[rule308x]

Hello,
Last year I bought a Lagunmatic 310 CNC knee mill. The unit did not have any of it's CNC electronics or motors so I thought it would be a good candidate for a conversion to PC control. After getting some great advice on how to start from Ericjgreen (who is doing an awesome job on his Lagunmatic 250 in these very forums) I got sidetracked with a lathe project. Anyways, I'm back to the mill now and lookin' for more advice! I ordered a 3 axis servo and drive kit from DMM tech in Canada, and an ethernet Smoothstepper board from CNC4PC.

The mill is filthy and has some surface rust on it. All of the way surfaces are caked with a mixture of dried grease and dust (old coolant?) but the do not seem to be worn out. There are ballscrews on all 3 axis and most of the mounting hardware for the old servos are there, including the belts and pulleys. I'm working on getting it cleaned up using Naptha, dollar store degreaser and WD-40. The machine is huge and with the 5hp motor that is currently mounted won't fit in my garage, so I'm working on enclosing my carport to house it. It stays dry and covered under there now, and I have been putting coat of oil on any cleaned, non painted surfaces

Here are some pictures, it looks way worse in pictures than in person. Or maybe I'm delusional!

Attachment 187898Attachment 187900Attachment 187902Attachment 187904
Attachment 187908Attachment 187910Attachment 187912
Attachment 187916

It looks pretty rough now but with some cleaning and elbow grease it should look much better. I'm much more concerned about the ways and screws being in good shape than how the machine looks, but I'll be painting it and cleaning it as I go. I'm hoping all of the ballscrews are in as good condition as the z axis but I can't really get to them to check without some dis-assembly.

Does anyone have access to some reference material that could show me how to get the table off without breaking anything? I have a "cherry picker" type engine crane to lift. I'd definitely be interested in instructions or a manual...

I'll try to post more pictures after some cleaning is done.

Thanks!

[erikjgreen]

Looks pretty good so far. Most of the parts are identical to my 250 as far as I can tell.

Which servo kit did you order? I'm going to replace my servos soon and I'll be interested in comparing performance.

Erik

[rule308x]

Erik,
I went with the DMM Tech .75KW AC servos. I got DYN3 drives for the x and y and a DYN2 drive for the Z axis. I'll also be using a smoothstepper and running mach3. Rate torque is 2.9NM and max is 7.2NM. The DYN3 drives will run the X and Y at 3000 RPM (rated) but the DYN2 will only do 1000 (rated). At least thats what the web site says! I ended up getting the whole kit with everything but the computer. It includes wiring, stop switch, proximity sensors, a break out board...pretty much everything I would have to source out myself. I'm sure I could have saved some money (the shipping is much higher than I wanted as DMM is in Canada) but the customer service seems really helpful so I just bit the bullet and got the kit. I'm a total noob so having everything from one vendor and all matched will be good for me, I think. I did get the smoothstepper separate because I'll probably be running mach on a laptop.

I received the smoothstepper today and notification from the shipping company that the Servo kit is on it's way so late next week to early the week after I should have all the pieces here.

BUT...while cleaning the unit I did find that there is noticeable play in the fore-aft ballscrew (not sure whether that's the x or y). Also the Left - Right ballscrew is really tight. I think the gib strip might be too tight but I'm still in the cleaning stages so I'll be breaking it down further the weekend. Were you ever able to obtain a manual for your unit that might include the proper way to disassemble the table?

I'll be posting some more pics tonight.

Thanks so much for checking in here! Your build thread is on my "read frequently" list! Seems like there are a few of us out there flying the Lagunmatic flag.

Later,

Jeff

[erikjgreen]

Cool. I'm looking forward to seeing how those servos work for you.

I got lucky in my surplus shopping and bought 4 SEM AC servos.. they're about the same torque rating as yours, but they range up to 6000 rpm, so I'm gearing them down more than you probably will. I'll be interested to compare performance.

What I found in my table was that the yoke that connects the ballscrews to the table (both screws cross through it) had some loose cap screws in it, which gave me play in X (the left/right axis) but not as much in Y (the front/back). By the way, remember that motion is relative to the spindle... if the table moves toward you, the quill "moves" away from you relatively, so that's Y+. If the table moves left, the spindle is moving right, so that's X+. The spindle itself is up+ and down-.

For dis assembly, I was able to figure it out from drawings in the manual I have (got it from Jsantos here). In short, you remove the ball screw supports so you can slide the table by hand. That includes the caps, the servo mounting plates, and the big hunks of steel that hold the bearings. Then remove the way wipers to access the gibs and loosen and remove them. Since the X table is only attached to the mill via the ballscrew nuts (and guided by the ways) you should now be able to slide it off to one side - I used a strong metal cart to hold it, and used the knee to put it at the right level. It would have been easier/safer to use an engine hoist.

Once the X is off you can access the lube system and the yoke and look for problems. If you want/need to remove the yoke or Y ballscrew you have to do it from the front or bottom of the knee. I did it from the front, using a 1/2" socket extension and a hex key socket to reach in and undo those bolts.

Much of my mill I put back together using new metric socket head cap screws from McMaster-carr. I also ordered new lube fittings online from another place and replaced all those. I do have a manual lube pump on the spindle for mine, I may replace that with an auto lube pump.

Let me know if you find a good process for tightening the gibs. I tightened mine until I removed the play in the table I could get with a short lever. I adjusted them later when I was servo tuning... the tightness of the gibs really affects the whole servo system a lot, it provides damping. Some folks tighten them until their servos start to overload, which I suppose is the max tightness. I'm still experimenting with that, and I'll have to do more when I get the new servos installed.

Erik

[Dstamp]

Nice looking project. I did the same with a really beat up YCM-30 and my only regret is that I didn't push through the project faster.

Now that it is running I have discovered all manner of things to make with it, the only difficulty is in prioritizing and chip/coolant containment. It's far from perfect, and the spindle makes a lot of racket from the spline, but it works.

Could you post some detail pics of the table extension and how they are attached/supported?

What CAM software are you planning?

[rule308x]

Ran into a problem over the weekend. The x axis tapered gib strip broke when I tried to remove it. Actually, just a small chunk of it came off when I removed the screw that tightens/loosens it in it's channel. The remainder of the gib strip is either wedged in tight or perhaps rusted or stuck in place. At any rate I ain't got it out yet. I'm still trying to locate a manual or source for parts but my day job has got me buried for the next several weeks so going is slow.
On a good note the servos should be here next week so I'm looking forward to that.
I'm going to post some pictures of the VFD and left side cabinet in a few minutes. I've been searching for some documentation for that as well. I think everything in the left side cabinet is still connected but I wanted to look it over to make sure i understand what's going on. I'm wondering if the stock VFD will allow me to run the unit off of single phase power? I have a 15hp phase converter for other machinery in the garage if that's not a possibility.

Could you post some detail pics of the table extension and how they are attached/supported?
Not sure what you mean...are you referring to the piece that telescopes to cover the y axis parts from coolant and gunk? I'll post some tonight if that's the cas.

What CAM software are you planning?
I'm going with mach 3 to start. I was leaning towards linuxcnc but mach looks really nice as well. The servo/driver system I bought "closes the loop" between the driver and the servo and most linuxcnc systems prefer to do so inside the computer, from what I understand. Perhaps if I can get the mechanical accuracy to where this would be an advantage I'll reconsider. The support community for both options are great, though.

Going to go take some pics...

[rule308x]

Well I finally go the x axis gib out. I don't think the broken piece is going to be a real problem but that may be wishful thinking. I might have the local machine shop weld and precision grind it.

Here are some images of the left side cabinet and VFD for the mill. I'm hoping the current VFD works, but I've priced replacements just in case. I've had no luck finding documentation on this particular model. I'd like to find out if it can be used to run the unit from single phase power. I know I'd have to replace the coolant pump with a single phase motor but that wouldn't be too big of a deal I suspect.

Attachment 188920
Attachment 188922

[rule308x]

Here are some pics of where I am at. I still have not been able to figure out how to safely remove the table. I got the gibs out late last week and I think the broken one can be repaired and ground without causing any problems. The pics make the mill look much filthier than it actually is, but I know I still have lots and lots of cleaning ahead.

Attachment 189542Attachment 189544
Attachment 189546

[Dstamp]

I slid the table of mine off onto a steel cart with a polyethylene sheet on top. With the table advanced all the way to one side and using the knee crank to fine tune the height, it was a pretty straightforward operation, didn't even have to hold my breath.

[Dstamp]

Well I finally go the x axis gib out. I don't think the broken piece is going to be a real problem but that may be wishful thinking. I might have the local machine shop weld and precision grind it.

Here are some images of the left side cabinet and VFD for the mill. I'm hoping the current VFD works, but I've priced replacements just in case. I've had no luck finding documentation on this particular model. I'd like to find out if it can be used to run the unit from single phase power. I know I'd have to replace the coolant pump with a single phase motor but that wouldn't be too big of a deal I suspect.

Attachment 188920
Attachment 188922

That's a nice VFD brand, I've used them in Thermwood CNC Routers before, but I doubt you'll be able to use with single phase input, as all that I am aware of spec single, 3 or both. People have told me it can be done, but never with an example, demonstration, or reference of specific brand or model. The black smudges above the cooling vent don't seem ideal, but may not be serious.

[rule308x]

Update 7-12
I had to take a few weeks off this project due to a big project at work. I have made too much progress in the meantime but I did receive the servos, drives and wiring from dmm. I have not tested them but I'm really impressed with the completeness of the kit. The components themselves seem very sturdy and well built although I don't have much to compare too. I'm pleased I went with the dmm kit at this point. I also bought a smoothstepper board.

After consideration I ordered a dedicated computer...I was planning to use a laptop I already have but I found a cheap refurb dell that should do nicely.

I have a rotary phase controller to run the vfd. I was hoping to run it on single phase but I'm not entirely sure it's possible. Oh well.

Thank you to the poster who commented on the vfd model. I'm glad to hear its a solid unit. I did notice the black streaks on the top and I'm praying that it's not serious. I've got some time off coming next week so I will do some more testing.

If anyone out there has manuals for any of this stuff scanned and would be willing to sell or trade for them let me know!

Thanks!

Jeff

[jsantos]

Jeff,

PM me with your email address if you need the Lagun manuals. I can send them to you. They include the docs for the 310.

I use a 3-phase VFD on my CNC router and I run it on 1-phase so you can certainly do that. However, you're derating the VFD by about a 1/3 if you run them off single phase. So if you have a 8- to 10-hp VFD, it can run a 5-hp spindle using single phase.

I got a Lagun 250S last year that I was looking to convert to Mach 3. But I haven't gotten around to doing the conversion as it's still working very well. I think I'll wait until it breaks before I do the conversion. I'm also looking at using DMM Tech, so I will be watching your progress like a hawk. :-)

Do you think that 750 watt motors will be enough to power your machine? I've been talking (emailing) to DMM about what I need for my CNC router rebuild (10X5) and they suggested the same kit that you're looking at, except they recommended the DYN-2 instead of the DYN-3. If that kit will power your 310, then it's probably way overkill for my CNC router.

[rule308x]

Jsantos,
I'll pm you in a few. Thanks so much! I do think the DMM motors with the DYN3 drives should be sufficient. I don't have all the numbers in front of me but I did check out the specs on the original motor and I recall the torque specs being sufficient. The DYN3 drives supposedly make a difference, at least in instantaneous max power (according to their spec charts)

I'm a little stalled on the project right now, having the manuals will help out a TON. I'm going to be back at it now that the weather is cooling off and I'll be inside more. Updates soon!

Jeff

[erikjgreen]

Just FYI you two, the original motors installed on these mills (Baldor Big Mho, Lagunmatic 250/310/320 @2500rpm) have about 1 kw continuous power and 4 kw peak power (available 1% of the time). However, I've found the original servos have relatively weak continuous torque - about 50 oz-in, or 0.35 nM continuous. Torque is really the most important thing to watch, speed is a close second.

It looks like the lowest torque motors DMM tech sells are about 0.7nM, which is more continuous torque than the original servos on your mill had.

Me, I'm replacing my servos twice.. I'm working on installing a set of DC brushed servos that will go to about 1.5nM continuous at 3000 rpm (original motors were 2500rpm) and once I get some power transmission issues worked out I'll probably replace those with some 1.5nM continuous/6000rpm brushless servos, sinusoidally commutated. At least I think so.. if the brushed servos work well I may just use the mill for a while... got a lathe project to work on.

Erik

[jsantos]

Jeff

Where did you get the specs for the original 250/310 motors? 0.35nM continuous torque seems pretty low. The motors that Jeff got (which I also ordered) are rated at 2.9nM.

We should get together sometime so I can return your power supply.

[erikjgreen]

Good idea, Joe

I got the torque rating from a post here somewhere. The motor labels themselves show stall torque (500 oz-in stall). Here's a copy:

>125 volts DC. They're Baldor "Big MHO" DC servos:

> Baldor Big Mho Permanent Magnet Motor
> Model # 4201990
> 500 oz-in
> 120 VDC 2500 RPM
> 10 AMPs Constant, 39 AMPs Peak
> Tach output 7.0 V/KRPM
> Volt Constant Kc=40 V/KRPM
> Transducer = Encoder 1000L


Erik

[erikjgreen]

> Baldor Big Mho Permanent Magnet Motor
> Model # 4201990
> 500 oz-in
> 120 VDC 2500 RPM
> 10 AMPs Constant, 39 AMPs Peak
> Tach output 7.0 V/KRPM
> Volt Constant Kc=40 V/KRPM
> Transducer = Encoder 1000L


Erik

Actually, scratch that.

I got better information on these from Baldor's site (I looked up a model very similar).

500 oz-in is continuous torque, equal to 3.53 nM. Peak torque is about 4x that (as you might guess from the amp readings) or about 17.65 newton-meters or 2500 oz-in max. That's at 39 amps draw.

Sooo... you can toss out what I said above about installing 1.5nm servos... I'll just stick with the original ones until I install the brushless servos somewhere down the line. Now that I've got them running using the Aerotech drives (which max out at 20 amps), my mill is jumping up and dancing.

Erik

[erikjgreen]

Just to complicate my life some more, I bought another CNC mill... a lagun 310

I'll be looking forward to seeing how your restoration goes, because I'll be getting going on mine sometime in January, I think. I've almost finished fitting the replacement servo drives to the 250, and it's humming along now, so I should be able to get the 310 running by spring sometime.

Erik

[jsantos]

Erik,

You're nuts! Where did you house the 310? In your bedroom? LOL.

Email me when you'd like to get together.

[erikjgreen]

It's in the same shop as my 250... it's a bit tight in there

Probably I'll have time to get together after the holidays....