount one of the G0704/BF20 mills, I'm really happy with mine.
Once I get my screws I could let you know what I think of them if you like.

Rob.
Click to expand...

I too am in the middle of a CNC conversion. Bought my ball screws and nuts on eBay from a Chinese supplier as well (Linear Motion Bearings). Could be the same vendor you used. Service and price was excellent. I received the screws and nuts and visually they looked good. The vendor sent a BK style housing instead of an FK style. Sent a note and within minutes received a response that the FK will be sent next day. Didn't ask for the BK housing to be returned.

Still building the mounting brackets so I haven't had a chance to check backlash yet.

Tom S
 
I have converted 4 mills and 2 lathes with all Chinese parts. from Sherline to my zx45 mill with no real problems. most of the steppers you buy from US sellers are made in china and relabeled. the thrust bearings that come with the ballscrews have to be shimmed to get the proper preload but work good once done. I have purchased stepper motors from 170oz/in to 4200oz/in and have never got a bad one. My zx45 has shown no wear in 2 years of steady use and none of my controllers give any problems. I do use large enclosure fans and filter the intake air though. For the money at $3800.00 including the new zx45 mill and 6" rotory table for the forth axis you can't beat it.
steve
 
Gary Ayres said:
Thanks for this. Will bear in mind what you say when I get started. 2000 bucks is too much...!
Click to expand...



Update:
One of the members wrote me privately and enlightened me to Galil controllers selling on ebay for around $500 for a 4 axis board that will accept dual encoder inputs! So the linear encoder isn't out of the question.
 
jumps4 said:
I have converted 4 mills and 2 lathes with all Chinese parts. from Sherline to my zx45 mill with no real problems. most of the steppers you buy from US sellers are made in china and relabeled. the thrust bearings that come with the ballscrews have to be shimmed to get the proper preload but work good once done. I have purchased stepper motors from 170oz/in to 4200oz/in and have never got a bad one. My zx45 has shown no wear in 2 years of steady use and none of my controllers give any problems. I do use large enclosure fans and filter the intake air though. For the money at $3800.00 including the new zx45 mill and 6" rotory table for the forth axis you can't beat it.
steve
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Thanks, I will most likely go with the Chinese or Taiwanese ball screws and motors and go with US made controllers/drivers.
 
Karl_T said:
This would be a good goal. Might i suggest you walk before you run and just get the plane Jane stepper system running first. Then do an upgrade.

BTW, I'd also suggest you spend time lurking (or even posting) on CNCzone.com. maybe not quite as helpful folks as here, but CNC is all they do and there's a LOT of knowledge there.

Karl
Click to expand...


Thanks Karl,

I hear you on keeping it simpler in the beginning but it would mean repurchasing the drivers and motors or having to add encoders to the motors in the future. I'd rather go all-in and get it done. I know the learning curve will be steeper but to me, the challenge is the fun.

Yes I have been lurking the CNC Zone, lots of useful info there.
 
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