uma

Folks, I have an UM2 with which i am experimenting a lot. Lately i have noticed a trend which i would like to pose it to the community. My hypothesis is that: the same model sliced using identical settings the only difference being UltiGCode vs Marlin in Cura produces different results. I have noticed that UltiGCode prints do not have any under extrusion issues. Whereas the same model under same settings printed using marlin shows signs of under extrusion. Is there something behind this or its just a random observation. I am planning to do some tests and i will upload photos shortly. Sam

Folks, Here is another challenge. I tried printing a galaxy S3 case using UM2. See the results for the problem i am facing. The model seems to be a reasonable curve in CAD. Even in Cura when i switch on support material the curve doesnt seem to be supported. However, when i printed on UM2 the results were dismal. Has anyone printed such curvy objects? What is the thumb rule to print curvy objects along Z axis. My settings Layer Height: .2 Speed: 35 mm/s Material: PLA temperature: 225 Heated Bed: 70C Thanks

@3dmaker4u, thanks for your suggestions. I shall try it out and post back

Folks, I would like to know about what kind of tests people do to find the right temperature for different material. I am finding that different material (PLA) work well at different temperature. In fact, i found that temperature impacts the bridging quality as well. (I kept the same temperature when i went from blue to green only to find that my part was unusable, i attribute this to temperature because the same part printed well with blue). So, I want to know what kind of tests people do to identify the optimal temperature for a particular material. Any best practices that you follow, please share in this thread.

@gr5 The quality of prints seems improving but i am facing two problems 1) The strength of the case varies based on the type of material used. For instance, when i used blue material the strength is high the case doesn't crack that easily. But when i used fluorescent green material the strength of the case seems to be weak for the same thickness. In fact, the case crack right where the side of the case starts. Any pointers to improve the strength? increase temperature, increase layer thickness. I am currently using 220C @ .2 Layer thickness 2) The under extrusion problem is still the same. I tried using Cura also but the under extrusion is still the same.

Warping is gone Yay! Printed it at 70C bed temp with Kapton tape: Kept the speed constant throughout at 30 mm/s The one thing i notice is under extrusion at the curves. Could that be a design issue as in the edge is too thin to be created. I made sure they are at least .4mm in width. Another issue is the surface finish of the top layer (the surface that touches the cell phone). Because Slic3r tries to optimize movement it does the infill in a random order. As a result i see patches of infill on the top layer. The finish is not smooth. If this is normal i probably need to get a dremel to polish this off.

@gr5 wow i am pumped up after seeing all the information above. Thanks a lot. I will post the pictures with arrows and explanations this time. I am slicing this at 0.2mm. I hope thats ok.

@gr5 please find the attached images. The warp is two dimensional. From the side view you can see that the right most edges are caved in. In both front and back views, the edges are caved out. Adjusting for shrinkage is ok provided the design has a repeatable shrinkage pattern. I dont see that happening. The summary from the post above: for parts that have height print on a heated Kapton tape or use a glue with Kapton? One stone at a time. I am sure i can get a fitting case soon

@gr5, yes the designs are beautiful but the holes are not part of the design. I have problem with those tiny holes as well as the surface finish. It is really rough and i am sure no one would want to use that as a cell phone cover. I figured that alignment has to be right to print a perfect case. But levelling in UM2 is not straight forward. It uses a 3 point leveling system. Most of the time the front two corners are ok but the two corners at the back are slightly bent inward. With only one screw to adjust i really cannot get a even leveling. I somehow figured out a way to get rid of the holes using a combination of design changes and slicer adjustments. But the new problem now is warping. I see that the bottom two corners of iPhone case warp inwards. I am printing using PLA @ 220 on a Kapton tape with heated bed turned off. I will post the pictures of the warping. Because of the warp the fit is not right. Uma

I am just blown away by the video! Wow. I need some clarifications here. 1) Is the material change done in between the print? did you use a cura plugin to do such a thing. 2) How does the printer know to start from the right Z height. I assume its one single program which waits for the user to change material. 3) What i am impressed with is the uniformity with which the layers are laid. Is that a Kapton tape? I am struggling to get the alignment right over the size of what you are printing. Finally, are there any posts that you have done to discuss the settings used? the slicer used etc? I am truly blown away by this stuff.

@illuminarti: thanks for the feedback. i did try printing at perimeter =1. The gaps were still there. It looks like i am pretty much stuck with a .4 nozzle. @gr5 thats one hell of a print. two questions 1) Is that a dual extruder or did you change the material mid way 2) What is the nozzle size for the print? It would be sweet if you could share your print settings. thanks

Hello, I am trying to print a cool iphone cover design for my wife. But i am unable to print without any holes. i figured that its a matter of extrusion width after reading illuminarti's post about extrusion width in Slic3r. But my problem is still not gone. let me explain. I set the extrusion widths to .4 because thats the nozzle size. When i tried to slice the model at that settings there are lot of holes in the model (see Repetier host screenshot) infact i printed the model and it came exactly like that. Then i changed the extrusion width to .2 (half of the nozzle size) thinking that i will be able to print these small designs. The repetier screenshot shows very little holes which made me happy. Unfortunately, i faced major problems while printing. 1) The first layer had extreme difficulty to stick. After a heavy layer of gum I was ok. 2) It almost seemed like the flow rate was not enough as i could see the lines were not sharp. The design looked disastrously bad even though repetier showed a clean picture. I am wondering whether i will be able to print a smaller extrusion width using UM2? is it even physically possible? How else can i print this intricate design? Are there any other settings that can help. i tried different infills, angles and a lot more combination. Almost all of them failed during the preview in repetier itself. Will i be successful in printing this design if i change the nozzle to a .2 diameter. What are the pros and cons? I appreciate your help. I need to print this gift quite soon. holes No holes @.2 width

@gr5 I am printing on glass. Yes its a pain to get the first layer right but the surface finish is beautiful if it sticks!

@Dim3nsioneer thanks a lot. I checked my settings and the bead width is within the limits of nozzle diameter. but it was good read though. Thanks.

Folks, Here is the problem i am facing. I am trying to print this intricate cell phone cover design using UM2. I am using slic3r for this design. the top layer finish and the intricate designs are not finished properly. I can see small blobs wherever the head starts and retracts. Moreover, the surface finish of the infill is not smooth. I am afraid this piece can be used with my cell phone. Following are the important settings Layer height = first layer height = .3 Speed = 30-50 mm/s (50mm/s on internal perimeter, 30mm on solid infill, external perimeter and all other areas where surface finish is important) Temperature for PLA: tried it from 220 to 235 in steps of 5. No difference Used lift Z feature in Slic3r so that the design is not spoiled during travel or retraction. The retraction settings used: 4.5mm @ 35 and 40 mm/sec Let me know what can be done to improve the surface finish.

@Vinay No the LED doesnt flicker normally but when the machine accelerates it sometimes flickers

@Nicolinux, Octoprint works perfectly with UM2. The baud rate needs to be 250000. I did not expect the Raspi and octprint to be so responsive. The real time Gcode Viewer is not working though. Uma

Vinay, the problem you are facing is similar to mine. Did you try tightening the small hex screw in the knurled rotor? It looks like it is sticking proud and knurled object is also projecting more than it should. After I tightened the hex screw it started working. I figured that the gap between the nozzle and the heated bed is an important parameter. Mine was less than 1 mm which made the extruder make some ticking noise. What i infer ithat as we build parts the pressure in the nozzle builds up considerably. This cause considerable pressure in the feeder mechanism. I may be wrong but after aligning the heated bed I did not see the problem again. Thanks Uma

Can anyone post the setting for UM2 connection settings for OctoPrint?

It seems like the problem is solved with a new screw. I am yet to print a large model to see whether the problem repeats. Thanks for your inputs. I will update by EOD. Uma

Can we control the UM2 using Octoprint? I tried connecting OctoPrint to UM2 and after setting the serial and baud rate to Auto the status message was operational. But i couldnt move or heat the bed using OctoPrint. At this point i am not sure whether UM2 is supported or not? Will it be coming in the future?

@SandervG i have replaced the set screws but the tension in the drive mechanism is still low. I tried loosening the long screw as well. Dont know where the problem is. I need to resolve this asap. the machine has been down for almost a week. Thanks for your support Uma

@gr5 you absolutely makes sense. Thats what i thought as well. The white square is at the top and the white roller is close to the lowest tension. But what i suspect is the broken hex head in the tiny screw. The allen key slips right after two turns. Would you mind posting a picture of your extruder gearing mechanism. I just want to know how proud is the tiny screw? I guess there is no standard part number fo the screw. I hope the Ultimaker guys come to my rescue. Uma

gr5, By adding a lot more tension to the white roller i think i risk knurled part to get loose even quicker. Because, the tiny screw comes loose when the white roller is not at high tension. Does anybody know where i can get the tiny screw? Happy new year folks! Uma

Hi SandervG Here you go! I am attaching the pictures. As i suspect either the screw or black casing seems to be the issue. Please advice. Is the small screw a standard part number? Can i get it in local hardware store? I look forward to resolve this. Uma