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Solved Bed Adhesion, I'm about at my whits end.

Discussion in 'Troubleshooting' started by mheath82, Dec 17, 2017.

  1. mheath82

    mheath82 New Member

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    I've had the C2 for a little over a month now. I've been able to make some high quality smaller prints after some tweaking but am having nothing but issue with larger prints.

    I've tried printing 2676324 on thingverse four times now. Every time, about 2-3hrs in to the print the front corners of the raft start to curl. It keeps progressing until the entire front of the raft is lifting off the print bed. I've tried new tape, I've wiped it down with rubbing alcohol, I've tried using hairspray and glue but have not had any luck getting larger prints to stick on the front end of the print bed.

    Any insight or guidance would be greatly appreciated.
     

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  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    PLA I presume?
    How hot are you printing it?
    Have you tried printing a temperature test tower to see where your actual best PLA print temperatures are?

    I ask all of that because when PLA curls it is usually a bad spool or printing too hot.
     
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  3. mheath82

    mheath82 New Member

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    Sorry, yes PLA. It's printing at 195c.

    I have not printed the temperature test tower but will do that. I just found it odd that it only curls at the front of the print bed.

    Thanks.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Either more air-flow at the front (causing more cooling and curling) or it is not level and that section is less adhered to the bed.
     
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  5. OutsourcedGuru

    OutsourcedGuru Active Member

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    * I only print with PLA (and sometime infused-PLA)
    * I've had a C2 for about eight months now
    * I wear it out printing parts
    * I routinely have problems with part curling for big parts

    I routinely attempt to rescue parts using a variety of techniques but it requires babysitting the printer. Sometimes I don't have the time to do that.

    1. Under most circumstances, adding a raft in Cura works. The raft curls and the part does not. This, however, results in poor bottom quality for the part. I've come to hate the poor quality associated with rafts.
    2. The PAUSE/RESUME buttons on the LCD interface work as expected. Use them when the part starts getting into trouble. If you attempt to heat-and-fix parts while the print is going, you usually end up pushing down sometimes on the print bed and this will negatively impact print quality somewhere else on the project. Pause the print job, carefully sneak the print bed off the mount and bring it over to work on it somewhere. I use some sort of spatula-like tool plus a hair dryer on the hottest setting: while applying heat to the offending corner, gently apply pressure to the entire top of the part. This often allows the part to re-adhere in that corner. Return the print bed, clean off any extra extruded filament from the nozzle and hit the RESUME button.
    3. Sometimes I do a fix-in-place attempt while the job is still laying down the first five layers. This involves using the back end of the supplied tweezers to follow along behind the nozzle as it lays down hot filament. I use a spare index finger below the print bed to apply equalizing pressure so that the tweezer doesn't press the print bed down (negatively impacting print quality somewhere). In this way, I'm re-training the plastic to lie flatter while it's still hot.
    4. If I know that I'm going to print a huge part, I will pre-heat the entire bed using the hair dryer while the extruder is coming up to temperature itself. Note: if I can use a hair dryer to melt the filament, then this has to be upwards of 140 degrees celsius. So, it's my intent to pre-heat the print bed to around 90 degrees; by the time the job actually starts, the bed is around 60 or so and will keep the first layer in check for a bit. If the first layer adheres nicely, this may often prevent a later curl-up.
    5. Most of my curling takes place in the front/left corner of the printer and is worse when the window is open (San Diego). I have been known to wrap the front of my C2 in Saran Wrap and to then heat the air a little from the top with the hair dryer.
    6. I have been known to heat the bottom/front/left corner of the print bed during a job with the hair dryer for the first twenty layers.
    7. I am using the Robo-supplied BuildTak print bed covering. I will likely never go back to the black tape square from earlier. The BuildTak is so grippy that I sometimes have to put the print bed into the freezer to get the part(s) to break free at the end of a session.
    8. I know my printer well. Since curling occurs in the front/left corner more than anywhere else, I re-orient parts if I can to the back/right corner of the printer. I have tweaked the Cura printer profile to print well beyond the defaults.

    I sometimes adjust Cura's settings so that the first layer is twice the default extrusion (height). If the bottom of the part doesn't matter that much, this is one of the best/easiest methods (other than rafts). I routinely adjust the first layer print speed in an effort to get better adhesion.

    Using a brim would also be a reasonably-good fix.

    I have a design in place for a heated bed and this should fix all this in a smart way rather than the tomfoolery I usually do.

    I just lost my third part in a row this weekend over first-layer adhesion. The footprint of the part is relatively small compared to the height. I lost the part somewhere during the last thirty minutes, which is pretty frustrating. I'll likely add a brim or be bull-headed and babysit it, perhaps. Too bad I can't show you the designed part—it's a beauty.
     
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  6. mheath82

    mheath82 New Member

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    Thank you Mark and OutsourcedGuru. These are excellent tips!

    On a side note, after checking to see if my print bed is level, I've also noticed that it bows quite a bit with larger parts so I've asked a machinist friend to cut me a custom aluminium bed. I've designed a quick levelling system and will hopefully add a heater at some point.



     
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  7. OutsourcedGuru

    OutsourcedGuru Active Member

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  8. OutsourcedGuru

    OutsourcedGuru Active Member

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    Alright, I added a 10-line/8mm brim to the part and of course it didn't break loose from the print bed toward the end. Note a sample from the many which failed spectacularly when they broke free. I don't love that I have to trim the part at the bottom but there's no sign of curling whatsoever.

    DSC_0353.png
     
  9. OutsourcedGuru

    OutsourcedGuru Active Member

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    Call Robo support and ask for some of the BuildTak squares.
     
  10. mheath82

    mheath82 New Member

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    I tried printing it with various settings. Seems I need to use a raft or it just warps on the first bead of filament and then the nozzle just runs over it and pushes it off the print bed. It is however, not turning out for me. The pic was the best result, printing at .2mm, 195c, 100% infill.

    At this point I'm ~90% failed prints so I'm starting to get discouraged. Or maybe I've just set my expectations too high and this is how it is.

    I did order a BuildTak square but it has not arrived yet.
     

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  11. Geof

    Geof Volunteer Moderator
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    so when you print with a raft you are hiding issues.
    If you can and are up to it please remove the raft and redo your z offset then post a picture of the fine tune z offset.
    What you want is a squish on the layer so instead of a bead imagine a "flat" top line. No ruts.
    Keep adjusting the fine tune until it looks perfect and send us a first layer picture. we can help get ya sorted.
    Printing on a cold bed is tricky but totally doable in PLA (and many other materials) but the first layer and hotend temperatures are very important to have correct to have good adhesion
     
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  12. mheath82

    mheath82 New Member

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    So I was in the process of doing this and I believe I found the problem. The aluminium frame that the print bed sits on is bowed. I put a straight edge on it (from back of printer to front) and sure enough there was about a 7mm dip in the centre. I will start a support case for this but in the mean time I ran out to Home Depot and grabbed 4x 5mm bolts and 8 nuts to rig up a quick post levelling system. After about an hour of moving the extruder assembly around the print bed and trying to adjust it just right I tried the C2 print test.

    It printed almost FLAWLESSLY! When I get home tonight I will try @OutsourcedGuru 's Cantilever Stability Upgrade again and see how it prints this time. (At least I will have it printed for when I get the print bed ticket sorted with Robo.)

    Thank you @Geof @OutsourcedGuru @mark tomlinson for all of your guidance and advice on this.
     
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  13. OutsourcedGuru

    OutsourcedGuru Active Member

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    PM me your postal address and I'll print and send one out to you. I admit that it's a little fussy right at the beginning (printing the stability plate) but after maybe the first twenty layers it's good to go (for me).
     
  14. mheath82

    mheath82 New Member

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    I really appreciate the offer @OutsourcedGuru but at this point Robo's official answer to my warped print bed frame thing was

    'We are not sure how this is happening but What I do is just pull the front edge down until is stays closer to the desired level, the aluminium will bend and stay if you bend it far enough.'

    Since I don't feel that is an appropriate fix for a brand new printer I'm going to try and exchange it at the retailer I purchased it from for another C2. We'll see how that goes.
     
  15. OutsourcedGuru

    OutsourcedGuru Active Member

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    You deserve a working printer so go that route. Me, I just enjoy a good challenge especially in the area of building a good printer so I'm like that.
     
  16. mheath82

    mheath82 New Member

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    Well the BuildTak did wonders for the adhesion. I'm still having an issue on the right side on the corners but it is much better than it was.
     
  17. OutsourcedGuru

    OutsourcedGuru Active Member

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    Before I recently dialed in my z-offset (having changed beds and just wanted to print immediately), I used my finger during the first layer to apply some gentle upward pressure to compensate for a slightly-off z-offset. If you know what you're doing and you have a subtle touch, you can get the first layer happy and then walk away.

    The better approach of course is to dial in the settings for z-offset and fine tuning.

    And to be honest, I've added about six paper shims under my aluminum bed bracket's screw/nut pairs in the right places to compensate for a slight twist in mine. The G29 autolevel is supposed to fix things up but helping it a little like this makes things less complicated.
     
  18. mheath82

    mheath82 New Member

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    I've still been back and fourth with Robo about the aluminium print bed frame being warped and am absolutely appalled at the response I received from Dave @ Robo support today. I asked that my ticket be escalated because his answer to my issue is to 'bend it'. If I wasn't afraid of crushing the bearings or bending the worm gear for the Z axis...


    "Hi Martin,

    We are asking you to do something that we have done here in the office to a few printers that takes about 2 min to fix and you seem to upset over having to do something so simple that instead of actually doing it weeks ago and printing all this time, you would rather spend all your time complaining about something instead of just following our advice and fixing this simple issue!

    Escalated!

    Dave"
     
  19. Geof

    Geof Volunteer Moderator
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    hey Martin (@mheath82 ) I have sent you a PM :D
     
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  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    That is an unsatisfactory response, thanks @Geof for getting Jerry involved

    Paid for a non-defective printer, expect a non-defective printer
     
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