Hello Everyone,
The past week of troubleshooting this Ender 3 V2 has been quite a ride.
I'm happy to say I am finally making some progress.
XYZ 20mm Calibration Cube
by iDig3Dprinting January 19, 2016
This is the latest test cube that I printed, and is the best one I have seen in a while.
My previous test prints looked like this:
Troubleshooting a Layering Problem
What was causing this layering issue?
Through researching and talking with some people in the 3D printing community, we determined this is Z banding, a deviation that occurs from a plethora of inconsistencies on the Z axis. Here is an article describing the many problems that can influence Z banding:
https://all3dp.com/2/3d-printer-z-banding/
In the case of my Ender 3 V2, this problem was mostly due to poor belt tension and bowden tube play, ( which can occur in the extruder and hot end couplings and is a common problem, generally caused from retractions.)
These weren't the only issues however.
Voltage throttling on the Raspberry Pi 3B + was also a problem, which I solved by overclocking.
Stock Tensioners were very problematic, and a major contributing factor to the Z banding.
I removed the 4.2.2 motherboard and have it outside of the printer with a new cooling solution. I wired to the main hot end fan, which runs whenever the machine is on, and is on a 24V system.
Roller wheels were probably not a problem but were replaced, and later this helped me discover the machines Z rails are not perfectly square, which also contributed to the Z banding.
Let's have a look at some photos and then I will discuss a bit more , these issues.
This was my printer when I first began this overhaul.
The viewer can see the new roller wheels , new tensioners, and motherboard pulled out.
It was a rather intimidating process for me, but everything went smooth for the most part.
Right now the motherboard looks like this, directly next to the printer.
I hot glued the fan in place for now, and when all is said and done, I don't think the motherboard was the issue, but I have no plans to place it back under the printer where it's blasted with heat from a heated bed plate.
Despite being pretty confident that it wasn't the mobo, I am still thinking it's better to have out from under the heat box.
I intend to design my own ventilated minimal case for it :)
I was reading a little low for the 24 volts, and this may or may not have been a throttling issue from the Raspberry Pi. This was prior to overclocking the RPI and I didn't verify after the new splice. Given that everything is working fine now, it is not a major priority.
I lubed up the new roller wheels with this synthetic Super Lube that I just recently purchased. The product cost me $10.00 USD, and can be used for a variety of mechanical purposes. It should last me years and overall I am quite happy with this purchase.
I was a diesel mechanic years ago and can say my body has been exposed to more petroleum based products than the average person, and as a younger man I never considered the health implications and didn't protect body most of the time.
It is probably wise to use gloves or some sort of protective covering (like a shopping bag in this case) to protect yourself, because the body will absorb the chemicals and it is just better to be safe than sorry.
The installation was pretty painless and I think they look great!
The new tensioners are a Creality product, the company that produces the Ender 3 V2, and this two pack was reasonably priced at $20.00 USD.
Considering they are nice metal machined components, and have a nice quality feel and fit, I have zero complaints, and they are a huge upgrade to this printer.
After all the parts upgrades and mobo modification, I was still getting the Z banding.
After cranking down the belts, I was still getting Z banding.
After overclocking the RPI, I was still getting Z banding.
It wasn't until loosening up the eccentric nuts on the Z axis roller wheels that I was able to produce this print, and one of the wheels does not sit flush on the rail.
Although it's difficult to see, the inside of this roller wheel (by the eccentric nut) does not sit flush on the rail, no matter what I try to adjust, because the rails themselves are not perfectly square with one another.
Replacing the wheels gave me a surgical like insight into the Z rails, and in the end I can say, there isn't much I can do about it.
The machine itself is a little out of square, and I believe it is just a machining problem.
The amount of bolts that fit it together are testament to the fact there there isn't much that can be done about this, as it all fits together like a very tight puzzle.
This amalgamates to one simple conclusion:
I will just need to make due with a slightly out of square machine.
I expect the one roller wheel that does not sit flush will wear down and notch into the groove over time, but I do not know for certain.
I have figured out that too much tension on those eccentric nuts will cause Z banding, and under tightened belts will also cause some horrific looking Z banding.
I consider this problem now solved, even though it was more than one issue contributing to the inconsistencies.
I have a better idea of what will cause Z banding and what to check when the problem inevitably rears its ugly head again in the future.
That's it for today,
