MakerGear Forum

Hi All,

Usually I print relatively small parts that are always centred on the bed, so this problem has not really surfaced until now. However, over the last couple of days, I have been printing several parts per print that almost fill the entire bed. Before I printed the first batch I checked for level and adjusted accordingly so as it was as closed to level as it was going to get (I seem to have a slightly bowed bed/glass plate which means that it's higher in the centre and lower at the extremes of the X axis). The print was about 13 hours long and it came out beautifully. The next morning I attempted to do a similar print, but the first layer was going down very badly. Towards the front-left of the bed I was barely getting any extrusion, but towards the back right of the bed it was extruding fine, but there was an obvious gap between the lines and adhesion was an issue. I checked for level and low and behold, the front left of the bed was pretty much touching the nozzle, and the back was slightly low.

Is it normal for the bed to become un-level to such an extant after just one print? My print and acceleration speeds are on the low side, so I can't see it being caused by violent starts/stops. Any tips on how to keep it level for as long as possible?

On a side note, I recently ordered the hardware to do the auto-levelling/tramming, as I cannot bear to level the bed every single print (it takes me an age!). Will this upgrade overcome this problem?

This has come up very recently in another thread, which I can't find at the moment. Make sure you begin the bed leveling process by tightening all three leveling screws as far as they will go, then backing off only enough to get it level. The spring tension should be more than enough to keep them from vibrating loose.

I think I must be the odd-man-out as far as bed-leveling goes considering how often it comes up and the huge amount of interest in the new bed-leveling system, but.....

I bought my printer this summer and I use it every day, I've completely finished 5 spools, have 3 that are almost empty and have 9 that are between 1/2 and 3/4 full. So I've run a decent amount of filament (maybe 15-20#?) over several months on hundreds of prints and I've NEVER had to re-level my bed once since my initial build (mine was a kit). I fiddle with the z-adjustment fairly often (I change nozzles when I change materials), but the leveling itself has never been touched after initial setup. When I used to print on glass with glue stick, I would remove the glass before chiseling off the print which probably helped, and now that I print on PEI the parts pop off easily enough that I never remove the glass anymore.

HTH,
c

It does help to start with the screws all the way in and then just back them off a little for the leveling. But it also helps to use a little thread-lock on the screws, or some of that thread-locking tape if you have it.

i have had to re-level mine once in the last 8 months, but i had a really bad habit of leaning on it to pry off prints without removing the glass first. (Not the best plan.)

Wow Vandal, I wish I was having your luck! I also wish I had enough time to do as much printing as you! I do remove the glass plate before removing the build in order to prevent any unintended adjustments, but it doesn't seem to help. Out of curiosity, what is PEI? I've ordered a Zebra Plate in the hopes I can get rid of the glass and glue, but still waiting for it to arrive. The joys of living the other side of the world...

Thanks for the tip JSC. I had done that relatively recently, but maybe I'll try it once more to make sure I didn't loosen them off a bit too much. Am I right in believing you have gone the auto-leveling/tramming route? If so, how are you finding it so far?

Ryan

PEI is also known as Altem (sp?)

I followed the procedure here:
http://forum.seemecnc.com/viewtopic.php?f=36&t=7452

He mentions sanding the surface occasionally to refresh it, I haven't found this to be necessary. I do wipe it down with alcohol whenever I get fingerprints on it. I would also consider using 2" wide tape if doing it again. It's the edges of the tape that give trouble when installing, twice as wide, half the edges....

cheers,
c

leveling should have to be done very rarely. first start off with jsc suggestion. those screws should have the springs almost completely compressed. if that is all ok then you need to be very careful that when you remove the glass plate that the heater and bottom of the plate is perfectly clean before you put them back together. just a microscopic grain caught between the heater and glass will throw your lvl off. also be sure that the rubber corner pieces arent hanging up the heater or glass plate. i adjust the bed/z gap often but i only need to lvl mine about every 6-8 mos.

I have not jumped on the auto-leveling or new leveling system bandwagons just yet. I can appreciate their value in making things easy for beginners, but I've already climbed that learning curve, dagnabbit, grumble grumble.

Jimc, I spend so much time worrying about the cleanliness of the print surface, I didn't even think to consider the cleanliness of the heater and the bottom of the glass plate! Thanks for the tip!

Well, the three screws were pretty lose, so I have almost completely tightened them, re-levelled the bed, set the Z-stop and now going for a trial print. I am printing in a light colour (white) for the very first time, and what is now completely obvious is just how bowed my print bed/glass is. The layers going down on the parts in the centre of the bed are perfect - no gaps, perfect extrusion etc. However, the prints towards the sides of the bed are completely different. The gaps are quite significant and very obvious, and the solid layers fail to touch the perimeters shells. On top of that, I have a lot of difficulty getting the first layer down the further it gets from the centre of the bed. I'm assuming this is not a leveling issues as its the same scenarios of both sides of the bed. If the level was out of whack, I'd expect to see it better on one side.

Is this a common issue that most people see and something we just need to live with, or should it not be this extreme?

Thanks for all of the help so far.

Ryan

Being tight in the middle and loose on the sides is extremely common. That is usually from the glass not being made perfectly flat. Sometimes it can be from the top x rail of the printer being bowed down. This can happen from too much belt tension. Fact is that it only takes a microscopic difference in any one of these to make a big impact on the extrusions in the first layer. Many of us use a mic6 alum plate for a build surface because its milled perfectly flat. Do a search. There are threads here on it.