Ratrig servo nozzle brush

With the introduction of beacon touch/contact, having a clean nozzle is essential, especially if you plan to use more than three samples. Therefore, a solution to clean the nozzle was needed. However, the Vcore-3/3.1 is tight on space, and the nozzle does not hang over the edge of the bed in any position. As a result, having a servo-mounted brush was necessary. That is why I designed this solution.

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For STL files, visit this link. Downloading from there helps support my work: https://www.printables.com/model/913748-ratrig-vcore-331-servo-nozzle-brush

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Instructions:

Disclaimers:

• The parts were designed to be printed via SLS; however, all parts can be printed via FDM on a standard 3D printer such as a RatRig. Please note that support will be necessary.
• A 270 degree servo is needed if you plan to mount the servo on the right.
• The spacer and screw length needs to be customized for your setup.

Click the image with your servo configuration and it will take you to the right STL file.

Left mount servo	Right mount servo

Customize the height of the spacer as needed so that the brush touches the nozzle:

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Parts needed:

• Printed parts:

  • 20kg_servo_mount.stl This is the part that holds the servo.
    • Servo_mount_long.stl If you have a ratrig bigger than 200mm or enough space and wanna make instalation easier use this file.
  • Brush_holder.stl This is the part that holds the brush
  • Spacer.stl The height of the spacer can/needs to be customized to modify the nozzle contact with the brush, this can be done in slicer (no cad skils needed).
  • Arm_Left_servo.stl The "left"/"right" in the name indicates where the arm mounts to the servo, so use this file if you plan to mount the servo to the right.
  • Arm_Right_servo.stl The "left"/"right" in the name indicates where the arm mounts to the servo, so use this file if you plan to mount the servo to the left.

• Electronics:

  • 1x: 270 degree 20kg servo

• Hardware:

  • 1x: Brass brush This one is pre cut but you can use any other brass brush and cut it yourself, in fact that may be better since you can cut it to fit perfectly.

• Fasteners:

  • 2x: Cap Head Screw M6x12 Used to mount the servo to the frame. You may have some leftovers from the ones included in the RatRig kit.
  • 2x: 3030 series M6 T nut Used to mount the servo to the frame. You may have some leftovers from the ones included in the RatRig kit.
  • 6x: M4 heatset insert The hole for the inserts is 5.6mm in diameter and 7.5mm in lenght. A 6mm long insert is recommended.
  • 6x: M4 screws The lenght of these depends on the size of spacer you use, but between 25 and 35mm should be enough. You will also need 2 6mm long screws to mount the servo.
  • 2x: M3x6 screw Used to secure the brush arm to the servo.

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Macro

Disclaimers:

• This specific macro loops the brushing moves, for that reason the "loop_macro" klipper extension needs to be installed: Looping Macros by voidtrance

Visit the voron-klipper-extensions repo for details.

If you have installed the extension just include the "brush_macro.cfg" in to your files and call the macro via "_CLEAN_NOZZLE_WITH_BRUSH"

To customize the macro use the variables:

Variable	Use
variable_brush_hotend_temp	Temperature the hotend will heat up to before starting brushing moves
variable_brush_bed_location	Absolute position of where to move the bed to deploy the servo brush
variable_brush_bed_move_speed	Bed travel moves speed in mm/s
variable_brush_toolhead_move_speed	Toolhead move speed in mm/s for brush routine
variable_brush_speed	Speed in mm/s for brush moves
variable_brush_deploy_angle	Angle of servo where the brush touches the nozzle
variable_brush_stow_angle	Angle of servo where the brush is out of the way
variable_brush_toolhead_x_park_location	Absolute position on x where the brushing starts
variable_brush_toolhead_y_park_location	Absolute position on y where the brushing starts
variable_brush_move_for_front_to_back	Distance to move in to the brush for side to side moves
variable_brush_move_distance_side_to_side	Distance of side moves on brush
variable_brush_move_distance_front_to_back	Distance of front / back moves
variable_brush_circle_radius	Diameter of brush circle
Variable_brush_fan_speed	0 to 255 - part cooling fan speed to use while brushing, helps cool down faster
Variable_retract_before_brushing	True or false
Variable_terminal_verbose	True or false - if it should output to terminal what the macro/printer is doing

This is what the macro does in order:

1. Move bed out of the way.
2. Heat hotend and wait for it to reach temp.
3. Retract if defined.
4. Park toolhead where the servo will deploy.
5. Deploy serrvo.
6. Wait for servo to deploy
7. Set temp to whatever the preheat temp is set to according to the RatOS variable: preheat_extruder_temp.
8. Turn on part cooling fan to speed up hotend cool down.
9. Call "_BRUSH_WIPE macro". 10. Set position to relative 11. Brush side to side. 12. Brush front to back. 13. Set position to absolute. 14. Brush clockwise in a circle. 15. Brush counter clockwise in a circle.
10. Loop points 10 to 15 untill the hotend temperature is equal to preheat_extruder_temp.
11. Onc ehotend temp is equal to preheat_extruder_temp break loop.
12. Turn off fan.
13. Stow servo.
14. End macro.

To see how I have it implemented on my printer check this repo:

• My variable usage: printer.cfg
• My macro: defaultmacros.cfg

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Changes

• Updated heat insert tolerances.
• Changed servo mount for easier assembly.
• Thickened servo arm for easier printing and stability.

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Other projects from the autor (me)

3D models / Prints:

• Mason jar ashtray A mason jar attachment to make almost every jar in to an ashtray.

Printer mods:

• Servo nozzle brush (printables). A servo attached nozzle brush.
• Servo nozzle brush (github). A servo attached nozzle brush.
• Endstops. A collection of custom endstops for 3d printers or cnc machines.
• Thermexp. A PCB to add more thermistors to a klipper printer.

Chrome extensions:

• Youtube ads auto skip. A chrome extension that emulates a click and auto skips youtube ads. Works even after adblock prevention measures.

Keyboards:

• Enclave. A custom mechanical switch macro pad. Works on QMK and can be used with klipper.