tag:blogger.com,1999:blog-6539093728798325673.post1296690037360021353..comments2018-07-19T18:29:39.437-07:00Comments on CubeX 3D Printing Blog: Z-gap consistency or inconsistencycubeX-3D-printmanhttp://www.blogger.com/profile/16386814853378553046noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-6539093728798325673.post-20388265883093900302013-08-09T22:12:01.838-07:002013-08-09T22:12:01.838-07:00thanks, I ordered it.
unfortunately, the Z-gap is...thanks, I ordered it.<br /><br />unfortunately, the Z-gap is more complicated than the magnet and reed switch.<br /><br /><br />the reed switch is a switch. its either off or on, and there is no other functionality. its not a sensor in the sense of a capability of sensing a variable or continuum of magnetic field strength.<br /><br /><br />Furthermore, the Z reed switch goes from its "OFF" to "ON" state at a jet-bed separation that is a comparatively loooonnngggg distance when compared to the ideal Z-gap setting of near ~0.1 mm.<br /><br /><br />You can watch this happen when you home, start a print job, press "z-gap", etc. The print bed raises and at a certain point it stops, then reverses direction momentarily.<br /><br />that is the point where the reed switch turns on. the reversal of direction is a way for the system to get a 2-point measurement of the point at which the reed switch turns on. You will notice that this occurs at a separation that is long before the very small gap that we ideally would like to program into the device. that separation... which is, IIRC, at least several milimiters between the print jet tips and the print bed.... represents what we might call a "starting point" or "Zero point" or perhaps the "origin" for the print bed.<br /><br /><br />after (above) that point, the system is recording the duration of time that the stepper motor is turned on, most likely as a function of current input. Similarly, when the print bed is lowered below that point, the system is still recording the stepper motor duration.<br /><br /><br />in general, thats OK and is not necessarily a bad or poor design concept because these types of stepper motors are extremely precise, and the electronics should be very capable of extremely precise measurement of the current that drives the motors during the adjustment or print process<br /><br /><br />My concern however is that, during the fine tuning process, repeatedly pressing the up/down button.... especially in extremely small increments like 0.02 milimeters, will result in errors that compound.<br /><br />I have tested it already, so I definitely know that there is a correlation.<br /><br /><br />If you set the z-gap (stock or presumably with the relocation kit) by pressing the "UP" button continuously up to .... whatever your particular unit represents as very close (mine reads in the 28.xx range, with 28.9x being the closest I have set it, and 28.4x being the largest gap I have set it).....<br /><br />and compare the resultant behavior to what occurs if you repeatedly press the up button in small bursts or small/brief intervals of time, so that you adjust it in increments of 20-60 microns (0.02-0.04 mm) at a time, possibly including pressing the "DOWN" button several times, you will notice that adjustment involving these distinct behaviors will produce drastically different results when you compare the consistency of the machine's Z-gap setting by successively checking its own ability to reproduce the z-gap that you had previously set(by setting it, then saving it, then pressing the Z-gap again to see if the machine can reproduce the position that you had set it)<br /><br /><br /><br />Additionally, it should be noted that Cubify/3D systems themselves actually admit in one of their documents that the CubeX is subject to ~0.05 mm of error in resolution. I cant remember off the top of my head which document it was in.... hell it might even be in the CubeX guide... but I'll look for it. <br /><br /><br />Sorry for the long comment, lolAnonymousnoreply@blogger.com