[Adasha_Machining]

I will try to explain all the details I have encountered so far as best I can. I am a small machine job shop. Mostly manual, this is my first CNC machine. I've been in business for the past 5 years.

The machine is a Takisawa TS-15 from 1981, runs Fanuc 6T.

I have a series of problems that evolved over the past couple weeks that have now turned into an all-stop situation. I have aerospace parts to run and I'm in full panic mode. I have scheduled a service tech, but I will not see them until Monday. If it is possible to discover the problem before then, I can cancel the tech and save myself untold amounts of money.

I've owned the machine since Dec 2022, it's been powered and running for only a few months now. When I purchased the machine it was dirty and stored outside for a couple months. It also froze - however that did not seem to create any structural issues.
The reason it took so long to get running was because I had to install a whole new hydro system (3 phase - the RPC wouldn't run the CNC) and I completely tore down the lathe portion of the machine to clean and inspect - it's in shockingly good condition, it's been rebuilt/reground at some point in the past 5-10 years and run very little since. No measurable wear on the box ways. Saddle has turcite.

The first issues I noticed near the beginning was if you manually operated the spindle fwd/stop/rev, the spindle would operate perfectly fine while running, with speed control, however, if running in forward and you pressed stop, the DC motor drive would inject the reversing current to brake the spindle to a stop but the main contactor would not disengage - the spindle would begin running slowly in reverse. If run in reverse, no matter the speed, if you pressed stop, the spindle brake would slow the spindle to a stop, then the main contactor would open and everything came to a stop.
I noticed if I slowed the spindle down in forward before stopping, the problem would not happen. I could run the spindle in forward, any speed, but if stop was pressed the motor reverse brake would slow the spindle down, but only if the speed was low when stop was pressed would the main contactor open. If stop was pressed at med/high speed, the spindle would slow, reverse, and stay running in reverse.
However, that problem went away.

Next issue, the chuck release pedal would sometimes not work. There is voltage at the pedal, I can see the binary bits change (zeros and ones) in the diag screen when the pedal is pressed so there is an input however the solenoid would not activate. This happened at the very beginning when I first powered the machine up. However, I was completely unfamiliar with the machine in the beginning. The issue just went away if I did a machine restart. The pedal issue did not again arise for a few more weeks.
In that time I was successfully learning how to operate and run the machine. I had successfully made parts, etc.

A couple weeks ago the pedal issue came up again. However, I believe I was only playing/testing the machine at the time and I believe a machine restart (or the restart the following morning) resolved the issue.

This past week I had been investigating some items I was unfamiliar with on the machine, ie, canned cycles, tailstock operation M-code, and chuck operation M-code. The chuck M-code in the manual operates the tailstock (M10-11). The tailstock codes do nothing (M27-28).
So in order to find the actual chuck code I tried every single M number until I found the ones that worked (M68-69).
I also learned the correct way to write the canned cycle block code that satisfied the machine (doesn't throw program alarms). Prior to that I had to post code in long format - no canned cycles.

This past Friday I was preparing a new-to-me 3 jaw power chuck for the machine. I powered up the machine and noticed the pedal did not work again, however, now that I knew the M-code for the chuck, I ignored it and went on my way fitting the new chuck (which involved making a new drawbar, and adapter nut, etc...)
When I went to test the new chuck, the pedal still did not work. I tried the spindle M-codes. To my surprise the spindle took off to full speed. I hit reset. in the MDI screen I entered a spindle max speed and tried again. The machine ignored the spindle speed and took off again.
Through messing around with the M-codes I noticed the chuck spun in the same direction regardless of input and every time tries to take off at max speed.

I shut the machine off to reset it, let it sit for a few moments before doing so. I loaded a known good program, zeroed and homed the machine/turret, let the program execute in single block mode. In the program the spindle is set to max 3000rpm, and the surface speed is set for proper cutting speeds - spindle takes off to max speed.
In any of these events I never let the spindle get to max speed because it's terrifying...

On the MDI screen I noticed if I execute a spindle start code, MDI will not let me input a spindle stop code. I can write M05 and hit input, but nothing enters. I have to hit reset.

I have spent the last two days going over everything on this machine I can think of - messing around with wires, moving things, tapping relays, ensuring connections are tight, no missing/loose wires, checked the spindle encoder connection. I can see various inputs in the DIAG screen - If I press buttons, pedal, spin the encoder, I can see the input in the binary bits.

One last thing I discovered about an hour ago is;
I could get the chuck pedal to function, once... IF I run the spindle in reverse, and press stop, in the millisecond after pressing stop and the main contactor releases, if I frantically stomp on the pedal the chuck will release. But then nothing else. It will not operate again. But now with the chuck released, I cannot run the spindle. I get the "red light question mark" on the operator panel saying the machine won't start the spindle with the chuck open. I can M-code the chuck closed and repeat this as many times as I want. However, all other problems still remain.

To me, that seems like a logic issue. The machine is waiting for something. Or an input is missing, or a relay/solenoid is not doing what it should, or a contact pad in one of the MANY relays/contactors is not connecting... This doesn't seem like a Fanuc issue. Problem is, I have no idea what I'm doing in the control panel, or what to look for, or where to start.
I will say this - the spindle control section of the rear electrical panel is VERY dirty. Clearly coolant has gotten into the cabinet through the fan port above, then rain I'm sure. The components are dirty and sticky. But I am hesitant to go soaking everything down with electrical contact cleaner or something, making things much much worse.
I'm not even sure if this is really the problem...

But in this current state, the machine is down, inoperable... I'm supposed to be setting up to run parts next week... And I'm in full panic mode...

[Adasha_Machining]

Well, I realize this was a very unusual situation, and I thank everyone for their warm replies and suggestions.
I'll update this situation - I went through a whirlwind of a 3 weeks roller-coaster to figure out what was wrong. I was also right on the edge of just buying another machine...
Well, after two service companies couldn't find the issue, and a renown spindle rebuilding company deterrent priced the spindle diver/controller repair job ($800 just to hook up the controller...) I took matters into my own hands after becoming flat out desperate...

Turns out the spindle controller was just dirty... Too dirty...
Right when I brought the machine home, it was obvious the previous owner allowed coolant to spray all around the back of the spindle bore. Spraying coolant around enough that it leaked into the exhaust fan opening above the cooling fans for the spindle controller. The spindle controller was CAKED in goopy gunk.
I wanted to clean this off very early on, but was too worried I would damage old, sensitive equipment. I even suggested this concern with several techs. These concerns were met with hesitation. Everyone just told me to get a new machine "your machine is 41 years old...".
So when I was at the end of my rope, I took the controller apart, the 4-5 circuit boards all stacked on top of each other, cleaned each one with alcohol and a soft brush. The black sticky gunk all poured off.
Butted everything back up and started the machine and everything immediately came to life. ALL of the problems were gone.
I did this on Thursday. I've been running 16 hours a day all weekend since to try and catch up. The machine has been running like a million bucks.

And to my credit of wanting to save this machine - I ran a 150 pc order with several critical dimensions. It ran all 150 (with the exception of a few adjustments) all within 2 tenths of each other. Most of the time the repeatability was 1 tenth... sometimes 2... There's no way I'd find another used machine with that level of accuracy and precision. Certainly not a 41 year old machine...
This machine was rebuilt in the not so distant past. All the bedways have been reground, turcite added. I cannot measure any wear on the bed box ways. None... So, ya, I'll run this machine until every last component is dead, or replaced and nothing original remains. 41 years old or not, being reground, I bet I'd be hard pressed to find even a brand new machine with box ways this accurate - if I could even find/afford a new machine that doesn't have linear glides...

So. That's that. Keep your machines clean, folks... And make parts. Lots.
Thanks

[machinehop5]

...Love old machines...that Fanuc 6T was great control the 6M were too...Yes, cooling Fans work if, the air can get to the heat sinks. Add more Fans as needed...Amazing your DC Spindle still works. Check the motor brushes it's maybe time to replace and the springs.

Thanks for the report,
DJ

[Adasha_Machining]

The brushes on the motor are nearly brand new. One of the spindle drive fans doesn't work. I will replace it.
However, I have been setting up a coolant mist/ridiculous motor/hydraulic heat exhaust system to exhaust the air out of the machine to outside. My shop fills with coolant mist, and the heat from the hydraulic system and motors raises the temp in my shop nearly 10 degrees in a couple hours. Madness.

I don't mind the older system. But frankly, I have zero experience with anything modern. I'm still learning.
What I do know is I am fine with Fusion 360 as a CAD software, however, it is atrocious for CAM lathe work. The Fanuc post processor isn't great. I have to go in and heavily edit the code after every post process. However, that is also teaching me G-code to the point it's almost easier to hand write the program code and punch it in manually rather than have Fusion post a program and make a big mess....

It's just hard to hold a candle to this small machines huge mass and accuracy. I would have been thoroughly disappointed if I had to scrap this machine.