© Boardworks Ltd 2005 1 of 17 Resistant Materials Evaluation Techniques These icons indicate that...

© Boardworks Ltd 20051 of 17

Resistant MaterialsEvaluation Techniques

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Learning objectives


Lea

rnin

g o

bje

ctiv

es To understand that evaluation is a very important part of the design and manufacturing process, and should take place at different stages of this process.

To conduct a research evaluation.

To ask prospective end users for feedback.

To test the final product.

To evaluate the final product against the design brief and the product and manufacturing specifications.

To recognize that when criticizing a design or product, it is necessary to include your own personal solutions or improvements.


To evaluate something means to judge its worth or value. These are the types of questions that are involved in evaluation:

How well has the product been designed?

How well has it been made?

How should I test my product?

What will other people think of my product?

Evaluation


Evaluation


Before you begin to evaluate, it is important that you understand the criteria that are used in a product design specification.These criteria influence the design of commercial products.A product needs to be evaluated against the product design specification.The performance of the product will need to be assessed against:

client needs designer needs manufacturer needs user needs.

Product Design Specification


Needs


The first motorways were built in Britain in the 1950s.

There was a need for a new design of road signs.

The new signs needed to make it clear that the road was a motorway.

They had to be able to be recognized and interpreted by drivers of cars which were travelling at high speeds.

Which other features can you think of that would be important for motorway signs?

Background

Motorway signs


What would your design for a motorway sign be?

Different needs


The colour blue for motorways was a good idea because it is clear and easy to recognize from a distance. The exact shade of blue took a while to decide. The signs were tested by getting people to drive at them at various speeds. What would I change?

Well, I designed the men at work sign. The first drivers said it looked like someone trying to open an umbrella. Then the newspapers joined in! I really wish I had tested this one a bit more. I wish that I had made the spade’s handle longer.

6

London

Basingstoke

Reading

A33

Now choose another road sign to evaluate.

A designer’s evaluation


There are two types of physical testing that can be carried out:

DESTRUCTIVE TESTINGIn destructive testing, a product is put under stresses until it is destroyed. This allows you to establish exactly how much force a product can withstand.

NON-DESTRUCTIVE TESTINGIn non-destructive testing, you test a

product to ensure that it functions correctly – the product will not normally be damaged by this.

Testing and evaluation


If you want to destructively test a product then you apply extreme conditions and record the amount of force it takes to destroy the product.

If the product is well designed, you will need to apply extreme pressures that are much greater than the forces that the product would normally encounter in real life situations.

When you test non-destructively, you are testing how the product functions under normal conditions. This does not normally destroy the product.

Non-destructive tests can include testing a product’s appearance, its measurements and its functionality.

Testing and evaluation


How expensive should it be?

Function

Form

Cost

To clean teeth.

One that fits comfortably in the mouth. One that fits comfortably in the hand.

What is the main function of a toothbrush?

What shape does it need to have?

Relatively cheap because they have to be replaced frequently.

Analysis of a toothbrush


One design solution is to have an electric toothbrush.

Can you think of any disadvantages to using an electric toothbrush?

The movement of the head means that teeth are cleaned more thoroughly and effectively than with a random hand movement.

The head is small and easily fits inside the mouth.

The handle is ergonomically sound.

The head is replaceable to reduce costs.

The batteries can be easily inserted at the bottom.

Electric toothbrush


This design of toothbrush aims to make the handle an ergonomically sound fit. A lot of research went into hand size, shape etc.

What is your evaluation of this product?

The ergonomic toothbrush

The finished product looks attractive but does it work?

Do you keep your hand in one position when you brush your teeth, or do you change hand position?

Why is the head so much bigger than with other toothbrushes?


This early video recorder was a very good idea at the time.

It was a very successful product and was bought by many people.

Can you see the problems?It is top loading.

This means that it cannot fit in a slim line shelf unit.

You cannot put anything on top of it (like a TV!).

You have to have access to the top.

How would you improve the design?

Analysis of a product


Don’t forget – evaluate every time you make a product! When you do, it is helpful if you can find as many different people’s opinions as possible.

Evaluate it against the specification – look back at your initial specification requirements. Have you fulfilled them all?

Get feedback from the end user – can the product be used successfully? Is the customer happy?

Evaluate it personally – are you happy with your product? Is there anything you wish you’d done differently, or are there any problems you didn’t fully solve?

Ask for information from the points of view of the client, designer, manufacturer and user/consumer.

Think of three questions to ask each of these people regarding the evaluation of your product.

Final evaluation


Key points


Key

po

ints

the clientthe designerthe manufacturerthe user.

The most important people’s opinions to take into account are:

Evaluating a product well involves evaluating it against:

its specificationany social issuesthe manufacturing processany potential improvements.

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