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Prints that were working now not

esrossiter
(@esrossiter)
Trusted Member

I don't get it.  gcode files that were printing fine now don't print at all.  it's like the stupid machine has lost it's freakin mind.  can't draw circles.  can't draw squares.   someone explain how this whole 3d printing gig is supposed to be fun, because it's really not. 

failed1
failed2

 

 

Quote
Topic starter Posted : 21/04/2021 8:50 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

It's sad to know that you are having problems. But don't get upset, I will help you to find the solution to your problem. Although 3D printing could give a headache sometimes, it is a pleasant activity.

 

In order to narrow down the possible causes, I would like to ask you some questions:

  • You mentioned in another post that you own an Ender 3, is that correct?
  • The problem started after some minor modification in your machine?
  • What material are you trying to print? Is it PLA?
  • If possible, would you share the .STL and .GCODE files? So I can take a look at them and compare with the commonly used settings. Which slicer are you using?
  • The pictures you showed are rafts or it is an actual part of the model?
  • How do you normally calibrate your bed? Are you using some adition helper for the bed?

 

If you can provide me with that information, I will be able to narrow down the options that are causing you so much trouble. If there is anything else you want to share, that will be great!

I look forward to your response…

Kind regards,

Pablo

ReplyQuote
Posted : 22/04/2021 12:05 am
esrossiter
(@esrossiter)
Trusted Member

Good morning, Pablo,

Yes, Ender 3 Pro.  No modifications to the machine.  Printing w/PLA.  Using Cura.  The photos show the first layer(s) after printing the raft.  One photo is supposed to be a square with two screw holes, that didn't even come close.  The other is the face plate to a raspi zero cam box.  Normal bed leveling and calibration is done using printing paper. 

 

Thanks for your time.

Eric

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Topic starter Posted : 22/04/2021 3:25 pm
esrossiter
(@esrossiter)
Trusted Member

Ok, so, it looks like tramming is going to be the bane of my existence in the 3D realm.  I re-sliced the .stl file I was trying to print (wall mount) and subsequent re-print failed miserably.  Ball of spaghetti, so I immediately looked at the bed leveling and it was way off.  Cleaned the bed, re-taped and then leveled and re-leveled, and current print looks really nice.  It's the first print I've attempted not using a raft, since I discovered prints will pop off the printers tape when using a bed temp of 45.  Prints would stick to the tape really badly using a bed temp of 60, so I did learn that.  Oh, I also started getting really brittle prints, they'd break easily, and you could see the individual layers not adhering to each other.  I went back through my notes and download sheets for the mods and it appears a lowering of the nozzle temp to 195 from 200 has fixed that, so I'm now 3 for 3 thanks to the information I'm learning in these courses. 

I'm still trying to figure out how my bed gets so out of whack.  The space I print in has fluctuating temps as it's not thermostatically environmentally controlled.  I wonder if the warm/cool/warm/cool cycle of midwest US spring temps is enough to do it, or whether the leveling springs really settle that much over the course of a weekend of non-use.

Current print underway:

IMG 2382

Thanks again, I really appreciate all the hard work done @ io3dp.

Eric

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Topic starter Posted : 22/04/2021 10:23 pm
Pablo
(@placherre)
Member Moderator

Hi Eric!

Thank you for the feedback! The files you sent are very helpful.

Now that I have the shape of the models you want to print, things are a little bit more clear. When I looked at the pictures yesterday, I had some doubts about having problems regarding the printer; especially when you haven’t made any changes. The print of the rafts have a great look but the first layer of the model is quite awful; it seems that the first layer of your model is not sticking correctly to the raft. The same issue happens when printing the first layer and the nozzle is too far from the bed: the melted material won’t stick on the bed; therefore, the nozzle will drag the deposited filament from its place, that is why the shape is not the expected.

Analysing the .GCODE file I see that you configured  a 0.24 mm layer high and the same distance between the last layer of the raft and the first layer of the model, which is a bit far from the ideal. The maximum distance in this case should be 0.2 mm in order to separate the model from the raft without damaging the model; but 0.1 mm works fine, it will take a little bit more of effort to separate both. Also, I noticed the whole print is done in 0.24 mm layer height. Assuming the diameter of your nozzle is 0.4 mm, you should be printing a layer height between 25-50 % the extrusion width; therefore, I recommend you to set up a layer height in 0.2 mm as maximum (an ideal too). In conclusion, when setting up the distance between the top layer of the raft and the model, change it to 0.2 mm (in Cura is the parameter Raft Air Gap, shown in the picture attached).

Cura Raft Air Gap

Raft Air Gap set up in Cura

According to the last explanation, I have the following question: why are you using rafts? If your build plate is in bad condition, it is all right. But I read in a previous post that you changed the magnetic flexible bed from the Ender 3 to glass. I have done the same, when the original build plate was seriously damaged after removing models. In your case, you should be able to print without a raft; unless you want to have a rough finish in the first layer (glass gives a smooth surface finish). In that case, it is all right then. Basically, rafts are used when you are using materials which tend to warp easily, like ABS. When using PLA, rafts only increase the time and amount of material at the end of the print. But again, if your goal is to have an impact in the first layer surface, it is OK.

I am sharing with you the .GCODE I personalised for the PiCam_Front_v14.stl file. Just to help comparing both configurations, I enabled the raft Build Plate Adhesion. Also, I am sharing a picture of the configuration (Raft Example 1 and Raft Example 2). Just to be aware, I have set up the Flow at 100% because I calibrated the extrusion last week. If you have a different flow percentage, the configuration varies from mine then. Therefore, I recommend you to copy the raft configuration in your slicer.

Raft Example 1
Raft Example 2

Cura configuration for Rafts.

Also, I kept the inner and outer wall speed at 15 mm/sec and the top/bottom layers speed at 20 mm/sec; this will give time to the filament to cool down properly. In addition, I enable the Optimise Wall Printing Order; by doing this, the nozzle doesn’t jump back and forth between the holes constantly.

Hope I was clear with the explanation and it will help you to solve your issue. If you have any further questions, do not hesitate to contact me.

Please, share some pictures and comments once you start printing again.

Kind regards,

Pablo

ReplyQuote
Posted : 23/04/2021 12:26 am
Pablo
(@placherre)
Member Moderator

Great Eric! I am glad that you worked it out and that you are succeeding with your printing. Also, I am happy to know that our information in the community is a helpful guide for you.

Sorry for my belated response. I hope the explanation in my previous post still will help you to improve your skills and add more details to your experience.

Regarding the bed temperature, be careful when setting up the temperature at 60°C when printing with PLA. The reason is due to the Glass Transition Temperature*.of PLA, which is close to 60°C. Therefore, you might experience some bed adhesion problems when setting up that value. I would recommend you to increase it up to 55°C as maximum. Just for the record, if you are using glass as your bed, the thermal loss is practically cero. On the contrary, if you are using the original magnetic bed of Creality, you might need to increase that temperature in about 3°C; due to the thermal loss between the bed heater and the model. I experienced that myself, since I have two Ender 3 Pro and I changed bed along time. The main difference between beds is the first layer surface: for glass is really smooth and the magnetic is rough; also, the magnetic bed is more reliable for adhesion without a helper.

About the springs, there shouldn't be a problem with the temperature variation. You will experience tensioning problems if those springs are compressed close to their maximum. There should be gaps between coils in order to work properly. If your springs are too tight, you should adjust the Z limit switch in order to give them space to adjust the bed level.

About the environment and changes of temperatures, you should be aware of current of air, which will affect the quality of your print. Especially, it might cause warping. In general, if your bed is leveled correctly, the bed temperature is correct and there isn’t air flow, your model should stay stuck to the bed at all times even without using an adhesion helper.

In conclusion, I recommend you to always check your bed level before you start printing; by doing this you will save time and filament.

*Note: GTT is a temperature where the material changes its molecular structure and becomes soft (but not melted). For that reason, the fan speed should be at 100% when printing (except for the first ayers). The deposited filament must cool down immediately from 195-200°C in order to avoid issues.

I hope this information was helpful too.

I am looking forward to hearing from you.

Kind regards,

Pablo

ReplyQuote
Posted : 23/04/2021 1:53 am
esrossiter
(@esrossiter)
Trusted Member

Hey Pablo,

Looks like I snuck an update in on you before your reply.  LOL.  I was able to get a couple of nice prints today, without rafts!  I did alter the settings in Cura per your recommendations.  I appreciate you taking the time to go through the .stl file settings.  I attached a pic and a vid in my earlier post.  Here's the finished product.

IMG 2385

It's a RasPi cam wall mount plate.  

Thanks again, for all you do.

Eric

 

ReplyQuote
Topic starter Posted : 23/04/2021 4:30 am
Pablo
(@placherre)
Member Moderator

Hi Eric!

You are welcome! I am happy that you made it, great job!

If you have more concerns or doubts, let us know.

Kind regards,

Pablo

ReplyQuote
Posted : 23/04/2021 6:03 pm
esrossiter
(@esrossiter)
Trusted Member

Hey Pablo,

Many thanks for your time, expertise and patient explanation.  I had to go research GTT... that'll make your head spin.  I read enough to grasp the concept so I understand what you were telling me.   I dropped my initial build plate temp to 55 and it seems to be doing well at that temp.  I appreciate any and all information you wish to share.

Kind regards, 

Eric

ReplyQuote
Topic starter Posted : 23/04/2021 10:04 pm
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