Fasteners falling out of the sn2!

Has anyone else had the fasteners unscrew themselves from the bed frame and two bottom rails of the sn2? all but ONE of mine came out and i had to take the slim top fasteners from the encloseure frame and use them to screw the bed frame to the rails from the top side down so they cant fall back out…

Have not had that happen, sounds like there could be excessive vibration when the linear modules are moving. If it isn’t causing print/etc problems, just use some blue locktite.

To be honest it seems like my SN does vibrate more than it should and has created issues with both finish and the ability to pop parts open that are printed with joints in them to the point i have to use a rotary tool or box cutter to separate the parts (hopefully without destroying them). Is it normal for a black residue to build up on the metal bands of the axis bars and whats the proper way to clean and do preventative maintenance on my SN?

The black grease is normal. Vibration is not, especially for 3-D printing. Check that the surface it is mounted on is secure and stable. If you are comparing the SM to experiences with a belt-driven printer, the SM will be slower and will vibrate more due to the leadscrew design of the linear modules. Awhile back, I came across some posts which implied that the effective speed of the SM is about 55 mm/s: people use it faster than this without problems, but if you are having vibration issues I would recommend dropping the speed down to 55 or less and see if that improves things.

See the staff post for recommended maintenance:
How to maintain the snapmaker in perfect condition

@edf it actually seems to be noisier at lower speeds. Mine rattles like a 1920 jalopy on railroad tracks during slow long movement and settles down during faster shorter movements.

True, it does get noisy, especially around 20 mm/s and less. That shouldn’t loosen any fasters though. The reason I would suspect high speed would be abrupt changes of direction at high velocity when the snapmaker is mounted on a non-entirely-rigid surface. Tuning linear advance, or using acceleration control via a slicer options Cura or an equivalent, would be the more sustainable solution if that were the case.

@edf As far as fasteners go, I’ve never had a problem. It makes me question the consistency of either the hardware (screws) or the tapped holes in the rails. For the linear rails fastening to the base plate, maybe use the light duty loctite that is intended for computer screws, that should hold them in perfectly fine. Do not use the heavy duty, you’ll never get them out again. Vibration takes more of a toll on screws staying in than rapid change of direction. Unless it’s obvious to be WAY to fast for the machine, at that point you’ll be audibly skipping threads on the lead screw.

Impossible, as linear advance is, amongst other things, dependent on the “springiness” of the filament being used. It would be impossible to determine a theoretical value that applies to all filaments equally.

The Marlin default of 0.22 is described in the documentation as being appropriate for a bigger distance than the snapmaker has (but also a different diameter filament):

Set K around 0.22 for 3mm PLA Direct Drive with ~6.5cm between the drive gear and heatbreak
Larger K values will be needed for flexible filament and greater distances.

@brent113 I know between very little and nothing about linear advancement and was just stating that I saw that posted recently, I wasn’t saying one way or the other if it should be calibrated or not. Only that I saw someone say that somewhere the last couple days. Sounds like the whole “a distant relative of a friend of a friend of a friends twice removed cousin said this and this” scenario I know lol.

I wonder who that was?

Linear advance k factor had a very nice effect on my machine. I don’t try it with each filament, the value I entered was substantially better than the machine’s default.

.06 is the value I used, and I recon if i really wanted to be finicky I would try it with different materials, but frankly its close enough.

Actually though, my petg seems to pour a bit oddly sometimes so thats probably the fix if i wanted to. if my flow rate isnt on the high side, you can see it getting fat and thin, likely 3-4 an inch even.