Bottom side of a print is never uniform
I'm using PrusaSlicer, then uploading my files to OctoPrint, then having OctoPrint print out my results on my Prusa i3 MKS3+.
My issue is that, with a larger surface on the bottom of my prints, a large part can be smooth, but the bottom surface is not uniform. I'm working on something where it would be a lot easier if I could have a smooth bottom surface to use as the visible part of a faceplate. While this isn't what I'm trying to print, it's a good example of my issue:
I had a similar issue with a much larger piece I was trying to print and it was warping. I solved the warping with glue. That was discussed in this thread and here's a shot of the bottom of the piece that warped:
That piece took a LONG time to print, so before I adjusted the print speed to slow it up, I just used glue and that kept it from warping. It's now mounted where I can't easily remove it and inspect the back at this point.
I've seen this issue on a number of prints: The back side, or bottom, of the print isn't a nice smooth surface.
I got good advice in the thread I linked to, but this is slightly different, so I wanted to address it in a different topic. I'm not having the warp issue with my smaller pieces, but I am getting that uneven surface. Aside from using glue or another adhesive to help the filament stick to the print bed, what other things should I do to address the issue of an uneven bottom layer? Or is that and the warping all part of the same issue?
As it is now, I'm restricted in what I can do with the design of my faceplate because I can't make the front of the faceplate the bottom of what I print without it looking bad when it's mounted.
RE: Bottom side of a print is never uniform
I only skimmed the past threads, but if nothing actually worked I guess that leaves only a few more options:
Your bed might also be badly warped so you should do the silicone or nyloc mod to tram things out.
Since it's the smooth plate you could try a quick acetone wipe since all other cleaning strats didn't work.
Maybe your bed temp is too hot for PLA.
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RE: Bottom side of a print is never uniform
When I first got my printer, I found the same issue. Had issues trying to do the first layer calibration as the measurements were all over the place. Just did the silicone mod to my printer. I also found that the distortion of the build plate changed with the temperature of the plate. I used OctoPrint and the Bed Visualizer plugin. The errors before were about 0.5mm. Now less than 0.1mm in the center. My procedure it to preheat for at least 15 minutes before printing.
Your larger parts are warping and adhesion is not strong enough to hold them down.
To reduce warping, ensure you are not printing in a draft, or in a cold room, try increasing bed temperature by 5°.
To improve adhesion check your first layer offset caibration; it looks like you could go a fraction lower. Make certain the print sheet is scrupulously clean, and add a brim.
If this is not enough and if the design is yours, try making the bottom a little thinner and break up any long stringers that run the length of the part higher up where they otherwise exert huge forces as the part contracts in cooling.
Cheerio,
RE: Bottom side of a print is never uniform
It took me a while to get back to this thread because I wanted to try multiple different things to see what worked. I have yet to do the silicone mod, but I will be doing that. (I was hoping I'd get to that before I replied, but it's going to be a good while...) I have used adhesive and that was a major help. It's not a 100% and perfect solution, but it's pretty good.
To reduce warping, ensure you are not printing in a draft, or in a cold room, try increasing bed temperature by 5°.
No drafts, but I can't increase the temp since I'm often printing unattended with long prints where I just can't sit there and wait (and have a space heater on) and I'd have to increase the temp for the entire 2nd floor of the barn, so that one is out, but I may try some experiments with a space heater for the first few layers and see if that helps.
If this is not enough and if the design is yours, try making the bottom a little thinner and break up any long stringers that run the length of the part higher up where they otherwise exert huge forces as the part contracts in cooling.
Interesting ideas - ones I can do since you suggested them, but ones I don't have the experience to have thought of at this point.
RE: Bottom side of a print is never uniform
No drafts, but I can't increase the temp since I'm often printing unattended with long prints where I just can't sit there and wait (and have a space heater on) and I'd have to increase the temp for the entire 2nd floor of the barn, so that one is out, but I may try some experiments with a space heater for the first few layers and see if that helps.
Without knowing how cold your barn is, it is hard to give suggestions. If it is cold enough, what you many not perceive as a draft, may be more than enough to cause problems with printing. The bed moving back and forth will cause a draft that you may not notice. Where I used to work, we had a 3D printer in one area. The temperature would fluctuate but no real draft. All kinds of issues with printing long prints. Finally, I convinced the people running the printer to put it in a cardboard box as a test. It worked and when I left, years later, the box was still over that printer. All the new printers were ordered with enclosures.
You may need to try the cardboard box idea for winter. I ordered an enclosure for my printer when I ordered the printer, partly due to my experience at work and to help control dust in my workshop. There are times when I have to clean my rods once a week due to dust so I am looking at how to seal the enclosure and filter all air going into it.
I have yet to do the silicone mod, but I will be doing that. (I was hoping I'd get to that before I replied, but it's going to be a good while...)
I think I took two days to do the silicone mod fully. I was also doing some other tests as well. I would have to look at my log book for details.
I didn't add any nuts to my mod. I put some Loctite 242 (off brand version) into the thread for the screws and just used some silicone tube. What delayed me was trying to get everything to zero. Won't happen since the head never goes to zero due to the head offset. Also I found, that the bed heating changed the settings.
I drew up and printed an angle gauge out of ASA so I didn't have to cool the bed down when I wanted to adjust the screws. I had printed out of PETG and that started to melt when adjusting since the bed temperature was close to the glass temperature of the PETG. I also created a spread sheet to arrange the numbers and make the degree calculations easier.
If I had to do it again, think I could be done in a few hours with what I know now.
No drafts, but I can't increase the temp since I'm often printing unattended with long prints where I just can't sit there and wait (and have a space heater on) and I'd have to increase the temp for the entire 2nd floor of the barn, so that one is out, but I may try some experiments with a space heater for the first few layers and see if that helps.
The operating range is 18°C - 38°C: are temperatures overnight dropping below this? If you are printing in a barn drafts are very likely... Try the cardboard box trick suggested by @robin_13, start the print and lower the box over the whole lot. There is no need to sit and wait; raise the temperature, and perhaps the bed temperature, in the slicer.
Cheerio,
RE: Bottom side of a print is never uniform
Am I the only one thinking putting a cardboard box over the top of a 3D printer in a barn might not be a good idea?? What are you storing in this barn?
Would it still work if you cut the top and bottom off and just used the 4 sides of the box?
RE: Bottom side of a print is never uniform
I understand the concern about the cardboard box over a printer and my print head went into thermal runaway earlier this year and melted. I was in attendance when it happened but the temperature on the display said everything was normal. it was hot enough to damage my SuperPinda.
I have done tests on starting fire to cardboard, and you need high temperatures to do that. Higher than your print head should be running. If your print head gets to a point of heating up the cardboard and starting it on fire, you will have the same issues without the cardboard. My printer enclosure gets to upper 30s when printing with PETG and ASA but not higher.
If not feeling safe with cardboard, make a box out of wood with a door. Many people run their printers in Ikea cabinets and don't think about it. Or a piece of sheet metal for the top. Many people use cardboard boxes for their 3D printers.
As I said, where I worked, the printer has been under a cardboard box for years and has done overnight prints with no one around. There box was built so it could be opened up to access the printer. I wish I had pictures. The 3D printer is an AirWolf.
Eds_3D_Odyssey brings up a good question about just four sides but as we learned in school, heat rises. The idea is to stabilize the heat in the area of the printer.
Now I want to test the idea of opening up the top of my printer and see the heat circulation. An interesting experiment. Now to get my thermal camera. 🙂
RE: Bottom side of a print is never uniform
@Robin_13 I agree that a cardboard box is probably safe as long as nothing bad happens to the printer. But if something bad does happen you just gave that small fire a large paper box to burn in a barn.
Have you run the experiment yet? The 4 walls should stop external drafts but will the heat rising create an internal draft? If it does how low will the draft go? This should work like using skirts.
Another thought what happens if you raise the box off the ground a few mm so the cold air comes in from the bottom?
RE: Bottom side of a print is never uniform
I am 100% in agreement on the fire risk since I have had a head melt due to a bad thermistor. New thermal model is supposed to prevent that but I am not sure about that since it depends on the thermistor that may be faulty. I am looking at some of the OctoPrint stuff to read thermistors and put a thermistor in the enclosure to measure ambient temperature. Also looking at having one right by the print head to do a second temperature around the head. If out of limits, shut the power down.
If I cannot get OctoPrint to do that, then I will build an Arduino controller to do that. I have read about some automatic kitchen fire extinguishers that people have used for their 3D printers. They can be ordered on Amazon. There is a fire suppression add-on for the Prusa enclosure that you can purchase for added safety. I may get one with my next Prusa order. That may be the best option.
Cooling near the bed is a bad idea. Using the OctoPrint bed levelling plug-in, I found out that heating the bed does change its shape. If I was going to put vent holes in, I would have them closer to the top than the bottom. Above the majority of the print height.
I have not purchased the IR camera yet. I don't have access to one through work anymore. Still trying to figure out what I want and what I need in one.
One of the first things I did when I got OctoPrint working was add a camera. I found out I have to add lights for the camera to work at night as I have a good habit of turning the lights off in the shop.
RE: Bottom side of a print is never uniform
Not a lot of point in building a Arduino controller, you can get a prebuilt one for £16: https://www.amazon.co.uk/dp/B0CBN18H5S/ref=sr_1_5?th=1
If I cannot get OctoPrint to do that, then I will build an Arduino controller to do that.
RE: Bottom side of a print is never uniform
Ah, yes, a 220V controller for 120V power. My plug won't even fit and I don't have access to UK plugs anymore. 🙂 I had looked at a North American version of those but they don't give me the tools I want. it is a good suggestion though.
No, part of the reason is I want more than one temperature point and I want to use a thermistor on my print head as the main sensor but a cabinet sensor as well. I then want to tie it all into the building alarm system. I have a stack of Arduinos. I do have an Arduino network hat that I could use. Project may change to a Pi for the networking features. Some of this is related to a future project and to learn more about interfacing and using single board computers for control.
I am also trying a pyrometer temperature sensor. These are a non-contact sensor like the ones used in point and shoot thermometers.
RE: Bottom side of a print is never uniform
What you want, what you need, what you can afford and the most important how much can you spend without getting yelled at by the wife. ;-))
Your experiment about heat circulation inside an enclosure would make a good YouTube video!!
RE: Bottom side of a print is never uniform
What you want, what you need, what you can afford and the most important how much can you spend without getting yelled at by the wife. ;-))
Yes, the decisions. Not top end, not bottom end, not phone attached, though, a phone attached one would be nice at times. I am retired but working on a contract for some work which will pay for it and other toys.
Your experiment about heat circulation inside an enclosure would make a good YouTube video!!
Hum, something to think about. It is a good point as some cameras have slow refresh rates which wouldn't work for that type of video. Could be different tests. I have seen a YouTube video on how even the print bed temperature is which started me on the path of preheating the printer for about 15 minutes before doing any major prints. I will add it to my different projects for the next few months.
RE: Bottom side of a print is never uniform
This is a good idea for Tango.
Not a lot of point in building a Arduino controller, you can get a prebuilt one for £16: https://www.amazon.co.uk/dp/B0CBN18H5S/ref=sr_1_5?th=1
If I cannot get OctoPrint to do that, then I will build an Arduino controller to do that.
RE: Bottom side of a print is never uniform
Wow - a lot of discussion, and stuff going in some interesting directions. Let me handle the stuff that applies directly to what I've said first.
Without knowing how cold your barn is, it is hard to give suggestions. If it is cold enough, what you many not perceive as a draft, may be more than enough to cause problems with printing.
We call it "The Barn" because it was a pig barn up through the 1970s or '80s. (One neighbor's Dad used to own this place and he loves to point out how much pig excrement he shoveled in that place back in the day! Only he doesn't use the word "excrement.") It's been seriously renovated now, with a 2nd floor added to it. It's fully heated and cooled, with a mini guest apartment and rec room on the 1st floor and my workshop, storage, and my wife's art studio on the 2nd floor. So we're not talking about a rickety structure. The thermostat has a bit of a range, especially depending on the season, but the temps are between 68°-71° (or about 20°-22°C).
The bed moving back and forth will cause a draft that you may not notice. Where I used to work, we had a 3D printer in one area. The temperature would fluctuate but no real draft. All kinds of issues with printing long prints. Finally, I convinced the people running the printer to put it in a cardboard box as a test.
Good point. And I see others talking about the issue of the cardboard box. The big issue there is that, as of now, I do most of my work at the computer in my study, in the house, a 500' walk from the barn. Eventually things will change, but for now, I wouldn't use a cardboard box for a longer print because I won't be in the room. True, I can monitor it with a webcam, but it'd take me time to get down there in an emergency. Part of what my plan is to make an enclosure for my printers. (I'm working on a stackable design where I can have 2 printers per level and all share power connections and venting.) But this project is part of that vent system, so I kind of need to get a few printable copies of it before I can make the enclosures and have them working. (And, regarding the venting, that will be controllable through home automation, so I can basically turn the vent on when a print is finished, ridding the enclosure of the smell some filaments can make.)
I think I took two days to do the silicone mod fully. I was also doing some other tests as well.
Good to know it can take a bit of time. That's my issue: Can't do it until I know I can start and finish it at a time when I don't need to get prints out. I'll probably do it when I'm working on the enclosures for the printers and my CNC system.
If you are printing in a barn drafts are very likely...
See comments above about that. It was a pig barn, but has been fully renovated and even has a floor added to it.
Many people run their printers in Ikea cabinets and don't think about it.
I have an idea in my head, haven't started sketching or doing measurements yet, of an enclosure I want to make using square aluminum tubing and heavy duty plastic attached to the frame (and easily replaceable). The doors would be plexiglass. But if there are Ikea cabinets that people seem to like for this, I'm open to hearing what kinds people have found useful!
RE: Bottom side of a print is never uniform
We call it "The Barn" because it was a pig barn up through the 1970s or '80s.
Been around them. Understand.
The thermostat has a bit of a range, especially depending on the season, but the temps are between 68°-71° (or about 20°-22°C).
My workshop temperature is below that but I have an enclosure. So it is a pretty stable temperature. Not what we would thing for a "barn." Since you are in a stable room, if you are worried about drafts from a forced air system, then cardboard side panels would help. No cover is needed. A forced air system can cause drafts. This is what caused our issues at work.
I have an idea in my head, haven't started sketching or doing measurements yet, of an enclosure I want to make using square aluminum tubing and heavy duty plastic attached to the frame (and easily replaceable).
Plastic is more flammable than cardboard from my experience.
Sounds like you have a plan on what to go forward with. One thing I read about is kitchen fire extinguishers that mount on a wall and will go off if they get to hot. I was looking at them when I got my printer. I may purchase a enclosure designed fire suppression system.
My printer is in a workshop where dust is an issue. Where I live, dust is a major issue most of the time it isn't raining or snow on the ground. I also do wood work and stuff in this shop.
For ventilation, I put in an Air to Air heat exchanger. It helps cut on the heating bills. I have a direct connection to the enclosure to the system so fumes, when it is venting are directed outside. A hepa and activated carbon filter will do wonders as well.