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box printed with soft walls that separate into many thin layers

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esrossiter
(@esrossiter)
Trusted Member

This print was really nice, looked good, until I took it off of the plate.  What is supposed to be a very rigid box is not, it is very flexible, which would be cool if that's what I had been trying for...  I don't understand what caused this.

The below is a pic of me squeezing the box, which shows the separated layers.  I'm stumped.  

IMG 2386

PLA, nozzle temp 195 (first layer 200) bed temp 45 (first layer 60) at 50mms.

.slt and .gcode files.

I seem to fix one issue and it causes another.  Any ides?

Thanks,

Eric

Quote
Topic starter Posted : 25/04/2021 11:12 pm
Pablo
(@placherre)
Member Moderator

Hi Peter!

I will analyse the problem and I will reply to you...

Kind regards,

Pablo

ReplyQuote
Posted : 26/04/2021 10:30 pm
Pablo
(@placherre)
Member Moderator

Hi Eric, I am back…

As I can see, the model looks pretty good, despite the issue with the walls you are showing in the picture. Let's call that problem “Vertical Delamination”. In order to clarify the source of this issue, you should check the following items:

  • Belt Tension: This might sound essential, but having an incorrect belt tension causes different motion when loose. When looking at the picture and searching for a pattern, the delamination only happens in a certain area of the box: two spots in front of each other while the rest of the wall is fine. The timing belts should be tight enough that should be as taut as possible and have no slack.
  • Under Extrusion: If the machine is under extruding, the filament deposited will be slightly thinner and they will not fuse properly. Since you have exactly 2 walls perimeter with no infill, every wall line will merge to the next one. Further below I will explain to you how to set, calculate and configure the E-Steps for the correct extrusion.
  • Experiment Wall Thickness and Infill Configuration: The thickness of the wall seems to be an exact multiplier of the nozzle diameter. I can count 2 walls of 0,4 mm, therefore the total thickness is 1,6 mm. Regarding the mechanical characteristic of the body, I recommend you to increase it, hence the box will be more stiff and you will not be able to bend it (still, this doesn't have to do with the wall issue). Therefore, set the Wall Thickness parameter to 0.4 mm or the Wall Line Count to 1; in addition, increase the Infill percentage value (30-40% should work fine). Also, I recommend you to choose the Gyroid option, which is the one that offers a better strength.  By doing this, the print time will increase. In my case, the printing went from 5 hours (with two walls) to 5,5 hours (with one wall and 30% infill). At the end of the post you will find a picture from my slicer, showing how it looks like when setting up 1 wall and infill.
  • Increase Printing Temperature: Dark colours, like black, tend to need a few degrees higher in the nozzle in order to bond properly. In your case, I suggest increasing it to 205°C in order to compensate. Maintain this value through all the print. Did you print the Temperature Tower for this filament?
  • Speed: Print Speed values are correct for the type of filament you are using. Even better, the wall printing speed is slower, which is excellent when trying to accomplish good results.
  • Fan Speed: Always remember to keep the fan speed at 100%, except for the first two layers where fan is not needed. If you do not run the fan at full speed, the filament deposited will not cool down fast and will not bond properly to the previous layer.

Up next, what I promised, I will explain you how to successfully calibrate the E-Steps in your Ender 3 Pro:

Before changing the flow rate on the slicer, you could make a quick check of your E-step calibration (the amount of filament being extruded). In this case, I will give a step-by-step guide:

  1. Heat up the Nozzle. In your case, heat it up to 210°C, just to make sure the filament will flow correctly. Note: dark filaments require a few degrees more (5°C) compared to the temperature of light colours.
  2. Make two marks on the filament from the extruder’s beginning: the first one at 100 mm and a second one at 110 mm (in case there is over extrusion, I will explain this later). Take a look at the picture below for reference (if you have a Vernier caliper, will suit you better, but a ruler works fine).
Filament Measure E Steps
  1. Next, go to the screen and enter the Main Menu > Prepare > Move Axis > Extruder > 10 mm Step > Roll the Select Wheel until you set 100 mm > Wait until the extrusion is finished.
  2. Next, measure the distance left between the extruder beginning and the mark you made. Remember if it is the 100 mm or 110 mm mark. Therefore, if the machine is over extruding, the 100 mm mark will be gone (that is why you made a mark at 110 mm); but, if you still can see the 100 mm mark, it means it is under extruding. Write down this distance.
  3. Now, find out how many steps are set up in the machine. Go to the Main Menu > Control > Motion > Steps/mm. Write this number down.
  4. Next, let’s do some math to determine which are the real Steps/mm. I will do it with an example:
    • If you measure 5 mm left to the 100 mm mark, then the calculation is:

      [Expected Amount of Filament (100 mm) x Current E-Steps (extracted from Configuration)] / Actual Extrusion Amount (95 mm)

    • If you measure 6 mm left to the 110 mm mark, then the calculation is:

       

      [Expected Amount of Filament (110 mm) x Current E-Steps (extracted from Configuration)] / Actual Extrusion Amount (104 mm)

  5. Once you have the real value of E-Steps, you should change it in the machine. In order to do this, go to the Main Menu: Control > Motion > Esteps/mm (click on the wheel and rotate in order to set the calculated number) > Ok (press wheel) > Go back on the menu > Store Settings (you will hear a beep meaning the change was made). Then, you can go back to the E-Steps value to check if the new value has been saved.

Once you set up the new value, the flow rate in your slicer should be 100%. Because you just calibrated the correct amount of filament being extruded.

The following picture is from my slicer, showing the 1 Wall and 30% Infill configuration:

PiCam Box v14   Infill Cut Away

I hope I was clear and didn’t add any confusion with the explanation… 😆 

Always remember, write down any changes you made, so you can go back to how it was.

Along the path you will find many drawbacks; but don’t loose the enthusiasm of this great world.

I can't wait to see your project working... 👍 

I wish you a good printing…

I look forward to hearing from you.

Kind regards,

Pablo

ReplyQuote
Posted : 27/04/2021 1:11 am
esrossiter
(@esrossiter)
Trusted Member

I checked belt tension and I've calibrated E-Steps.  I'll adjust the recommended settings in Cura and try again.

Thanks, Pablo.

Eric.

ReplyQuote
Topic starter Posted : 27/04/2021 5:15 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

All right then! Let me know how it goes and if you need further assistance.

Kind regards,

Pablo

ReplyQuote
Posted : 27/04/2021 5:49 pm
esrossiter
(@esrossiter)
Trusted Member

Pablo,

To answer one of your previous questions, I did print a temp tower with a diff brand and color of PLA filament, and I saw absolutely no difference in any of the layers at any temperature.  I have a post about the exercise in the temp tower forum group.  I have not printed a temp tower using the Hatchbox black filament that I'm working with now.

I printed the front plate for this raspi cam box at 205 and it came out really brittle again, and easily broken.  I reprinted this piece at 210 degrees and it is much stronger now.  I'll let you know how the box itself turns out, but printing at 210 seems to be adequate.

 

Thx, again.

Eric

ReplyQuote
Topic starter Posted : 28/04/2021 8:01 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

Great news then!!... I am happy that you are finding the way...

Whenever you have time, try to print the temperature tower; but it seems you found the correct temperature setting. 

Kind regards,

Pablo

ReplyQuote
Posted : 29/04/2021 12:43 am
esrossiter
(@esrossiter)
Trusted Member

Spoke too soon.

fmr
fmr2

😠 😡 🤬

ReplyQuote
Topic starter Posted : 29/04/2021 4:18 pm
esrossiter
(@esrossiter)
Trusted Member

I changed nozzles and tried a different filament.  Leveled the bed at 9 points manually.

Same results.  Brittle, breaks easily, and the walls don't adhere to each other.

I could see the walls weren't adhering so I aborted the print.

IMG 2404

what a trip.

Still puzzled,

Eric

 

 

ReplyQuote
Topic starter Posted : 29/04/2021 10:11 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

This box is getting tricky…

So far, the problem is happening in the same place with the same pattern, which is good. There is still something that needs to be changed.

Before continuing printing, I recommend you to check the interior of the Bowden tube or the hot end in order to verify for obstructions made by debris from previous filaments. I remember once having extrusion problems and the main problem was that the end of the Bowden tube (in the hot end side) was full of melted material. After I cleaned it I stopped having extrusion problems. If you find any obstruction, remember to recalibrate the E-Steps. The problem you are experiencing is related to a bad bond between walls and under extrusion is the main reason.

Did you try to print with one wall thickness and infill? I will send you attached the .GCODE file that I used to show you in my previous post. Since your model has the thickness of 2 walls, you can reduce that number to 1 wall and complete the space with gyroid infill.You can adjust the Wall Line Count (change it to one) or the Wall Thickness (set it up to 0.4 mm); if you change one, the other adjust since both are linked. Regarding the infill, I recommend you to use gyroid because it gives a stronger quality to the models. Setting up a 30% infill should be enough to have a rigid box. The next pictures show the advanced settings for the two parameters I mentioned.

Wall Thickness Set Up

 

Infill Set Up   Advanced

If you still want to print with two wall thickness, you could adjust the extrusion width. Since you are using a 0.4 mm diameter nozzle, you could adjust it to 0.45 mm in order to compensate for the shrinking of the filament. You can find this setting under the Quality tab. Since the rest of the print seems to have a good shape, only modify the Wall Line Width (I show you this parameter in the following picture). This will force the slicer to construct the walls differently.

Quality Settings   Advanced 0.45 mm Mod

Also, I verified your model's dimensions. The wall where you are having the bonding problems is 1,6 mm thick, which is exactly 4 wall counts. In addition, I suggest to increase 5% the extrusion Flow; since the problem you are experiencing is related to a lack of extruded filament. By increasing the extrusion amount you will help to close the gaps.

Regarding the temperature, I would keep it at 210°C. The bonding issues are also related to low extrusion temperature; but this is not the case.

I look forward to seeing you succeeding with this project.

I wish you good printing!

Kind regards,

Pablo

ReplyQuote
Posted : 30/04/2021 3:08 pm
esrossiter
(@esrossiter)
Trusted Member

Hey Pablo,

No, two walls is not a necessity.

I either missed this or spaced it:

Posted by: @placherre

set the Wall Thickness parameter to 0.4 mm or the Wall Line Count to 1; in addition, increase the Infill percentage value (30-40% should work fine). Also, I recommend you to choose the Gyroid option,

I implemented the above and it printed but was still very brittle and broke when I was trying to get it off of the bed:

image 67175937

I'll look at the bowden tube and recalc the E-Steps.  I have tasks backing up in other arenas, so it may be a few days before I get back to this.  The only other thing that's changed is the humidity in the space I print in has doubled since winter time.  I was at about 24-27 percent, and now the humidity in the space is over 50 percent.  Temps during printing I can keep relative at about 75 degrees.

Still stumped,

Eric.

 

 

ReplyQuote
Topic starter Posted : 30/04/2021 5:06 pm
Pablo
(@placherre)
Member Moderator

 Hi Eric!

Thank you for your reply!

In this new picture I have more detailed things to look at. I will investigate it and I will reply to you.

Regarding the humidity, do you keep your filaments in sealed bags? It is also recommended to place a desiccant bag, which absorbs the humidity.

Just before you leave, would you print a calibration cube? I am sending the .STL file attached. Once you print it, please send me a picture of three faces.

Thanks in advance.

Kind regards,

Pablo

ReplyQuote
Posted : 30/04/2021 5:44 pm
esrossiter
(@esrossiter)
Trusted Member

Hey Pablo,

Yes, I keep the filament in sealed bags w/desiccant, in a sealed tote that also has desiccant packets.

Calibration cube printed.

image 67184129
image 67157761
image 67159809

 

Thx again,

Eric

ReplyQuote
Topic starter Posted : 01/05/2021 12:28 am
esrossiter
(@esrossiter)
Trusted Member

Pablo,

Were you able to look at the calibration cube pics?   

Thanks,

Eric

ReplyQuote
Topic starter Posted : 17/05/2021 11:47 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

Welcome back!

I had the chance to take a look at the pictures. The three faces look nice, without signs of what is causing the problems in your model. I was able to discard some causes. However, I have a couple of minor considerations regarding the cube images:

  • In the Y face picture I can notice some “elephant foot” phenomenon. This is due to a small clearance between the nozzle and the bed or a high temperature set up on the bed. Just check the correct bed level and the bed temperature. If I can recall, you were printing at 55°C, so that shouldn’t be a problem.
  • In the X and Y face I can notice the infill poking through the outline. Since you are printing with one wall line, this can occur. Also, you could tell the slicer to print the outline before the infill.

Now, about the issues in your project. I agree with you about the filament moisture, since all printing filaments are hygroscopic (capability of absorbing humidity). Previously, you mentioned that you increased the nozzle temperature up to 210°C. Although the print didn’t come up satisfactory, there was an improvement. With this in mind, the moisture present in the filament absorbs part of that temperature and it will evaporate when printing. Consequently, the filament will receive less heat and the layer won’t bond correctly. In addition, PLA filaments have satisfying results when printing closer to 200°C. I believe that 210°C is too high for such material; what is more, you must cool down much faster (or decrease printing speed in order to reduce temperature properly). Maybe you could try drying the spool in the oven (like cooking a turkey...). There is more specific equipment for this task; but, using the oven is a home made solution. However, your oven should be able to hold the temperature accurately. Once you heat it up, later place the spool once the target temperature is reached (for PLA is 40-45ªC, just enough to keep the filament under the Glass Transition Temperature). Be cautious when performing this procedure and keep an eye every now and then, since you should keep the spool at least 4 hours in order to remove moisture (the longer, the better).

Furthermore, under extrusion is a possible cause of your problem. The signs of under extrusion are weak prints that crumble, crack or tear under light forces. Also, I notice some visible gaps in the holes placed close to the middle (see first picture attached). If you can check any obstructions in the hot end or the bowden tube, make sure the filament is freely to move. Once I kept having issues with my prints related to under extrusion. After reviewing the extruder, I found a reduction on the bowden tube at the hot end side. I discovered a small area reduction, causing improper filament feeding. Another sign of under extrusion could be seen in the second picture attached. When looking closer at the hole area, I was able to notice a small gap line. 

Under Extrusion Pi Cam Holes
Under Extrusion Pi Cam Holes 1

Additionally, check the verify the extruder E-Steps calibration in order to ensure a proper feeding. 

I look forward to hearing back from you…

Kind regards,

Pablo

ReplyQuote
Posted : 18/05/2021 3:26 am
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