Warped bed and used printer?

Hello A5S sufferers,
sorry to start that way but that’s what I am currently doing...just suffering... more than one week now but I wasn’t able to print any acceptable piece on the A5S....well it’s certainly my fault...but I hope to get some advise from you guys....
Let’s start with the assembling of the printer...a bunch of tiny screws M2, M3 and M4? That was the first point in time where I thought that could be funny...3 tools, one for every size coming with the printer...great!
So it must be cost saving in production to drill holes of different size for the same purpose....
Anyway, assembled it and tried to load the filament...but I couldn’t....after a short investigation I found a piece of filament already stacking in the extruder. Argh! Did I get a used one for the price of a new? Asking the after-sale chat they said it’s usual because they test each printer before shipping! Lol I’ll come to this later...but could you guys confirm you had a piece of filament blocking your extruder on your brand new printer?
So next thing - bed leveling.... leveled the four outer points and moved to the fifth....Argh...scratching noise...the bed is so badly warped...a hill like Mount Everest in the middle....must be about 0.4+ mm higher
than the edges...after-sale chat asked support with the response ...I should level the edges 0.3 mm and the middle 0.1mm and it will print...sure...somewhere...tiny pieces...and the nozzle would scratch in the middle...
So I asked for a new bed, but from some other threads in this forum I had the feeling I should rather look for a new bed on my own...so I did....and guess what...this new bad was already warped when it arrived...before I exchanged it I straightened it manually...may be I should make a little Video how to do...
The design of the bed has a problem by default...I owe you a beer if you can show me a heated bed out of the box that isn’t warped with a hill in the middle...
So I mounted my new bed and it doesn’t have the problem with the hill in the middle anymore...but it is still not 100% even...so I have seen the great videos on mesh bed leveling from you guys...and I really would like to install the latest custom firmware...but where can I find it? What is the latest stable version? And before installing it...where can I find the latest product firmware for backup?
Thanks for your help, 
uwbe25

p.s. Was there any lucky guy in this audience, who could print a 300x300x2mm test piece out of the box directly on the „diamond glass“? I hope to get 1000 answers...

Comments

  • uwbe25uwbe25 Posts: 3Member
    Sorry, I didn't come back to the JGAurora testing...when they really test each printer, how could mine pass the quality check?

  • uwbe25uwbe25 Posts: 3Member
    Hello again, thanks for all the great videos from Da Hai and Samuel and the community! I am currently printing my first feasible part! Awesome guys!
    Well, some tweaking was necessary to get my A5S working (farewell warranty!).
    1.) I straightened the new bed with a hammer (only do this if you know what you are doing :-)) and the warped bed problem was solved...leveling looks really good.
    2.) The U-profiles, where the heated bed is mounted on were twisted in themselves. So there was a lot of tension on the M3 screws, which hold the bed. They warped the bed on the edges due to the tension.... I drilled up the holes to take tension from the screws and put some larger washers on the bottom of the spring and before the set screw...
    3.) Now another print test, cross fingers...beautiful outer walls...but unfortunately...lines doesn't stick together...empty spaces in the print...under-extrusion :-(. I remembered one video from Samuel?, where the community firmware was explained and that it fixed an under-extrusion of 14%. At that time I didn't really understood what it meant...now I know. But setting the value in the slicer didn't help in the first place. The under-extrusion seemed to follow a pattern. I put my finger onto the filament before it gets into the extruder and could feel how it moved...but every 20 seconds or so it stopped and the filament stopped to get out of the nozzle...mmh, its a new printer...watching more videos from the community and then I did two things: I exchanged the "new" nozzle with a new one and took the bowden tube out of the black cover tube and shortened it as much as I could (I saw this in one of the videos)...
    ... now you see a happy German... printing since 11 hours and 31 minutes... and it really looks good so far... but as always with the Germans...there is something to complain about. I have to baby-sit the print because the turns on filament coil don't lie side by side but overlap sometimes. In this situation the sling pulls closer until the extruder cannot pull more filament and the whole print gets wasted. In the videos I have seen you have printed huge objects..which I guess took 2-3 days!... how do you ensure that the filament comes save from the coil without blocking? 
  • giantrobot2001giantrobot2001 Posts: 94🌟 Super Member 🌟
    edited July 9
    Your machine was used.  Perhaps a return that would be like new, except somebody else was already tweaking the components.  Might have been a flighty teenager.  I own 3 A5S machines. I recieved two such machines, and had to fix them.  I did get one from the factory, and you could tell it was fully factory sealed.

    I believe the 14% underextrusion issue is regarding the factory firmware on the A5, not the A5S.  I have not seen as many posts lately, but Samuel has blesses the community with modified firmware.
    Apparently the A5 is disfunctional without better firmware
    This is not the case for the A5S, which has a completely modern 32bit board.  While you may not be able to do things you want to do with the factory firmware, it is completely functional and the extrusion rate is accurate.  You may want to update the firmware for minor optimizations or for specific modifications, like changing the throat for higher temperatures and increasing the top limit.

    From the posts, It looks like many people here use bed leveling systems. Mesh bed leveling will print along the dome rather than cut across it, making the extrusion very accurate.  I think I could manipulate one out of the box and do a 300 x 300 x 2mm first print, but I am getting very use to the diamond bed, I like to manually level my simple, albeit slightly curved, bed and if you think about it am more than happy to print a flat part on a flat print rather than create a bed contoured part.  After the first layer, my part is square!

    The dome on the three units I have (and they all dome a little) they seem flatter when they get to print temperatures anyway.  I don't know.  One of my printers beds seem very flat at 60c :)  I like to use a brim because I can see the effect of the tip pressure and I can therefore get desperate and turn a couple knobs on the fly after watching it circle the part.  As an old print shop worker I should know better than sticking my fingers anywhere near there.  Please don't lose a finger.  I'll maybe grab one or two and turn them an eigth turn as needed to make the material flat and even.

    Building the A5S - I want to do a video because bed leveling on these machines frustrates people (and just dealing with the tiny knobs), I want a video that includes opening up the case and making sure connector plugs are tight right from the start, it's a known issue.  There is some cable issues that need to be addressed on the outside.

    In the first step, the gantries on my machines are at nearest to exactly 90 degrees from the unit bed frame (not the unlevel bed). I recieved a bent unit, and had to put just two of the little assembly bolts in (allowing it to be loose for my twist) and torque the whole assembled unit straight doing a funny bear hug toward one side, and gloves are recommended if pushing on edges. NOTE: Never tweak a bearing rail at all - no pressure on the bed to make things straight - no pressure on the cross rail. ever

    When you assemble the AS5, you get the frame at 90 degrees, then I also gently turn the motor dampener on one side to get the crossbar level with the case perfect.  I believe some additional frame support could be used because of the potential linear forward or back tilt .  I have not fabricated the framework, but a bar from high top to the far bottom back that lets you set the gantry pivot. 

    For example, if your machine is slightly leaned one way or the other, the two back leveling springs will have a different amount of compression from the two front springs.  The issue of things being square is compensated at the bed, and therefore insignificant in the print so I don't think people notice much, but it makes quick manually leveling the bed easier if the screws are somewhat same tension, same place!

    With the screws a tiny bit loose, and perhaps some not even in... I grab my drywall T-Square, but just a big cardboard triangle or anything with a square corner. Square the bed down to the case with a caliper; bed surface to side rail....adjust the screws should be about same length theorhetically if the internal rails are square with the case. Now check the two main components, and tighten down square.  Yes I use pressure and tweak the frame and tighten it down straight best I can.

    Once the frame of the machine is right and straight and square, the four springs should be tensioning evenly during leveling, without any really tight or loose.  I like the even feel, and my manual bed leveling is quickly mastered on all my machines prior to each print.  If all are off because it's leveling the bed too low or too high, it's easy to adjust the stop switch on the side to lower or raise the entire relative bed level.  You will not scratch your bed if you check all 5 points and they aren't too tight.

    Regarding the black diamond bed, I scrub it regularly and vigorously with 70% ibupropyl pads and keep it perfect.  Blue tape for some non-PLA parts.  Use your nails or a credit card if necessary.  Do not use metal on your diamond bed. Hot or cold, scrub, scrub, scrub.  Hold bed still with other hand if it's cool as needed (and don't make the stepper motors free spin to much in general.  Move the head and bed gently - Apparently you can generate a spike if they slide real quick, or that may be urban legend)  All the time scrub it back clean and make it a habit.  Your PLA will always give back great results and adhesion, and I believe it helps the diamond surface last longer if you maintain it because it scrapes and cleans off easy.
    Post edited by giantrobot2001 on
  • Samuel PinchesSamuel Pinches Posts: 2,661Administrator
    @uwbe25 - welcome, and thanks for sharing and documenting your experiences!

    The bed when cold should be flat. It will typically only warp when (a) if the levelling screws are pulling it into a non-flat surface or (b) when you heat it, as the heater plate is one sided.

    If you take the glass off, you will see it is perfectly 100% flat. It is the heater board that warps when heated, and which causes the glass to flex slightly in this way.

    There is no cheap easy solution to solve this. Mesh bed levelling is the easiest "band aid" solution.
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