Hey, thanks for the info dump. I hope to be installing my kit in the next few weeks and this will help me quite a bit.
It's been 1.5 years, but I FINALLY ran the mill last night for 4 hours and it worked perfectly from startup to shutdown. I want to preface this message saying this is NOT a slam on IH. It is what I had to do to get the mill to work the way I needed it.
I'll start by saying I'm not the average hobby mill user. I bought the IH for the size and price point. Looking back, I probably should have just bit the bullet and got a used Mazak or something, but I'm very new to the machining side of things and didn't want to drop that kind of cash on the first mill. I've NEVER machined a thing in my life, so ALL of this was new to me.
I'll start with the IH CNC conversion. As most are seeing, the CNC kit took forever to get to me. Not the 6 months some are waiting, but probably 3 or 4. But once I received it, the fun of converting the mill began. That went very smoothly all things considered. Instructions were ok - but there were many hours spent on the phone clarifying things. When it was all said and done, I did have a mill that could be controlled under computer power. It took probably 6 weeks to get to that point.
So the mill is up and running, life should be good, right? I sure wish it would have been that easy. Although I've been using the mill for the past year, it hasn't been without issues.
The biggest problem I had at this point was erroneous limit trips. Everyone was thinking noise issues. I grounded everything, shielded everything, ran power wires away from signal wires. But still about ever 2 or 3 hours of run time there would be a trip. I learned to live with it, but many of my parts take 16 hours of mill time for each part. So it was a balancing act of how much I could do before the machine tripped.
The first thing to go was the x axis motor. IH thought it was because the gibbs were too tight. Me being an inexperienced machinist couldn't argue that, so I loosened up all of them and replaced the x motor. It ran ok, but I was sure the Y was going to go also at some point. I could just tell it didn't have the "oomph" it once did.
About 4 months ago I decided to start doing a little research. I didn't want to replace the y motor with another motor of the same size if it did go. It was strange how it all worked out, but I was researching the y axis motor but still used the mill now and then. One day I snapped a 1/2" bit and realized the spindle motor was running, but the spindle stopped turning. That's when all hell broke loose. I had severed the shaft from the VFD motor. The key had basically worn down to half it's size until it must have got wedged between the shaft and collar, and then just snapped the shaft off the motor. It was at that point that I had enough, and the rebuild began.
The real reason for this message is to help anyone who was in my same position. I won't say what I did is the right way to do things, but in the end, I now have a VERY solid system that I can rely on. It was a great feeling last night to walk out to the shop, turn on the machine, home it and run a part for 4 hours while watching it on a video camera from my lazyboy before having to go back down to change tools.
Here's what I ended up changing out.
1.) VFD Motor. One of the members was selling a 2hp Leeson. I picked that up (he did some work on the shaft to make sure it was going to fit like it should so I didn't snap another shaft. I totally disassembled the head and replaced all the bearings, including the spindle bearings. My mill was always very loud, and that made a WORLD of difference. I also replaced the oil with dextron when I was finished.
2.) I totally redid the electronics box. I remember early on IH told me to not use a breakout board and definitely not a smoothstepper. I was still getting erroneous trips with the stock electronics before the upgrade, so I figured it couldn't hurt to try something different. Here's what I changed... yes the list is long! (I gutted the box and started from scratch)
a.) cnc4pc Breakout Board - c11T
A WORLD of difference. All I can say is GET ONE! It removed about 200 wires inside my box and cleaned everything up. It also allowed me to troubleshoot things much easier since there are LEDs for everything. I still had a limit trip now and then, but it seemed less frequent after this board. The nice thing is it monitors the Geckos and e-stops if there are any issues.
b.) Replaced the gecko 320s with 320x. I knew one of the geckos was bad - or was pretty sure it was bad. So I wanted to replace it. Going to the 320x, I didn't change much with the driver, but it does allow to throw 20amps at the motor for 1 second before it errors out. I don't know that I need that feature yet, but I thought it was a good idea.
c.) Smoothstepper. That was also a GREAT investment! It works exactly as planned! The problem with the parallel port is that we are at the upper bounds of bandwidth using even 60khz signals. Since we have 1000 line encoders, it's pushing alot of info across that parallel port. Moving to the smoothstepper really quieted everything down and made things work so much smoother.
Now for the mill itself.
3.) Replaced x,y,z motor with 850oz motors from homeshopcnc. After talking to some people, I realized they were not overkill, and I'm glad I went that big. I used to run my mill at 70 ipm x and y and 50z. Now I'm at 120 x and Y and 100 Z without any issues. That's fast enough for me and my projects, but the more important thing is it's rock solid. I did have to turn the shafts of the motors down so I could drop to a 15 tooth timing pulley which basically dropped the ratio to 3.2 to 1 instead of 4 to 1, but with the added torque of the bigger motor, I've seen no issues.
4.) Replaced all the encoders with AMT102-v encoders from digikey. Reading on the list, they seemed like a great replacement for the usdigital ones which supposedly have noise issues unless you use a capacitor. I noticed instantly the drives quieted down when I installed the first one. BUT, it wasn't just a swap. The ballscrew end had to be turned down to 8mm which meant tearing apart the whole mill. It was well worth it though.
So after basically reworking the whole system, I only had one issue left. The limit switch would trigger now and then. What I finally found out was that it wasn't a noise issue at all. It was a faulty wire in the limit switch enclosure. Unfortunately it isn't easily fixed, but since it was on the z axis I could live without one of the limits. I just cut the wire and everything worked as it should. Damn noise issue!
I'm hopeful I have everything working now. Things were VERY promising last night. I use the tormach tooling system for all my tools, and last night I turned on the machine, homed it, and hit start. There was no fiddling with anything - no checking heights, etc. It was absolutely flawless.
I said early on, I'm not the average hobby machinist. My parts are sometimes 22x12 and are all 3-d surfaces. It can literrally take 4 hours on one tool operation and I have many per piece. Plus I use a vacuum plate to hold my material, so I have an extra 120lbs on top of the bed at all times. (which is why the smaller motors just couldn't handle it)
What I really wanted to say to others out there is don't be afraid of the breakout board or the smoothstepper. If I would have known what a difference they made, I would have scrapped everything from IH at the start and just went that route. So much easier to wire and work with!
Once again, I don't claim any of this to be the "right" way to deal with this, but I can honestly say it worked for me. I'll be out at the shop tonight to start another session and hopefully it's as rock solid as it was last night.
Hey, thanks for the info dump. I hope to be installing my kit in the next few weeks and this will help me quite a bit.
I also built my kit, and it was a great learning experience. i am more than willing to help answer any questions. the most frustrating thing on building the kit is not knowing if all your electronics will work as planned or if you somehow caused some unexpected error like a false limit trigger to happen.
I'm curious -- how much of the IH kit did you end up replacing, or at least how much did you spend replacing items? I could easily reuse some of these things on my other projects, but I'd like an idea of how much extra cash I might be laying out.
I'd hate to even think how much I spent. I don't look at the receipts - it makes me feel better. Figure 3 geckos ($110 each - but you probably don't need to replace these - the 320s are fine I'm sure), 3 motors ($160 each) 3 encoders ($30 each) breakout board - ($130), Smoothstepper - ($160) - Spindle motor - ($300 used - only replaced it because mine died) and way, way too much time. Probably around $1500+ to swap all that stuff. (plus a few cases of beer to the guy who turned all the ballscrews/motors so they would work with my setup) But a new kit would need around $900 to beef it up minus the parts I mentioned above.
I'm glad I did it though. The bigger motors are worth it - the electronics are worth it. I just wish I knew it all up front. Granted some of the pieces of the kit were still needed, but looking back, it wouldn't be hard to purchase the whole conversion kit in pieces. But I didn't know anything back then, so I had to go through this learning process to get to where I'm at today. IH does have a good kit - just underpowered for my use.
And remember, this is what I had to do for my usage. I'm sure not everyone has to go through all of this. But this will be the first night I look forward to going out to the mill and starting it up instead of wondering what I'm going to have to deal with this time.
Thanks, that helps quite a bit. My other project this summer (assuming I get to start the CNC retrofit, otherwise it's my only project this summer :-) is to build a 4'x4' XY table for low-drag tools (plasma cutter, engraver, etc). If I have to follow your route at least I'll have parts for the table....
I only had to replace the z axis motor. the x and y are running just fine and i can run over 100 ipm. but it took lapping the ways on my older machine. also i recommend adding a automatic one shot oiler, this one mod made all the stiction on the ways go away. this did cost about $600 for the complete kit with pump, lines, filter, and restrictors.
the motor and vfd i bought for mine were on ebay and only cost me $250 total. i also used a 56c motor that was face mount and made a custom adapter to mount the motor.
my geckos are running fine and they are the original 320 series. i did not use a break out board but would recommend a smooth stepper for future use. also i bought a nema enclosure to mount all the electronics. now the IH kit doesn't come with these parts anyway and its on top of the $4500.00 my stock encoders are working fine. i did buy a bunch of molex connectors which i will eventually replace with itt cannon connectors, this allows me to disconnect the mill from the cart that holds the nema enclosure and computer.
total i probably have another $1000-1200 into a working IH on top of the $4500 for the kit. i also bought the nmtb 30 spindle when it was on clearance for $75.00
Glad to hear you got it all working. I had been reading that the smoothstepper really wasn't needed for Gecko/servo motor setups, but actual facts are either hard to come by or hard for me to understand. I'm no electrical guy so am a little slow on the uptake in that field. What exactly did it do to help solve the issues you were having. I have the C11 board made for the Gecko drives wired in place already and was quiting with that, well at least while I am doing the ball nut mounts and one shot oiler system. The enclosure is now fully wired internally and doing what I can while awaiting the rest of my kit.
You are probably right, you don't NEED the smoothstepper. And actually, I'd try to get the machine up and running without it first to make sure all of your wiring is working properly. The reason I tried the SS was to try to get rid of the "noise" issue I was having that turned out to be a bad wire.
I will say that everything was much smoother after going to the SS, so I'm definitely not going back. Plus now I don't have to worry about having a PC with a parallel port any longer.
As for connectors, I use these for all my connections to the electronics box:
I have 8 pin connectors for the encoders/limit switches, and 4 pin connectors for the motors. I also use a big NEMA enclosure to house everything.
Ran the mill last night for another 4 hours - flawless. Life is so much better these days!!!
Last edited by sdfoiler; 05-12-2010 at 11:15 AM.
Glad to hear you've got your machine the way you want it...how 'bout some pics of the parts you're making...
It looks like i got all the right stuff for my mill then. Except for the SS. Do i really need to go there. All's i need now is some spare lead screw supports so i can start my build. want to keep the originals just incase something goes haywire. Quick question on the VFD and motor. Is there not a direct fit motor with the right C-face to mount to this head? Also what kind of limit switches did you use.
I found an older copy of the build instructions online, and some of the steps are "send this part back to us to be milled/updated". Did you have to send anything back?