I just got my Mbot cube this weekend, and have been testing it with a few first prints. I’ve noticed that while printing objects (using PLA) that have hollow sections and the printer creates the hexagonal infill pattern, the plastic doesn’t have time to adhere to those sections on some passes. I’m leaning towards the possibility that it’s because the extruders are moving too fast over the pattern. The outer shell of most prints looks good for the most part, but internal structures are pretty sloppy. The outer shell seems to also print at a slower rate than the internal. Would slowing down the feed rate fix this? Or is it a temperature issue? Temp is usually 230c, but I’ve also tried 225c and 220c and had a similar result. I guess I just need some advice on which settings to tweak.
I think a really good example of this problem was with the iPhone 5 dock from Thingiverse. It has a channel through the bottom for a charging cable, and as it was printing the infill, the strings of plastic that didn’t adhere correctly basically blocked the channel. Adhesion of the base doesn’t seem to be a problem, and I’m getting fairly consistent extrusion (I think).
A small update to my original post. So, this evening I tried a different direction, increasing the temperature and speed. I noticed when looking at the defaults in the Mprint software, that adjusting to the higher quality level increased the speed up to 40mm, and the recommended temperature for accelerated extrusion was 230. So, I just started a print job using the high quality setting, and increased the temperature to 230. The results so far are significantly better. I really didn’t expect the faster speed to work at all. My adjustments before were to go slower, but now I’m wondering if the slower speed was causing the filament to get too warm on the build plate.
I’m going to try another build that has an infill pattern using these settings and see what kind of difference that makes. The part I’m printing now is a smaller part that’s pretty much solid, so there’s no infill pattern at all on this one. But, the edges are much more consistently straight now.
Also, I noticed on a previous print that the belt on the left side of the y-axis was a little loose. I have a feeling that may have been contributing to the problem as well. I’ve tightened up the belts, hopefully it’s having an effect. So, between the new print settings and adjusting the belts, I may have already solved the problem myself. Hopefully if anyone else runs into this problem, this post might be useful. However, any other tips anyone has related to this would be greatly appreciated.
1.when we print with PLA ,we often set the temperature around 220 ,if it’s hot in your country ,you can try 210 .when we print with ABS ,we set it around 230 .
2.if there is holes on the model ,if maybe caused by the speed ,but mostly you can set create the object infill here is a setting date you can reference
I tried adjusting the temperature by 5 degree increments and also found that 220 seems to be the magic number for PLA. I’ll try running a print at 50/80 as you showed in your message and see how that does. What I found was that on taller objects, I was getting a little bit of a tilt on the front edge of the object. I have a feeling that it’s due to the Y-axis bars not being lubricated enough, and the belt is causing the extruder to skip slightly. I’m going to try to fix that issue this evening and see how that does.
I think I may have found the problem with the tilt/alignment issue. I thought that the x and y shafts were needing some lubrication, and while taking care of that, I was manually moving the extruder around to check to make sure it was smooth. I found a spot towards the front of the build plate where it felt like the belts were slipping. After moving it around for a while, I adjusted the belts to tighten them up some more, and still felt the slipping. So, I found another issue - the Y-Axis motor itself was slipping. One of the screws on the gear that turns the belt was very loose, and the gear itself was slipping part way through the cycle. So, I tightened up the screws, and it’s moving much smoother now. I’m getting ready to try a print job now to see how that affected it. Fingers crossed!
Success!!! The slipping gear, tightening the belts, and using the suggested settings totally paid off. It printed the test part I was trying to build perfectly! Not a single flaw, nice even pattern, it’s incredible!
greetings n well wishes… in general… mbot or any other 3d printers… r generally experimental machines… reasons being that the software… firmware… n drivers r pretty very much developed by independent developers or company… althou i would like to emphasize that there are still some of these “experimental” machines faring way much better than others :-)… needless to mention MBOT being one of the top :-)…
i started to experiment with 3d printers only 2 years back… it was a very frustrating procedure… the lack of support… n also the quality of the kits… so my first 3d printers were useless machine… lacking even the most basic user manual…
as i experiment more with other printers… n getting more successful prints… i start to realize that it most cases… weather u get a good print or not it’s not about following the instructions from the manual… but experimenting n failing ur prints :-)… yes u need a lot of patience to do that… n in most cases… we just want to design a customized 3d product n start printing it… expecting to hold the final print in our hands few hours later…
take for example… u might hv successfully printed one item yesterday… n when u tried 2 print the same thing again… it might not look as define as the last… or it may simply failed to print after a few layers… it could be due to the filament that u r using… ur room temperature… n ur setting… at times… i leave the setting to the default setting n get very nice print… at time… i might hv to tweak the setting to as high as 240 degree on PLA… using at least 4 shells n increasing the infill so that it might be comparable to last print with default setting…
do not get discourage if ur prints failed… play with the setting… gradually with small value changes… compare ur prints… take note… u will enjoy the whole procedure more…be experimental… cheers n take care…
Like you I recently received my MBot Cube Single head and have been enjoying the world of 3D printing.
I found I had a similar issue as you, where with taller objects (as short at 3.5cm), I was getting a slant on the print. For example, I printed what is essentially a hollow cube, and it looks like it’s in italics!
I’ve checked belt tension - Good, checked the small bolts that prevent the gear from spinning on the shaft on the Y-axis - Good. I did as you said and moved the extruder around the build platform, but cant find any areas that are loose.
I have a feelings something is slipping but cant quite find what. Any suggestions?
Try locking the stepper motors (it’s an option on the menu) and then try manually moving the print head around yourself. If it moves at all, then the screws aren’t tight enough on the shafts. That’s what was happening to mine - there was significant slippage when the motors were locked.
Also, try adjusting the temperature and print speed settings a little. I tend to run my PLA prints a little hotter than the recommendations (235c). I get much better results from that. The recommended in the software is 210c, and when mine prints at that temperature, the layers barely adhere because the plastic cools too quickly. A lot of that is due to environment though.
Also, try to seal off airflow by covering your printer. That helped mine tremendously.
Thanks for your response.
I printed another Cube shaped object and there was no slant to it… Weird, maybe there was an error generating the G code. It did start making some noises as though one of the rods was loose when the extruder was near the middle of the build plate however this didn’t seem to affect the print at all. I will try your suggestion with locking the motors and jiggling.
