Project Logs

Collapse

• Selected Hardware

  MC88 • 01/08/2022 at 05:09 • 0 comments

  Extruder: Direct Drive - Orbiter F2.85mm Dual Drive extruder by Dr Robert Lorincz

  https://www.thingiverse.com/thing:4860182

  • This extruder is specifically designed for 2.85/3.00mm filament.  The design is well documented and can be replaced with the Orbiter v2.0 if 1.75mm filament is desired for future printing projects

  Hotend: 3mm Direct V6-style hotend

  • This hotend is directly compatible with the Orbiter extruder

  Mainboard: RAMPS/Mega combination

  • This mainboard combination was already in my inventory, but is also one of the cheapest and most common boards.

  Stepper Drivers: BigTreeTech TMC2208

  • These stepper drivers offer stealthchop if run in legacy mode, or can be run in UART mode to fine-tune the stepper current.

  LCD: BigTreeTech 12864 Full Graphics Smart Controller

  • This LCD panel was already in my inventory.  It is an inexpensive LCD screen that will display the information required and allow changes to be made using EEPROM/

• Initial Project Goals and Considerations

  MC88 • 01/08/2022 at 01:22 • 0 comments

  Objectives

  1. Print with 2.85/3.00mm filament as it is becoming quite cheap and can be used when 1.75mm filament is out of stock
  2. Reduce overall noise level during printing - the noise level must be (subjectively) negligible when beside the printer
  3. Minimize cost by using stock components when possible

  Evaluation

  Objective 1: Print with 2.85mm/3.0mm filament

  • Issue: The stock extruder is not able to print using 2.85mm filament
    • Solution 01: Design and 3D print an alternate bowden extruder as a drop-in replacement
      • Issue: The minimum bend radius of the PTFE tube and larger filament cannot be met given the stock position of the extruder
      • Issue: Alternate positions on the printer do not meet the minimum bend radii
    • Solution 02: Use a 'flying extruder' similar to some delta-style 3D printers
      • Issue: The cantilevered X-axis gantry and enclosed Z-axis tower present challenges regarding the deflection and mounting of this style of extruder
    • Solution 03: Use a flex-drive style extruder such as the Flex3Drive
      • Issue: The minimum length of flexible shaft for this extruder is relatively long compared to the size of this printer.
      • Issue: Anecdotal reviews of flex drive extruders are not overwhelmingly positive, but are generally positive.
      • Issue: Most extruders of this style are designed for 1.75mm filament, so a redesign would be required.
    • Solution 04: Direct Drive Extruder
      • Issue: NEMA 17-driven extruders are relatively heavy, even with very short 'pancake' motors
        • Solution: Use a 'featherweight' extruder: https://hackaday.com/2020/11/05/a-featherweight-direct-drive-extruder-in-a-class-of-its-own/
          • Issue:  Tests for deflection and useability on MPSM printers are non-existent or difficult to find.

  Objective 2: Reduce overall noise

  • Issue: The stock A4988 drivers produce motor whine that is quite distinct and noticeable within a room
    • Solution 01: Replace the stock stepper drivers with quieter drivers, such as the TMC2208 or TMC2209 chips in stealthchop or legacy mode
      • Issue: Replacing the chips requires sufficient soldering skill and may be too 'complicated' for less experience individuals
      • Issue: Additional supplies would need to be purchased to properly and cleanly replace the onboard A4988 chips
    • Solution 02: Replace the stock mainboard and use 'plug-in' stepper drivers
      • Issue: A replacement mainboard can be expensive, relative to the low MSRP of the printer
        • Solution: A low-cost board(s) such as the RAMPS/Mega combination is sufficient for basic printer operation, and is well documented
        • Solution: Alternate 8-bit board - Low cost, but less documentation than the RAMPS board
        • Solution: SKR board - these boards are not particularly expensive, but the higher cost will likely not yield noticeable benefit on this printer
        • Solution: Alternate 32-bit board - see SKR board justification above.
        • Solution: Gigdigit 'quiet' replacement board - An easy and straightforward solution, but regularly out-of-stock.
      • Issue: the stock LCD screen is not compatible with most mainboards not specifically designed for the MPSM
        • Solution: Use a cheap, common LCD such as the 12864 LCD screen
          • Issue: The monochrome screen is not as attractive as the stock full colour LCD
        • Solution: Reverse-engineer the stock screen to work with an alternate mainboard
          • Issue: The effort and equipment required to reverse-engineer the pinouts is likely not worth the time and effort
      • Issue: The stepper driver vrefs and/or current values are not officially published
        • Solution: Gigdigit has published stepper currents for the motors, based on their quiet board.
  • Issue: The stock 30mm hotend fan can become loud when part cooling is set to a high level
    • Solution 01 : Use a 40mm fan with similar static pressure and airflow properties.  The fan can spin at a lower rpm, to achieve the same cooling, which will result in lower sound
      • Issue: The stock hotend and E3D v6 style hotend fan shrouds are not designed for 40mm fans
        • Solution: 3D print an adapter
        • Solution: 3D print an alternate 40mm compatible shroud
    • Solution02: Use a 50mm fan with similar static...

  Read more »

View all 2 project logs