Z truck racket

[unitedcases]

Has anyone ever had a Z truck go out while carving? I ask because on one of my machines something is making a racket that sounds like a miss. It's not a laboring sound like the motor straining. It's like the bit is skipping. I don't know if that makes sense. The point of the question was to see if anyone that has had a Z motor go out during a carve maybe describe it? I even noticed the noise a couple times during the air carve portion of my project. Leads me to believe a bearing maybe in the truck itself? I hope I didn't confuse anyone. I plan to swap in my spare truck to see if it goes away and I guess if it does I have the culprit. However I have no idea what to change other than rebuild the whole thing.

[fwharris]

Can't say that I have but you might check the square hole in the top hat to see if it might be rounded out.

[unitedcases]

The machines just got done, synchronized carving, and I was going to do a visual just to see if anything obvious was standing out at me.

[unitedcases]

Ok. Visually looked thru the top hat and the top of the spindle looks a bit rounded. And that makes sense since the sound I was hearing was sort of a miss. So I have the machines next to each other and I disconnect both flex shafts and I notice that the good machine has 3/4 inch sticking out of the sheath while the noisy one has 9/16 sticking out of the sheath. Both shafts are laying out of the machine at the same angle. I then remove both flex shaft cores and note that they are both the same length. When I push the good machine shaft back in it springs back out like it should. The noisy machine doesn't really spring back out. Now I am confused.

[unitedcases]

So the machines are put away and my mind is clear. I bet the sheath isn't inserted into the cut motor all the way causing the flex itself to not stick out as far. Tomorrow when I drag them back out I will check that before I start anything.

[Digitalwoodshop]

I had a Ticking Noise in a Z Servo Motor years ago.... I swapped a Z Motor and gearbox with another machine and it went away... So I then moved the servo motor back to the now good machine leaving the gearbox and the ticking was back... SO it was the servo motor... not the gearbox or truck... Never opened the servo, I wanted too.... Remember if you EVER open a Servo Motor the Magnets COULD go BAD.... I posted on this once... You need a magnetic keeper but the factory has a machine to energize the magnet after assembly... I know some are thinking... "I never heard that".... but it is true... I grew up in the NAVY with Servos....


http://www.servotechusa.com/blog/bid/31931/Disassembling-your-own-DC-Servo-Motor/

Separate the Armature from Its Magnetic Field without Causing Demagnetization

There are many types of magnets. The most popular types used in servo motors are Neodymium Iron Boron (NdFeB or NIB), Samarium Cobalt (SmCo), Alnico, Ceramic, Ferrite and Rare Earth. Certain magnet types require that their fields not be broken. If a motor or tachometer armature is removed from the wrong type of field frame, the magnets will loose their strength effectively ruining the servo. The only way to rectify demagnetized field frames on a disassembled servo motor is to recharge the magnets. Otherwise the servo will never run properly.

[unitedcases]

I had hoped the fix would be easy. And it was. Not the piece that actually inserts into the cut motor but the sheath part that is epoxied into that piece that goes into the cut motor, had come unglued. So I pushed the sheath back in, a 1/4 of an inch to be exact, and now the flex shaft protrudes 3/4 of an inch out the end of the sheath like it is supposed to. Waiting on the epoxy to dry now.

[cestout]

Something else to watch for.
Clint

[unitedcases]

Definitely. I really think had I not had machine #2 sitting right next to it I wouldn't have compared. It took me putting them away for the night and clearing my head to see it. Going to run it tomorrow to see if that fixed. And to be honest it was a very simple fix.

[mikemi]

Good catch. I will have to check both of my machines to be on the safe side. I haven't had the flex shaft out of either one of them for a long time, so I will lube them while I am at it.

Mike

[Racer Dad]

I have a Z stall and I'm trying to get the flex shaft out but it is stuck! Where do I go from here?

[unitedcases]

Stuck in the z truck?

[unitedcases]

Just to report, the sheath was the problem. The best I can tell it only rounded the very upper bit of the square hole. Been running and sitting here for about 25 minutes with no more crazy racket to report.

[unitedcases]

Well, As I feared, the damage has been done. Carved well for about an hour and a half and the slip has came back. The sheath hasnt moved so undoubtedly the top of the square spindle hole is a bit too rounded. Going to swap in my spare truck for the next carve and see what happens.

[unitedcases]

Well, on my third truck in the same machine and still getting intermediate skipping. Going to swap out the flex core next and see what that does. I hope somebody is getting something out of this. Because I sure am not.

[unitedcases]

I dont know what I was thinking. The machine is carving right now, so I figured why not swap out the flexshaft core right now. And I did. Havent heard any racket yet. But the flexshaft core looks totally fine. What gives? Anyone?

[bergerud]

Could it be that the motor end was the end that got rounded out?

[unitedcases]

As best I can tell both ends look the same. The noise was happening about every 2-3 minutes before. Almost like it would wind and wind until it had to give or maybe it is wore out and winding and shrinking in length because of the winding causing the slip. I have been sitting since that last post and I definitely waited about 5 minutes before I posted. So 10 minutes and no noise. Baffling. My first flexshaft made it about 1500 hours before I had to swap it out. Guess I wont gut those trucks just yet. They may deserve a second chance now.

[bergerud]

Did you probe into the motor end and make sure the bottom of the hole is not filled up with moly gunk.

[unitedcases]

Pretty dry in there actually.