The Gartree School

School Postcode: LN4 4PN DCFS number: 5409
Staff member who developed this case study: Su Colman
Email contact: ms.colman@gartree.lincs.sch.uk  
School telephone: 01526 342379 No. on roll: 520
Brief pen picture of school: Gartree Community School is a small, friendly secondary covering key stages 3&4. In Technology we offer GCSEs in Food, Graphics, Resistant Materials and Textiles.

1. The Teacher CPD Course:

The Project Brief:
I am developing a new course for year 9, as I am delivering an RMT/Graphics element of the carousel that I am calling Product Design. The plan is to design and make a product and packaging with a graphical element using resistant materials and incorporating systems and control and some CADCAM that will be suitable for the new POS. This year students have had little or no electronics learning before, but next year, the groups will have done an assignment with LEDs and soldering.
Specification:
  • make a box suitable for money and electronics, using hand tools/CADCAM
  • include a graphic design element to appeal to teenagers
  • include a decorative element via CADCAM (currently vinyl cutting)
  • design a PCB to provide light and sound when money is put in the box
  • design a net suitable for the product packaging

Concept Sketches:

1. Electronic circuit development:
a) Circuit diagrams/schematics
b) PCB artwork
c) Program details
The Final Circuit Board:
Commentary:
2. CAD/CAM Development:
I have been using 2D Design Tools to produce the outlines that can be used to drive either the laser cutter or the router. I imported a .bmp file of a shark to create the outline for the top edge.

I used the line tool and snap to grid function to make an accurate outline to give comb joints to assemble the box.
We decided to test the joints by cutting card on the laser cutter. This revealed two inaccurate edges that needed modification, one on the top face, the other on the base.

I corrected the errors in the top and base walls, and cut a second prototype on the laser cutter, using thicker card and rastering the text and outline of the shark. I was happy with the fit, so we cut the box in blue light collecting acrylic.

This worked extremely well. I decided to try the file on the router, cut in MDF. I added the required features (line thicknesses, sprues) and 3mm MDF was tacked into place in the router.

I used a pad saw to cut the sprues, then filed the internal corners to square them out and allow them to fit. After sanding, the box assembled well.
Final CAD Design:
CAM Manufacture:
Commentary:

2. The Student Scheme of Work

Aimed at Key Stage: 3 (year 9)
Estimated time available for project: 39 periods of 50 minutes
National Curriculum PoS covered by Scheme of work:
1.1.a, 1.1.b, 1.3.c, 1.4.a, 1.4.b, 2a-h, 3b, 3j, 3m, 3n, 3o, 3p
The Scheme of Work:
Brief: “A specialist chain of gadget shops is looking for a new design for a money box to appeal to teenagers.They want it to include lights and sound, and appeal to boys and girls.”

Specification:
  • the box should be large enough to accommodate money and the electronics components.
  • the box should be decorated in a way that would appeal to teenagers.
  • the electronics should include light and sound
  • the electronics should be triggered by money going into the slot
Week Activity Risk Assessment NC/Links Homework
1 Design Brief and Task Analysis

Research - find 4 examples of money boxes and analyse god/bad points, and decde how they have been made.

Discussion - banks and money boxes - encourage saving - current practices		 No risk 1.1.a, d, 1.4.a, 2.d Write a questionnaire to get target market preferences
2 Use 2D Designer to lay out a cutting plan for the box including British Standard Dimensions.

Hand draw an isometric view of the box.

Collect a range of possible images for the front, giving reasons for the choices		 No risk 1.3.a, 2.a Get responses from 10 people to the questionnaire.
3 Freehand - layout for box front 200x160, cutting line 140 from bottom.
Use pen tool to create outlines.

Paste into 2D Designer and modify, join and split nodes		 No risk 1.4.b, 2.b Write up questionnaire results, graphs and analysis
4 Using the router to cut out designs, notes on using hardware and software.

Making the box - joints theory p110 CDT book - butt, lap, dovetail, finger

Materials - MDF - what and why - eco advantages?		 Use of router 1.4.c, 2.c, f Each student comes at lunchtime to cut own work
5 Using tools to cut the box - marking gauge, try square, tenon and coping saw, chisel, bench hook.

Making a template for the side and top walls - how big is money?		 Use of cutting tools 2.c, f Write up tools and processes used, see www.Technologystudent.com/joints/fingjt1.htm
6 Making the back
P109 CDT - clearance, countersink and pilot

Files and sandpaper

Drilling out for components using templates		 Cutting tools and drill 2.c Write up using woodscrews p109 CDT
7 Systems and control - input, process, output

Symbols used in flow charts
Substituting components

What do we need for input, process, output?
Drawing the circuit		 No risk 2.a Write a flowchart for making a cup of tea
8 Making a PCB

Drilling a PCB and populating it with components
Flying leads for some components

Following the diagram, soldering the components		 PCB drills, soldering irons 1.3.b Resistors, diodes and flash PIC’s
9 Making the coin slide

Completing and assembling components

Decorating the box - vinyl cutter		 Drills and other tools 2.f, 1.3.c Advantages and disadvantages of using paint or vinyl
10 Control - writing the program to control the components using flowchart software.

RTTL files

Testing the circuit		   2.g, 3.n, o, p, q Complete control program and print for folder
11 Final assembly
Cone for speaker
Peer review
Evaluation of product, suggested modifications		 Tools 2.e, h Production plan for making
12 Packaging as marketing - review of packaging - cultural issues (colour, images) environmental issues, lifestyle and image

How to create a useful package		 Scissors 1.1.a, d Self evaluation
13 Final packaging making
Photo to record product
Sort paperwork
Review SWANs		 Scissors    
List the design decisions (from David’s Barlex’s Nuffield D&T pentagon) you will be asking pupils to make.
Conceptual - teacher decision
Technical - teacher decision
Aesthetic - outline/teacher, detail/student
Constructional - outline/teacher, detail/student
Marketing - outline/teacher, detail/student (actual target market and packaging for the product is part of the assignment)
Student Outcomes:
Commentary:
This has been an invaluable opportunity to develop a new scheme of work and also to stretch myself and my confidence and understanding in electronics.

For the assignment I made several models using laser cut card and acrylic, a facility I don’t have at school, but the clear acrylic model has proved invaluable in being able to demonstrate to students how the final product works. They really like the look of the acrylic and many have asked me if we can get a laser cutter!

To make the product accessible at my school, I have made a few changes to the design. Some areas have been modified to ensure that the students can complete the product in the available 13 week slot, some areas to make the product affordable.
• the materials used are 4mm MDF for the fronts and 9mm MDF for the box.
• basic parts for the box are cut by me using the circular saw
• students mark and cut finger joints to assemble the sides, bottom and top. The number of fingers has been reduced to three interlocking sections on each joint, to make the process simpler.
• the money slot is made by drilling then using a coping saw to remove the material.
• the mountings for the PCB are drilled with a pillar drill.
• the fronts are designed by the students, then cut on the Denford Microrouter Compact.
• batches of PCBs will be made ahead of time and part drilled, and students will complete the drilling and populate the board.

| am currently running the scheme of work with two groups of year 9 students. It has been enthusiastically received, and many of the students have put in extra time at lunchtimes to “do a bit more on my project, Miss”.

The two groups I have are the top and the lowest ability in the cohort, and both are enjoying the work and are especially pleased with the output from the router. They are amazed that the paths they create in the software are so faithfully reproduced by the machine - it makes the process of CAD CAM very real to them. The CAM fronts are the main bottleneck, but the outcomes are so good, I could not go back to having the students cut their own by hand.

We haven’t yet started the electronics part of the making, that will come after the submission deadline for this assignment. All of the students who were at the school last year have used soldering irons and some components with me in the Year 8 assignment, but using a PCB is new and one of my main concerns is the level of frustration they are likely to encounter as they try to complete their boards and make mistakes, particularly in the lower sets.

I presented the project to two of our school governors as part of a departmental feedback session and was delighted to find that the governors concerned are both electronics engineers and have volunteered to come into school and help me with trouble shooting circuit boards when the time comes.

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