ADR-009: Modular Puck System

Status

Accepted

Context

The Amalgam requires mounting points for: - Z-motors and leadscrew nuts - Main electronics/brain board - Extruder/toolhead on X-carriage - Future toolheads (plotter, laser, etc.) - Modular upgrades without redesign

In 2026, mounting solutions are: - Integrated parts (printed directly into structure) - Bolt-on brackets (custom for each part) - Modular pucks (standardized mounting interface)

The Amalgam’s “forever machine” philosophy and multipurpose gantry require a standardized mounting system that allows: - Future upgrades without redesign - Easy repair and replacement - Tool swapping for multipurpose use - Bootstrapping (print on small printer, use on large)

Decision

We choose the Modular Puck System - standardized mounting interfaces for all major components.

Why Puck System?

1. Standardized interface: All components mount via pucks
2. Future-proof: Upgrade without redesigning entire structure
3. Easy repair: Broken puck = reprint single part
4. Multipurpose: Same frame can hold different toolheads
5. Modular: Pucks interchangeable between tiers
6. Parametric: build123d generates puck variants from config.py
7. Bootstrappable: Small parts, printable on donor printers

Puck Types

1. Z-Puck: Mounts Z-motor and leadscrew nut to M12 frame
2. Brain Puck: Mounts electronics board to M12 frame
3. Extruder Puck: Mounts toolhead to X-carriage (modular toolheads)
4. Motion Puck: Mounts linear rails (for tinker path)
5. Tool Pucks: Plotter pen, laser, CNC spindle (future expansion)

Puck Philosophy

“The chassis is eternal, the tools are transient.”

Consequences

Benefits

• Modular upgrades: Swap toolheads without redesigning carriage
• Repairable: Replace individual pucks, not whole assemblies
• Multipurpose: Same frame for 3D printing, plotting, laser
• Parametric: One codebase generates all pucks from config
• Small prints: All pucks fit within 150mm³ (bootstrappable)
• Scalable: Puck sizes adapt to motor/bearings/hotend dimensions

Trade-offs

• More parts: More assemblies = more bolt points
• Interface complexity: Must maintain consistent puck interfaces
• Stacking tolerance: Multiple pucks = cumulative tolerance issues
• Weight: Additional mounting hardware adds mass

Why NOT Integrated?

1. No upgrades: Changing toolhead requires redesigning carriage
2. No repair: Broken part = reprint entire assembly
3. No multipurpose: Can’t swap to plotter/laser
4. Large prints: Integrated carriage may exceed donor build volume

BOM Implications (Generic)

Scenario A: Standard Tier 3 Build (Recommended)

• Parts needed:
  • 3x Z-Pucks (printed, hold motors + nuts)
  • 1x Brain Puck (printed, holds MKS SKIPR)
  • 1x Extruder Puck (printed, holds Wade + hotend)
  • 3x X-carriage linear bearing clamps (printed)
  • 20-30x M5 or M6 bolts (puck-to-frame and puck-to-component)
  • 40-60x washers and nuts
• Cost implication: Very Low (~$5-10 AUD for hardware)
• Donor compatibility: All donors (3D-printed)
• Print time: ~10-15 hours total
• Components: All modular, replaceable

Scenario B: Salvage-Specific Pucks

• Parts A: Donor motors are different size (oversized NEMA17, etc.)
  • Parts needed: Parametric pucks from config.py
  • Adjust config: MOTOR_SIZE, MOUNT_HOLE_PATTERN
  • Regenerate: build123d creates custom pucks
  • Cost implication: Very Low (~$5-10 AUD)
  • Donor compatibility: All donors
  • Note: build123d handles dimension changes
• Parts B: Donor board is different shape
  • Parts needed: Custom Brain Puck from config.py
  • Adjust config: BOARD_MOUNT_HOLES, BOARD_DIMENSIONS
  • Cost implication: Very Low (~$5-10 AUD)
  • Donor compatibility: All donors
  • Note: Standard board patterns available (Creality, Anet, Prusa)

Scenario C: Toolhead Upgrades

• Parts A: Wade → StealthBurner (Voron)
  • Parts needed: New Extruder Puck (StealthBurner compatible)
  • Salvage: Existing Wade, pucks, mounts
  • Cost implication: Low (~$10-15 AUD for new puck + hardware)
  • Donor compatibility: N/A (new purchase)
  • Note: Just swap puck + toolhead, no redesign
• Parts B: 3D Print → Pen Plotter
  • Parts needed: Pen Plotter Tool Puck
  • Salvage: Everything except toolhead puck
  • Cost implication: Very Low (~$3-5 AUD)
  • Note: 30-second swap via puck interface

Scenario D: High-End Upgrades (Tier 4)

• Parts needed:
  • 3x Enhanced Z-Pucks (with vibration damping)
  • 1x CAN Toolhead Puck (for EBB36)
  • 1x Motion Pucks (MGN12 rail mounts)
• Cost implication: Low (~$8-12 AUD for hardware)
• Donor compatibility: All donors
• Note: Same frame, upgraded pucks

Scenario E: Emergency/Improvised Pucks

• Parts needed:
  • Print pucks with custom dimensions for non-standard parts
  • May need to drill mounting holes by hand
  • Use generic bolt patterns
• Cost implication: Very Low
• Warning: Not supported by build123d scripts, manual dimensioning required

Implementation Notes

Puck Design Philosophy

All pucks follow standard pattern:
1. Frame Interface: Mounts to M12 rods or X-carriage
2. Component Interface: Standardized bolt pattern (per component type)
3. Interlock: Tab/slot or chamfered edges for alignment
4. Serviceability: Easy bolt access, removable without disassembly

Z-Puck (Motor Mount)

Function: Mounts Z-motor and leadscrew nut to M12 vertical rod

Design:
- Motor mount: 4x M3 bolt holes (NEMA17 standard)
- Nut trap: Captures leadscrew nut (M8 or TR8)
- Frame clamp: Slides over M12 rod
- Jam nuts: 2 per rod to lock puck in place
- Adjustable: Can slide up/down for initial positioning

Configuration:
Z_PUCK_HEIGHT = 60.0  # From config.py
MOTOR_OFFSET = [X, Y, Z]  # Relative to rod center

Brain Puck (Electronics Mount)

Function: Mounts main board to M12 frame

Design:
- Board mount: Matches board mounting pattern (varies by board)
- Cable routing: Cutouts for wire looms
- Fan mounting: Optional cooling fan for board
- Frame clamp: Slides over M12 rod
- Adjustable: Height and rotation

Standard Boards (Pre-defined Patterns):
- MKS SKIPR: 100mm × 100mm pattern
- BTT SKR 3: 95mm × 100mm pattern
- Creality 4.2.2: 110mm × 70mm pattern
- Anet V1.0: 115mm × 75mm pattern

Configuration:
BOARD_TYPE = "MKS_SKIPR"  # From config.py
BOARD_MOUNT_PINS = [[x1, y1], [x2, y2], ...]  # Auto-generated

Extruder Puck (Toolhead Mount)

Function: Mounts extruder/hotend to X-carriage

Design:
- Extruder mount: 4x M4 bolt holes (Greg's Wade pattern)
- Hotend mount: GrooveMount pattern (16mm diameter)
- Z-probe mount: BLTouch/PINDA mounting tabs
- Carriage interface: Bolts to X-carriage bearing clamps
- Modular: Swap entire puck for different toolheads

Toolhead Variants:
- WADE_PUCK:      Standard Greg's Wade
- STEALTHBURNER:  Voron StealthBurner
- SHERPA:         Sherpa Mini
- ORBITER:         Orbiter 1.5
- PLOTTER:         Pen holder
- LASER:           Laser module

Configuration:
EXTRUDER_TYPE = "WADE"  # From config.py
TOOLHEAD_PUCK_TYPE = "WADE_PUCK"
Z_PROBE_OFFSET = [X, Y, Z]  # Auto-adjusts in config

Motion Puck (Linear Rail - Tinker)

Function: Mounts MGN12 rail to M12 frame (optional upgrade)

Design:
- Rail mount: MGN12 bolt pattern (M3 screws)
- Frame clamp: Slides over M12 rod
- Adjustable: Precise alignment set screws
- Shim slots: For rail parallelism adjustment

Configuration:
MOTION_SYSTEM = "RAILS"  # vs "RODS" from config.py
RAIL_TYPE = "MGN12H"

Tool Pucks (Multipurpose)

Function: Convert 3D printer to other uses

Variants:
- PLOTTER_PUCK: Pen holder + Z-lift mechanism
- LASER_PUCK:  Laser module mount + safety interlock
- CNC_PUCK:    Spindle mount + dust shoe
- CAMERA_PUCK:  Time-lapse camera mount

Benefits:
- 30-second swap: One puck interface
- Software profiles: Klipper configs per tool
- No redesign: Frame stays same

build123d Puck Generation

# config.py drives all puck generation
from config import *

# Z-Puck generation
z_puck = create_z_puck(
    rod_dia=M12_FIT_DIA,
    motor_size=MOTOR_SIZE,
    nut_type=leadscrew_nut
)

# Brain Puck generation
brain_puck = create_brain_puck(
    rod_dia=M12_FIT_DIA,
    board_type=BOARD_TYPE
)

# Extruder Puck generation
extruder_puck = create_extruder_puck(
    extruder_type=EXTRUDER_TYPE,
    hotend_type=HOTEND_TYPE
)

Puck Mounting Pattern

Standard Bolt Sizes (from config.py):
Z-Puck:           M5 bolts (strength for motor weight)
Brain Puck:       M5 bolts (board weight)
Extruder Puck:     M4 bolts (precision, lighter)
Motion Puck:       M3 bolts (rail standard)

Standard Spacing:
M12 rod clamp:    40mm bolt spacing
Bearing clamp:     60mm spacing (dual-bearing carriage)
Board patterns:    Per-board (defined in config.py)

Maintenance

• Check tightness: Every 100 hours
• Inspect for cracks: Annual visual inspection
• Re-tighten after moves: If printer relocated
• Swap pucks: If upgrading components

Common Issues

• Puck slips on rod: Increase clamp pressure, check M12 diameter (lumpy factor)
• Bolt holes misaligned: Verify config.py dimensions, regenerate pucks
• Puck too loose: Add shims or adjust clamp design
• Cracked puck: Check print quality (infill, perimeters)

References

• ../manifesto.md: Section “The Modular ‘Puck’ & ‘Spider’ Concept”
• Parametric Design Pattern
• docs/AI-Conversations/ [Relevant conversations about modular mounting]