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donnyfl

Plastic ball of nothing

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Hey guys, first post on my Two week old UM2. The past few days I've been printing fine then last night I decided to go for it and print out 5 1 inch rings. It was a 6 hr job because I wanted 100% infill. This morning I went into my office excited to see 5 finish product but I was disappointed by a lump of solid plastic lol. So I cleaned my build plate thinking maybe it is that but again first layer would not stick well, then the nozzle would swim in it's own bath of melted plastic. Here are some pictures

F5D63E4F-9FAF-4E9B-A3E7-B23DDBF64DA6.jpg

I removed the filament by the nozzle to check it out and this is what I see. Is the feeder pressing to hard into the filament? I've had issues with the feeder where it would really dig into the plastic. Took it apart and it was working fine the past two days up until now.

31E1794D-4531-43E8-B340-4F08261EF348.jpg

I am using the filament that came with the UM2. Let me know if I can provide any other info to aide in the trouble shooting. Thanks!

Here is my cura settings if that helps

cura.png

 

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How does the material look on the other end, in the feeder mechanism? That amount of inprint from the feeder is normal I think.

How is your bed leveling? That looks like the nozzle might be to high from the build plate, thus not pressing the first layers enough.

 

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Well I would increase the layer depth to .300 and reduce speed to 40mm/s and try your 5 print again, watching. If the first few layers all adhere nicely then stop the print and play with your two settings, i.e. gradually moving them to where you want, which seems to be 150 microns at 100mm/s. I have to say these settings to me are strange. If I was using 150 microns then I would be aiming for something with a decent finish and I would not use 100mm/s to achieve that!!!

 

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Thanks for the input everyone. I ended up taking out the filament, making sure everything is moving correctly. Then recalibrated the bed. I usually do the paper test but this time I decided to get the nozzle as close to the glass as possible. It is now printing well again.

This is with 100mm/s

36C9D0B6-46C5-4C6F-8FA1-FF912D8C0A27.jpg

57E9BBFC-7238-475B-BB65-90052B039A5A.jpg

I make internal pieces for air guns so these go inside of a shroud. I am a beginner with CAD and currently using TinkerCad. What I find is that when I make the outside diameter let's say 28mm. Cura/printer prints out perfectly. However, the inside hole is a challenge to get right. I have to play with the numbers to make that slide onto the barrel nice and snug.

Is the left fan suppose to go as fast as the right one? I notice that my left fan changes speed from time to time. The right one is always super fast and spins at a constant speed.

 

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"What I find is that when I make the outside diameter let's say 28mm. Cura/printer prints out perfectly. However, the inside hole is a challenge to get right. I have to play with the numbers to make that slide onto the barrel nice and snug"

I printed something similar last week. The external diameters were accurate in a range of 0.05 to 0.10; the internal diameters were (in)accurate in a range of 0.45 to 0.55; backing up your findings. Of course it is though far easier to measure the external diameter accurately

 

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If your fan is changing speeds it's likely that it has a wonky connection. Move the wire mesh out of the way and check that the connectors have a solid connection. Also make sure that the wires inside the connectors are held in place properly, sometimes they can slip out of the connector housing. This will give you an idea what to look for.

As for the holes being too small, that's just a matter of the plastic shrinking. It's a bigger issue on the inside of the hole as there is nothing keeping it from collapsing in on itself. This is just the nature of the beast and you'll have to compensate by making the holes bigger in CAD. The same applies for more "advanced" production like injection molding.

 

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If your fan is changing speeds it's likely that it has a wonky connection. Move the wire mesh out of the way and check that the connectors have a solid connection. Also make sure that the wires inside the connectors are held in place properly, sometimes they can slip out of the connector housing. This will give you an idea what to look for.

........

 

In my opinion it may be a doggy fan, as both of the fans that cool the printed piece are connected in series, so if its a doggy connection both fans would have speed changes

 

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You guys definitely have a good eye! I never noticed that the left fan is bent upwards compared to the right one. Every time I am observing the fan, I am just staring at the blades. I have since emailed FBRC8 based on dynamism recommendations. The unit is less than 2 weeks old.

Last night I was able to print two really nice pieces then in the morning before work, I let it run again having more confidence. Then 20 mins later when I came back I saw this:

B8802980-1858-426A-84FD-21DDCAD68C5C.jpg

My bed is heated to 60 degrees and I always make sure the bed is clean with a layer or two of the glue.

 

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Donnyfl

Bending that left fan back down will probably help quite a bit, as it is the fan closest to the nozzle. It`s only a thin sheet of pressed steel so you can bend it back down with your fingers, give it a little push.

Bed at 60 is good, you do not need too much glue, just a very thin layer watered down is fine.

 

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I was contacted by fbrc8 support last night and tried a few things. I bent the fan back down or tried to but it still leaves a 1/8 gap compared to the right fan.

1. Recalibrate using paper method, also using default settings for PLA. Nozzle = 210 and bed = 60. One layer of included glue and using Ultimaker filament that came with the unit. Result = another plastic ball

2. Recalibrate using paper method but this time once I felt the paper being tugged, turn knob 1/4 counter clockwise. Again settings set to default for PLA. Result = plastic ball

3. Calibrate using eyeballing method, get the nozzle as close to the plate as possible. Same results. That's where we left off with fbrc8.

Last night I was searching the forums and read somewhere that someone didn't use glue and set plate to 75 degrees and that worked well for him. So this morning I cleaned the plate, gave it a quick rub with alcohol, set plate to 75 degrees and it worked!

54E747D6-4867-4318-8792-21527938F4F8.jpg

Here is a video of what usually happens when I tried the earlier methods

http://vid1105.photobucket.com/albums/h350/donnydu/3D/D0960F70-A528-4446-8C61-1356399EF669.mp4

Do you guys normally use a bed temperature higher than default for different materials?

 

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Hi Donny, really I think 75 is too hot for PLA; it might work but it is masking something else wrong in the setup. For that circular piece you are printing I suggest you try changing the skirt settings. Use 2 skirts and set them 20mm away. This will allow the skirt to take some time and for the pressure in the extruder to stabilise before you actually start printing. Set bed to 60-65, really 60 should be enough. If you go to 65 then turn the bed down to 50-55 after the 1st layer. In these temps I am talking about the printing surface, which if you are using glass, that will be the surface. But your temp measurement will be off the bed and the glass will be cooler than the displayed measurement. If that is the case then for 60 set the temp to at least 65 to get 60 on the glass. If you have a digital thermo you can measure this directly.

 

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Hi donnyfl,

There were countless times the very same failure happen to me. Nowadays, it's a matter of 3 minutes to fix that.

I echo yellowshark - the PLA doesn't need anything hotter than 60C.

In your place, I would re-calibrate the bed and clean it up dry. My favorite - some cheap display cleaner wiped with soft cloth until the glass is pristine clear and clean. Then, the PLA sticks to the glass.

 

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OK, saw it. Looks like the printhead is still a bit far from the glass, so the molten plastic doesn't make enough contact with the glass to stick on it.

Is it possible perhaps to make a good zoom on the printhead while it moves on and starts printing?

In any case, you may simply pull up the glass plate a bit towards the nozzle when it tries to print, and see what happens. If, all the sudden, the plastic starts to stick, then the theory is correct, and you will need to turn up the three leveling screws till the point the plastic sticks to the plate properly, without you having to pull it.

BTW, I clean the plate before every print, otherwise the PLA doesn't stick well indeed.

 

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Thanks Shurik, been working with Fbrc8 trying different heights and different things but nothing is working. Last night I tried to print with the brim and this is what it looked like:

3DE6F8AD-6CFD-4B01-AC00-482EEE357415_1.jpg

I've calibrated the machine many times before and the print came out great with the same gcodes I am using now. Just haven't been able to get any sort of success lately.

277A04D4-532F-41F0-8BE8-08106E275CE9.jpg

This morning feeling fresh out of bed I decided to give it another go. Cleaned surface, applied a light layer of glue, bed temperature at 60 and nozzle at 210. Did the paper calibration until I felt a little resistance as stated in manual.

Results: https://www.dropbox.com/s/hnlwds0w3nqeov9/Video%20Mar%2027%2C%2010%2021%2046%20AM.mov?dl=0

 

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Hi donnyfl,

It looks like the brim was printed OK, and the layers of the part were not. That's weird, indeed. Were the side fans operating already on the first layer?

What filament brand do you use?

Looking at the video, I still think that the glass can be slightly risen up by a tiny bit, carefully using the calibration screws. The paper sheet calibration is never perfect. I had the very same situation like on the latest video, and it was only the matter of the fine-tuning the calibration.

 

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I have to echo above, nozzle seems slightly too far off.

Also... what seems to me is that this first layer is printing pretty fast!! Check in Cura that the initial layer speed is more like 20mm/s rather than what looks like 60!

 

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After playing around with the machine yesterday morning I was able to finally get consecutive good prints! Paper method did not work for me, what did work was eyeballing the nozzle so that it touches the plate then backing off until I could see light through it then I stopped. I couldn't slide a standard paper underneath it but it still printed really nice.

So first and last layers should be printed around 20 mm/s? I'll make changes to my gcodes. Thanks you everyone for your input and feedback.

31606F3F-2966-4E17-BB86-49DFA8B4BE86.jpg

 

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In the video you posted it looked like the bed gap (i.e. first layer height) was way too off. I bought feeler gauges off ebay for £2, and they are a worthwhile investment, but learning to level the bed and getting that gap just right is critical.

Usually, once you have levelled the bed and fine-tuned the gap, you will not have to redo that for months.

A good trick to help doing this is to first loosen the screw at the back of the bed - there is only one in the middle. One full turn should do it.

Then print a 10cm hollow square with a brim that has around 20 - 30 lines. This will allow you to fine-tune the bed levelling by eye with something that is actually printing. You do the adjustments for all three screws while the priting is happening. This will help make things very accurate.

For larger print jobs, I have the bed tuned well enough to allow printing the first layer of PLA onto glue stick at around 35mm/s, 0.2mm layer height.

 

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