Housing+Designs


Tips and Techniques > Homepage > __Housing Design__

Welcome to the Tips and Techniques, Housing Design page. Within this section of the Digital Design & Technology Wiki you will find useful tips and techniques for the manufacture of electronic projects within schools. The aim of the this section is to provide information and resources in text, picture and video format that can be used for developing electronic projects or can be shown in the classroom to aid students in creating quality end electronic products.

**Contents  **

1.0 Home
2.0 Housing design 2.1 Overview 2.2 Line bending 2.3 Vacuum forming 2.4 CAD/CAM 2.5 Construction techniques 2.6 Also see 2.7 References 2.8 External links 3.0 PCB mounting 4.0 Battery access/mounting 5.0 Project enhancements

**Overview**

 
When we refer to a housing design within the context of electronic school project we are actually refering to the physical project that houses the electronics or PCB of the project. On this page are several tips and techniques for designing simple, cheap and easy to make housings that can turn an electronics project into an electronics product.


**Line Bending** __What is line bending?__ Line bending in the technique used to bend thermoplastic using a strip heater. [|Click here for more info (external link)] __How can line bending be used to produce quality project housings?__ Line bending is not usually considered as a method of producing actual project housings, however this method is a quick, cheap and simple way of producing partcial or full housings for projects. This can be done in several different ways. __Partial housings__ The partial housings method is a method whereby the PCB is held in place by a line bent piece of plastic which does not completely cover the pcb, i.e. the PCB is fully or partially visable. Advantages Cheap to make Quick Easy Fit for purpose Good access to components and batteries Disadvantages Not usually a method used in industry

//Examples of partial line bent housings// __Development or net housing__  A development or net housing is a line bent housing made from plastic that like a packaging development/net folds up into a box that completely covers the PCB or has parts purposefully removed for access to certian components; usually batteries. Advantages Professional Can be integrated with CAD/CAM (using CAD/CAM to cut the development and etch the bend groves) Disadvantages Complicated to design and construct Plastics can be easily glued to aviod this process

//Examples of development or net housings// NOTE: The example below, although was design using CAD and the development cut using a CAM machine it has purposeful parts of the net cut away to allow access to the batteries mounted on the PCB.

<span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">**Vacuum forming**

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__What is vacuum forming?__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Vacuum forming is a simplified version of thermoforming whereby a sheet of thermoplastic is heated to its moulding temperature and then stretched over a mould using air suction. ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__How can it be used to produce quality project housings?__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Vacuum forming is a very common technique present in almost all school workshops across the country, however because the moulds often take along time to produce schools often suggest, especially at key stage 3, that pupils design and make a simple shape from thin plywood or cardboard that fits ontop of a pre-manufactured generic mould to personalise their projects. <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Although this allows pupils time to experience the process of vacuum forming it doesn't allow pupils to produce individual, professional and visually exciting end products. ==== ====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">There are a couple of ways that teachers can deliver projects using pre-manufactured moulds but allow pupils the choice to vary and personalise their projects. ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__1. Varying project outcomes__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">When delivering an electronics project in school, teachers should try to design different uses for the same circuit and combine this different use with the same generic vacuum forming moulds. This allows the pupils to decide what they are going to make, giving them more choice and hopefully more interest in the project. ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">For example,
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Shown below is the frisbee project as designed by Sheffield Hallam University. Alongside this project are two further projects which use the same circuitry and vacuum forming moulds but the result or project outcome are entirely different. ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__2. Sublimation printing__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __What is it?__   ==== ====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> A printing process in which a specialist ink/dye is heated and converts into a gas, this gas can then be inpregnated into any polymer based material which permanently traps the gas as the image of the orginal dye. ==== ====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __What does it do?__   ==== ====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> Sublimation printing allows pupils to design a graphic product uisng any software package on a PC and then using a adapted normal injet priter, print out the image onto a specialist paper. Using a heat press the image can now be pressed onto any polmer based material (e.g t-shirts containing polyester, HIPS plastic sheet) to provide a permanent transfer of the image. The image remains permanent because as the press heats the specialist ink/dye it turns into a gas at the same time the polymers of the material absorbing the ink/dye begin to open up and trap the gas within them. Therefore when the material cools the result is an image that is literaly 'trapped inside' the material. ==== ====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __How can it be used to produce quality project housings?__   ==== <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> Sublimation is a fantastic way to integrate graphics into a project. Pupils can use any number of graphic software packages to design a graphic product that enhances their project. This graphic product can then be inpregnated within their project material to give a long lasting professional finish. Sublimation printing is not only a fantastic aid in subject such as Textiles and Graphics within school, it can also be used on HIPS sheet prior to vac-forming resulting in patterned vac-formed plastic, great for adding zainy and wacky artwork to resistant materials projects. The housings of the three projects shown above (frisbee, battling top and spinner) have used sublimation printing prior to being vacuum formed or which the result is obvious. <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-SIZE: 110%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">    <span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> <span style="FONT-SIZE: 90%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Click here for further info

<span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">**CAD/CAM** <span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __What is CAD/CAM?__ CAD stands for Computer Aided Design and CAM stands for Computer Aided Manufacture. The abbreviations CAD/CAM are usually used to describe the technique of creating a design on a computer package (CAD) and manufacturing the design using one or more of a range of machines that are controlled by the computer (CAM). __How can CAD/CAM be used to produce quality project housings?__ CAD/CAM is a standard industrial technique used to manufacture almost all of our consumable products and using CAD/CAM pupils can produce extremely high quality project housings. The abbreviations CAD/CAM refers to a technique which can have a massive range of outputs depending what CAM machine is connected to the output of the computer. Using CAM machines in any project is a good way to speed up the manufacture of projects as pupils can be given a demonstration, perhaps watch a couple of piece made and then the rest can be manufactured during the week ready for the next lesson. Furthermore, the majority of housings produced this way require little or no finishing. This section will attempt to breifly cover several of these CAM machines that are more commonly found in schools and provide some tips on how these can be used to produce project housings.

__Laser Cutter What is it?__ A Laser cutter is a CAM machine that cuts a variety of materials using a high power laser. The point on the material at which the laser is concentrated either melts, burns or vaporises away leaving an edge with a high quality surface finish. Although in industry laser cutters are used to cut a variety of flat sheet and 3D objects, the laser cutters found in a small percentage of schools are always flat sheet cutters. The thickness of the sheet that can be cut depends on the material. __How can it be used to produce quality project housings?__ Project housings can be designed using CAD and quickly manufactured to an extremely high standard. Due to the fact that the Laser cutters found in schools can only cut flat sheet material the easiest way to create a project housing is to build the housing up in 'layers', with the centre several 'layers' being hollow to allow room for the PCB to sit. //Examples of Laser cut layered housings// <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__CNC Router or Milling machine__ <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__What is it?__ A CNC router or milling machine are both CAM machines that can be used to cut and shape a variety of materials, however it is usually wood or plastic which are used. Similar to the hand router the CNC router using a variety of router bits in many different shapes whilst a miller usually usually cuts just straight lines. The material is fixed to the bed which stays static and the motor, which moves on all three planes, then uses the correct size and shape cutting bit to shape the material to the relevant CAD drawing. <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__How can it be used to produce quality project housings?__ Most schools have CNC routers or milling machines available and these can be used in a variety of different ways to produce and personalise housings for projects. Using CAM machines in any project is a good way to speed up the manufacture of projects as pupils can be given a demonstration, perhaps watch a couple of pieces made and then the rest can be manufactured during the week ready for the next lesson. Furthermore, the majority of housings produced this way require little or no finishing. //Examples of products produced using a CNC router or Milling Machine// <span style="DISPLAY: block; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif; TEXT-ALIGN: center">

__<span style="DISPLAY: block; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif; TEXT-ALIGN: left"><span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Desktop Engraver __<span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __What is it?__ A desktop engraving machine is again a CAM machine very similar to the CNC router just on a smaller scale, designed for small cutting jobs and sign making. However, these machines are often found in schools due to their low cost and versatility. __<span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> How can it be used to produce quality project housings? __<span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> When making project housings these machine can be used to cut thin plastics to create net or development housings as well as line bent housings. Another great advantage to using a desktop engraver is that the machine can be programed to scibe on all the bending points of the housing ensuring all students bend their housing in the correct place. This machine is also great for adding finishing touches to projects such as 'engraved' lettering or designs.

__Rapid Prototyping/Manufacturing__ __What is it?__ Rapid Prototyping is the automatic production of often complex 3D objects using a method called 'solid freeform fabrication'. A design produced using CAD is translated into thin layers and using a 'solid freeform fabrication' machine the object can be physically produced. This process can be used to produced very complex often 'impossible' shapes such as balls inside balls. The 'solid freeform fabrication' device can operate in a number of different ways. Once the 3D shape has been translated into very thin layers some of these machines use lasers to cure liquids into solids to form the shape, whilst others use lazer to melt metal powder and others use nozzle technology to extrude hot plastics. <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __How can it be used to produce quality project housings?__ Rapid Prototyping is usually a very expensive process not financially viable in schools, however these methods could be used to produce exemplar housings to show pupils. This could also be a great process to show KS4 and KS5 pupils and could provide a good educational base for a trip to a local company or university to showcase this method. //Examples of rapid prototyping//

====<span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"><span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> <span style="FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Construction Techniques  ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__What does this mean?__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Construction techniques is the way in which the project housing is constructed. If a project housing has been manufactured using either the vacuum forming method of a CAD/CAM method, how is it all going to fit together? ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__How can the construction technique used contribute to a quality project housing?__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">There is no point in producing top quality housing components using industrial methods if they are then simply sello-taped together to produce the final product. The way in which the housing components come together to form the final product is just as important as the housing itself. This section will try to breifly cover several methods of joing housing components together, giving brief examples of each. ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">__Nylon Nuts and Bolts__
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Using nuts and bolts to secure two housing components together sounds linke a rather cruude method. However, the use of nylon nuts and bolts is rare but provides a removable professional finish that is light weight and easy to use in the classroom. ==== <span style="FONT-SIZE: 80%; COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">How to use them <span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> <span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> media type="custom" key="2064226"

Advantages

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> Professional finish
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> <span style="FONT-SIZE: 110%; COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">Disadvantages  ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> Very fiddley
====<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> Where can I buy them from Middlesex University Teaching Resources (MUTR) Online: http://www.mutr.co.uk/product_info.php?products_id=153    ====

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> How much do they cost?
<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> £0.03-0.05 each

<span style="FONT-SIZE: 80%; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">
<span style="FONT-SIZE: 80%; COLOR: #000000; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __Adhesives__ Adhesives can be a quick and easy solution to joining project housing together. In schools there are usually a couple of these readily available. __PVA (Polyvinyl Acetate)__ PVA is a typical adhesive found in all schools, this might also be called 'wood glue'. This glue provides a very strong, permanent bond between all woods. Uses On all woods Paper Cloth Advantges Very cheap Minimal risk to health and saftey Easy to clean Disadvantages Drying time Cost £1.50+ per litre <span style="FONT-SIZE: 80%; COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif"> __Tensol__ Tensol is a catalyst cement that provides a high strength bond to most thermoplastics exspecially Acrylic. Uses Acrylic Advantges Gap filler Very strong Bond sheet Acrylic Disadvantages Toxic so teacher must apply Cost £20.00+ per litre

__Dichloromethane__ Dichloromethane is a solvent adhesive widely used in schools to bond plastic joints and is ideal for bonding project housings together. Uses Thermoplastics Advantages Very strong Ideal for butt joints Disadvantages Evaporates in air so needs to be used in ventelated places Cost £5.00+ per litre

<span style="COLOR: #0080ff; FONT-FAMILY: 'Lucida Sans Unicode', 'Lucida Grande', sans-serif">**Also see**

**References**

External links

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