Solved *Read pg 8 if you use a Geckotek bed!* Changed power supply, now y axis waves

OK, model (the one in the last pic) is done, and other than over-heating issues, which I fully expected printing a single tower, the issue is gone.

This leads me to believe that the problem is only showing up when the printer has to go from one tower to the next. Could it be missing steps along the Y axis as it transitions from one tower to the next?

 

The thing about the ripples is it isn't wider and narrower. The layer actually shifts. Each layer is the exact right dimensions, just not in the right place on the Y axis. The layer shift just goes back and forth on the Y axis. Best I can tell, the same number of layers are involved with every wave.

 

Taking some measurements of the model, it fits within the max dimensions in the design. I test fitted the part and it does work, but is very unsightly. So its not really a leaning method, as the wave is contained within the model's designed outer perimeter.

 

The issue NEVER appears at a lower Z height. Doesn't start until about 38 mm in Z height.

Its almost like a jerk/acceleration issue, but I turned everything down once and it didn't help.

Here is a pic of the infill. Its....perfect.... If there is any wave/ripple, it isn't visible or nearly as pronounced, which make it almost scream software issue?

I don't understand how this could all happen just by changing power supplies. I run 2 PSUs, the 12V in the Robo and an external 24V to run a Geckotek heater bed. The 24V went bad (component burnt was the C4 capacitor, per board markings) and took out the fuse in the AC plug in the Robo. I replaced both cheap Chinese units with Mean Well units. Turned it back on, used the same program and settings, and here we are with this weird issue.

 

I am running a print with multiple towers, turned down the movement speed to 3200 mm/min. We will see if that helps. Maybe the new PSU is driving the steppers softer/harder and can't handle 3800 mm/min like the old PSU? Weird the problem disappeared when I printed a single tower.

 

I'm off for an appointment, will take some pics in a few hours.

 

Sorry didn't get back, just got internet again. Storms have been causing a LOT of issues around here..

Anyway, last night I took down the machine, cleaned, tightened all the belts/pulleys, etc. I ran a test print and slowed acceleration and Y axis jerk values to a crawl. STILL have the horrible Y axis layer shift wave thing going on. Not any better, maybe even a bit worse.

Some pics attached. The print JUST got done, plate going to be too hot to move for a while yet, but I got a pic of the running gear.

 

Random thoughts from a noob...

1. In order to replace the power supply, you had to be inside there somewhere: re-check any connections in the same area where you were. Also, if this is a one-sided issue then it could be something blocking the travel of a part. Make sure no ribbon cables are interfering with any belts. Make sure that the entire printer doesn't now wobble (like a bad dining table in a restaurant); perhaps there's a packet of ketchup under one of the legs like back in high school. Try using your hand on the top of the gantry to stabilize everything for a few layers to see if it temporarily behaves itself.
2. If a power supply can't supply the same power (current x voltage) as the last one did, it will either compromise on the output voltage or current. If the output voltage isn't enough sometimes, it's difficult for me to guess how that would affect the part. Probably unlikely, but what if the old power supply was heavier (more mass) and so it helped to dampen wobbling...?
3. Does the problem only occur on the right-most tower, for example? Could be something blocking the full movement or say, slowing it down (debris in the mechanism, lack of lubrication).

If it were me, I'd take the STL into Cura, rotate the collection 90°, print it again and "follow the defect". It will follow the printer or with the part.

And then, I might try horizontally slicing the parts 1/3rd from the top and print just that. Measure the original defect from the bed in both cases. The defect will either remain "x inches" from the bed or it might surprise you and coincide with something on the part.

I just looked up Mean Well and I had some problems recently with a 5V/10A variety which I bought at Fry's: "switching power supply". Had to ditch that for my particular project since my "green" ethernet switch plus the switching power supply would see-saw back and forth from ON/OFF mode. The ethernet switch would see idle and lower its power requirements and fake out the switching power supply below the minimum power expected, toggling it momentarily off for a power cycle (reboot-like) event. The net result was like a surging of power out of it. It might be worthwhile to put a volt meter on that and see if it consistently supplies the expected voltage.

Also, what happens if you turn off the bed heater two vertical inches into the project? If it's better, maybe that new 24V heater is lowering the voltage on that circuit (the wires that come from the circuit breaker panel somewhere in your house).

 

I just put the old power supply back in. Kind of jumped the gun replacing it before I found the burn fuse.

I put the old stepper driver back in. Everything is oiled very well, working smoothly, and moves freely.

Short of replacing the RAMPS and everything on it, I'm going to be stumped if this doesn't fix it. Probably still stumped if it does, but I will return the power supply to Amazon.

 

Too early to tell, but I'm starting to maybe see waves

Will know more in a couple more hours

 

Pic:

 

OK, print done going back to OEM PSU and stepper driver.

Problem is much less pronounced, but more erratic. With the old PSU and replacement stepper driver, it was a perfect saw tooth pattern, getting more pronounced as it increased in Z layers. Now with the old parts, its still there, but less pronounced but much sloppier.

I'm going for broke and trying another tall model now, but I have low expectations.

Remember: before I changed the PSU, this machine was running PERFECTLY.

Replace the entire RAMPS board?

 

I'm using a the stock RAMPS at this point. I checked hardware, everything is tight.

I just don't understand, all I did was change power supply. Has to be something in the electronics, doesn't it? I've had this thing tore apart *many* times, never an issue.

Replace the entire RAMPS and everything on it time?