Zide
1
Hey guys.
I’ve been lately trying to do a test print of the marvin model on my Printrbot Simple metal (newest version).
I’m using Cura as a slicer, printing with 100 microns layer height, a fill density of 25%, print speed of 50 mm/s and a printing temperature of 205 °C.
My material is regular black PLA. I’ve always had problems where my print wouldn’t stick well enough to the print bed, and the last layers would be scratched up by the nozzle. Therefor I turned the flow rate down to 90%.
My Marvin here turned out good, but it looks like it started to warp on one side of the print after it had finished the feet. Overall the edges of a layer sometimes peel up a bit, making the following layers look horrible.
I know that the first layer is really important and has to stick well, but no matter what I did, some edges always seem to warp up and create these scratches/marks at the sides. I guess it has something to do with warping, but the material is PLA, and there is no real fix for that. Though I have an assumption that my fan shroud is not cooling the layer correctly.
The left side looks normal.
The right side on the other hand has a roughed up surface.
These problems have been bothering me alot and I just want to make clear and good looking prints. Maybe some of you have a similar problem or maybe even have a solution for it?
Thanks!
I don’t know your printer, but I have this problem because my printer have a cooler in only one side.
If that’s the case, try rotating Marving 90 degrees so his face faces the cooler, to get better details on the face and cool both “ears”. But you may still have a not so good print on his back. So think about improving your cooling. There are some free models out there.
Cheers.
1 Like
Indeed, Seems like a cooling fan issue. Try rotating the marvin 45 Degrees - it might not solve all the problems , but just confirm this theory.
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Zide
4
Thanks, this really didn’t come into my mind! So rotating Marvin seems like a good solution in this case, but it may not always work for every model.
I noticed that my fan shroud has almost no air output at all, the fan has problems with my current shroud as it seems. Im currently printing a new shroud, so hopefully I can get better (and maybe more even) cooling. I dont know how much wind should be coming out of the shroud, but testing will show.
Just done my first test print, Marvin, and I too had melting issues. Never printed small objects so never came into “melting” problems on my models. In my case the PLA was not cooling quick enough, as my stock fan shroud pointed at the model from the back. The back was perfect, but the front (Marvin’s face) started to melt and deform upwards on each layer.
A quick Google got me on the track of not being cooled (plus with it happening away from the cooling fan) so I changed my layer timing to at least 15 seconds per layer. Then the print took longer to do each layer, allowing the PLA to cool at the front more, and thus the next layer didn’t compound the issue.
My first print finally turned out great (see it in my hub) for my printer and I learned a lot about timings between layers, cooling PLA quickly, working with small model files. And I have subsequently printed a new fan shroud which wraps the print nozzle with air flow directed 360 degrees at the print. Am going to print another Marvin with my original settings which caused him to melt and warp up with the new fan just to prove in my head how little differences affect the final outcome.
I am learning quickly with 3d printing that small and subtle tweaks to tiny parameters and variables can have huge results to your final printed outcome!
Best of luck!
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Hey,
No - the opposite! You need the cooling!! 
Getting a better fan shroud and increasing the minimum layer time will help cool the plastic in time before the next layer is applied to it. If you don’t cool it quick enough the next layer will melt it slightly - causing it to deform and bulge and clump/melt together. That’s what looks like is happening to the front of your Marvin. In Cura - In Advance tab under Cool - change your Minimum layer time from 5 to 15. Quick cooling for PLA will also help retain the finer details too and help in overhangs and bridges - giving you an overall sharper result all round.
From what I recall with the Simple Metal, the fan is pointing in from the left and blowing left to right (as you look at the printer). I am guessing your Marvin is printed so his face is looking at you. If you see the melt pattern, it’s on the side furthest away from the flow of air.
I have a Printrbot Simple 1405 so the fan blows in from the back. Same issues though, the front of my Marvin would not cool in time and looked all melted and deformed. I have printed a 360 blower for the 1405 and so far it seems to work well. The stock shroud for the 1405 created a lot of blow back too which this one doesn’t seem to… we will see!
http://www.thingiverse.com/thing:356001 This one is for the Metal and seems to get a lot of praise… Try printing that out. If you don’t have a fan at the moment, try 190°C, 30mm/s speed and a minimum layer time of 20 seconds to help the PLA cool without a parts fan? I’d probably wait for your new fan though!! 
Zide
8
The recommended temperature for my PLA actually is 190°C!
I have found a replacement fan blade part, looks like my fan is running again, but a bit slower.
Ill try giving the layers more cooling time, and when my new fan comes I’ll try out the 360° cooler to cool my project more evenly.
Ill try printing Marvin without cooling very slow today again, so let’s see if that helps!
Zide
9
I just wanted to mention something really quick.
I now printed a fan shroud (https://www.thingiverse.com/thing:878681) which cools the print from all sides instead of only one. It’s not exactly the same as shown in the link, but it overall works. It looks like the warping got reduced a lot, but it is still there. Obviously my 3d printed replacement fan is not as strong as the original one, and I am still waiting for my replacement fan to arrive, but I think that things should get a whole lot better once I get a new fan!
The only thing that I currently don’t like is the bulky design of the fan shroud. It’s almost completely flat with the nozzle and it makes it impossible to see whats going on under there…
I’ll report back once I got a new fan and eventually found a slimmer/higher fan shroud.
Agree with you on the inability to “see what’s happening”. Not too keen on my version which cover all the print nozzle. It works a lot better than the basic shroud, but I can’t watch it, so it feels a little “out of control” I may try one with multiple nozzles on the shroud rather than a full 360 “loop” to keep my mind at rest?!!
Zide
11
I see. Well I still dont know if the new replacement fan will help with my problem. The new shroud seems like it helps, but its really big. I’m looking for one that eventually sits a little bit higher, but it looks like there are no higher versions of it.
Have you decided on a two-nozzle cooling system yet? I dont seem to find such a cooling shroud anywhere…
While im waiting for my new fan, it looks like new problems occured. My first layer now seems to be sticking poorly for some reason. I applied new tape, cleaned it with alcohol, even sanding it. The brim and other parts of the first layer curl op on the sides, and it gets worse the more it prints of the brim. I tried loweing the nozzle even more, but I dont know whats going on with my first layer now.
The brim started off weird, and the first layer didn’t stick well, the rest looks normal though. (I’m currently printing another version of the 360 cooling shroud, this time with cooling enabled.)
Hiya,
I have a Simple 1405 so it’s not got the same layout or mounting as the Simple Metal. The version I am thinking of printing is Printrbot fan shroud 1405 by thehair - Thingiverse This is the next version of the one I have already printed as the author upgraded it as he didn’t like his original version.
That brim is weird, not sure what’s going on there?! looks like a weird cooling/warping issue??
Zide
13
Lowering the nozzle didn’t help with the brim. I’ll try sanding the tape, maybe printing brims becomes easier.
The design looks interesting, once I get my replacement fan I will see if that fixes the problem first, and if not I’m going to test different fan shrouds.
EDIT: I’ve found another one. It still has more or less the same design, but at least the nozzle itself becomes visible now. Going to print and try that one out (http://www.thingiverse.com/thing:725248)
Zide
14
Hey everyone again.
I just got my new fan, it looks like it doesnt help with the PLA curling up…
I’m still experimenting with different settings, and I’ll try to print very, VERY slow, as well with less extrusion again, hope that will do.
If this is not going to help, im going to try something new out. I’ve been thinking about using a 12v radial fan together with an adapter (like here http://www.thingiverse.com/thing:1146509) to finally get strong and reliable cooling. These fans are somewhere to 5€, so it wouldn’t be bad to try one out. Unfortunately these come from China, so it’ll take a while.
Im going to do a status update once I tested printing slower and with less extrusion. Take a look at the pictures tho, I still get the same problems. Seems like they always occur at the spot farthest away of the fan. I guess the 360 degree cooling shroud doesn’t help much when the fan is too weak.
It looks like you might be printing way too hot or might have a extrusion issue. Might be the first. After you get your fan fix, try lowering the temps in intervals. After I printed the Marvin my first time I realized that 200C was too hot of a layer temp for such a small design. I am using simplify3d and after a few print setting changes I have my first layer still set to 200C but after the first layer I am printing at 184C. My PLA prints are looking 10x better after that small change.
Zide
16
I’m currently printing as low as I can, with 185C. My fan should arrive soon, I’m not sure if it will solve the problems…
Zide
17
It looks like extrusion problems could be the reason for this very well. Cura has settings for the flowrate of the extruder, but I should also calibrate my steps/mm. I’ll see if this helps!
If it ends up the fan doesn’t help it could be a extrusion issue. Try printing at a slower speed such as 20 mm/s to start. If the print still looks terrible drop it down to 15 mm/s. If you can get the print to look good at a slower print speed then you can try increasing the flow rate of the extruded filament as you start bumping up the speed again.
I’ve had similar issues in the past with Cura and my printrbot where parts of the print looked like crap. In the end I discovered that my printrbot was always extruding more plastic than the Cura software expected. Ended up switching to Simplify3d to get the controls I needed to fix this. Not sure if Cura has any additional controls for modifying extrusion in newer versions of the software.
Just a side thought, see if Cura has a outline parameter speed you could adjust. If you could reduce the print speed for the outer walls off the print that could help with both the cooling and extrusion issue. That way you could still print the inside fill at 50 mm/s but when it is printing the outer shell parameters it could print something like 30 mm/s so it would have time to lay down the correct extrusion and still have time to cool properly.
I Had a similar Problem with my Gmax 1.5+ XT. For me the Problem was slic3r was putting too much filament though the nozzle. so I Dropped my flow rate from 1.0 or 100% to .8 or 80% and it has made all the difference (and saved me some filament). It could also be you’re printing your PLA too hot and it can’t cool fast enough (good choice to upgrade the fan), and because of that; the PLA can’t hold it’s shape correctly.
So try Printing at %80 flow rate and dial back the temp and see if that helps.
