156B Week 7

Overview of Status of Analysis, Design, Fabrication, Tests, etc.

• • Heating

    • Tested secondary heating pad that came in 

      • will need two to heat the container evenly and keep it at consistent temperature gradient throughout

    • bought smaller stainless steel container for tea brewing

      • will need outer metal bowl to attach heating pads to so that heating pads are not directly attached to tea container

    • Water will be cycled through flow-through heater and output will be pushed into brewing container at right temperature

      • using time-based controls

    • Pad adhesive seemed to burn at the operating temperature

  • Gate Valve

    • Met with electrical engineer on the sponsor's team (Matt) and tested 3D printed stick attached to stepper motor

      • adjusting the shape of stick/arm to fit the coffeemaker

      • needs more room above the kettle, will need smaller kettle

    • Motor mounted on reinforced shelf at the same height as the gate valve

      • arm and motor mated through machined aluminum adapter

  • Magnetic Stirring

    • Motor connected to a magnet drives a second magnet in the kettle, rotating and stirring the milk to prevent it from boiling over, and also mixing the tea once it drops into the kettle

    • Adjusted mounting of flow through heater to fit motor for stirring and to minimize attraction to other metal parts

      • will need to add height to the current base for motor to fit

Accomplishments from Previous Week

• • Measured temperature gradient of secondary heater

  • ordered more parts

    • another heating pad, insulation, smaller metal containers for brewing tea, separate stirrer

  • Ran multiple taste tests with Prince to confirm proper tasting tea

  • Tested the 3D printed arm for gate valve opening

  • Cut away unnecessary metal parts and redirected the wires/circuit to minimize unwanted attraction to the metal parts

  • Machined motor/arm adapter

  • Tested the motor torque against the gate valve

Goals for Next Week (list names after each item). Use specific and measurable objectives.

• • Test new parts

    • Will need to test two heating pads onto the small metal container with water heated from the flow through heater

      • make sure that the brewing temperature stays around 90C

      • test to see if the adhesive is burning at the operating temperature (if so, remove with alcohol)

    • Test ordered stirrer to make sure it works with our objectives

  • Find the operating temperatures for the stirring motor, determine if heat shielding is necessary

  • Reinforce the mounted portion of the plastic base with plastic on the inside and metal sheet on the outside

Sponsor Comments from Last Meeting and Actions Taken to Address these Comments (indicate date of comments and if via email or in person)

• • Look into thermal switches

    • will probably go with time-based controls and not temperature sensor based

  • AC relays

    • talked to Electrical Engineers (Kevin) who is currently working on it

Instructor Comments from Last Meeting and Actions Taken to Address these Comments  (indicate date of comments and if via email or in person)

• • Take initial temperature of water to be room temperature

Comments from Other Students in the Class (indicate date of comments and if via email or in person)

Risks and Areas of Concern

Resources or Information Required but not Available

Schedule

• • Need to be able to assemble everything together

Budget (list amount spent and amount remaining)

• • $390 spent; $410 remaining

Progress on Report and Webpage