Live & Learn.... I Guess (Again)

Today I re-learned 1 thing & newly learned 2 others.

The thing I re-learned is to pay attention to the bowden tubing inside the hotend. Over the past week or so, it was getting harder & harder to get filament through the nozzle. There were a number of symptoms: [LIST=1]

  • the waste line I print down the side of the printbed started 'stuttering'. By that I mean a dotted line would be printed, instead of a solid 1.
  • it was getting harder to manually push filament through the nozzle.
  • I found I had to raise the temperature of the nozzle.
  • I had to increase the flow rate. [/LIST] So, today, I dissassembled the hotend and cleaned it out. I also cut a new piece of Capricorn tubing to go between the extruder and hotend (it's only about 3 to 4 inches. When I looked at the tubing I removed from the hotend, the cause of the issues became clear: the tubing had shrunk, so the inside diameter was less than it's supposed to be. The last 10mm of the tubing was also charred.

    [ATTACH=JSON]{“alt”:“Click image for larger version Name: _MG_3632.jpg Views: 0 Size: 873.5 KB ID: 6821”,“data-align”:“none”,“data-attachmentid”:“6821”,“data-size”:“medium”}[/ATTACH] [ATTACH=JSON]{“alt”:“Click image for larger version Name: _MG_3633.jpg Views: 0 Size: 834.1 KB ID: 6823”,“data-align”:“none”,“data-attachmentid”:“6823”,“data-size”:“medium”}[/ATTACH] [ATTACH=JSON]{“alt”:“Click image for larger version Name: _MG_3634a.jpg Views: 0 Size: 682.5 KB ID: 6822”,“data-align”:“none”,“data-attachmentid”:“6822”,“data-size”:“medium”}[/ATTACH]

    Replacing the tubing fully restored the flow rate. This experience does, however, make me more interested in an all-metal hotend.

    The new things I learned are about bootloaders.

    The 1st thing I found out, the hard way, is that flashing firmware to a control board by using an ISP Programmer, one that connects directly to the ISP header pins on the control board, will literally wipe out the bootloader. My ISP Programmer came with the Creality BLTouch kit I received recently. I can still flash firmware to the 1.1.5 Silent board, but I have to do it by using the ISP Programmer. I cannot do it over USB. I am currently investigating how I can re-flash a bootloader onto the board.

    The 2nd thing I found out is that bootloaders actually reduce the space available for firmware. So, if I want to load Marlin 2.x, and have BLTouch capability, I can opt to burn the firmware via ISP Programmer, and thus gain back the space that would have been used for a bootloader, & let the firmware use it. This could make it possible to fit firmware that might otherwise be too large for the available space.

    [SIZE=8px]#clog #shrink #capricorn #skipping[/SIZE]

  • Just remove SDCard Support or get an SKR board to replace the antiques. :slight_smile:

    With a proper 32 bit board flash memory is no issue.

    I have an SKR 1.4 Turbo on its way. I may also order a Creality 4.2.7 board from Amazon, since they’re so inexpensive.

    But those boards have non replaceable stepper drivers, so the price tag may appear later.

    Maybe, but they’re cheap enough it doesn’t really matter that much.

    In other news, I finally got a bootloader back on the printer, but not the way it’s supposed to be done. The way Creality says to do it is to use the supplied USB ISP programmer with the ProgISP_1.72 program. The only issue with that is I have not been able to get ProgISP_1.72 to accept any bootloader file. It always returns an “invalid line” error when I try to load the file, which is even odder because it does accept normal firmware hex files. The sheet that comes with the Creality BLTouch kit doesn’t have a URL that actually leads to a page where I can download a bootloader file. The URL they provide is just a generic 1 that goes to the Creality site.

    The way I actually got a bootloader back on the printer is thanks to’s U1.R2.B3 firmware. When I compiled it in Arduino IDE, I paid close attention to the summary text in the status window at the bottom of the screen. By scrolling up & down I was able to see the name & location of the hex file generated by the compiler. When I went to that folder, I found 2 hex files: the expected 1 as shown in the status window and another one with the same name, but with “bootloader” tacked onto the end of the name. Thank you Tim Hoogland! I loaded the hex file into ProgISP_1.72 (which loaded with no issues) & burned it to the 1.1.5 Silent board over the USB ISP. After that, I rebooted the printer & was able to update the firmware to U1.R2.B5 via a USB connection.

    The BLTouch is now functional & it doesn’t try to crush the front rail of the printer because it has the wrong probing coordinates.

    Using the 20x20 mm squares I’ve posted about, I was able to dial in the Z Offset. I actually altered the Z Offset dynamically during the print, changing the setting for each half of a square. Turns out I only need an offset of -1.025.

    A thought came to mind as I was trying all these different things: why don’t the manufacturers simply put an ICSP 6-pin connector on the control board & have it accessible through the side of the chassis, instead of forcing people to open up the chassis? It seems rather silly to make it so difficult, no to mention that an small adapter board is needed to access the ISP header pins because they are way too close to the LCD display connector. They’re also too close to the edge of the board, making them difficult to access.

    Yep, I see an all-metal hotend in your future. I’m trying to get someone to try this out and tell me how it is before I pull the trigger haha:

    Currently I’m using the gulf coast version of the micro-swiss, and it works just fine. But the above mosquito-clone design runs a lot cooler and should have higher flow even in the ‘standard’ flow version.

    As for the creality board, no point in getting that if you’re getting the 1.4 turbo. Are you getting 2209 drivers for that?

    That could be very interesting. I have been unable to make my all metal (cheap) hot end work at all to date. But I don’t often try any more.