Espresso Machine Disassembly

Introduction

• The espresso machine pump was selected as the main analysis subject due to its role in pressurizing water flow.
• The disassembly process allowed observation of connections, spring-damper structure, and constraints, although internal parts could not be fully measured.
• This limitation required theoretical modeling combined with experimental verification.

Theoretical Modeling

• The pump piston was modeled as a spring-damper dynamic system.
• Assumptions included estimated elastic modulus and damping values due to limited access to internal parts.
• MATLAB simulation was used to predict piston movement, expected flow rate, and noise characteristics under different pressures.

Experiments

• Flow Rate Measurement

  • Measurements at 0 bar, 4 bar, and 6 bar.
  • Observed ratio: 1 : 1.36 : 1.65 (close to theoretical 1 : 1.3 : 1.6).

• Noise Measurement (dB)

  • 0 bar: 72.4 dB
  • 4 bar: 70.5 dB
  • 6 bar: 64.5 dB
  • Noise decreased as extraction pressure increased.

Results and Discussion

• Theoretical assumptions and MATLAB predictions were supported by experimental results.
• Minor discrepancies were due to parameter estimation errors, such as unknown spring stiffness.
• Despite limited disassembly, the dynamic system approach was effective.
• The workflow demonstrates system modeling, simulation, and experiment as a transferable methodology.

Conclusion

• The pump analysis combined reverse engineering, dynamic modeling, and experimental validation.
• Key insights:
  • Flow rate and noise can be predicted with a spring-damper model.
  • Experimental results support the theoretical assumptions.
• Future work: full disassembly and direct measurement of material and spring properties to refine the model.