Cube3 Maintenance

[jssamp]

I wonder what maintenance requirements are for these printers. For other devices like this that have not been deprecated by the manufacturer you could expect to find spare parts and such to extend their working life. But since they are not interested in selling repair parts, performing proper maintenance pops up in my to do list.

Does anybody have information on procedures or requirements in this area, like lubrication or tensioning the belts? Maybe somebody who had a Cube before the factory shut it's doors and got some information from them? I was watching a video by (I think it was) Makers Muse the other day in which he detailed his discovery that flawed prints were due to worn and loose belts and the gears and pulleys. The combination of inaccuracies in position added up. He made a lot of sense.

Do any of you ever adjust or check such things on your Cube3? If so, what do you do and how do you go about it? I have had the covers off to clean out all the bits of filament that have fallen down inside of it over the years, but that's as far as I have gone mechanically so far. From the look of it I think I might need to clean and lube the linear rails. They are getting a lot of tiny bits of filament and dust built up. The x motor belt looks like it is getting worn beyond what I would like to see. If I can't find a replacement I might at least turn it around so that the teeth of the drive gear engage with the unworn part of the belt.

I could use any advice and experience that you all have before I tear into it.

[TommyDee]

Maintain the nozzle. Depending on the setup, the tip does require cleaning when it starts showing signs of problems.

The first failure component is the little bearings on the end of the X-axis belt.

[jssamp]

I have been having to clean the tips after nearly every print. Plastic tends to curl on leaving the nozzle. Sometimes I have to help guide it out when purging. I am thinking about getting some cleaning filament. What do you think? Ever used it? Does it work or is it just I high priced boondoggle?

After several prints, not as much as a tenth of a kg of filament I would estimate, I have to manually clean the nozzle out to restore the ability to get a good quality print.

The first failure component is the little bearings on the end of the X-axis belt.

I certainly hope to head that off. Have you have to replace or tighten the belts at all? I would expect the belts to fail before the bearings, but that is from automotive experience, not 3D printers.

[TommyDee]

I do know about 'tip poisoning' where you can build up carbon near the exit orifice and it screws with these tips forever. I am very careful not to overheat a PLA tip for instance with ABS temps. Having said that, this is what the cleaning filaments are about. They even included a section with my Nylon for CubePro. You will need to jig something up to hold the nozzle reliably.

Know I only poisoned one tip in the years I've been using my Cubes, What I do is to reverse-feed a wire through the nozzle with the tip heated with a small torch-lighter. Takes some finesse but I get it done in a quick pre-print session if I need to.

Since the orifice has a nice polish, it does pretty well with cleaning. If there is some carbon where the diameter necks down, it does weird things. One thing that really has me worry is changing a PLA filament to an ABS and using an ABS temperature purge. Any residual PLA could 'burn' during the early print process and never purge.

[jssamp]

The stuff I pulled out of my nozzle makes me think that's what I am facing. I've just ordered some cleaning filament. I'll do that before I try printing again.

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Doesn't it seem like good news is always accompanied by bad? I decided to take the heat shield off to do some cleaning and maybe level my print head, you know, exploring. The good news is I think maybe I have identified at least a part of my print problems. The bad news is it's not as easy to fix as turning some set screws.

IMG_20221108_032140.jpgIMG_20221108_032237.jpgIMG_20221108_032208.jpg

I am fairly certain that both of those brass inserts are supposed to have set screws in them. One of mine is missing. The other one looks like it might have been over-tightened in the past. Whatever happened, the carrier is cracked. I have read somewhere about someone else having this same problem. I can't recall where or who, but I think they made a metal support bracket to repair it. I might have to search for solutions to this since there is no source for replacement parts that I know of.

It briefly occurred to me how ironic it is to need a part that I could print if it weren't for the fact that the part belongs to my printer, but I don't think I could print a suitable replacement anyway. Dimensional accuracy of my model and material properties of my printer filament would not stand up to the abuse this part must take.

Would some Plastic Bonder epoxy help this or does it need to be replaced? I am wide open for suggestions.

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And does anybody happen to know what the size of the set screw is? That I should be able to find but I don't know if I have anything that small on hand. I'll have to look through some unsorted screw bins.

[TommyDee]

Looks like M3 maybe 5mm long(?)

[jssamp]

Could it be 2.5mm? 2.5mm grub screws normally use a 1.3mm hex drive while 3mm ones generally use 1.5mm drive. I guess I could wait until I get back home and take out the one I have. Should be back by tomorrow.

[TommyDee]

Checking the wrench size is a good way to tell. Indeed, M2.5, maybe even M2, could be right. Looks to be the same diameter as the nozzle. Pretty sure it is metric though.

As far as the white plastic bit, most of these are cracked, if not from the factory, soon thereafter. They setscrews can only be used if you loosen the screws on the vertical surface. It is meant to allow the two nozzles to be at the same gap, which is critical for 2-nozzle operation. This should have been set at the factory.

However, before messing with this adjustment, be sure the nozzles are fully seated. If they are not, then they will vary over time.

With the modified heads, it is good to match a pair of nozzles to a machine. You never have to worry about gapping or balancing the two sides. I've noticed 2 distinct depth nozzles will rest at from one nozzle to the next. So if you find a poorly matched pair, try a different pair.

I find this adjustment the most problematic. It is very hard to get to the screws into the rail's carrier. You will likely need to shorten a hex wrench to get it in there. But the broken piece is not too problematic as all they do is assist balancing the nozzles.

[jssamp]

I am away from home but I will try to get the two nozzles leveled when I return. I have only 3 of the nozzles so maybe I'll be lucky and 2 will match. Is the match based on something more than the depth the push nut is set at? I have noticed that the tip of two of my nozzles seem to be more rounded than the third which has more define angles and a flat tip surface. You can see the tips in the last photo above. The right side tip has a flat face profile, the other one is more rounded.

To make sure they are fully seated would it help to set them in without the housing, just the metal nozzle, to see how far it protrudes? The plastic part you designed doesn't hold it up from seating fully does it? Assuming everything else is correct (42mm tube, etc.) But there is a bit of play from the spring, about 0.5-1 mm.

[TommyDee]

Looks like someone got a little carried away with that rounded tip. Normally, yes, they are flat.

The push-nut can be 'too low' and not allow the tip to fully seat. Using the tip-resetter, you can reset the height as the push-nut will slide if the spring is completely compressed. That is all you need to do. But do use your 3rd tip if it still has a hint of flatness.

The plastic black cover on at the business end of the nozzles tends to attempt a seal. I am not sure just dropping the nozzle-only into their pockets will be sufficient. I'd recommend adding the spring pressure the head provides.