156B Week 3

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

• • Presented Updates and Progress to Sponsor

  • Further Research on Design ofMounting Structures

  • Looking into DUT Design

Accomplishments from Previous Week

• • Looked into different load cells from various vendors (both button and s-beam load cells)

    • Compared Pros and Cons to finalize which one to go forward with

  • Researched into read out displays for different load cells

    • Compared Costs

  • Created CAD design for sensor mount

    • Using proper screw sizes and dimensions for accurate analysis

  • Looked into different heat sensors

    • Thermocouple, Thermistor, RTD

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

• • Sam

    • S-Beam Load Cell Read Out Displays

      • Check if third party instrumentation is compatible with other load cells

    • Look into Multipoint Calibration

  • Damon

    • Force Analysis of Plate and Joints

      • Check Fastener Analysis in Simulation to find proper screw sizes

  • Daniel

    • Work on making the mounting fixtures easy/user friendly to satisfy ease of use priority to customers

      • Perform CAD/Hand-drawn designs

  • Richard

    • Look into solutions to mount 3 different heads for the various head sizes

      • Perform CAD/Hand-drawn designs

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

• • Try looking into the Cooper Instruments & Systems Load Cell for read out display or signal conditioning instrumentation

    • Already using the load cell in previous model

  • S-beam Load Cell would be better than button load cell, due to higher accuracy and lower cost.

  • Current CAD Design of mounting fixture may be too flimsy

    • Too complicated with screws

    • Too many moving parts?

  • DUT

    • Dimensions

      • Settle on average from all head sizes

        • 25x25mm or 1x1in

      • Good Geometric tolerance and Smooth Surface to ensure proper contact to thermal heads

    • Generating Heat

      • Depends on Head Size

        • ~5W/10W to 100W/200W power for minimum to maximum head sizes, respectively

          • Use 150W as a good average

        • Vary voltage to get different power

      • Look into Cartridge Heaters

      • Heating time shouldn't be an issue

        • Try performing analysis with cooling fluid information

      • Look into Heater Resistance and Responsiveness analysis

        • Thermal Resistance of Thermal Head from Heater to Fluid?

    • RTD

      • For accuracy, use thermal epoxy

        • Company already uses thermal epoxy for other projects, could use that

      • Pt-100 RTD model is already used in Cohu with other projects as well

    • Safety Concerns

      • Cut off power when reached maximum temperature in order to not damage SLK thermal head

        • Circuit Breakers?

        • Thermal Switches?

        • Thermal Fuses?

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

• • How to get higher accuracy for Load Cell?

    • What causes Hysteresis, Linearity, and Repeatability Errors?

  • Location of Strain Gauge on S-Beam Load Cell?

  • Error of non-vertical loading on S-Beam Load Cell?

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

• • N/A (No presentation to the class this week)

Risks and Areas of Concern

• • DUT

    • Safety Risk

      • Incorporate a kill switch

    • Ensure mounting doesn't conduct heat generated from DUT

      • Don't let the SLK head heat up from generated heat

Resources or Information Required but not Available

• • N/A

Schedule

• • Describe upcoming milestone

  • Update Gantt chart.

Budget (list amount spent and amount remaining)

• • N/A

Progress on Report and Webpage

• • Updating Webpages