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Posted (edited) · No luck with CPE

Hi - 

 

First let me stipulate I am relatively new to 3D printing.  I have done my fair share of printing larger and mechanical parts (as R&D is what we do) but I want to apologise in advance if my question is a trivial one and I am simply overlooking something obvious.

 

I have modelled a part in PLA and it is time for printing the prototypes that will be used for field testings.  These parts have large flat surfaces, so initially I though bed adhesion should not be a problem, even though I am aware larger flat surfaces can come with their own set of challenges.

 

I started with the smallest of the parts, ±22mm x ±100mm x 70mm footprint, a simple bucket shaped object.  I always start with with the default Cura profiles, MAYBE altering wall, bottom and top thickness, but that is it.  The rest I leave as it is.  The first print started fine, but about 1 hour into the print, the far right corner lifted from the build plate.  From there things just got worse.  My Settings:

 

  • Profile: CURA CPE default profile (also reduced speed and fans by 25% on a second run)
  • Filament: Ultimaker CPE
  • Printer: Ultimaker 2+
  • Bed Adhesion: Tried both Brim and Skirt
  • Bed Adhesion assistance: Magigoo
  • Bed Temp: 70C
  • Nozzle Temp: 250C
  • Flow: 100%

 

After tge first failed print, I cleaned the bed with water, wiped clean again with Isopropyl and then added fresh coat of Magigoo.  Results was even worse.  Could not get the brim to stick even.  Levelled the bed again (even closer to the nozzle).  Again Brim would not stick.

 

Wiped the Bed again with water, added another fresh coat of Magigoo.  Changed brim to skirt.  At least this way the print starts, but as with the first attempt, the far right corner warped and lifted from the bed after about an hour.  I then enclosed the front, reorientated the print by turning it 90deg and cleaned the nozzle (atomic method).  Same result unfortunately. 

 

Just to make sure the bed was level, I switched to PLA again... printed perfectly.  Attached is an image of the very simple part I am trying to print.

 

Would really appreciate some help. At wits end here... 

 

Regards, Friedl.

 

Screenshot 2021-02-22 at 09.24.13.png

Edited by friedl_basson
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    Posted · No luck with CPE

    Did you switch off the cooling fan? Or set that at a very low speed?

     

    For PET, which I think is very similar to CPE, I always print without fan if the model allows it, thus if it has no overhangs and no bridges. Otherwise I use the absolute minimum amount of fan.

     

    I usually print PET on bare glass. (Although some say this is not recommended, as it might cause a too good bonding, and might chip the glass.)

     

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    Posted (edited) · No luck with CPE
    1 hour ago, geert_2 said:

    Did you switch off the cooling fan? Or set that at a very low speed?

     

    For PET, which I think is very similar to CPE, I always print without fan if the model allows it, thus if it has no overhangs and no bridges. Otherwise I use the absolute minimum amount of fan.

     

    I usually print PET on bare glass. (Although some say this is not recommended, as it might cause a too good bonding, and might chip the glass.)

     

     

    Hi @geert_2 - 

     

    I will try disabling the fan completely.  I have reduced the fan speed by 35% (off the already reduced speed in the Cura default profile), but have not reduced it to zero.  My guess would be around 50% of normal fan speed.  On this particular piece it should be a problem as there is no overhang.  Ons the other two parts, there are 'roof structures' but I use normal supports for that.  Should I still disable the fan?

     

    I know I can obviously test these, but those are about 8 hours into the print and with the cost of CPE here locally, so would preferably try to avoid any misprints if possible 🙂

     

    Kind Regards,

    Friedl.

    Edited by friedl_basson
    additional info
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    Posted · No luck with CPE

    Without knowing your model, your printer and your particular CPE, I can only guess...

     

    The best thing you could do, is cut out the most critical and most representative parts of your model, such as overhangs or bridges. And combine these into a new *small* test model which takes only maybe 30 minutes to complete and doesn't use much filament. Test and optimise on this until you get it good. Overdo in one direction, then overdo in the other, and gradually find the optimal center. This is going to cost time, but you learn quickly. Of course there can still be scaling problems later on, such as bonding that might reduce with time. But then at least you get the overhangs and bridges good.

     

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    Posted · No luck with CPE

    @geert_2 - 

     

    My apologies, I thought the printer info included in the original post would help, I have a lot to learn 🙂 

     

    • Profile: CURA CPE default profile (also reduced speed and fans by 25% on a second run)
    • Filament: Ultimaker CPE
    • Printer: Ultimaker 2+
    • Bed Adhesion: Tried both Brim and Skirt
    • Bed Adhesion assistance: Magigoo
    • Bed Temp: 70C
    • Nozzle Temp: 250C
    • Flow: 100%

     

    With regards to smaller model, I have printed these successfully.  It seems the detachment from the build plate happens 1hour+  into the print.

     

    I will follow you advice, reduce fan speeds and increase bed temp to 80C then.  I will print the part sent previously first as it is the simplest one and was the one giving problems.  If successful, I will attempt the more complex models.  Thank you for your advice, I will post my results 😉

     

    I have attached screen grabs of the the two main pieces and the assembled unit.

     

    Regards, Friedl.

     

     

    Screenshot 2021-02-22 at 18.28.55.png

    Screenshot 2021-02-22 at 18.28.17.png

    Screenshot 2021-02-22 at 18.28.04.png

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    Posted · No luck with CPE

    My bad, I had missed that printer-info.

     

    Yes, trying a higher bed temp might also be a good idea: mine is around 80-90°C for PET (I don't know by head, but I definitely increased it from the original 70°C). The bed temp has te be close to the glass transition temperature, where the material starts to become soft. If lower, bonding reduces. If higher, the part may become too soft and sag, warp or peel off.

     

    What you could also try if you suspect time reduces bonding: *immediately* after a small test print completes, manually heat the bed to the same temperature as during the print, e.g. 80°C. And then let it sit for the night at that temp. In the morning, see if corners have lifted, and try pulling it off. But of course without brute force, always gently. If you print a tiny cube of 10mm, if the bonding is good, you can't pull it off. If the bonding goes bad, you can. But again, always be gentle.

     

    Forgot to mention: also consider using a brim: maybe in Cura, or as a custom designed brim (=designed in CAD, as part of the model). This also helps reduce corner-lift.

     

    I guess you are going to print the pale lid on its back, thus with the huge tabs facing the glass? In that case, consider free hanging supports for the tiny overhangs for the screws. But again: first test this concept on a small test model.

     

     

    Custom brim around the left model (the right one is post-processed and polished):

    DSCN6032.thumb.JPG.956086cf9ab2ee915b21b6eaba774967.JPG

     

    Custom brims designed in CAD around the pink and orange supports, and around the cube:

    ostrcp_key_v20_zoom.thumb.jpg.c85991865979ff09557a37d9ca6ad20f.jpg

     

    Free hanging supports:

    supporttest12b.thumb.png.504e11c4d360abd18960d889c271f2a4.png

     

    Other view of the free hanging supports: they are kept in place by the strings from the material, and are thus very easy to remove:

    supporttest12c.thumb.png.a4bbb089d43486b97df974e68e645196.png

     

    Cross section. The ribs on top of the supports are 0.5mm x 0.5mm. The inverted staircase at the bottom of the supports is 1mm x 1mm. The gaps and little "connection tabs" are designed and tested for this particular model, you may need to change dimensions for yours. Hence the need for a tiny test model, containing only this concept.

    supporttest12d.thumb.png.928a8b2050f412c67de15eea58791d75.png

     

     

     

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    Posted · No luck with CPE

    Hi @geert_2 - 

     

    Wow thank you for the comprehensive response.

     

    With regards to the brim, I tried printing with one even though I initially thought (due to the large flat surfaces) it wont be needed.  The brim produced even worse results.  It would not even finish the 8mm brim before it starts curling upwards and lifts off the bed completely 🤯

     

    The concept of free hanging supports are amazing!!  Thank you for the tip.  

     

    You are correct, the bigger parts are printed with the flat surfaces on the bed, this way minimising supports needed.  I have been printing the supports for the 'screw flanges' with break away supports, using PLA they came away easy as well.  Have not gotten this far with CPE as I first need to get all corners of the part to stick and not curl up.

     

    The strange part is that is was the very same corner that warped and pulled away from the build plate, regardless of the orientation or placement of the part.  I might al rig a small probe to test the actual bed temp and look for any inconstancies.  For now I just need to get one prototype out, preferably not with PLA  😄

     

     Kind Regards, 

    Friedl.

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    Posted · No luck with CPE

    Yes, irregular temperature could be a factor: I once measured it, and at the edges it could be quite a bit lower. Maybe due to the rising hot air pulling cold air in from below. Also, under the nozzle-fans the bed can be much cooler, especially on small objects where that fan is continuously blowing on a small spot.

     

    Also check the bottom surface of your prints: is it squeezed equally flat in all areas? Maybe if one corner is too far off, the filament is not squeezed well, and that could cause it to bond less. See the pic how my prints typically look.

     

    Grease or oil also comes to mind, but if you already cleaned that area multiple times, it shouldn't be...

     

    Photo of typical bottoms of my prints (this is PET):

     

    DSCN6083.thumb.JPG.6fa2f0776aca10a340718c2065decdbf.JPG

     

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    Posted · No luck with CPE

    Hi @geert_2 - 

     

    Looking at your photo, I could probably raise the bed (or lower the nozzle) a little bit.  Having said that, I am using the Ultimaker calibration card that came with the set of Nozzles and there is quite a bit of friction already when pulling the card from under the nozzle.

     

    Do you have auto bed-levelling??  I would probably spend my last savings to upgrade even it was only for that purpose 😄  Well, that and Dual Extruders, hehe.  The UM2+ was a good way to get started with 3D printing, but for the type of models I print, I can most certainly see the need for the second extruder, whether it being a different colour or dissolvable support.

     

    At the moment the only way for me to achieve dual colours, is to emboss on the one part and then phically print out the same as a new part.  Then try to insert into the embossed area.  As you can see in the image, this does not always go according to plan, even with 0.25mm nozzle 🙈

     

    IMG_0229.thumb.jpeg.862083d90dc3c86487de9d3a1ffe7058.jpeg

     

    Thanks again for all the effort.  I have done a couple of PLA models of our enclosure again to make sure everything is the way it should be.  Will probably attempt a CPE print then tomorrow as they are quite lengthy prints (8 hours top and bottom each). 

     

    Regards, Friedl.

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    Posted · No luck with CPE

    I have manual leveling on my UM2 printers. I did that according to the official procedure in the beginning. Since then I only adjust it occasionally on the fly. I start a print with a thick skirt (5 lines or so), or when printing the brim if I use brim (rarely), and then I watch closely how the first layer is, and adjust on the fly by moving the screw a 1/8 of a turn, and then watch again, etc. I think it is a little bit closer now than originally, indeed. But I only adjust that maybe once a year... My bottom layer is 0.2mm thick: I found that 0.1mm is too thin and a bit uneven, and 0.3 is too thick and gives lesser bonding than 0.2, especially for objects with very small holes like in my photo above. Everyone has his own taste: I like the simplicity of manual leveling, like manual shifting in a car, and a manual handbrake. :-)

     

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    Posted (edited) · No luck with CPE

    @geert_2 - 

     

    haha, I get it... I used to drive a manual car, but since moving to Cape Town (hectic dead-lock traffic) I switched to Automatic 🙂

     

    Thanks for all the tips, I will adjust my first layer to 0.2mm and see.  Might be my saving grace.

     

    EDIT: Never mind, I suppose it is printing that sections as support, not infill 🙈

     

    Off topic, hope you don't mind; My Cura started behaving suspicious, for some reason, the infill pattern (and density) does not change no matter how I change the settings.  See below.  I have selected triangles and as you can clearly see... the infill is not Triangles.  No matter what Is et it to, or even to 100% infill, this is the result??

     

    Any idea what causes this?

     

    1670160463_Screenshot2021-02-24at19_13_54.thumb.png.b2089b23de70c35bfa1cb7f39e0f9332.png 

    Edited by friedl_basson
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    Posted · No luck with CPE

    This might be support..

     

    Thanks

    Torgeir

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