[dazp1976]

I'll be going for a 1.8kw 3000rpm servo for my PM25 clone (belt driven, 2 spd version).
All I need then is for someone to turn me out a larger replacement pulley for it
Want to get it overdriven (still 2 spd) to about 3000rpm & 6000rpm at the spindle.
This should still give me the same torque as I have now but double the speed.

[ChrisAttebery]

Having a 6K+ top RPM is a game changer.

[ChrisAttebery]

I tend to leave my machine up and running so that if I get an order I can just throw some material on the machine and run a job.

After I updated the enclosure for my mill the Cycle Start button didn't seem to work or would only work sporadically. I opened up the controller and found that one of the input terminals was loose. I tightened it up and the cycle start button started working again.

After that I noticed once or twice that if I left the machine alone for a while I would come back and the mill was at the tool change position like the cycle start had been pressed. It also moved to the tool change position once while I was loading some material on the machine. Each time I stopped the cycle and rewound the program.

Yesterday my wife called me and said that the garage was full of smoke. I told her to call the fire department and to call me back when she knew what was going on. She called back and said some sawdust was smoldering and that they got it out and wanted to know how to turn off my CNC mill. I had the machine set up to cut sheet goods on a small riser table that I had made. The riser table clamps into the vise. Apparently the machine started a cycle with a program that normally uses two tools. The second tool is a 3/8" spot drill that is about 1" longer than the first tool (a 1/8" router bit). I had Mach Standard Mill set up to skip measuring repeatable height tools which means that it will start right into a program when the cycle start button is pressed. The machine proceeded to drill holes and mill slots into the 1/2" MDF spoil board. The spot drill made a mess out of the MDF and the riser but thankfully it didn't catch fire. The garage smells like smoke but otherwise the damage was limited to the riser and spoil board.

While I was vacuuming up the mess I noticed that I got a static shock a couple times. This leads me to believe that there is a grounding issue.

Once I get some time I'm going to dig into the controller and cycle start button to see if I can find anything. I'm also going to run a dedicated ground line from the controller to the mill. Hopefully that will take care of this problem.

I'm also going to change the way that I park the machine from now on. Anytime I'm done with the machine I'll be throwing the breaker that feeds the spindle motor. I may start hitting the E-stop every night too. I've avoided hitting the E-Stop in the past because I was afraid the machine would lose its position, but the more I think about it I don't think that will be the case if the machine isn't moving when the E-Stop is hit.

[CL_MotoTech]

Wow, sorry to hear about this. I'm glad you got off (relatively) scot free though. I just built a new controller, I think I'm going to do a triple check on it.

I always leave my controller and software off when I'm away, it only takes two minutes to start up and if you save your fixture it's the same as when you left. It shouldn't lose position unless you stall a stepper or stop a program mid run.

[pippin88]

Unfortunate, but I also question the wisdom of leaving your machine on all the time.

Apart from the issue of phantom starts you've had, there is also the fact that steppers are consuming power even when at idle.

If you have home switches, I see no advantage to leaving a machine on. If you don't have home switches, get them.

[CL_MotoTech]

At a minimum you should have activated e-stop if only so you weren't needlessly feeding power to your steppers while they are idle.

[691175002]

Experience has made me absolutely ruthless about electrical interference and grounding problems, because the moment you see unexplained behavior in a machine its hard to trust it again.

If you are careful its generally not hard to eliminate EMI, but you have to apply a lot of judgement since the guidelines sometimes contradict each other. I generally apply them in this order, which is a compromise between effectiveness of the measure and its difficulty/cost.

1. Keep noise producing and noise sensitive wiring as far apart as possible.
2. Have a low impedance ground connection for each component.
3. Keep ground and 0v separate except where they should be connected. (This one can be tricky. Typically you want to connect them at one point.)
4. Avoid bad ground loops. (Loops that are large enough or positioned in such a way that they will act as antennas)
5. Use shields and filters where necessary.

[fpm06001]

what motor are you running?

[ChrisAttebery]

I guess I never updated this thread after the phantom cycle starts. I re-wired and rerouted my cycle start, pause, and E-stop switches with a new multi lead cable and grounded the shield to the controller's chassis. Problem solved. I also got into the habit of closing the program and turning off the breaker to the spindle after I'm done with the machine.

Over the holidays my spindle was acting up. Sometimes it wouldn't turn on, but when the spindle was turned off it would sometimes hum or turn at a few rpm. I finally track it down to the relay on the C6 that I was using to enable the spindle controller. Luckily it has two relays and I wasn't using the second so I just swapped the enable over.

[CL_MotoTech]

Good to hear you got back on track! Mach 4 cranked my spindle up one time with my touch probe in the spindle. Not cool, and I haven't used Mach 4 since. With Mach 3 or UCCNC I've never had the same issue, so as far as I can tell it was a software issue.

These machines can be fickle beasts, especially for luddites like me. But when they run and run well it's a pleasure. I've taken to shielding all of my wiring, doing so requires relatively little effort in the scheme of things, and it's one less thing to worry about. Even at its best, I find my G0704 to be a bit of a maintenance hog, though it's getting better with each tweak.

Great looking conversion by the way!

[ChrisAttebery]

I haven’t updated my thread in a while so here it goes...

After 6+ years my spindle motor developed a clicking noise. The pulley side bearing is on its way out. I’m headed to the bearing shop to pick up a new set.

I got tired of using a ratchet to swap tools so I bought a DeWalt 20V 3/8” impact driver. OMG! One of my best purchases ever.




Yesterday I machined a work stop for my vise. I’m so tired of using my calipers to set parts in the vise.

[ChrisAttebery]

I got a new set of SKF bearings installed in the motor. I broke them in by running the motor at at 750 RPM steps for an hour each. I got the machine back together and was making chips over the weekend.

After 6+ years my spindle motor developed a clicking noise. The pulley side bearing is on its way out. I’m headed to the bearing shop to pick up a new set.

[ChrisAttebery]

It's been a about 5 years since I replaced the spindle bearings. Now that I replaced the bearings in the motor the spindle bearing noise has been getting worse. I tore the spindle apart and the lower bearing is pretty rough. The bearing that I use to support the spindle pulley is a little rough too.

I was looking at the offerings at VXB Bearings and decided to try some ABEC 5 bearings for the spindle this time around. They are ~3x more expensive, but they should have 1/2 the runout of the low cost ABEC 1 bearings that I've used in the past. The total for the three bearings was $92 plus tax and shipping.

For future reference here are the part numbers:
Pulley support bearing: 6007-2RS
Upper spindle bearing: 7005C P5
Lower spindle bearing: 7007C P5

[ChrisAttebery]

I received the new bearings a couple weeks ago. It's amazing how much quieter they are. You get used to the noise of the spindle over a couple years and don't realize how loud it has become.

When I first put my machine together I had to sand the journals on the spindle to get the AC bearings to fit. I didn't have a lathe at the time so I used 320 grit and turned the spindle by hand to try to not work on one area more than than the others. This time around I chucked the spindle in my lathe and measured the journals. There's about .002" TIR on the journals. The bearings sit on the high spots so the spindle isn't out by that much, but I measured .0015" TIR 1" from the spindle face. I decided to order a new spindle from Grizzly and see if I can improve the TIR. I'll use my 13x40 lathe to fit the journals this time around.

[Kenny Duval]

You've got a lathe. Build yourself a tool post grinder instead of buying another spindle. Grind the bearing bores and taper in to spec. You'll learn another skill in the process. If you get it worng you can always order another spindle or do both. order one to run on and rebuild the other.

[ChrisAttebery]

The problem is that the bearing journals on the spindle are undersized already. The bearings are a slip fit onto the shaft. Any grinding I do is going to make them smaller. I'd have to turn them undersize and sleeve them. I also thought about grinding the taper in place on the machine. In the end I decided that since a new spindle is only $90 that I'd prefer to start with a good spindle. That also allows me to keep the mill up and running since I use it on a regular basis for my business.

I may try to rebuild the old spindle once I get the new on in place.

You've got a lathe. Build yourself a tool post grinder instead of buying another spindle. Grind the bearing bores and taper in to spec. You'll learn another skill in the process. If you get it worng you can always order another spindle or do both. order one to run on and rebuild the other.

[ChrisAttebery]

Well, my motor just went up in smoke. I got 7 years of hard use out of it. I was milling some steel, went into the house for a bit, came out to check on the machine and I could smell burnt electronics. It was still running. Then right when I walked up to it the breaker for the spindle tripped. The motor was over 250F. I let it cool down but it sounds like something is shorted out in the motor.

This isn't good. I bought the motor as a close out from PM. I doubt they have a replacement. I'm not sure where else I'll be able to find a 1100W 4200rpm DC motor. Not only that but I'll have to machine a new mount and pulley.

[ChrisAttebery]

Uggg, It gets worse. I installed my original 750W motor this morning. I figured that I could get by with it for a little while. It sounds bad. Like low power and bad bearings bad.

I'm leaning towards a 2HP AC motor and vector drive as the replacement. I just need to figure out which ones. I'll have to cobble a temporary mount together until I can get the machine back up and running.

[ChrisAttebery]

I went ahead and ordered a motor and VFD from Automation Direct. I went with the MTRP-002-3BD36 2hp, 3600rpm motor and the WEG Electric CFW300 series vector drive. My DC motor was 4500 rpm so using to the 3600 rpm motor with 25% overdrive should give me the same RPM range and more power available.

[CL_MotoTech]

That's a nice looking setup for a very reasonable price. I spent way more, and while i got more motor, it's probably overkill.