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nighthowlers

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Posts posted by nighthowlers

  1. Hi Fellow Ultimaker Hackers!

     

    I made a large number of mods to my UM2 almost as soon as I purchased it. The parts pictured below have seen <20 hours of printing time and are essentially new. Asking $100 + actual shipping for everything! (FYI just the hot end pack runs for $85). These are all original OEM parts. I am also listing this on Ebay so if interested, we can deal through Ebay so that you have peace of mind in buying.

     

     

     

     

     

     

    20201122_165146.jpg

    20201122_165154.jpg

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    20201122_165203.jpg

  2. 23 minutes ago, JTDesign said:

    Very soon I will be listing my Ultimaker S5 for sale. Gently used. I bought just over a year ago, so it’s just out of hardware warranty.

     

    Question, is it customary when selling a used printer to accept returns when no longer under hardware warranty? 

     

    No I have almost never seen private sellers accept returns, however in case something is not right or was not described appropriately, honest buyer/parties work out a solution. If you sell via PayPal, I as a buyer would only purchase via PayPal Goods and Services. That means, you should take good pictures and list the details as accurately as possible. On receiving, if I as a buyer find discrepancies, I can open a dispute with Paypal and the resolution would likely result in the buyer sending the printer back and getting their money.

     

    As a seller, you can protect against fraudulent Paypal disputes by taking lots of pictures and describing the printer in detail.

  3. 25 minutes ago, geert_2 said:

     

    Thanks for your answer.

     

    I was not thinking of the voltage drop in the measuring wires (you are right, that will not be a problem indeed), but if the drop would be in the controller board, or already before that in the power supply? Then you could find out if it is the supply that is at fault (eg. too weak), or just the thin copper traces in the board itself? If it were too thin copper traces, maybe they could have been bridged by soldering a thick wire over it. That was why I asked.

     

    I am still an old-school guy with the desire to make all wiring armoured, and able to survive a lightning strike, or an airplane crash, without too much damage. So I find these modern thin and fragile copper traces on printed circuit boards kind of scary.   🙂

     

     

    Aah!Sorry I misinterpreted your question.

     

    Very good question indeed. One hypothesis I had was the PSU could be 'faulty'. If you look at the derating due to temperature for the powersupply, it could underperform (and result in voltage sag) in warmer climates. Temperature wasn't an issue for my PSU.

     

    So it could be 1) I genuinely had a faulty/non-optimal power supply or 2) 220W is just isn't enough.

     

    I suspected the latter (could be wrong) because at its peak the printer consumes about 220-230W (190 peak heating, 35W peak extruder, 20-50W transients from motor).

     

    As far as the board traces, I do not think. It is really well made. It looks like 4Oz copper with pretty wide traces that power the heater and other power hungry aspects. Plus, when I looked at it with a thermal camera, it did not show any 'hot spots'.

     

  4. On 5/19/2020 at 5:04 AM, geert_2 said:

     

    A question: where exactly did you measure this voltage drop? Was that directly on the connectors coming from the supply? Or further down in the circuit board? In the latter case, too thin wires on the board, or too excessive resistance in for example fuses or protection circuits on the board (if any?) could also contribute to the voltage drop. While in the first case, obviously, it is the power supply and/or its wiring itself that is causing the trouble.

     

    @geert_2: I measured it at the 24V connector:

    image.png.66a694fa4780ea6cd3ebab77be47c5ca.png

     

    You are right about voltage drop over significant distances or over thin traces. With a high-impedance measurement (a voltmeter or oscilloscope) that is not an issue. The voltage drop over thin traces or long distances (aka high resistance) is V_drop = I*R. When making a high impendance measurement the I is very small and such drops are negligible (not zero).

     

    Second, it is irrelevant. Let's say I measure 23.5V instead of actual 24V. Goal of my measurement is not to measure exact voltage, but to measure the change in voltage. The step change in voltage was exactly lined up in my scope experiments to the exact timing of bed heater. That is all I needed to know. In a well designed circuit (or one resilient to the drop), respectively, there should be no drop or the performance should not be affected.

     

    Could the minute drop in voltage affect my exact measurement of the delta change in voltage drop? Yes. But again, for the purposes of the issue at hand it does not matter. The drop due to heater is ~400mV and with a 1M-Ohm probe at 24 V we are talking about a measurement drop of 0.000024‬V. 

     

    Quote

    Since it seems that the bed-heater draws too much current, do you think people could solve this by keeping all current circuitry and sensors intact, but just connecting the bed-heater wiring to a relay (mechanical or solid-state), and add a separate power supply for the bed connected to that relay? So that the main current now goes via the relay and separate supply, but the rest of the controls are intact? Maybe this could be a solution for people who are less skilled in electronics than you are?

     

    I did keep ALL the current circuitry intact. All I did was disconnect the heater wires and connected them to my "external heater controller".

     

    A mechanical relay is a pretty bad idea due to how often it will be turned on/off. This would also preclude anyone from using PWM control. It will wear out quickly. A Solid State relay is better.

     

    I highly recommend a ultra-low Rds MOSFET as the right mechanism. No heating of the MOSFTET, no heat sink needed and that's how its actually done on even the Ultimaker board.

     

    One alternative for non-EE folks would be to use a product like these: Amazon Link. I am not a big fan of these. You will see how all the MOSFETs have a big heat sink. This is because these are cheap MOSFETS with high Rds and dissipate heat. I could not find something else.

     

    I will look for an alternative and post here. If folks could afford it, Pololu G2 (or anything that series of devices) is ideal. They are robust, engineered to perform, and top of all, SAFE!

  5. 9 hours ago, dadoblu_2000 said:

    thanks for your offer of construction of the component but I write from overseas I am in Italy, I find it difficult to change the firmware, where can I find the file?

     

    The source files for the firmware are here:

     

    Ultimaker2 source is here:

    https://github.com/Ultimaker/Ultimaker2Marlin

    Ultimaker2 plus is here:

    https://github.com/Ultimaker/UM2.1-Firmware

     

    You just need to download Arduino IDE, open the Marlin.ino file, and compile. To upload, connect printer to PC, select the right COM port, select Mega2560 as the board, and hit upload.

  6. 10 minutes ago, dadoblu_2000 said:

    a really nice job, considering the dual extruder DXU upgrade that I want to deal with if you want to replicate your project in my printer can you tell me if the components can be found on the market and / or if they must be assembled by yourself?

     

    Only one component is something I built/soldered. I am happy to make one for you at cost (I ended up with parts for several because of minimum PCB/Digikey/Mouser orders). That component is the PSU breakout board. If you don't mind a bit of a hack, you could literally cut the connector off a new power supply and just wire it to the rest -- you don't need it. I wanted the connector to look like factory installed at the back so I went the route of making a PCB.

     

    The Pololu G2 is something you can buy on Amazon (LINK to exact item I got). Again, this is a bit pricey but I over-engineered. You can get the lower current ones or a different MOSFET/controller. You will note that the G2 is actually a poor choice since it is a H-bridge motor controller which means you are paying for 4 MOSFETS! This is pretty stupid, and I bought it because I know Pololu engineers stuff really well for *high* current and did not mind paying extra to save myself time in looking for an alternative.

     

    The cut-off TE relay is also from Amazon - here. Again, same reasoning, I wanted to keep everything safe so opted for a very high quality relay.

     

    Rest was simple firmware tweaks and a 3D printer mounting plate.

     

  7. 6 hours ago, ReallyBadDancer said:

    Thanks @IRobertI, here is a picture of the same print from before the layer offset issue on the left (you can see the beginnings of it manifesting) and then on the right, after with z-ribbing.

    image.thumb.png.d7750d1b42cc571c04be60957879c0cc.png

     

    The poor overhang quality on both prints seemed to be due to bed adhesion problems that I managed to solve from reading some forum posts here, and some temperature tuning. The Ultimaker is such an easy to use printer that I really didn't need to read much online before now.

     

    This is super interesting. The image on the right looks very close to the issue I just resolved, however I would not suggest that is the cause because you had the printer working fine before you identified mechanical issues. My cause for prints like that was electrical and it would not just solve itself. It had to be there all along -- unless, power supply is degrading or is now being operated in much warmer ambient temperatures (causing wattage derating). 

     

    Just for the heck of science.. can you reprint the same but with NO bed heat? Use Blue Tape to have the part stick.

     

     

  8. To bring closure to this thread, I have solved this issue for at least my printer. I tried several different software fixes such as PWM vs. Bang-Bang control of heat bed etc, and none were helpful for me. The issue as @Torgeir has pointed out is that there is a significant voltage drop.

     

    In the (poor) screenshot of the oscilloscope you can see the drop in the 24V line when the heat bed turns ON/OFF. The drop is around 400mV. 

     

    voltage_drop.thumb.jpg.4919ce0cd14478d22e8aeced60fcfbe7.jpg

     

    With more time (and will) I wanted to figure out what subsystems are susceptible to this voltage drop (is it the ADC for temp sensors?, is it the change in temp for hotend? etc.) but instead I chose the easy route and just modded my printer as follows. It seems like a bit heavyweight mod, but at the end of the day, this substantial drop in voltage suggested to me at least one of the following if not all:

     

    1. The power supply is under powered
    2. Lack of resiliency in circuit design to cope with 1.5% 24V drop
      1. This could be as simple as filter caps
      2. Or better Vref for ADCs and such
      3. Or need for better PID/temp control of hotend

    I don't know which of the above it is.

     

    Here is what I did.

     

    I made custom circuitry and mods to support an independent heater power supply and control. To (over) engineer it for safety and spec, I went with high quality power control modules. For example, instead of rolling my own MOSFET board, I chose to use the ever popular and reliable Pololu G2 which is designed for 24V 21 AMP continuous draw and still be warm to touch! 

     

    20200429_093746_A.jpg.edce4ffab5f9898a5e144bfed0dff2c4.jpg

     

    image.thumb.png.d0d05870610144b4a522969589eda158.png

     

    Items Needed:

    1. I had to design a simple little board to breakout the KPJX power supply. This was the only custom electronics component. Again, I chose high quality high amperage rated connectors (TDPT 2,5/ 2-SP-5,08 - 1017503) and good quality electrolytic caps.
    2. 24 V Cutoff relay. If you look at the UM2 Mainboard, there is a 555 timer that brings up the 24V supply once the input is stable. I did not want a scenario where a floating PWM pin or some other mistake on my part could ever turn the heater ON if the power to the printer is off or the mainboard is in-operational. As such, the main power is cutoff from rest of circuitry is there is no 24V on UM2+ Mainboard.
    3. Pololu G2 21Amp version. This board uses really good MOSFETS with very low Rds and excellent perfomance. They are an overkill for our 7 to 8 amp application, but this means, I do not require any active cooling. Under a thermal camera I found the MOSFETs to only get upto about 35-40 deg C.
    4. A 120W 24V Meanwell PSU. Again, a bit over powered since the printer barely uses 60W (without heater) but the price difference was negligible and I took into account temperature related derating.

     

    Changed the heater control PIN in firmware to use an unused pin on EXP3 header. This pin is then connected to the MOSFET board (PWM on Pololu G2) to turn the heater ON/OFF.

     

    image.thumb.png.1f247ddd58cf8157e5b41bdec98dc427.png

     

    Designed a Mounting Plate (my first CAD where it had to fit an existing part [UM2] 🙂 )

     

    MountingPlate.thumb.jpg.b3df8cce768b2fc339219fae3bef1047.jpg

    OverallBoard.thumb.png.f6d175a12976f6e364ef1480238f6be0.png

     

    Made sure it looks like factory fitted and modeled it after the original way the connector is cutout at back. I think it came out really well.

     

    3d_connector.thumb.jpg.b5572ad8b79fb77c94d1c15f8cb8e7a2.jpg3D_Underneath.thumb.jpg.be22537f805e0450c82a3e8fc2f22dd1.jpg

    20200510_142119.thumb.jpg.aa86874822a53d901ab0254eb85a6d88.jpg

     

    Mounting plate uses unused screw holes in UM2 to securely stay in place (not happy with tape.. but had to move on :-)). The original heater wires are connected to the new circuitry using a high ameprage WAGO connector for easy removal. All wires have ferrules attached. Reverting this mod to original printer will take ~10 minutes with only permanent mod being the connector hole.

     

    20200510_142102.thumb.jpg.dd954b2208504b8b62909f92e6566473.jpg

     

     

    Summary: My prints now have no bumps/lines and look like they did in my experiments with heater OFF. My next improvement is that the 24V still has high frequency ripple from the motor controllers. I hypothesize that the really fine lines on print (variations, not layer lines) are a result of that. I have to decide whether I figure out what the underlying problem is (why extrusion changes?) or filter out that motor noise.

    • Like 1
  9. 17 minutes ago, kaupang said:

    Hi guys,

    Case closed. My Norwegian bank contacted the US bank - durstey took money and disappeared. Period.

    Poilice also closed case - they didn't believe  it was possible to find the guy. Probably understandable - in the bigger view of the world, this is a case "about peanuts". Sad enough.

    Take notice of what SandervG wrote - be careful, and use routines giving you protection.

    rgds. Bjorn

     

    Sorry to hear. Same here. My money is gone but at least here, the FBI case is still open. I also provided them with his TWO IP addresses that I was able to gather on my own accord. Those IPs are traceable to a unique mobile network subscriber and I am hoping someone does. If I do hear back, I will ping you so that you could have your police involved as well.

     

  10. Dear @rcfocus: Thank you so much for the detailed and elaborate response. I completely understand what you mean by a non-optimal grounding path. I think it does have to do something with noise (as @Torgeir also alluded to). See one more data point below.

     

    I turned the bed heater ON exactly in middle of the cube (so it was ON at 100% from middle to almost 3/4th way complete). No impact on quality, but as soon as the bed reaches it set_point of 60C and starts modulating ON/OFF, we see extrusion variations that correlate with the ON/OFF almost perfectly.

     

    Bed_on_ok.thumb.png.3505c3b6fee2904a85ce9ff00fbedab6.png

  11. 4 hours ago, Torgeir said:

    Hi there,


     

    Sorry, but I do not think this is caused by temperature variation, the lines is to consistent so it has something with the X/Y axis -stepping error.

    Actually, it might be the missed micro step problem, the stepper keep synchronized at every "full step", but can have micro step offset. I've never seen as much as this, but it is possible for sure.

    This problem can be seen on some of the printed object we do, some more than others, depending on object slicing and printer settings. So many things we all know..

     

    I did this; "shortening of the ROSC (reference oscillator) adjusting resistor" modification, in order to avoid missing steps caused by lack of back EMF.

     

    By pulling the ROSC pin to ground, mixed decay is set to be active 100% of the time, for both rising and falling currents, and prevents missed steps. (Allegro datasheet advice)

     

     

    Yeah I think this is some sort of stepping issue as well that happens as a result of current deficit. Maybe. I will look into ROSC, thank you for all those pointers! 


    Edit: @Torgeir: I just read through that discussion about missed microstep. That is very interesting. I will try out the ROSC mod.

  12. 9 hours ago, rcfocus said:

    The extruder temperature you measured is based on the serial output of Marlin. But the firmware doesn't know that the grounding level is dynamically shifted. So, the firmware (PID or other) will still try to make the temperature reading stable while the actual temperature is drifting.

     

    I mean, you can NOT depend on the serial output. You have to use an external device to measure the nozzle temperature.

     

    Hi rcfocus, that is a great point, and I will measure the V rails to make sure.

     

    BTW, I am not sure what you mean by "ground level shifting". That is a term I've never come across and unfortunately unable to interpret. GND is simply a label reference for measurement purposes. In such a floating circuit what matters is the net potential difference, which should be 24V. Maybe what I interpret by ground level shifting is that when the power budget is exceeded, the power supply becomes current limited and is compensated by a reduction in voltage (i.e. 24V drooping).

     

    Even if that is the case, I am not sure how it affects the PT100 measurement (it might but seems unlikely to my brain).

     

    The PT100 temperature sensor is a differential sensor that is being amplified by the INA826, whose output is then sensed by the ATMEGA ADC. All of these are running off a +5V supply which is generated by the buck converter. Droop in +24V should not affect the 5V supply (unless supply falls below 18V -- A4403GEUTR has an input operating range of 9 to 46V).

     

    So two things:

    1. Check how much the 24V power supply, if any is changing

    2. Measure EMI noise or such on 5V rails

     

     

  13. Okay, so I went with the hypothesis: that the bed takes up plenty of power and that causes temperature variations in the extruder. As a result we see micro extrusion variations.

     

    Experiment

    The idea was to run a print job with and without BED_HEAT and conclude if

    1. there difference in quality and;
    2. if it can be attributed to temperature variations in extruder

    I edited my Gcode for Cube test such that mid-way into the print it would turn the BED_HEATER to OFF. I I collected temperature data as frequently as Marlin would print to Serial. I wrote a quick analysis script to collect results from multiple runs and compute stats. See below.

     

    Conclusion:

    1. There is basically no measurable difference in extruder temperature whether bed is ON or OFF.
    2. There is a significant difference in quality of surface finish when BED_HEAT is OFF. Figure below shows exactly when the bed turns off half-way into printing (as programmed).
       

    Picture1.thumb.png.f30c181e05127b356e33cf18542614a1.png

    Temp_Variation_Plot.thumb.png.00aa15c409afcf362e3b0fbfbf768047.png

    # HOTEND TEMP ANALYSYS
    Average difference from set point (all range): -0.045 degC
    [BED ON] Average difference from set point: -0.054 degC STD 0.757 VAR 0.572
    [BED OFF] Average difference from set point: -0.036 degC STD 0.524 VAR 0.275

     

     

    Dammit. 😞🙁

     

    New Hypothesis: BED_HEAT is causing motion artifacts, position inaccuracy or extruder motor motion artifacts. It could also be an issue only on Z-axis? Cause that moves infrequently and when it does needs inrush current. There also seems to be a 'pattern' that likely mimics the ON/OFF of BED_HEAT.

     

    Few ideas to test this:

    1. Measure motor currents
    2. Measure and log any droop in +24V supply voltage (could be the motor inrush currents)
    3. Reduce bed power (takes longer to heat up.. but meh, I can live with it)
    4. EMI from bed heating (highly unlikely.. its resistive and switched ON/OFF at Marlin bang-bang rate, which I don;t know what it is..)
    5. See if the fat/vs thin layers seem shifted or consistent all around? Could be overshoot as well in motor position. 
    6. Most likely candidate is that the tuned accelerations and peak velocity need to come down -- they could have been tuned with bed heater off and a bit lower current on motors is mucking it up.

    Any other ideas why bed heater could be causing the lines in print?

  14. 12 minutes ago, Torgeir said:

    Forgot this one, I'll think the later firmware use "bang-bang" mode not PID, cause PID created lots of harmonics radiation not allowed for devices like this. Also PID can make distortion to sensors in it's own system, right, -it disturb itself..

    Just like an audio amplifier starting to squeak if the mic come to close to the speaker..

    I.E. The high current pulses from the heat bed wires act as an antenna radiating high energy harmonics all around the

     

     

    That's right, but I think the PID loop is pretty slow, of around 7 Hz, so EMI isn't an issue as much. If really, I can shield the cables. Fortunately, electronics is in my wheelhouse so I will figure this out and report back for posterity in case someone has these issues.

  15. Okay friends, it looks like I am a LOT clsoer to the source of the problem. 😄

     

    3 hours ago, geert_2 said:

    Long ago there has been a discussion if the heated bed could be the cause?

     

    I think this is it!! Although I did not follow the floating ground aspect, my guess is that the PID needs better tuning. When the bed fluctuates power, it is causing micro-variations in the nozzle temperature. What bothers me is that such a minor temperature variation can cause this. I am in process of running an extensive log of temperatures and will report back. Thank you @geert_2 for bringing this on my radar!

     

    2 hours ago, Torgeir said:

    First, forget about checking the heat bed common ground theory.

    (Both, the heater and the PT100 sensor have separated ground, so a construction like that would give massive error

    (not 50 deg. C). In such an error the printer would stop instantly (hi priority issue).)

     

    @Torgeir, so yes, it is not related to ground, but looks like it is dependent on the heated bed being operational or not.

     

    Note how much cleaner the edge is with bed heat OFF. Also note, the surface when reflecting light is a lot more consistent.

     

    WIN_20200417_13_28_08_Pro.thumb.jpg.8a28ee2d3360b6498704d25da6bdc327.jpgWIN_20200417_13_32_05_Pro.thumb.jpg.7e977dc613f21cab2b33a2f0ca1899a5.jpg

     

    When looking in person (sorry hard to capture in photos), there is about 70-80% improvement in surface quality and the micro-extrusion variation.

     

    This also explains why I saw slightly less of such variation on higher speeds (70-80 mm/sec), the reason being, the temperature variations are happening at a certain slow rate. When the print is sped up, the printer goes through many more layers before the temperature variation (or whatever the heated bed causes) has a change to impact it.

     

    I am going to monitor and log detailed temperatures and try and tune the PID. If that doesn't help, I am gonna see what the underlying reason is and make a modified circuit possibly to separate any power impact of heated bed on rest of circuitry. I might run a separate power supply or add filtering circuitry.

  16. 1 hour ago, Torgeir said:

    Second New Hypothesis: While re-lubing the axis I noticed that when I move the head by head in X-axis, instead of making a nice consistent zeeeeeeee sounds, it makes, zeee000zeeee0000zeeee000. Visual inspection shows that the back right X-pulley has a very slight runout. I guess this is because it is not centered on the 8mm rod?

     

    I've built my UM2 and have a plastic bag full of pulleys, that is not up to good standard, as they have some wobble. In your case, you may try to shim up the pulley using "shim" of brass.

    Usually they are oval at one side, for testing you may use paper and then tighten the set screw.

     

     

    I ordered two new pulleys from a Ultimaker supplier (fbrc8.com) and will change it. I think this could be playing a role.

     

    Quote

    Now a question; did you rice the nozzle temperature when you made the "circular tower" flow "speed" test?

    IMO. I think your model look better at the lo part of the model, however this latter one look much better than the first model.

     

    No, I used the GCode from a community member (from a file called Mini_Speed_Test in the Bondtech Extruder thread). I checked and the temperature is never changed in GCode. The lower layers may look better (and they are) but they suffer from the same "micro extrusion variability". 

     

    Quote

    During normal printing, how much does the nozzle temperature fluctuate up and down?  (should be ±1 deg. C)

     

    Edit: Why is your first model white at the bottom or top?

     

    The temps shown remain 209-210. So I would say yeah, between +/- 1 deg. C. Its not white, its just over exposed as I was using a macro lens and took the image in sunlight.

  17. 18 minutes ago, geert_2 said:

    Long ago there has been a discussion if the heated bed could be the cause? If it would draw so much power that the ground-level (zero volt) would shift up, and if the temperature sensor would use that same ground wiring, this could cause errors in the temperature the main board "sees". And then it would adjust incorrectly.

     

    Oh, that's a really interesting thought. Will test!

  18. 5 hours ago, geert_2 said:

    I think effects like this might also be caused by fluctuating temperature, because that changes viscosity and flow-rate (=less back-pressure when more liquid). And maybe also by a worn-out white teflon coupler?

     

    But I don't know a good means to reliably measure the temperature from the outside? A thin and heat-resistant sensor that you could move into the nozzle from above might be best? (Of course after removing filament, removing bowden tube, and cleaning the nozzle.) And then let the printer run, "printing" this same object. Thus it goes through the same moves, same temperatures, same heated bed, but only without filament?

     

     

    Yeah, the underlying issue does seem to be what I would generally call 'extrusion variability'. The reason I think it is not the 1) Extruder assembly 2) Nozzle 3) Heater Block or 4)Heater Catridge/Temperature sensor because before I had upgraded to the UM2+ kit, I had the same issue. The UM2+ kit basically is brand new extruder and the whole head assembly.

     

    This leaves the mainboard (which could not be sensing the temperature accurately) or something about the motion system.

     

    Edit: BTW, a good way to measure the nozzle without taking it apart would be with a thermal cam.

  19.  

     

    Out of curiosity I printed the mini speed test. See below. I notices that the inconsistent layer lines are a LOT LESS at higher speeds (like 70-80mm/sec). This gave me a new hypothesis: Maybe the axis need re-lubing and at high speeds the momentum overcomes certain resistance. In addition, based on @rfocosta advise, I thoroughly cleaned and re-lubed all axis and also ensure the axis are aligned and belts are appropriately tightened. This unfortunately, did not change anything😞

     

    Picture1.thumb.png.4c5e494f969bd06be6429394faf4776c.png

     

    Second New Hypothesis: While re-lubing the axis I noticed that when I move the head by head in X-axis, instead of making a nice consistent zeeeeeeee sounds, it makes, zeee000zeeee0000zeeee000. Visual inspection shows that the back right X-pulley has a very slight runout. I guess this is because it is not centered on the 8mm rod?

     

    What I fail to understand is that if this X-axis pulley was the source of inconsistency, why do I see it on all 4 sides of a cube and not just in the X-axis motion direction?

  20. 1 hour ago, rcfocus said:

    What you said "I am seeing 'fat' layer vs thin layers that extend in all directions." This could be caused by a dirty Z lead-screw. When a machine is used for a very long time. The Z lead-screw will be very dirty. Please fully clean the lead-screw and then lubricate it again.

     

    I am going to clean it fully and re-lube with Magnalube and report back.

     

    Quote

    Btw, a used hot-end will be very dirty too. 

     

    I actually just installed the UM2+ Extrusion Upgrade Kit with the Olsson block on Friday 🙂

  21. Hello Experts,

     

    I bought a UM2 with 28 hours on it (so basically new). Tried a few prints and noticed that the surface finish was sort of disappointing. I posted results of my MiniCalTest here (note the surface finish😞

     

    On Friday I received the UM Extrusion Upgrade Kit and installed it. I followed all instruction and also verified that all belts are tight, the axes are aligned and bed is leveled. I was hoping for improved surface finish, however I am not sure it improved it.

     

    The surface finish looks fine when looking at the object, however on closer inspection or under light, I see a lot of what seems like inconsistent extrusion. In the following macro images and in direct light, the defect is accentuated.

     

    BLACK CUBE: My $175 Monoprice Printer

    RED: UM2+

     

    DSC01896.thumb.jpg.9f599962c0d88814acea6bdb24f0addc.jpgDSC01901.thumb.jpg.5b58317e89b0092fa5141845000148b7.jpgDSC01902.thumb.jpg.a4a736a73d2b087dc628dc5aedf0cd60.jpg

     

    Things I have tried

     

    1. Different Layer heights. I have tried from within Cura and Ultimaker's default profiles of 0.1 and 0.15. I have also tried my own 0.12. The most consistent result I have had so far has been with 0.32 layer height and a slow speed. 
    2. Speed. I have tried lowering the speed to 45mm/sec and the surface finish did not improve.
    3. Suspect Z-stage I printed a long cylinder to see if some parts of the Z-lead screw might be sticking or something. The surface finish defect is consistent across all the surface. There doesn't seem to be a pattern (to allude to some lead screw wobble?)

      20200412_162957.thumb.jpg.4f704b4671b44bed2f2aa5cb56fa91ac.jpg

       
    4. Suspect Z-wobble I made some measurements with my optoNCDT capable of measuring down to nanometers. I measured the movement in X-stage as as result of lowering or raising the bed by 50mm at Feedrate of 2000. I can only see a X-movement of 0.14mm which could be because the bed wasn't leveled or my measuring apparatus wasn;t perfectly parallel to Z-plane. I cannot rule out the wobble either.
      image.thumb.png.171ced6cb2bce577dd1208042d90f5f6.png

      Here is a video -- does the Z-lead screw Wobble looks too much? It does have some run-out the top. Can someone please confirm with a UM2/UM2+ if they see this too? (Try watching at 0.75X speed)
       
    5. Try different materials. I have tried Ultimaker Blue PLA, Ultimaker Transparent PLA and MatterHackers PRO Tough PLA. No difference in the surface quality finish.
       
    6. Try different Extruders I started with the UM2 extruder, then with the Extrusion Upgrade Kit tried it with the white extruder. I am now running Bondtech DDG extruder (with correct firmware changes).

     

     

    I bought an Ultimaker because I did not want a project and rather a printer that just works. For the most part that is true, however I am not sure if I am being OCD and looking at this parts with lighting shone from a certain angle and everyone has this kind of surface finish or its just me? Can someone please share what your parts look like with flashlight on top and shining down on layers (this makes uneven layers drop shadow).

     

    Any help or guidance is appreciated!

     

    Thank you and stay safe. Cheers!

     

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