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Odd Print Behavior on Small Part


Pridanc
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Posted · Odd Print Behavior on Small Part

Folks,

I fairly new to the printing fun with all my work for my personal "old guy" motorcycle restoration and general fun shop. All work is for myself and neighbor with the bottom line here of me saying I love the learning but nothing is crucial here. 

 

One of the parts I print in ABS is the box for a motorcycle battery as we, on occasion, make them ourselves.  ABS works well for the temps the battery lives in and and might try PP next for the greater impact resistance but that's another discussion.  These are not huge but decent size and print, IMO, perfectly.  No warping, no defects of any kind.

 

For a friend recently, I was asked to make a support piece to attach a switch to his motorbike. Got the part drawn up as we needed and went to print it.  For some strange reason I always get an odd ugly print the first 20% of the print and then it all goes near perfect to the end. 

 

I've tried printing the part laying down as well as standing up and both times the first bit coming up off the bed is just not acceptable, even between friends.  I've tried a few changes in CURA (5.4) with no visible change but as I'm so unfamiliar with all of this, I'm not sure what else to change or to look at without suggestions.

 

One thing I might try but have not done so yet, is to lower the quality. No other reason than just a way to change something. I am too ignorant about CURA  (OK, any slicer) to make any informed decisions. I'm just guessing and changing.

 

As time permits, please look at the attached photos and files. One of the photos still has supports attached as I was trying to change the outcome but the changes didn't work so I won't be removing them!  Note that the rough / poor quality is always from the build plate for a short while before it all goes well. Also note, as I did not have a saved  .3mf file, I just now went in and created one. Fairly sure all the settings were the same as when printed but I can say that regardless of support choices, some temp and feed choices, nothing seems to change in the print.  Sorry to be so vague.

 

Any thoughts or suggestions are greatly appreciated. 

Sincerely, PDC

SnaSide.jpg

SnaStanding.jpg

French No Taper v103.3mf

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    Posted (edited) · Odd Print Behavior on Small Part

    That's pretty ugly.

    There are a couple of things going on there.

    The flat piece isn't actually in contact with the second shape.  Here you can see the gap between the meshes.  It's only 0.05mm and it MIGHT stay together.  Although computers are stupid, they are also accurate.  The part has a gap so Cura is being accurate and acknowledging the gap.  That needs to be addressed in CAD and the parts properly "unioned" (if that is in fact your intent).

    image.thumb.png.85c1219d916eb6963799a0d2fdbbecea.png

     

    When you have a fillet on the build plate, support is tough for the first couple of layers.  I usually move parts like that up 1mm or so off the build plate.  That allows the support for the first couple of layers of the radius to form correctly and actually support something rather than just being there.  If it's your design you might want to consider a chamfer rather than the fillet as a chamfer wouldn't need support.  That would allow you to change your Over Hang angle to 50° up from the 10° of your current setting.

     

    In regards to the poor first layers, check your Z system and check for play on the right end of the X beam.

    If there is any binding in the Z it can cause inconsistent layer heights.  Z-hops can make the situation worse as the X beam moves up but doesn't come down correctly.  The situation gets better as the nozzle rises on the part.  I had to put a 0.3mm shim behind the Z motor bracket on my Ender to keep the threaded Z rod straight up and down throughout it's movement.  Since the X beam is cantilevered - if it can be wobbled up and down on the right end it can also bind.  That one is a PITA to fix as you really need to pull the X beam assembly off the top of the machine to get to the mounting screws.

    Check all the Z trolley wheels as well.  They are mounted with eccentric nuts so you can adjust the tension to the slots on the aluminum extrusions.  You should just be able to turn any trolley wheel with your fingers.

     

    Simply increasing the Infill Density doesn't help the strength a lot.

    This is with the Infill Density at 15%, Infill Line Multiplier 3, Infill Line Directions [0], Overhang Angle 50°, and the part is 1mm off the build plate.  You could park a car on this.

    image.thumb.png.4d025c464cd1490ec73c2c7ad475ae25.png

     

    If you hover your mouse over my avatar you will see a motor"cycle".  The only printed part on it is the Ipod mount on the left side.  I'm in Florida and the mount is silky silver PLA but it has held up other than discoloration from the sun.

    Edited by GregValiant
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    Posted · Odd Print Behavior on Small Part

    Greg, Rockstar stuff,  TYVM

     

    My friend is in AZ and temps above 110 in the summer are common all of which means didly since talk about temps and PLA do not make it so as you point out. 

     

    On the other hand the DD motor support now on my Ender 3 V2 was originally made from PLA (I said I was ignorant right?) and when printing stuff inside the enclosure, it melted like a popsicle in the sun.  Surprisingly the print finished almost perfectly. See that pic for a laugh. The trolley wheels were even rubbing on the underside of the folded over support grinding away at the plastic.  This did not affect the part at all as far as I can tell.

     

    I have a dual screw/motor Z arm which I check for level using some digital gauges before every run. Well, before every first use at start up after a shut down.  It stays bloody accurate when left on but a shutdown can cause it to loose its level. 

     

    So, and this is me asking, I should connect the plate that you clearly show is not part of the body to the body?  In CAD, it is another part but I can make them as one. Being the old fool, I didn't even think for a moment they'd be seen as separate parts by the slicer where they meet up even if , duh, they are two parts.  I have so much to learn.

     

    Oddly, those curves you speak of are made up of a chamfer and a fillet to mimic the curve I want. Long story is that I know the actual curve I want (not made from chamfer/fillet)  but cannot apply it to both surfaces as needed and have yet to hear back from the CAD folks with a way to do it otherwise. They will as they always have.  CAD, like printing, is new to me (beginning of May) so the curve is steep. I'm a bulldog so I will get there from here, just isn't always the simplest way!

     

    Added infill was for no other reason than my friend will put a small bolt hole in it somewhere once he has it so might helps its crush resistance ever so slightly?  Since I used to make bits out of carbon with Nomex honey comb "infill",  anytime someone chose to put an unplanned hole in it was simple. Drill the hole completely through, sneak a 90 degree pick through one or both side of the hole, spin the tool to ruin the honeycomb, tape up one side / hole and fill the void with epoxy. Once dry re-drill the hole and you have big strength. I suggested something like this to my buddy but as you point out, probably not needed.

     

    Does having extra infill HURT the resulting part?  I'm just a big chicken but always willing to try other steps.

     

    With your suggestions I'm now going to

    A) look hard at my x/z gantry. Never forget, I print other things with perfection (my level of perfection) so this part looking goofy is a conundrum to this old rookie. 

    B) fix the CAD model and

    C) slice the model using your suggestions. Lastly?

    D) cross fingers.

     

    I don't have the words to thank you for this other than...Thank you!  Greatly appreciated. I'll get back with you once I've given it another swing.

     

    All the best, sincerely, PDC

    Limp DD support.jpg

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    Posted · Odd Print Behavior on Small Part

    Greg,

    Full disclosure, I did not check to see if the X gantry (Hotend & Extruder) moved without issue which is sad since I said I would  !  I think a squirrel ran by and that was it. Thoughts gone.

     

    I did however go back to CAD, make the part one, then go into CURA and apply the settings you suggested including raising the part up off the bed. Sadly, the issue has not changed at all. 

     

    For no factual reason, I feel the issue has to do with heat (no reason to say that, but my gut) and that the lower part is an over hang. Again, this is just me drawing straws and guessing as I've way too little experience to make any changes from experience. Tough spot.

     

    Oddly, I had been printing at 240c, did a temp tower test and found that from 210-235, that 215 was the nicest. This makes me go "huh?" as even Polymaker say print temps are 230-250.   Easy to say that "temp test" doesn't make it up but again I've got an odd feeling in the pti of my stomach. Something is odd and staring us in the face. Too bad I'm blind to that so far.

     

    At the end of the day, we can say for a fact that the issues exist in the overhang areas but in those areas, even the flat areas get hurt too.  Once XXXX is reached, print becomes perfect.  XXXX could be

    a) once the overhangs are over with and/or

    b) combined "trapped" temps change?  This thought is just silly me saying well maybe the bedtemp, nozzle temp, enclosure temp all conspire in the lower overhang region to ruin things until that changes?

     

    So for grins I'm going to  print an overhang test. Then I'm going to print the same part but without the chamfer/fillet curves to see what happens.  IE, that lower area will be square/rectangular with almost no overhang other than the curve of that Side Plate that you pointed out was not really attached to the part until I attached them.

     

    I'm a big kid so stuff like this is no more than a speed bump I'd like to figure out, but can leave me shaking my head. In my limited experience, this one is odd for sure!

     

    May not be able to do any tests until Monday as family is coming over so bear with me. Feel free to say anything as you won't hurt my feelings.

     

    Love your bike, thanks for sharing. I got into printing to help our needs in our motorbike work. Sometimes parts are used as is, sometimes we print a part to check fitment then have the part make in metal. 

     

    All the best, enjoy the weekend, 

    Sincerely,

    PDC

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    20230902_125505.jpg

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    Posted (edited) · Odd Print Behavior on Small Part

    Does having extra infill HURT the resulting part? 

    No, but unless you have the infill configured as ribs it doesn't really help either.  It's like other design considerations - from what direction is the part being "loaded".  I usually set the infill to be at right angles to the walls.  With certain colors and materials, if you have the Wall Line Count set to less than 3 you can get shadows or deformation that is visible on the outside because of the infill.

     

    I'm looking at the DD bracket and I'm laughing.  I'm guessing that happened during a short print because if it had been a long one it would have bent over backwards.

     

    I should connect the plate that you clearly show is not part of the body to the body? 

    If it is supposed to be a feature of the part then yes.  In CAD move it so there is 0.00000000 gap and then do a "union" or "join" or whatever the software you are using calls it.  Cura will notice and print the entirety as a single model.  The infill will cross over...that sort of thing.

     

    If you know where a hole is going to be in the model you can bring in a support blocker and configure it as a cutting mesh with all walls.

     

    This gets paused and two nuts inserted.  Actually, there were 6 pauses in this and the last pause was for a 3/16 x 9" steel reinforcing rod to fight the warping that would occur do to the ambient temps.

    image.thumb.png.4f1e706787a384d4041b41b2c23e6a40.png

     

    Here is the area below the nut pocket.  A 12mm tube from the Cylindrical Support Blocker plugin configured as all walls.

    It will help keep the model from deforming when the screw is tightened.  Infill even at 100% just doesn't get it done.

    image.thumb.png.d1c7eb3c1438192ad55a61e643f7e26b.png

     

    The 3mf file is how I set up to print your model.  There is a support blocker that keeps any support from under the piece that is resting on the build plate.  

    I hang on to the ends of filament rolls for little tests like this so the PLA (in this case) was not the best.

    DSCN3173.thumb.JPG.e85e210a5b76179895e7e03fe05fde00.JPG

     

    DSCN3167.thumb.JPG.0814ac2475bdb8a757334ce9276c2a01.JPG

     

    It's a little part so the printer will be bouncing off "Minimum Layer Time" and generally running at "Minimum Print Speed".  A good layer cooling fan is therefore a must.  Even printing with materials that might be prone to warping I think at least some fan is necessary for this model.

    Here is the project file from that print.

    GV No Taper v103.3mf

     

    Edited by GregValiant
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    Posted · Odd Print Behavior on Small Part

    Greg, fantastic stuff!

     

    Before my questions, the print I was doing when the DD mount folded was a 7 hour print. It completed and perfect as I'd want the print to be. Go figure right?    I feel that the wheels of the carriage stopped any further fold and basically I was lucky.

     

    My camera only looks at the base of the extruder (nozzle area) and all of the print so I never once looked at the DD mount folding as it was not in the picture.  Another lesson learned.

     

    So to be clear, you printed the little part without support? Standing or laying, and if laying, on which side? Plate side or other?  

     

    Again, your opinion is that  I should turn the fans on ever so slightly at first or through the complete print? 

     

    Happy to give it a whirl as well as learn how to turn the fans off in GCODE after some of the print IF you feel I should?  If you feel that this can be achieved in CURA, I can do that as well. My single brain cell says I can do this in CURA but I'll have to look.

     

    Sorry to ask such goofy questions but remember, I know nothing.

    All the best,

    Sincerely PDC

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    • Solution
    Posted · Odd Print Behavior on Small Part

    I printed it standing up as you did.  It was with PLA so if you are using another material things could be different.  

    I'm pretty confident that it's a printer issue hiding in the weeds and that's why I printed it.

     

    Regarding cooling - Ask and thou shalt receive.

    Unzip the file below and put "AddCoolingProfile.py" into the configuration folder "scripts" sub-folder.  On Windows it's "C:\Users\username\AppData\Roaming\cura\5.4\scripts".  For other opsys you can use the "Help | Show Configuration Folder" command in Cura.

    I've submitted a pull request for this.  Eventually it might make it into Cura.  I use it all the time.

    The "By Feature" mode works well on larger prints but jumps the speed up and down too much on smallish prints.

    For your print using "By Layer" will work.  You can turn the fan on and off by entering the "Lay# / %" as 25/100 to turn the fan on full at layer 25 and then 30/0 to turn the fan off at layer 30 then 40/50 to turn it back on at layer 40 at 50% speed.

     

    AddCoolingProfile.zip

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    Posted (edited) · Odd Print Behavior on Small Part

    Greg,

    Once again, many thanks for the words and the fan control Profile.  You rock.

     

    I will, I swear, take the machine apart and see what appears if anything. I'm not convinced it is the mechanical's but always worth verification. I take all suggestions seriously.

     

    So to be clear, you printed it standing up without supports, or with supports as you showed before?  Just want to start with the best shot since you printed it perfectly.  I am using ABS in an enclosure. May not need that OR the heat of the enclosure.  Fan just might be the answer.

     

    Anyway, one step at a time and I promise to keep you informed for everyone's knowledge. 

     

    Stay well,  PDC

    Edited by Pridanc
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    Posted (edited) · Odd Print Behavior on Small Part

    There was a poster here who was printing motorcycle fairings in ABS and was having trouble here and there.  He finally figured out that the insulated enclosure was holding too much heat and his parts weren't hardening up as they should.  A little fan was the answer.  He also built an exhaust fan and ducting for the enclosure to keep better control of the ambient temp around the part.

     

    I spend time here and on Github with an occasional side trip to Reddit and over a period of time folks have brought up the subject of "I wish Cura had a setting that could __________ .  I've taken to writing scripts to fill in that blank.  Some are pretty off-the-wall but most could be of service in specialty situations.  This weeks project is a post processor that retracts, lifts the nozzle 1mm, and then does a pattern running back and forth over the print with the fan on.  I had found that putting the roof on over a cold support interface made removing the support much easier and cleaner.  Exactly how useful it might be I really don't know.  I had one print where the support was trapped and was tough to get out without smashing the print.  Not a problem anymore!

     

     

     

    Edited by GregValiant
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    Posted · Odd Print Behavior on Small Part

    Greg,

    You already know that I so greatly appreciate your words and thoughts. I will do my best to follow your thoughts and to use your fan control app along the path of figuring this out.

     

    I promise I will be back with everything I find as it is important that what I find gets shared.

     

    And BTW, we have a Bonneville project underway that was to gets its body printed but the consensus is that to print a shape strong enough to withstand the aero load will weigh a bunch more than a carbon shape so instead we will print the molds and make the needed carbon parts from them. 

     

    Regardless of my words and meanderings,  thank you so very much for all your help.

    Sincerely,

    PDC

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    Posted (edited) · Odd Print Behavior on Small Part

    Greg,

    Huge Kudos to ya!  Your fan speed by layers trick fixed it completely. You SO rock.

     

    At first I was hovering over the print and messed with the Cooling Fan speeds on the fly since the numbers displayed were "way higher" than what I thought I'd specified.   

     

    OMG what a fool.  Clearly not knowing what to use as speeds I guessed and made a slice with the  first few layers at 35%, then 30, then 25 and finally 20 for the next 40 layers and then Off altogether for the remaining 130 layers or so. The total layers "cooled" were those that fell into the 12mm where the prints had been garbage suddenly clearing up.   My problem was that I wrongly thought the Fan speed % numbers being displayed were off. Umm...not so.  :-)

     

    I'd forgotten that the screen only displays up to 100% speed.  BUT since 255 is that 100%, then the display of 89% was correct for my request at 35% of total fan speed available.   (Then 76.5%  so on and so forth were the displayed numbers based on my requests in your Fan Speed by Layers fix)  Perfect!

     

    Pure magic and IMO if CURA don't implement this then they are silly. Just my .02c

     

    Last question. Your Profile has accelerations at 1000.  Standard to me are 500 and our actual print speeds are same for all intents and purposes.  Does it matter? Does it help?  Again, I'm ignorant so thanks in advance.

     

    I'm going to mark this thread as Answered so TYVM.

    All the best,

    Sincerely, PDC

     

     

    Edited by Pridanc
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    Posted · Odd Print Behavior on Small Part

    A post processor for the layer cooling fan has been a request on GitHub for 6 years.  I forced myself to learn some Python and took on the project.  What better way to learn than with a 900 line script right?

     

    Congrats on getting it sorted out.  Funny how a material that doesn't really like the fan running will respond correctly to a bit of cooling in certain situations.  I print a lot of PETG and it has issues similar to ABS.  It's really why I wanted more control over the fan.

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    Posted · Odd Print Behavior on Small Part

    If you get out to Bonneville in 2025, come on by. As a bike person, we'd love to have ya.

    Sincerely,

    PC

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    Posted · Odd Print Behavior on Small Part

    I had some minor input on the "World's Fastest Goldwing" project and I always wanted to get out there but I never have.  My son has a 1982 Suzuki GS850 that he wants to do as a "dustbin" bike.  It will look like a Bonneville racer (if he ever gets it finished).

     

     

     

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    Posted · Odd Print Behavior on Small Part

    Great Stuff. If your son ever creates the Dustbin fairing, love to see it.

    Stay well, PDC

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