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Erratic behaviour (The Printer - not me !)

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    Erratic behaviour (The Printer - not me !)

    Hi,
    I have a Wanhao 4DS which has started acting badly. I cannot get a whole print done without the X or Y axis stopping and juddering. It leaves a blob of ABS as it keeps extruding while stuck in one place. Sometimes the print head gets sent hard --X or hard --Y, but it is quite random when it does it and whether it just stops and judders over the print. It doesn't matter which nozzle I use. The machine is about 10 months old and has had light use.

    I think it may be a cable problem or an overheating driver.

    Originally I thought it might be related to my recent upgrade to Makerbot 3.18, but if that produced a faulty x3g file it woulf fail at the same place each time, which it does not.

    Anybody had this? Or any thoughts what might be wrong. I have ordered a new motor cable for the Y axis as this one moves about, but I am getting irritated by this fault as I have a print to do.

    Cheers,

    Rob

    #2
    It could be all kinds of things. To start simple, are you printing from an SD card? I have had a similar issue come from a corrupted card. Re-formatting the card fixed it for me. Not saying that's what this is, but it's a place to start.

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      #3
      It could be that the motors our underpowered?? but I would have thought this not to be the case in an off the shelf printer. What have Wanhao said?

      www.idig3dprinting.co.uk Your one stop, 3D printing shop

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        #4
        I had some shuddering in my X axis several weeks ago that was causing layer shifts. It did not stop like yours, but the culprit was the belt. I tightened it up and the problem went away. A couple of Weeks ago i had something similar happen to my Y axis, Turned out there was a tooth that was very rough on the motor pulley. I torqued the belt down after some smoothing of the pulley (the smoothing made it worse but i was not afraid of cutting the belt anymore, this is why i torqued it down) and the problem is gone. I ordered new pulleys, but i made a mistake of getting the wrong ID ones (6mm instead of 5mm). I have not reordered yet.

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          #5
          Hi Andrew,

          I have several SD cards and it happens on different cards, so I don't believe that to be the problem. I also thought it might be a stepper cable, but it happens on both X and Y. The next thing I am going to check is the MB fan, as it could be a driver overheat problem.

          Cheers,

          Rob

          Comment


            #6
            Your're probably right on that one given it happens with several cards. I just like to start with the simplest possible solution.

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              #7
              I hope it is now sorted. I changed the MB fan and at the same time cleaned and lubricated the guide rails using FIXT dry film lube with PTFE. One of the drivers did not seem to be properly seated. It is now !

              As soon as I started to print my second print the right extruder wrapped filament round the feed roller. I am beginning to think that these machines are more high maintenance than my wife

              Cheers,

              Rob

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                #8
                The problem persisted and it was suggested that the X axis cable could be broken inside the insulation, so I changed it. The problem persisted. Then I found the SD card reader extension cable was crumpled, so it was suspect. I removed it and went native into the sd card reader and the machine now prints well.
                I also changed to all-metal hot ends and replaced the heated bed (which had a bow of about 0.5mm and was difficult to set up as level). I think the all metal hot end upgrade was expensive for marginal improvement.
                Why is the card reader in such an awkward place ? I have to use artery forceps to remove the card. I am going to replace the SD slot extension, but I will know what to do if the printing fault returns

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                  #9
                  Does anybody have any idea why the SD card reader has a cover with a gap big enough to drop the card through and into the bowels of the machine ? I can only think the designer of the machine (Wanhao D4S) had a brain fart. I have put a piece of plasticard over the hole for the moment, but I am seriously thinking of getting a bulk order of SD cards so I only have to dismantle the machine to recover them when I run out of cards.

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                    #10
                    I've seen that issue with a lot of devices. It's worse with microSD cards. I like your bulk card order idea. Sounds like a good workaround.

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                      #11
                      Since my last post on this topic (3.5 years ago) the 4DS has been behaving, except for when another cable went intermittent. So I changed it and it cured the messy printing. One thing that I have done is install a WiFi SD card, so I can log onto it and upload and delete files without messing about taking the card out.

                      The card is a Toshiba Flashair and I had to modify files on the card to get it to work the way I want it. Now it works well, but the range of the card is quite limited, so I have to have it near (within 6ft) to get a reliable link.

                      Now, however, the machine is faulty big time. It won't grip the filament enough to push it thru the hotend. So the feed gear just grinds the filament away. This has come on gradually and I think it may be weakening springs on the pressure rollers (both extruders show the same problem). Having tried all sorts of half arsed solutions, none of which worked, I think I have ended up with stepper motors with bent shafts as the filament extrudes and then stops fairly rhythmically when loading filament. So this evening I have ordered a new dual extruder complete (Nozzles, hotends with thermocouples and heaters, feed mechanism, heat sinks and fans). The complete works. I hope it does the job as it has used up my pensioner's pocket money for October and November.

                      In my attempts to fix it, I installed some Chinese all-metal feed mechanisms - waste of time and money - they were so badly made I had to mill out the recesses to get them to fit on the stepper motor. Now they are in the scrap bin. Also I think the springs on the all metal extruder were too strong and that caused damage to the steppers.

                      I will keep you posted on the results.
                      Last edited by cropwell; 10-30-2019, 12:47 AM. Reason: More details on the WiFi SD card

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