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slowtwitch
05-13-2013, 10:23 PM
It's been some time since I posted anything on these forums. Heck, it's been sometime since anybody has posted. Anyway, after reading Mechie's post, I figured I might as well jump in. Maybe revive these forums :)

I made a few changes to the mill and more are coming. One of the changes was the cooling system....it had to go. I was sick and tired of the tiny little drain getting clogged up and the pan filling with coolant. So I drilled a 4 inch drain hole on the opposite side of the original drain. I also upgraded the coolant pump and tank.

Here are some pics...

http://i46.photobucket.com/albums/f109/slowtwitch/P5130012_zpscc7f3623.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130012_zpscc7f3623.jpg.html)

http://i46.photobucket.com/albums/f109/slowtwitch/P5130013_zps78bfc57e.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130013_zps78bfc57e.jpg.html)

I re-purposed my grand kids toy box :) Right now , it has 20 gallons in it. I think I can do 25 :) I was originally using 2" pvc for the drain, but found that it didn't drain good enough...chips were collecting and such. So i bought some heating duct and made up what you see in the picture. This works well and I'll probably make up another tray using 18 gauge steel. The pump is a submersible utility pump from Harbor Freight and it works great...plenty of pressure. As you can see, I also re-used the mikini coolant setup. It's now my filtering system.

I don't have a picture of it, but after cutting the hole and removing the old drain setup. I epoxied in two pieces of 4" diameter, about 2" long tubing (one for each drain). Without this, the coolant would travel through molecular adhesion, beyond the tray area and you'll get coolant everywhere....Oh and thanks to the coolant issue, I also removed the power supply from under the mill and installed it in its own enclosure, mounted on the rear wall of the mill.

I also installed new plumbing for the coolant..using 1/2" pvc. Where the original setup came up from the drain area, it now comes in through the rear.

http://i46.photobucket.com/albums/f109/slowtwitch/P4130024_zps95af1781.jpg (http://s46.photobucket.com/user/slowtwitch/media/P4130024_zps95af1781.jpg.html)

I also installed a wash down hose....

http://i46.photobucket.com/albums/f109/slowtwitch/P4130025_zps98f16a69.jpg (http://s46.photobucket.com/user/slowtwitch/media/P4130025_zps98f16a69.jpg.html)

So much better than blasting chips with air.

I had some neoprene laying around and figured I put it to some good use....

http://i46.photobucket.com/albums/f109/slowtwitch/P5130028_zpse1d42df6.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130028_zpse1d42df6.jpg.html)

So what's up for the near future... I mentioned it in mechie's post. I'll be installing these.....

http://i46.photobucket.com/albums/f109/slowtwitch/P5130002_zpsd7181878.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130002_zpsd7181878.jpg.html)

They are... a 1200 oz.in and two 940 oz.in steppers. I been having some issues with the Z loosing steps and instead of chasing my tail looking for the reason, I'll just install all new steppers and digital drivers.

Lastly, I have some choices for the spindle motor. I have a 4 pole motor setup, very similar to Allen's setup. I also have a Kollmorgen 3KW servo, it has a resolver attached to it and I found a driver for it that may work. But, this servo stuff is kind of a new to me and I don't want to have the mill in limbo learning this stuff.......I also have this bad boy... A FLENDER HIMMEL 3KW (4hp) AC motor.

http://i46.photobucket.com/albums/f109/slowtwitch/P5130014_zps3eade1c8.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130014_zps3eade1c8.jpg.html)

The beauty about this thing is that it has a 4 1/2" mounting base.. The frame is aluminum, but the front bracket is cast iron. Total weight is about 40 lbs.

http://i46.photobucket.com/albums/f109/slowtwitch/P5130018_zps4aa3efac.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130018_zps4aa3efac.jpg.html)

When i got it home, I took it apart to make sure things were ok and found that the fan was missing. I was kinda of upset, but, I figured I can come up with a solution and here it is....

http://i46.photobucket.com/albums/f109/slowtwitch/P5130022_zps7d5edf72.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130022_zps7d5edf72.jpg.html)

I had a couple 220 volt case fans taking up space and put them to use..... I gutted out one fan to act as a spacer to clear the shaft.

I hooked the motor up to a vfd and gave it a test run. It ran great at 4000 rpm, so i took it to 6000 rpm, then to 8000 rpm, I went to 10,000 rpm and it purred like a kitten. I chickened out going further, but, it sounded like it could take more.

I'm really leaning towards this motor as all my machining is with aluminum. I've also been looking at maybe a second mill and it won't be a Mikini .....

That's it for the updates... and sorry for the long post ...was kinda bored and hopefully we can revive these forums :)

mcphill
05-14-2013, 09:24 AM
I totally fried my coolant pump last week. I hadn't used coolant in forever, so it had all evaporated. The V25 version of BobCAD defaults to "coolant on". I was cutting wood, and didn't need coolant. After 15 minutes of running it started to smell, but I thought it was due to the treated wood I was using. A bit later I saw a waft of smoke, and reacted - finding some flame down in the coolant "pit"! Needless to say, I am pretty sure the pump is toast... Glad to see your Harbor Freight option, will be getting one of those. I also lost all the accessories (coolant pump, lights, oiler), so I suspect it did finally pop a fuse/circuit breaker. I haven't looked in to where to reset that yet as I had to hit the road on a business trip...

I'll post some pix and video of what I made in a few days...

mechie
05-14-2013, 12:54 PM
"They are... a 1200 oz.in and two 940 oz.in steppers. I been having some issues with the Z loosing steps and instead of chasing my tail looking for the reason, I'll just install all new steppers and digital drivers."

Slowtwitch, make sure your stepper motor will fit in the z-axis location; it can't be any longer than the current stepper motor unless you plan on putting spacers under the z-axis column. If you want to reduce the load on the z-axis, you could replace those gas springs on the column with pneumatic cylinders (link toMcMaster-Carr (http://www.mcmaster.com/#standard-air-cylinders/=mqxm0z) )and increase the air pressure in them until the current running the z-axis stepper (measured with a current clamp) is the same when the z-axis goes up as when it goes down. I assume the z-axis is loosing steps when it is going up, but there could be a lot of force going down if you are drilling / plunging. I've considered using the air cylinders and a dedicated air reservoir myself to reduce the wear on the z-axis, since the current air springs don't provide a constant lifting force. There are also magnetic springs, but they are buko bucks link:LinMot - Products - Magnetic Spring (http://www.linmot.com/products/magnetic-spring/)

slowtwitch
05-14-2013, 01:28 PM
Thanks for the info. I'm already looking into replacements gas springs. I figured I would need something different if I go with any one of the AC motors.

slowtwitch
05-17-2013, 07:04 AM
I mentioned in an earlier post that I moved the power supply from underneath the mill to the rear. Here are some pictures....

I re-purposed this control box that was being thrown out were I work

http://i46.photobucket.com/albums/f109/slowtwitch/P5150002_zps11bb098a.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5150002_zps11bb098a.jpg.html)

Made up a new mounting plate out of some scrap aluminum and bolted all the components to it.

http://i46.photobucket.com/albums/f109/slowtwitch/P5150008_zpscdba3515.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5150008_zpscdba3515.jpg.html)

I ran a temporary conduit to access the soon to be replaced electronics...

http://i46.photobucket.com/albums/f109/slowtwitch/P5150009_zps72e5d83b.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5150009_zps72e5d83b.jpg.html)

The new electronics will be installed in metal boxes mounted to the rear panel, next to the power supply. I'm just waiting for the company to replace the control boxes at work and scrap them :)

Lastly, I decided on a different breakout board. I initially was going to use a CNC4PC C23 board, but, have switched to a PMDX 126, with their 107 speed control. Will see how that all goes :)

jid2
05-21-2013, 11:09 PM
PMDX 126 +107 + Ethernet Smoothstepper is a nice setup.

SWATH
05-23-2013, 09:55 AM
Hey Pete,
Good to see you back in the saddle. It was sad to see this forum die for so long but understandable. Great Mods and I hope to be able to use my machine soon as well. I'm currently setting up my garage to move it into so I can get it out of the house. I've been thinking of doing a youtube series ala John Grimsmo when I can get my life and family back together. I've been out of the CNC game for some time, first marginally so due to this ridiculously buggy and dodgy Mikini, then I had some major unexpected health issues that I'm still trying to work through, then found out my 1yo baby has cancer and have been virtually living in the hospital with him since December, only to return to work to be told I'm being laid off this fall from massive budget cuts at the NIH. So yeah life's hard sometimes. My gears are now shifting into providing an income source for my family through my currently stagnant business, and I will choke every ounce of life left out of this flaky machine to make that happen. Learning from your mods and the mods of others like Allen and Phil will help me do that.

I've been soundproofing, smellproofing, waterproofing, climate controlling, wiring, and lighting my garage to make the move sometime within the next month or so. Then my number one problem will be the *&%$&&^%)&%&^%$&% spindle. I'll tackle that when I get to it though. I just don't know enough about it to do the conversion yet or even what parts I will need or which direction will be the best way to go with that, but I'll have to make do for awhile until I can raise enough money. I light duty machining kickstarter project may be in my future we'll see. I would love to sell this thing and replace it with a Tormach or UMC 10 something but I have to make this Mikini turd work for now.

My next purchase will need to be the smallest quietest air compressor I can find that will be enough to run a small sandblasting cabinet. Something with no bigger than a 30gal. tank because my garage is tiny. I don't know much about compressors other than the 6 gal 3.4CFM@90 one I have absolutely sucks for anything but a brad nailer and is louder than a freight train.

slowtwitch
05-23-2013, 11:29 AM
Swath, It's great to see you posting again. I hope all goes well for you and your family. I think as a group we can overcome the issues with this mill. I too thought of selling, but, I just couldn't bring myself to pass this mill on to some unsuspecting soul. As Allen, Mechie and others have said, the mechanics of this mill are sound...it's just the friggen electronics that suck.

Hang in there... if I can help you... I will.

As for an air compressor...there are some really quiet ones out there (search ultra quiet air compressor). The only thing is that most are for nailers and such. If you can't find one of the silent types to suit your needs, look for an older reciprocating unit that requires oil. I had an old 2hp Kellogg with a 60 gallon tank, that was rather quiet...bought it on Craigslist for $80.

I'm getting very close in doing my conversion. I found a company in England ( Beltingonline.com, Supplier of power transmission and conveying products (http://www.beltingonline.com/) ). I had a hard time finding a pulley to fit the Mikini's belt size in the states. They made up a pulley for my new motor. It cost $72.00. They bored it for my shaft size...which is 30mm and cut in a keyway. I was going to make a new mounting base, but, it looks like I can reuse the old one.

All the components are on my workbench and I'm going to wire everything up and give it a test run...hopefully this weekend.

mechie
05-23-2013, 11:57 AM
Hi Swath,

First off, sorry to hear about your son's condition. As for the Mikini, my wife is always chiding me about how I spend so much time on my mill, and so little comes out of it, hence the Flashcut / Electrocraft mods.
For the smells, you may consider getting an activated charcoal filter (see Mcmaster-Carr 4043T45). I put one near my dehumidifier's exhaust fan so it cleans the air almost continuously. Also, I found making a plastic enclosure like the one found somewhere on CNCzone or youtube really cuts down the odors. My 4th axis leaks hypoid gear oil...umm such a nice fragrance...and that odor is almost eliminated by the cover. I've found that 1/8" polycarbonate works well; it's relatively inexpensive, tough. easy to saw without cracking / chipping, and it bows a little in the middle, so coolant drips into the enclosure instead of pooling on the edges. I did have to reinforce it with some aluminum 'L' shaped bar though, because it sagged a little too much.
For the spindle mod, I'm trying to post what I hope others will find useful. I've had to do tons and tons of research on motors, motor controllers, steppers, wiring practices, et cetera, and I'm a mechanical engineer whose worked alongside electrical engineers. I can't imagine what the average Joe Mikini-owner would have to wade through to make this happen. Best of luck, and let me know if you have any mod-related questions.

SWATH
05-23-2013, 01:30 PM
Thanks guys,
My son took a major beating from surgery and chemo but thankfully he survived and is in remission now and is expected to be fine for the most part. He lost some hearing, bone marrow, his hair, most of his liver and his gallbladder, but is a smiley little baby again now. About 100 cases of this particularly rare and aggressive type of cancer a year in the US...jackpot.

After reading Phill's links about Flashcut I've become highly intrigued. Of course I can't justify the price right now, but it looks like a great option. It made me wonder if upgrading to servos at the same time would be a good idea if for nothing else than the positional feedback, I don't know. I guess right now I'm 90% concerned with the hinky spindle, and 10% concerned with the other electronics. Anyone thought of using a torquey servo for a spindle? I assume it would be really expensive. I'm at the point where I don't want to run this machine enough just to make money, I want to run it enough so I can replace it with something else and then use that one for the business. So maybe upgrading things on it has a diminishing return but I need it to run at some capacity right now to get to that point. All I want is for it to work as advertised for the time being.

The other thing that bothers me a little about the machine is the R8 spindle. I hate to invest in a whole bunch of R8 collet chucks when I would like to use a machine with an ATC in the future whether it be the TTC with a Tormach, or a BT30 with a UMC10. I know I can adapt it to use TTC but to me it's kind of pointless without even a power drawbar.

I checked out the really quiet compressors but they have way too little CFM to use for sandblasting. I've read you need at least 10CFM@90PSI for that. I would really like a 2 stage oil lubricated 30 gal for under $500 but it is not a critical tool at the moment.

The smell and sound of the machine won't be an issue after it's moved into the garage. It is currently IN my house in the basement, bad idea. I just didn't realize Vactra #1 way oil stunk so bad.

The guy at Lowes tells me they are having a sale on shop vacs this weekend so I think I might pick up one the little 5gal stainless steel Blue Hawk vacs and dedicate it to vacuuming chips out of the machine. I think that would be much easier than trying to scoop them out with turkey forks and keep aluminum and steel separated for the scrap yard. I actually bought a big magnet to get the steel chips out but it is messy and tedious too.

I've got to do something like your coolant drain setup Pete. It kinda sucks a little the way it comes. My pump still works though so I may just wait until it breaks too, which judging by the sound of won't be long.

slowtwitch
05-23-2013, 03:47 PM
Thanks guys,
Anyone thought of using a torquey servo for a spindle? .


I thought about using this Kollmorgen.....http://i46.photobucket.com/albums/f109/slowtwitch/P5130026_zpsef26b146.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5130026_zpsef26b146.jpg.html)

It's rated at 3KW and 6000 rpm...has a resolver for feedback. I am still learning about servos, so it's sitting on the bench till i can figure things out. There seems to be limited info out there about these things and folks that do know about them are very cryptic in their answers.

I may have mentioned it in another post that I'm also going to see about deciphering the pinout on the servo controller and bypass Mikini's BoB and use a CNC4PC board or the PMDX, to see if it would make any difference with the spindle. I keep thinking about the quality of the PWM signal and such that is produced with the Mikini board. Also, I want the capability to override the limit switches from Mach when a limit switch is activated. Currently, when a limit switch is activated, I shutdown the machine, move the stepper/ball screw by hand and turn the machine back on.... thanks to my non working front panel.

One thing I will do this weekend...is trial fit the 3kw A.C. motor. I installed the pulley and I want to check the fit. I may hot wire the motor to the VFD and see how the Mikini likes 10,000 rpm :D

SWATH
05-23-2013, 04:36 PM
I would love to see the honker on there. Since it is 3KW would you have to upgrade the amp rating of anything to handle it? Wouldn't that be jumping from ~10A to ~13A? I don't know what the Mikini electronics are rated for in reality but Phil told me something like the 20A circuitry is actually rated for up to 30A.

I would just love to see some kind of motor work correctly without too much hassle especially an AC servo.

slowtwitch
05-23-2013, 09:25 PM
I mentioned that I installed a second drain hole....here it is...

http://i46.photobucket.com/albums/f109/slowtwitch/P5230013_zps012f4ec9.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5230013_zps012f4ec9.jpg.html)

I centered it with the webbing in the castings that are underneath the base. I didn't have a hole saw that would cut the casting, so I did it the old fashion way....a bunch of holes close together and then filing it smooth. It really relieved the back log of coolant that i use to get. Especially when the narrow portion of the front and back of the tray would clog up. I am really pleased with the way the coolant mods have worked.

Now for the fun stuff.. I removed the Mikini servo to see how things would fit with the AC motor. I thought I could reuse the original flat metal bracket, but, the center hole was to big. so I decided to make a new bracket....Here it is with my new pulley...Btw, these are HTD5 36 tooth pulleys, 25mm wide. It's wider than the original, which is 20mm, but, I figured the front pulley will keep the belt in place. The belts are HTD 5m-450 20 mm wide.

http://i46.photobucket.com/albums/f109/slowtwitch/P5230001_zps8edecb99.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5230001_zps8edecb99.jpg.html)

and here it is mounted.....The belt fit great.

http://i46.photobucket.com/albums/f109/slowtwitch/P5230003_zps49931a3c.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5230003_zps49931a3c.jpg.html)

another perspective...

http://i46.photobucket.com/albums/f109/slowtwitch/P5230008_zpsd74282a0.jpg (http://s46.photobucket.com/user/slowtwitch/media/P5230008_zpsd74282a0.jpg.html)

I also turned on the mill to see how the Z would react to the new motors weight. I was pleasantly surprised that it responded like the original motor was still mounted. It moved nicely pressing just the up/down buttons. Pressing shift and up/down for full speed also sounded good. Over the weekend, I'll put it through some workouts using an indicator, to see if it's losing any steps.

As mentioned in my prior post, I'll install the motor and do a temporary hook it up to the VFD and see what happens. Maybe cut some aluminum. :D

slowtwitch
05-27-2013, 07:11 PM
Well I had a chance to try out the AC motor on the mill. All I can say right now is WOW!!!!!! Why did i wait so long???????????? But, let's back up a bit......

I installed the motor and hooked it up to the VFD. It's the famous Huanyang unit that has been written about a thousand times on the forums. It's a 4kw unit. I bought it on Ebay for $150.00 shipped. I have one on my lathe and it's been running for close to two years. I initially had a problem with getting up to speed, but, it turned out to be a parameter issue. I forget which one it was right now, but, I had 60 typed in and changed it to 350 and all was good. Anyway, this is still a temporary setup, as I'm still running Mikini's BOB.

As I have mentioned in a prior post, the gas struts seem to be doing their job with the added weight of the motor. I'm installing all the electronics on the back of the machine...trying to eliminate as much of the cabling in the interior of the mill as I can. So I added a cable chain to keep things in order.

That's enough of the writing stuff, here's a video .......This is the mill cutting at 7600 rpm. I had it up to 10,000 rpm...but just cutting air :)


http://www.youtube.com/watch?v=YOfj4v2uHBg

I'm still running a program made for the Mikini...hence the slow feed and dept of cut. I also turned down the coolant nozzles for filming purposes.

Some initial thoughts... I think Allen experienced it...the machine sounds so much more solid when cutting. Someone mentioned something about having mass and I have to agree with them. The code written in the video was a conventional cut, but, i was really happy with the finish after everything was cut. With the Mikini servo, you can see some marks on the angled sides of the parts. They just about disappeared with the new motor.

Next up, install the new drivers and the PMDX 126 with the Ethernet SmoothStepper. Then the steppers :cool:

more to come........

mcphill
05-29-2013, 05:49 AM
Can you elaborate on the wiring needed for just this? I think I have one of those servo motors and a controller... "All" you need to do is wire up power and give it the PWM signal going to the current spindle motor driver? Can you link the post that describes that if it exists, or provide a little more detail here? Does it work in both manual and Mach modes, and for FWD and REV directions?

slowtwitch
05-29-2013, 06:05 AM
Can you elaborate on the wiring needed for just this? I think I have one of those servo motors and a controller... "All" you need to do is wire up power and give it the PWM signal going to the current spindle motor driver? Can you link the post that describes that if it exists, or provide a little more detail here? Does it work in both manual and Mach modes, and for FWD and REV directions?

mcphill, The motor i'm using is not a servo. It's a 4hp ac 2 pole motor. I using a Huanyang VFD to run it. I'm also eliminating all remnants of Mikini's electronics. Thus, there will be no manual mode.

Right now the motor is "cobbled in" wire wise...by that it's not connected to a breakout board. It's controlled directly from the VFD with a potentiometer. When i start the transformation to the new electronics, i'll try to have detailed wiring info :)

mcphill
05-29-2013, 06:20 AM
Ah, I see. Thanks!

slowtwitch
06-01-2013, 03:21 PM
Hello folks, This morning, I removed the spindle column in my quest to replace the Z stepper. I was kinda of shocked at what I saw :eek:,

This is what welcomed me...... This is where the Z stepper is located. It's amazing how the swarf finds it way.....
http://i46.photobucket.com/albums/f109/slowtwitch/P6010017_zpsa9429fbc.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010017_zpsa9429fbc.jpg.html)

How deep is it......
http://i46.photobucket.com/albums/f109/slowtwitch/P6010003_zps61a1228f.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010003_zps61a1228f.jpg.html)

The stepper was immersed by about an inch....It's a wonder the bearings didn't fail or the motor's rotor rusting up or even shorting out.
http://i46.photobucket.com/albums/f109/slowtwitch/P6010011_zpsb9af5cb6.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010011_zpsb9af5cb6.jpg.html)

There is a drain hole in the rear, but, it's only about 4 mm in diameter. It easily clogged up.
http://i46.photobucket.com/albums/f109/slowtwitch/P6010020_zpsd4f4e718.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010020_zpsd4f4e718.jpg.html)

I was also surprised to see that the column was not pinned or keyed. I also didn't like the fact the conduit (for the wiring that goes in the rear of the column ) was not connected to anything...it just lays there with the wires going into to it

Anyway, as Mechi has stated, using the 1200 oz stepper will require spacers, as it's a tad longer. I'm machining a pair of 1 inch spacers. I took measurements and I don't see any issues with using my smallest tooling and collets reaching my work pieces. I'm also going to drill a nice size drain hole. That's what the tape is indicating...the location of my drain pan.

I plan to reroute all the wiring differently. Probably exiting at the top of the column.

I'm also going to test something different for limit and home switches. I have proximity switches, but, I seriously thinking of something like this....

http://www.youtube.com/playlistlist=PLme8A5tJEaiar3NSxiq8SknNxUCEWXpaa (http://www.youtube.com/playlist?list=PLme8A5tJEaiar3NSxiq8SknNxUCEWXpaa)

They don't seem to be effected by swarf or coolant. We'll see :)

more to come....

howecnc
06-01-2013, 04:58 PM
I am actually in the process of pocketing out that area and building a cover with a drain for that same area.

slowtwitch
06-01-2013, 07:04 PM
I am actually in the process of pocketing out that area and building a cover with a drain for that same area.

I drilled a .750" hole in that pocket and epoxied in a piece of pvc tubing about 1.5" long. The pvc will prevent fluid from clinging to to the underside of the casting and dripping elsewhere. Btw, the casting is close to 1" thick in this area.

Another thing I noticed when dismantling the column.....
http://i46.photobucket.com/albums/f109/slowtwitch/P6010006_zpscee41b9f.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010006_zpscee41b9f.jpg.html)

http://i46.photobucket.com/albums/f109/slowtwitch/P6010008_zps1f9339b1.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6010008_zps1f9339b1.jpg.html)

These are the bolts that hold the column to the base. As you can see the thin washers that were used where not doing their job. I wondered why my indicator detected movement when I pushed the column. I test fitted a hex bolt and there is clearance for a socket. I'll be ordering some grade 8 bolts to replace these.

more to come.....

mcphill
06-01-2013, 07:43 PM
And the hits just keep on coming! Amazing how many stupid decisions/actions were taken in building these machines. Most/all of the ones I am aware could have been done MUCH better for no more money! I just don't get it...

howecnc
06-02-2013, 10:59 AM
I am pocketing it out so I can remove the Z axis stepper without having to remove the column.

slowtwitch
06-02-2013, 02:24 PM
I am pocketing it out so I can remove the Z axis stepper without having to remove the column.

That would sure make things easier :) I also looked at what would be involved in moving the Z stepper to the top of the mill. I think it's doable and I thought about doing it, but, I need to get the machine up and running....maybe in the future....

SWATH
06-02-2013, 04:42 PM
Interesting find! They must of fixed that issue at some point because that area on my mill is open. I could take off the stepper from the underside if I wanted. I also notice the Z column flex with a dial indicator when I pull down or push up on it. I though that was normal but maybe not. I seem to be avoiding the Z stalling when I eliminate vertical rapids and keep the Z motion nice and slow, so I wonder if it is just too much weight for the stepper motor to handle and that speed (100IPM and slow acceleration). Fortunately I think it would be easy for me to replace the Z since I don't have to take off the column. I still wonder though how they tram it from the "factory" with no way to adjust it.

What is the main argument against using servos? Cost? It seems a much better way to go after having busted so many tools and parts from loosing steps with no positional feedback. I become paranoid about taking my eyes off of it for 5 sec. In fact I basically just stand there with my hand over the E-stop. That sucks for an hour long program.

slowtwitch
06-02-2013, 06:58 PM
Swath, I don't think they really tram these things. The just rely on what ever their machining process gives them. I never saw any kind of inspection sheet stating its accuracy, or that its was even done. On my mill I can see where they actually took a disc grinding wheel on a portion of the base where the column sits on. Fortunately, my spacers are sitting on a machined section.

I also checked my Z settings in Mach. The velocity is 75 and acceleration is 50. With the old stepper it handled the new AC motor with no issues. When was the last time you checked how accurately your XYZ are over a known distance??? I do this every time I change something....a setting, a new drive, stepper, etc.

As for servos, that would be an entertaining venture. The cost as well as the learning curve can be an issue. I think if I wanted to go with servos, it would be time for a new machine...something like the new Novakon Torus Pro with servos.

Today, the wife and I went out to see some friends (Day labor blues band) play at a benefit concert. Had some great food, sweated a ton..thanks to the heat.

When we got home, I changed into my work clothes, went into the shop and played with the mill. I did some experimenting with my proximity switches. As many of you know, these switches are really accurate and work well. But, you will get that occasional tripping and then you will have to reset. All my machining is with aluminum and I don't know how many times a piece of aluminum will find its way and attach itself to the contact area of the switch and set off an e-stop.

On another forum, someone (I believe it was Ray L.) mentioned encasing the switches in some type of non conducting medium..plastic, HDPE, etc. Where the thickness of the plastic in the sensing area was just enough that aluminum would not set it off, but, steel would. Hmmmmmm.

I kept thinking these things are sealed pretty good and decided to go a different route. I found a plastic box and measured the thickness of the lid... it was .060". I hooked up the sensor to a 12 volt supply (Brown lead positive, Blue lead negative) and passed a steel bracket over it and the led on the sensor came on. I then put a piece of the plastic on top of the sensor and passed the steel bracket over it, again the led came on again.

With the plastic piece still in place, I passed over a piece of aluminum over the sensor and the led did not come on..even pressing against it, the sensor led would not come on....

Here's my ghetto solution....I simply super glued a piece of plastic to the switch.
http://i46.photobucket.com/albums/f109/slowtwitch/P6020006_zpse0d6dbc6.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6020006_zpse0d6dbc6.jpg.html)

http://i46.photobucket.com/albums/f109/slowtwitch/P6020007_zps926545da.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6020007_zps926545da.jpg.html)

Ok, maybe a bit to much super glue. I'll be neater with the ones going into the mill :)

Hopefully this will cut down on the nuisance re-set situations.

howecnc
06-03-2013, 02:01 PM
I think I am going to replace mine with a mechanical switch.

SWATH
06-03-2013, 02:11 PM
Hmmm, that must be another fix. My stepper power supply is 72v so I guess conceivably I could just add a bigger NEMA 34 stepper to the Z. I guess maybe another driver too. 99% of the time all my axes jog fine at 100IPM, but it's that 1% where a stall becomes a calamity. Reducing all my Z rapids to 20 IPM seems to have reduced the mean time to failure to about 0.5% or half of what it was. Still sucks, ruined some more plaques and broke an engraver yesterday thanks to the mysterious stall. This morning everything went fine on a 1.5 hour program then literally in the last 30 sec. Z stall on a retract (20IPM) then plunge right into the work. Sometimes I wonder if this machine is cursed. Anyone think a smooth stepper might help?

slowtwitch
06-03-2013, 02:35 PM
Swath, have you tried just switching the drivers...x with z or y with z ?????

SWATH
06-03-2013, 02:47 PM
No I haven't, the stall happens so randomly and infrequently it's hard to trouble shoot. I can try doing that and just cut air for a long time, then come back to see if it's still on position, and if not then on what axis the stall occurred. Is that what you are thinking?

slowtwitch
06-03-2013, 03:22 PM
No I haven't, the stall happens so randomly and infrequently it's hard to trouble shoot. I can try doing that and just cut air for a long time, then come back to see if it's still on position, and if not then on what axis the stall occurred. Is that what you are thinking?

Yep, see if the stall happens to x, if that is the one you switched.

mcphill
06-03-2013, 07:00 PM
When I put my USB SmoothStepper on ALL the motions seemed SO much better. I think it is certainly worth a shot before doing to many other investments. If you don't like the SS, there should be a reasonable aftermarket to sell it back in to...

slowtwitch
06-03-2013, 08:08 PM
When I put my USB SmoothStepper on ALL the motions seemed SO much better. I think it is certainly worth a shot before doing to many other investments. If you don't like the SS, there should be a reasonable aftermarket to sell it back in to...

mcphill, you really have a good point there. I don't think I would run any Mach based machine without one :)

SWATH
06-03-2013, 11:10 PM
I'm thinking about doing that. Do you guys know if the ethernet jack on the Mikini integrated computer works? Mine is full of black silicone but I wonder if I pick it out if I can use an ethernet smooth stepper.

slowtwitch
06-04-2013, 04:37 AM
I'm thinking about doing that. Do you guys know if the ethernet jack on the Mikini integrated computer works? Mine is full of black silicone but I wonder if I pick it out if I can use an ethernet smooth stepper.

The jack does work, but it's a pain to clean out ... Actually , my son uses the Mikini computer now in the basement to surf the Web :)

mechie
06-07-2013, 09:05 PM
I would love to see the honker on there. Since it is 3KW would you have to upgrade the amp rating of anything to handle it? Wouldn't that be jumping from ~10A to ~13A? I don't know what the Mikini electronics are rated for in reality but Phil told me something like the 20A circuitry is actually rated for up to 30A.

I would just love to see some kind of motor work correctly without too much hassle especially an AC servo.


Wow Pete, those are huge motors. One reason the spindle sounds so solid with the large motors is you now have a giant giroscope mounted to them. Every time a cutter takes a bite, it twist the spindle ever so slightly, but now the spindle has a massive giroscope on it that is being rocked back and forth with each cutter bite---and big giros resist rocking. 187248 You could get the same effect using the original spindle if you mounted it on a stiff three-foot-long pole (not exactly practical, but do-able). Another reason the cutter cuts smoother is probably that it has all the inertia of the big motor's armature. This leads to smoother cuts, but it also leads to bigger shocks on the spindle bearings (I think Phil from Mikini alluded to this in his conversation with Allen). This may shorten the life of the bearings, but it doesn't sound too hard to replace them from Allen's post.

allenj20
06-14-2013, 11:49 AM
I just stumbled accross this thread having been busy with my G0602 lathe cnc conversion. Wow Pete you have been busy, nice work on all the mods man.

SWATH sorry to hear about your kid, and glad to hear he is doing better.

SWATH
06-14-2013, 12:18 PM
Thanks Allen, we're just trying to put it behind us as best as we can and move on although being at the hospital is becoming our new way of life it seems. Maybe I'll trick this machine out well enough to keep it and pass it down to him as a relic of being dealt a crappy hand and overcoming it through perseverance and ingenuity.

slowtwitch
06-14-2013, 09:43 PM
Wow Pete you have been busy, nice work on all the mods man.



Allen, good to hear from you :) It's been a busy, kinda of nerve racking week. I took a "Honey Do" vacation this past week, mostly to finish our front porch (which has only been in the unfinished state for 4 years...ouch!!! and believe me the wife let me know it...lol).

Anyway, I did have a chance to work on the mill...thanks to a bunch of rainy days and waiting for joint compound to dry. I installed all the limit and home switches. This was kinda of time consuming, as I had to make all new brackets and drill new mounting holes on the mill.

Next I made up my 1" spacer blocks for the column (thanks to Mikini engineering), so that I could use my new Z motor. You can see it here, as well as the new bolts and washers.
http://i46.photobucket.com/albums/f109/slowtwitch/P6140018_zpsc45e6896.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6140018_zpsc45e6896.jpg.html)

Since I was installing new steppers, I thought of replacing the stepper to ball-screw couplings...maybe stainless steel units. But, there is a problem...I could not find couplings that would fit. The Mikini..at least on mine are 50mm long by 34mm in dia. The longest one I could find was 45mm. I was a little concerned with the amount of bite the smaller coupling would have and nixed the idea and used the old ones.

One thing that bothered me about the mill for some time was the number of conduits inside the milling area. I reduced it to one......The X axis motor and switch lines.
http://i46.photobucket.com/albums/f109/slowtwitch/P6140017_zps17e9e67a.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6140017_zps17e9e67a.jpg.html)

I used electrical knockout covers to cover the old holes and silicone them in.

All the wiring has been re-routed to the back of the machine...Here are the Y and Z limits and homing lines...
http://i46.photobucket.com/albums/f109/slowtwitch/P6140015_zps703b8d51.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6140015_zps703b8d51.jpg.html)

and the VFD, power supply...
http://i46.photobucket.com/albums/f109/slowtwitch/P6140011_zps1556d449.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6140011_zps1556d449.jpg.html)

Here is the PMDX 126, Ethernet Smoothstepper nestled into their new home...
http://i46.photobucket.com/albums/f109/slowtwitch/P6140010_zps71a571fe.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6140010_zps71a571fe.jpg.html)

Now for the Murphy's law stuff...first I had a problem with the PMDX board and the VFD playing nicely together. The main issue was that I didn't have any torque at 3600 rpm..which is the rated speed of the motor. The motor ran great with the panel mounted potentiometer, but, for some reason under Mach3 PWM spell...no luck. The VFD is rated at 3kw and the rated amperage is 11 amps..the same as the motor.

Naturally, this took up a bunch of time, trying this and that. That's when I went over to my lathe (which I also converted).... it had a 4kw VFD, rated at 17 amps... What the heck, I thought. I moved the 4kw VFD to the mill and it worked. I took it down to 1000 rpm and could not stall it :)

But, now my lathe is in need of a VFD... fortunately, the lathe is over powered with the 4hp motor and I was able to get a new motor today. A brand new Baldor inverter duty 2hp, 4 pole motor...the best part, only $130.00 on ebay and it's a local pickup. It even has an encoder. Should work well with the Hitachi vector drive that I originally bought for the mill.

Another issue I had were my connections. I thought I would solder the ends of all the signal wires and the motor leads and eliminate frayed ends, when inserting them into the connectors. What I didn't know was that as i would tighten down on the screws, the wire kinda squirted out just enough to make a poor contact...thus causing me to chase my tail for a couple of days.

Problems like no movement of the axis's, The Z axis sounded like it was jammed tight...I could go on, but, I want to move forward....Anyway, I redid all the connections and re-inserted them naked :) I turned everything back on...went over to the keyboard and pressed some buttons and I had movement on all the axis's !!!

I messed around with some motor tuning's and everything sounds so smooth.

Lastly, I did a quick check on my tram and found that I'm leaning forward by .002". and leaning to the right .0015". When I trammed the mill sometime ago, it was out by .004" on both readings. I'll do some shimming tomorrow :)

All that's left is to hook up the coolant pump to a relay, connect the limits and homing switches and get the probe in place. One last thing, I may have an opportunity to get the rotor in the mill motor precision balanced...some friends from my electric motor winding days offered :) Some Kluber grease in the bearings... Mmmmm, 12,000 rpm could be a possibility .....

more to come....

mcphill
06-15-2013, 09:02 AM
Do you have any details on what you did with the limit and home switches?

slowtwitch
06-15-2013, 07:44 PM
Do you have any details on what you did with the limit and home switches?

Nothing really special. I just used some aluminum angle and flat bar to make the new switches work. I left myself about .500" play to the end of the screws, just in case I over shoot the limits. I used a .010" feeler gauge to set the distance from the switch to the parts that will set them off...

Here are the "Y" limit and home switches, they needed a .375 block to get them to where I needed them.....

http://i46.photobucket.com/albums/f109/slowtwitch/P6150002_zps6e1ea36d.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6150002_zps6e1ea36d.jpg.html)

The switch on the other end is basically the same :)

Here are the "Z" switches.....
http://i46.photobucket.com/albums/f109/slowtwitch/P6150001_zpsc050f00d.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6150001_zpsc050f00d.jpg.html)

and the bottom one (a little fuzzy)....

http://i46.photobucket.com/albums/f109/slowtwitch/P6080001_zpsa838f0c9.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6080001_zpsa838f0c9.jpg.html)

In the above picture, you can see where I filled in the space behind the black cover. This was an open area about .750" . I figured I block it up to stop some of the swarf and coolant that was getting into this area and down into the Z stepper pit.

I also picked up the motor that I bid on Ebay for $130.00......

C-face
http://i46.photobucket.com/albums/f109/slowtwitch/P6150004_zpscd45c715.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6150004_zpscd45c715.jpg.html)
and it has feet :)

http://i46.photobucket.com/albums/f109/slowtwitch/P6150002_zpsca23a5c0.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6150002_zpsca23a5c0.jpg.html)

It's all cast iron and weighs about 62 lbs. I also liked the name plate's max rpm :D I thought it had the encoder installed, but, no such thing. I have a couple encoders laying around. Maybe I'll play around with them when I get some free time.

Lastly, I trammed the mill today. It took some time, but, I think I nailed it. -X and +X are dead on, as are the Y's. I used a .0005 dial test indicator to get the results.

Tomorrow, I'll try to finish the wiring and do some motor tuning. I did have a chance at running the motors at 250 ipm. :D But, i think I'll settle out at about 120 ipm.

I'll try to get a video of the motors in action...

more to come....

SWATH
06-16-2013, 12:57 PM
That is definitely a nice looking motor. After I read that you bought one on ebay I did a little searching and found pretty much what I was looking for:
188440

Picked it up new w/encoder for $200 (it is $1200 from automation direct, y551-a772 (http://www.automationdirect.com/adc/Shopping/Catalog/Motors/AC_Motors_-_General_Purpose_and_Inverter_Duty_%280.25_-_300HP%29/AC_Motors_-_Inverter_Duty,_Marathon_%280.25_-_100HP%29/Marathon_Black_Max_w-z-_Encoder_%280.25HP_to_30HP%29/Y551-A772)). Now I just have to figure everything else out.

Pete,
Since you have your gas struts off, can you figure out what the weight of each one is? I figure with the increased weight it may be necessary to beef these up.

slowtwitch
06-16-2013, 05:01 PM
Swath, The struts are already back on the mill. But, they were pretty stiff. Easily in the 40 to 50 lb. area. I don't have any problem moving my Z. There isn't a hint of strain or hesitation.

Btw, that is one nice motor you got there :D

slowtwitch
06-22-2013, 09:19 PM
Well, the mill is finally back in running order....yeeeeessss. I'll try to take a video of it running. I'm pretty happy with the spindle motor. I cut some parts at 6500 rpm and it cut like butter. I also tried out a new 2" face mill to see how good the tram came out. All I can say is wow :)

The new steppers and drives made a ton of difference in the way all the axis run. Everything is so smooth. I don't hear that resonance sound when making a circular interpolating cut. I goofed on some G-code making my new control panel. Using a .250" end mill to make a .610" hole, I punched in 50 in/min feed and a cut dept of .260" by mistake. The machine made the cut so smoothly!!! I couldn't believe it...scared me a bit...lol. I admit, I chickened out and changed it to a more comfortable setting.

Next on the improvement list ... repack or change the spindle bearings. Nothing is wrong with them, just playing it safe.

Here's my new control panel, it's my first attempt at this kind of stuff.....

http://i46.photobucket.com/albums/f109/slowtwitch/P6220004_zps79a7a631.jpg (http://s46.photobucket.com/user/slowtwitch/media/P6220004_zps79a7a631.jpg.html)

I powder coated a piece of aluminum and then did the engraving.

I'll be using an I-pac II keyboard emulator .... The I-PAC (http://www.ultimarc.com/ipac1.html) ...to control the buttons and such

Some thoughts of the entire process. If I had the time, I would have gone the servo route for the spindle. But, i needed a working machine to keep my customers happy and getting a servo setup would have taken a bit of time. Installing the AC motor is great for my needs, as I only cut aluminum.

The total cost of this adventure was...

Spindle motor and Drive - $240.00
Stepper Motors and drives- $680.00
Smoothstepper ESS - $190.00
PMDX 126 breakout board - $175.00
Pmdx 107 Spindle control - $57.00
All the little things about - $150.00
Total - $1492.00


As I was cutting parts for some customers, i actually felt comfortable walking away from the machine :) I couldn't do that with the old electronics. This gives me a chance to work on the servo drives I have.....

mechie
06-22-2013, 11:03 PM
Awesome, Pete! Great job on the wiring too; I tried to be as neat as possible with my wiring, and label what I could, but it doesn't look as nice as your machine.

slowtwitch
07-27-2013, 08:11 PM
I had some time today to take some video of the mill. Excuse the lousy editing :D Anyway, I am pleased as can be with all the upgrades.

Some of the benefits are...I have cut down on the time it use to take to machine my parts. The inside of the machining area looks cleaner without all the extra wire conduit dangling about. It's actually a pleasure to work with the mill again.


http://youtu.be/rJBVWh9qdec

Here's a picture of a set of brackets just off the mill.....

193736

take care

mcphill
07-27-2013, 10:40 PM
Wow, you did a lot of work there! I can't believe you left the "1610L" stick on it! You are at more like a 3854Z in the controls and spindle changeover you did!!!! All you have left are the castings and linear bearings, right?!?

slowtwitch
07-28-2013, 06:56 AM
Wow, you did a lot of work there! I can't believe you left the "1610L" stick on it! You are at more like a 3854Z in the controls and spindle changeover you did!!!! All you have left are the castings and linear bearings, right?!?

Yea, I have to come up with a different name. You mentioned castings. I thought about epoxy filling the castings, but, decided that would be to much work.

I don't think I will be doing anymore major modifications to this machine. Just some maintenance issues when they come up, like spindle bearings. If the urge to try servos comes up, I'll just look for a Haas Mini Mill :D

allenj20
07-28-2013, 11:47 AM
Holy crap Pete you have taken the Mikini Mods to a whole new level, nice work and great looking parts too. So is everything working out the way you had hoped with your product?

slowtwitch
07-28-2013, 12:55 PM
Holy crap Pete you have taken the Mikini Mods to a whole new level, nice work and great looking parts too. So is everything working out the way you had hoped with your product?

Allen, it needed to be done or I wasted a ton of money buying this machine. As for the product I'm making, it's like anything else in business...you have your ups and you have your downs. Right now the product has payed for all the modifications and is paying off the machines and my new garage. I think once they are paid for... I'm retiring. I just want to walk out my backdoor...walk 17 feet to my garage and work on my 57 Volkswagen :)

slowtwitch
07-30-2013, 06:12 AM
Hello folks, I had some time last night to look into the issues with my control board. It looks like I didn't install a driver, supplied in the software package that pokeys supplied. This created the quirkiness that I had with the board. Here's a video of the board in action........


http://youtu.be/rV9qq0V6wvA

If anyone is interested in using pokeys, Rod over at Woodworkers forum has a detailed post on it's setup.

Console the Key Emulator Method - Page 2 (http://www.woodworkforums.com/f170/console-key-emulator-method-98939/index2.html)

enjoy....