Personal Projects

Competition Class Automatic Espresso Machine (March 2025)

Requirements:

  • Competition-class espresso

    • Defined by the Barista Championship

  • Fine bean grind, consistent dosing, grind distribution, tamping to ~25 lbf, extraction water pressure of 9 bar, water temperature around 90 deg C, 25 s brew time, 25 mL of espresso volume

Part design/sourcing:

  • Grinder

    • Conical vs Flat Burrs

      • Flat burrs tend to heat up from repeated use but produce more consistent grounds for a better-quality shot; selected for its grind quality

    • Width of Flat Burrs

      • Wider burrs grind faster, 60-80 mm is common in high end grinders

    • Motor Selection

      • 1500-3000 rpm is standard for flat burr grind speed

      • Bodine 0261 (1700 rpm)

    • Motor shaft to Flat Burr shaft gears

      • GoBilda 2317 Bevel gear, 24 tooth, 1:1 ratio to maintain full rpm of motor

  • Tamping

    • Linear Actuator

      • Firgelli Micro Utility Actuator Model FA-MU-38-12-2

      • 38 lbf Max Load, 2 inch stroke length, mounted with M5 stainless steel bolts

    • In-Line Load Cell

      • DYMH-103, up to 30 kg (66 lbs) capacity, M5 rod end

      • Interchangeable filter for different ground dosages

  • Brewing

    • Boiler Type

      • Double Boiler for fast boil time and large volume

      • Allows for milk steamer attachment

    • Water Pump

      • 8 L/m, 12 V, High Temperature

    • Water distributor inside tamp/group head

    • Interchangeable & removable filters for single or double shots

  • Main Manufacturing Methods:

    • Assuming commercially available product, mass manufacturing methods were prioritized, and longer cycle time processes were reduced as much as possible

    • Sheet metal stamping and brake bending

      • Outer housing (Stainless Steel or Aluminum)

    • Die casting

      • Tamping assembly, puck holder, grinder burrs (Stainless Steel 316L)

    • Injection molding

      • All plastic parts (housings, main mounting structure) (High-temp, food-safe - Polypropylene)

    • Welding/Brazing

      • Boiler Vessels (Copper or Stainless Steel)

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