Week 18 - Applications and implications

Week 18 - Applications and implications

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Individual assignment

propose a final project that integrates the range of units covered. Projects can be separate or joint, but need to show individual mastery of the range of skills covered. Where possible, you should make rather than buy the parts of your project. Topics for this week are included below.

what will it do? Specification

The product must:

  1. cure carbon fibre parts using open and closed moulds at a minimum of 80 deg C up to 14 hours
  2. accomodate an internal volume of at least 300 x 200 x 200 mm
  3. be programmable according to a set temperature/time schedule
  4. be mains powered
  5. have a safety cutoff??
  6. allow for local control of temperature via simple 'set' temperature using a simple 'bang-bang' thermostatic control
  7. allow for remote control via computer programme with wired/wireless connectivity, including PID temperature control
  8. accomodate a vacuum pump connection
  9. regulate temperature in at least two internal locations to within 2.0 deg C
  10. include relevant heat transfer, electrical and electronics theory - and be a useful exemplar for students wanting to carry out a project which includes these topics
  11. have sufficient documentation to allow for this to be reproducable with similar equipment

The product will ideally:

  1. have a programme to load .csv files for the temperature/time schedule
  2. plot the set and actual temperatures in a live feed
  3. accomodate curing cycles up to 130 deg C
  4. include 'smart' capability, whereby PID 'tuning' is based on performance history and some learning/AI capability
  5. not include the subframe of an existing product (but be designed/made by me)
  6. not include the heating element of an existing product (but be designed/made by me)
  7. not include the fan of an existing product (but be designed/made by me)

Who's done what beforehand? Research and competitor analysis

Denis Terwagne's 2017 final project
I was quite inspired by Denis Terwagne's 2017 final project which was a physics tinking kit, to provide a cleverly designed platform for students to play with various aspects relating to physics theory. I also found this PID controlled carbon fibre curing oven (here's the link). diy curing oven
This was a really useful project to learn from, I'm aiming to do something similar, hopefully more sophisticated but smaller since I will only really work with small samples.

I was also impressed by this project:here's a good project in terms of presentation, it's a light display.

Here's a link to a project that includes a library with code for making a PID controller, including with an adaptive tuning algorithm.

And here's a good tutorial for writing code in arduino IDE to create a PID controller

And here's a link to an open source PID controller with all the documentation.

Here's another project where they've made a PID controlled oven - although they bought the PID controller.

And here's an interesting paper on testing smart thermostats. Finally, this guide explains how to go about tuning the PID in a systematic way...I wonder if this can be automated?

On a slightly different note, here's a useful guide I will need to put my thermistor measurements into a Wheatstone bridge. Since the relationship between the voltage reading across a thermistor and temperature is highly non-linear, we'll need to use a bridge to do this correctly.

Raw materials and components, sources and costs...Bill of Materials

Classification Part name Source Cost per item Number required
ELECTRONICS ATMega32U4 FABLAB INVENTORY £3.32 1
RED LEDS: 1206 FABLAB INVENTORY £0.24 3
22 OHM RESISTOR: RES-US1206FAB FABLAB INVENTORY £0.007 2
499 OHM 1206 RESISTOR FABLAB INVENTORY £0.007 3
RES-US1206FAB 680 OHM RESISTOR FABLAB INVENTORY £0.007 1
10K OHM RESISTOR1206 RESISTOR FABLAB INVENTORY £0.007 3
10uF CAP-US1206FAB CAPACITORS FABLAB INVENTORY £0.24 1
1uF CAP-US1206FAB CAPACITORS FABLAB INVENTORY £0.24 2
0.1uF CAP-US1206FAB CAPACITORS FABLAB INVENTORY £0.24 1
18pF CAP-US1206FAB CAPACITORS FABLAB INVENTORY £0.24 2
CSM-7X-DU 16 MHZ CRYSTAL FABLAB INVENTORY £0.88 1
MINI-B USB CONNECTOR FABLAB INVENTORY £0.77 1
CONNECTORS (FTDI) FABLAB INVENTORY £0.02 1
SPST_TACT-EVQQ2 BUTTONS FABLAB INVENTORY £0.34 3
24V 10 A RELAY EBAY £3.23 1
6 pin OLED SCREEN amazon £4.95 1
HEATING SYSTEM MAO5 - 5 V DC FAN EBAY £4.49 1
24 V DC, 10 A HEATING ELEMENT EBAY £4.88 1
24 V DC, 10 A Universal Regulated Switching Power Supply INDUSTRY MALL - EBAY - https://www.ebay.co.uk/itm/181881169501 £12.99 1
3pin active temperature sensor ebay £0.96 1
MAIN CASING 13 MM HIGH TEMPERATURE INSULATION, 6 X 61cm x 366cm x 13mm EBAY £30.00 1
MAIN CASING CARBON FIBRE VINYL COATING EBAY £6.26 1

what parts and systems will be made? and what processes will be used? Fabrication processes and materials

Sub assembly Part name Material Fabrication process Number required
MAIN_CASING FRONT_CONTROL_PANEL 2 MM PLY LASER CUT 1
FRONT_CONTROL_PANEL 2 MM PLY LASER CUT 1
FRONT_TOP_PANEL 2 MM PLY LASER CUT 1
FRONT_BOTTOM_PANEL 2 MM PLY LASER CUT 1
SIDE_PANEL 2 MM PLY LASER CUT 2
BACK_PANEL 2 MM PLY LASER CUT 1
TOP_PANEL 2 MM PLY LASER CUT 1
BOTTOM_PANEL 2 MM PLY LASER CUT 1
BUTTONS SILICONE CAST 1 (3 BUTTONS)
FEET PLA 3D PRINTED 4
HEATING SYSTEM 2 MM PLY LASER CUT 1

what tasks need to be completed? Key tasks list

what is the schedule? Planning and management

week 1 (starting 21/5/18):

week 2 (starting 28/5/18):

FINAL WEEK (starting 4/6/18):

what questions need to be answered? Issues tracking

How will it be evaluated? Critical review

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