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thorphar
24-12-2014, 03:55 AM
http://www.mycncuk.com/attachment.php?attachmentid=14204&stc=1


So this is my Warco Knee Milling Machine. Just as a project I would love to convert this machine in to a CNC Milling Machine and hopefully make some money off that machine or just use it for projects. I have now had some experience in constructing the electronics after building my custom power supply for another custom CNC router. I know i should convert the leadscrews to ballscrews however money is tight so Im gonna expect some inaccuracy. Im pretty comfortable on how I will be attaching the steppers and driving the axis', however Im not too sure what size motor to go for. I know that the three main contenders would be the Nema 34 or 42 or just not going for a stepper at all and going for a servo. However, as I have already mentioned this is a project and not a Job therefore money is tight. I have found a good kit for the Nema 34 with DM860A drivers and 60v/350watts power supplies at a really good price. Im slightly concerned about the holding torque. I know that the handwheels on the mill atm are easy to turn by hand so I guess you don't really need much holding torque. Any suggestions on the size of stepper would be wonderful. I don't wanna make a mistake buying inadequate steppers.


Also any suggestions on good suppliers of timing belt pulleys in the uk or aboard (with cheap shipping) would also really help.

njhussey
24-12-2014, 08:42 AM
I'll be converting a Warco Major next year. For the drives you'll need over 100V to make the Nema 34 steppers perform, ideally 240v drivers. The one area you don't want to scrimp is the electronics. Zapp is a good place to buy these, or you could try Aliexpress.

kingcreaky
24-12-2014, 08:46 AM
i definately need a milling machine in my life.

no further comment.

JAZZCNC
24-12-2014, 09:56 AM
Don't go higher than nema 34's it's not needed.
Like neil says you need lots of voltage with 34's to get good performance so buy mains voltage drives. These are what I use with nema 34's http://www.zappautomation.co.uk/electrical-products/stepper-drivers/n-series-stepper-drivers-step-direction/2m2280n.html

Seem expensive but you don't need a PSU so it cuts down on price and complexity and they are the only thing I'd fit to large 34's.

Size wise then you won't need massive motors these should work but I would get some idea of weight your lifting or moving first. I've seen nema 23's fitted to X & Y on these before so these will easily do it with some to spare. Thou I think you'll need the extra for the Knee.
http://www.zappautomation.co.uk/electrical-products/stepper-motors/nema-34-stepper-motors/sy85sth118-6004b.html

JAZZCNC
24-12-2014, 09:59 AM
i definately need a milling machine in my life.

no further comment.

What like my new little toy.! 14205

Neale
24-12-2014, 10:08 AM
I'll be interested to see how this goes as I have a Warco VMC myself that is on the list for a CNC conversion. There was an earlier thread on converting a VMC but that was a few years ago and technology and components have moved on a bit since then, maybe. Certainly the x and y slides move easily with the handwheels but the z is pretty heavy if you are driving the knee (although it doesn't need the same feed speeds, I guess, unless you are into 3D milling, so could be geared down somewhat).

thorphar
24-12-2014, 06:19 PM
Don't go higher than nema 34's it's not needed.
Like neil says you need lots of voltage with 34's to get good performance so buy mains voltage drives. These are what I use with nema 34's http://www.zappautomation.co.uk/electrical-products/stepper-drivers/n-series-stepper-drivers-step-direction/2m2280n.html

Seem expensive but you don't need a PSU so it cuts down on price and complexity and they are the only thing I'd fit to large 34's.

Size wise then you won't need massive motors these should work but I would get some idea of weight your lifting or moving first. I've seen nema 23's fitted to X & Y on these before so these will easily do it with some to spare. Thou I think you'll need the extra for the Knee.
http://www.zappautomation.co.uk/electrical-products/stepper-motors/nema-34-stepper-motors/sy85sth118-6004b.html


Thanks for the advice on the high power drivers. Just for future reference and to confirm my thoughts. What are the main advantages of High Voltage drivers over the lower voltage type.

Just popping the three HV Drivers and the steppers (3 of each) in to the cart jumps the price up to 786.30. Is there anyway of reducing the price. I have looked for the HV drivers on ali,however they are the same price and also would incur import duty. Any suggestions on getting the steppers cheaper or using slightly different HV drivers. :)


Thanks for all your help.

I would also agree with KingCreaky, CNC Mill is a must have :).

JAZZCNC
24-12-2014, 07:30 PM
Any suggestions on getting the steppers cheaper or using slightly different HV drivers. :)

No sorry can't help on buying cheaper but sure there will be some if you look hard enough. Personally I don't bother because it's worth more to me than the small savings to be able pass any problems back to Gary at Zapp and have replacements the next day.!

Regards price then unfortunatly when it comes to large motors and good performance then it's a case of do it right or don't bother. Large motors simply won't give good performance unless they have the voltage. It's very very common for people to buy large motors with low power drives only to be sadly dissappointed with the performance. It's also common for 3 or 4Nm Nema23 motors running correct voltage on good drives to out perform under powered 34's.!!

Edit: I reckon with this machine you'll get away with 4Nm 23's running on Em806 digital drives with 65V and ratio for X & Y axis. just use a 34 on Z Axis or use 23 and larger ratio with counter balance to help assist.

Web Goblin
25-12-2014, 12:30 AM
I looked at the warco knee mill but ended getting the gh universal. just fitted a dro to it. Can I have the power feed unit?:whistle:

Nice machine Jazz. Where is the controller?

i2i
25-12-2014, 12:47 AM
What like my new little toy.! http://www.mycncuk.com/attachment.php?attachmentid=14205&stc=1Nice Semco bedmill there Jazz, is it an 800 or 1000. I have 4 x 600's, great machines the first vmc's.

JAZZCNC
25-12-2014, 12:48 AM
Nice machine Jazz. Where is the controller?

In that blue box on floor in front of it. It's Anilim controller which normally hangs off that arm on side, DC Drives etc are in cabinet on rear. Now redundant to be replaced with Servo's and Cslabs controller.

JAZZCNC
25-12-2014, 12:54 AM
Nice Semco bedmill there Jazz, is it an 800 or 1000. I have 4 x 600's, great machines the first vmc's.

It's 1000 and cracking machine or it will be when it's done. Still under cover at minute waiting for my attention when weather breaks and I eventually get some free time for my self.

gavztheouch
25-12-2014, 01:13 AM
Jazz, what brand of servos are you thinking about using?

i2i
25-12-2014, 01:14 AM
i've got plans to throw HSD router heads on two (24k rpm 6.8kw bt30 atc), a slotting head on the third and keep a low speed head for steel work on the forth. Great machines and mega value.

thorphar
29-12-2014, 03:13 PM
Thanks for all the help with the suggestions and advise.


I have made some progress :). I have decided to go for the Nema 23 from zapp 3.0Nm for all axis'. I have also chosen to only control the x,y slides and the quill hand-wheel. I have chosen the Quill rather than the knee due to many reasons. The main problem is that there is a lot of slack between handwheel and the actual movement of the knee, the only way to fix that would be to change out the gear. Due to money and time being a major factor in this project I decided to say clear of that. The way in which I think the machine will work is by lowing the quill about an 1" or depending on the max height for clearance and then bringing up the knee to meet the work piece to the tip of the cutter. Once I have raised the knee manually, I would lock the knee and then all the z operations would occur through the quill. I am aware of the problems with lowing the quill on such a small machine, however Im prepared to bare with the limitation that would ensue with opting for the quill option.


As i mentioned earlier I will be buying the Nema 23 from Zapp
https://ci6.googleusercontent.com/proxy/3DjFhe66frnTzRDak21Cd_r-DDf9vktSHPBJB8-kNEkk94CCHalQ-75GKM3iiXRMf2ysJTbn70Jjxsm4uurJ-HNrIAHO0xV1kJOo2KEGn_E0KDursDG8QmqQfMVVU2q2Vf_7zKu 0cId7N1xh4mbfwS9WHNp40f6IPYpp0XMolj1YAg=s0-d-e1-ft#https://t.yesware.com/t/a5684e9958fd739ab87fd7f5f1c40515c902c17e/72d43411cbd92100e13ec23283bc734c/spacer.gifhttps://ci6.googleusercontent.com/proxy/AhUnjlmd_9Jmf7vDTS9CVulzeiy1lJv40R9h3B6hsgjPOTYYeV WGVS6XbnvE8hi6ZptzQujNVVcS_VF6Q9nXknY6-9gOYKQmpNNaMHoaSZEqGfhMsw_ecvJOeKix6AlP8IKDx3FaQVT _jtj2hb9dGc-t9P1segqCa76pDvpjMwDN=s0-d-e1-ft#http://t.yesware.com/t/a5684e9958fd739ab87fd7f5f1c40515c902c17e/72d43411cbd92100e13ec23283bc734c/spacer.gifhttp://www.zappautomation.co.uk/sy60sth86-3008b-nema-23-stepper-motor.html

and my fav ZP5a-INT
http://www.zappautomation.co.uk/zp5a-int.html

using the AM882 Driver
http://www.aliexpress.com/store/product/New-Leadshine-AM882-Stepper-Drive-Stepping-Motor-Driver-80V-8-2A-with-Sensorless-Detection-SM414-SD/402081_570168083.html

and a custom power supply.

I will be using rectangular box section for the mounting system between the stepper and the axis
http://www.ebay.co.uk/itm/281145148732?var=580212490514
(http://www.ebay.co.uk/itm/281145148732?var=580212490514)
For the xy and I guess z depending on if I operate the z through the quill or the knee i will be using (16:48) stepper: axis drive however I could go for (14:60) for the knee.
http://www.beltingonline.com/timing-pulleys-bars-272/
(http://www.beltingonline.com/timing-pulleys-bars-272/)
Im also looking for a NEMA Wall mounted like Enclosure to mount everything inside however Im not having any luck.

Any suggestions or views on the knee Vs. quill would be very helpful. Suggestions on removing the slack between the hand-wheel and the actual movement of the axis would be awesome too :).

JAZZCNC
29-12-2014, 05:49 PM
I think one of the problems with the quil and the knee is the backlash in both drive trains. Most of these machines I've seen CNC'd have some kind of external bracket with ballscrew that grips the quil and ensures there's little to no backlash. Some use direct to quil but i think often they get modded to use a ballscrew to get around backlash.

Like you say the Knee is just raised by hand to some level near what's required befroe starting job.

When you say NEMA case what do you mean exactly.? I use these http://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/CM_Metal_Enclosures/index.html

njhussey
29-12-2014, 08:47 PM
I'll be doing the Z axis by using an external bracket (I believe the correct term for the plate is "honking plate") and ballscrew. As Dean says there's lots of backlash in the quill handle so I'm not going that route!

thorphar
29-12-2014, 09:41 PM
I'll be doing the Z axis by using an external bracket (I believe the correct term for the plate is "honking plate") and ballscrew. As Dean says there's lots of backlash in the quill handle so I'm not going that route!


Could you show me a photo of what you mean by this method ? Sounds cool though

njhussey
29-12-2014, 10:29 PM
If you look in the mill conversion threads for Robin Hewitt conversion you'll see exactly what I was talking about. Robin has already converted a warco mill, though not one like yours.

Robin Hewitt
31-12-2014, 12:01 AM
I did the Warco Major. I think your plan to convert it using the existing screws is exactly the right way to go, that is what I did, but you will need a screw to drive the quill if your motor doesn't have the legs to lift the bed.
Once you have a working cnc mill you can decide if you want to make it better.
A man has to ask himself, how much backlash is too much? :beer:

thorphar
31-12-2014, 02:43 AM
Just on the first stages of design. This is the first version for the x-axis cnc mounting. I am looking at using 48 tooth 9mm HTD5 and 16 tooth 9mm HTD5 pulleys. Next drawings will be for the y-axis. Im saving the z-axis till last as I think it will take me a very long time.

I forgot to add the slots on the stepper mounting to allow for belt tensioning.

i2i
31-12-2014, 11:27 AM
have you thought about driving the base of the z axis screw rather than the right angled motion shaft. More direct than either method you described.

Robin Hewitt
31-12-2014, 11:32 AM
There are 2 kinds of toothed pulleys, timing belt and power transmission. I use XL pulleys because I have been caught out by backlash the one time I strayed. I am not saying HTD5 is wrong, but have you checked?

thorphar
01-01-2015, 08:35 PM
have you thought about driving the base of the z axis screw rather than the right angled motion shaft. More direct than either method you described.


Good thought.

I did have a thought about direct driving the x and y with a stepper. However, after looking at other conversions it seems that everyone has done belt systems rather than direct drive, and only direct drive on smaller machines. All that I could think of for being an advantage would be that you would increase the available torque. Im not sure how much torque is required however im sure that a single Nema 23 3Nm stepper would be suitable for operating the axis'.


If anyone has any some thoughts on this, again any suggestions would be sooo helpful.

i2i
02-01-2015, 03:03 AM
Not exactly what i meant. What i was suggesting is to drive the actual Z screw in the knee with a stepper "through a belt reduction if you require", but not through the angle drive present on the front of the knee.

thorphar
04-01-2015, 08:08 PM
Not exactly what i meant. What i was suggesting is to drive the actual Z screw in the knee with a stepper "through a belt reduction if you require", but not through the angle drive present on the front of the knee.

I was interested in what axis' would require a belt system in order to reduce cost. I did some tests on the handwheels using a newton gauge and a lever. Here are the results I got.



Axis
NM


X
1.68


Y
1.41


Z-Via Knee
8.0




I also wobbled the handles and measured how much slack there was in the screw.



Axis
Slack


X
0.85mm


Y
0.06mm


Z - Via Knee
0.08mm








Im gonna do some more testing but it seems i could get away with out the belt system on the x and y and just direct drive with a 3Nm Nema 23 and use a belt system on the Z.

thorphar
05-01-2015, 12:04 AM
In light of this recent discovery. I have re done my basket.

I use to use AM882 however, after looking around online someone mentioned the DQ860MA Driver being ok instead of the AM882. Im just worried about the lack of sensor less stall detection not being on the DQ860MA. Thoughts ?

Apart from the drivers im pretty sure on the rest, however if anyone see a major mistake, please let me know.

For the Z-Axis driven through the knee

2m2280N High voltage driver
Nema 34 - Sy85STH156-6204B 12.1Nm
suitible coupler to go between the Nema 34 and the z-axis rod.

For the x and y axis

Nema 23 3Nm
DQ860MA
Custom Power Supply
Coupler to go between Nema 23 and Axis drive.


I use to use flexible couplers, however in this kind of situation i believe a solid coupler would be appropriate. I don't know of any good suppliers for solid couplers however Im pretty sure I can make them.

ZX12RUSH
06-01-2015, 10:46 PM
Like this.
http://www.mycncuk.com/attachment.php?attachmentid=14322&stc=1http://www.mycncuk.com/attachment.php?attachmentid=14323&stc=1http://www.mycncuk.com/attachment.php?attachmentid=14324&stc=1


Works quite well for a my uses.
Some of the parts used

Stepper motors
http://www.ebay.co.uk/itm/German-Ship-Free-Ship-3-PCS-Nema34-Stepper-Motor-1232oz-6A-118mm-CNC-Foam-Mill-/171117223690?ssPageName=ADME:L:OC:GB:3160


Stepper driver
http://www.ebay.co.uk/itm/Single-Axis-CNC-Engraving-Machine-Stepper-Motor-Driver-Controller-TB6600-0-2-5A-/201196761093?pt=UK_BOI_Industrial_Automation_Contr ol_ET&hash=item2ed842f005

Although I have blown 2 up. One was by turning the Travel handle while it Was moving.
With careful treatment they now seem ok. I would like to try something better. May be a Gekko....

Ball screws on X Y X
I bought 2 Chinese Ball screws with 4 Ball nuts , and had the machine the ends to 16mm, then made suitable sleeves to fit the bearings.
http://www.ebay.com/itm/2-anti-backlash-lead-screw-ballscrew-RM2005-800-1500mm-4-ballnuts-/250631784672?ssPageName=ADME:X:RTQ:US:1123

ZX12RUSH
06-01-2015, 11:00 PM
EDIT
Posted twice

Clive S
07-01-2015, 12:03 AM
Nice Job. Did you not consider higher voltage drives to run the nema 34 motors. ..Clive

JAZZCNC
07-01-2015, 11:06 AM
In light of this recent discovery. I have re done my basket.

I use to use AM882 however, after looking around online someone mentioned the DQ860MA Driver being ok instead of the AM882. Im just worried about the lack of sensor less stall detection not being on the DQ860MA. Thoughts ?

Stall detect only works after 300rpm so it's not such a big deal for a mill. But what is bigger deal is how they handle resonance better and give smoother running motors. The DQ860ma are not as good in my experience so I wouldn't use them over AM882 or better still the updated EM806.

Richard
08-03-2015, 11:14 PM
Like this.
http://www.mycncuk.com/attachment.php?attachmentid=14322&stc=1http://www.mycncuk.com/attachment.php?attachmentid=14323&stc=1http://www.mycncuk.com/attachment.php?attachmentid=14324&stc=1


Works quite well for a my uses.
Some of the parts used

Stepper motors
http://www.ebay.co.uk/itm/German-Ship-Free-Ship-3-PCS-Nema34-Stepper-Motor-1232oz-6A-118mm-CNC-Foam-Mill-/171117223690?ssPageName=ADME:L:OC:GB:3160


Stepper driver
http://www.ebay.co.uk/itm/Single-Axis-CNC-Engraving-Machine-Stepper-Motor-Driver-Controller-TB6600-0-2-5A-/201196761093?pt=UK_BOI_Industrial_Automation_Contr ol_ET&hash=item2ed842f005

Although I have blown 2 up. One was by turning the Travel handle while it Was moving.
With careful treatment they now seem ok. I would like to try something better. May be a Gekko....

Ball screws on X Y X
I bought 2 Chinese Ball screws with 4 Ball nuts , and had the machine the ends to 16mm, then made suitable sleeves to fit the bearings.
http://www.ebay.com/itm/2-anti-backlash-lead-screw-ballscrew-RM2005-800-1500mm-4-ballnuts-/250631784672?ssPageName=ADME:X:RTQ:US:1123


Very nice looking build! So apart from blowing a few drives, any other problems?

bogstandard
09-03-2015, 02:15 AM
You asked earlier on about drive belts.
Well this site from the UK seems to have almost anything you could want.

http://www.beltingonline.com/rubber-timing-belts-40/


John

thorphar
11-03-2015, 09:58 PM
Thank you all for the advice and help relating to this conversion. Here is where ive got to so far. I have managed to create a mounting system for the x and y axis drives. I have three nema 34 1600oz stepper motors. I have a custom ball screw to drive the quill. What I need to complete is the quill drive system. Im hoping to use the 2 Axis CNC to help create the parts for the quill drive. Things having been moving slow due to problems that occurred with the Chinese supplier for the Stepper Motors.


I have attached a photo of the machine so far .


http://www.mycncuk.com/attachment.php?attachmentid=14853&stc=1