Rugby School Thailand Design & Technology Senior School

2.6 Selecting tools / processes

Learning outcomes

By the end of this unit you should have developed a knowledge and understanding of:

how to select the correct tools and equipment for specific tasks
safe working practices for completing your own project work
how to select the most appropriate manufacturing processes to realise design proposals
how designs are developed from prototype to mass production
the effect on the manufacturing process that is brought about by the need for batch and mass manufacture
the importance of health and safety in a commercial setting

Introduction

Successful manufacture is influenced by many factors such as

the material and material cost
product function
scale of production
proposed retail cost

Designers need to have a sound knowledge of materials and how they are processed so that final manufacturing decisions can be made in conjunction with the manufacturing team.

The main aim is to select a manufacturing method that is both suitable for the material and product, as well as economic in terms of materials and scale of manufacture.

One example is yoghurt pots which are made in high volume via thermoforming. Multiple moulds on one sheet keeps waste to a minimum while providing the draft angles for ease of mould removal.

Vacuum forming is less suited to small scale production given the time taken to make the moulds as well as the material wasted when the mould is removed.

Selecting Correct tools and processes

Selecting the correct tooling involves knowledge of manufacturing processes as well as the materials used for each manufacturing process.

Let’s take a game controller as an example:

The casing for the controller is made from a polymer so it could be blow moulded to produce a hollow shape for the internal components to fit into, but that process does not produce the high level of detail necessary.

Vacuum forming would also results in a hollow shell, but not have uniform thickness and would have excessive waste. The two halves could not have any complex interior details either.

In this case, injection moulding is the best method as it could have precision elements, textures applied and interior fittings for circuit boards etc.

Safe working practice

Safe working practices serve to keep the person doing the work, as well as those in the vicinity, from harm. These safe working practices may include a set of guidelines for the person(s) in the workshop to follow.

See Unit 1.9 for more information.

Risk assessments are a good way to initially consider what may cause harm to people, and the way in which people can be protected, as much as is practicable, from hazard or harm.

Commercial manufacture typically involves more staff than bespoke manufacturing being undertaken by a designer maker.

Employers must maintain safety standards across a wide range of potential situations with a varying number of people with different experience levels.

The following checklist might be used:

duration of the job, risk of RSI, accidents due to boredom
identifying hazards that could be controlled before and during manufacture
machinery and equipment condition and reliability
electrical safety of power supplies, leads etc.
availability of PPE, safety guards, signage etc.
emergency equipment such as stops, fire extinguishers, clear access to fire exits etc.

Prototype to mass production

In commercial manufacture, prototype products are often the starting point for future productions of batch or mass-produced products.

Given the time and resource limitations for students, it is unlikely that products will ever be produced beyond a one-off outcome or small batch of a range of smaller products. However, these should still be considered ‘prototypes’ rather than commercial products and it is still important to consider how these might be manufactured in more industrial environments.

In other words, it may be a ‘one-off prototype’ that you realise as an outcome, but you should still consider how you take that design into larger scale production, including the choice of materials and manufacturing processes.

Already covered extensively in previous units and additional presentations, here is a quick reminder of the several types of prototype:

Visual prototype: this is concerned more with the appearance of the product including shape, size, proportion, materials, colours etc. but may not necessarily be functional. It may even be made from styrofoam, 3D printed or constructed from other modelling materials.

Proof of concept: this is a working prototype and, conversely, may not actually represent the look of the final product, but will be functional so it can be tested and evaluated.

Production prototype: this is a combination of both and will look and perform like the intended product, but the tooling and planning for mass-manufacture may not be completed yet until the prototype has been fully tested and evaluated.

Batch and Mass manufacture

The number of components or the complexity of the product and the volume of production will determine the type of machinery used to create a product.

Designers have to consider many things including function, materials and cost, as well as what manufacturing technologies are available and affordable for the product being manufactured.

There are four key terms associated with the volume of production:

one off production

2. batch production

3. mass production

4. continuous production (this is a form of mass-production)

One-off

is a product that has been designed and manufactured for a single, specific situation. Most one-off products are hand made and often referred to as ‘bespoke’. They are likely to be expensive to reflect the skill of the maker and the higher quality materials used in their manufacture.

Batch production

is where a set number of products are made at one time. Often used in food production where a baker may bake a batch of products at one time then again later in the day depending on demand.

They may also be large batch products such as a limited edition camera or games console. There will need to be some way of ensuring products are manufactured to the same standards.

Mass production

is where large quantities of the same standard product or component are made. Mass production is used for products that we use every day and, for which there is therefore high demand, such as light bulbs and polymer food and drink containers. This scale of production is likely to have investment in large scale manufacturing equipment, employ more people and have more complex manufacturing and assembly stages.

Continuous production

is used for when there is a continued need for the product and these are often consumables such as food, water, milk, gas, electricity and even packaging. Coca Cola make their own bottles so they need to do this continuously to meet demand. There is essentially a never ending supply of these consumables.

For each of these production methods, a different manufacturing method will have to be considered and this could also affect the type of materials used.

A plastic bottle could not be made accurately or in large enough quantities by hand or using basic machinery, nor is it practical to invest in injection moulding tools and machinery to make just a few polymer based items.

Investing in CNC machines to make a few wooden products is not practical so they would be made using a range of hand tools and smaller items of machinery.

A product might be hand carved from wood in very small numbers but, on a larger scale, mass moulding might be needed in which case a material that can be formed as a liquid, such as metal or polymer, might be used instead.

Summary

Successful manufacture is influenced by factors such as the material, material cost, product function, scale of production and proposed retail cost.

The main aim is to select a manufacturing method that is both suitable for the material and product, as well as economic in terms of materials and scale of production.

Ensuring the safety of employees, visitors and others within the workplace is key in terms of good practice.

Many employers make use of safety and process checklists to consider aspects such as the duration of the job, machinery, PPE and emergency equipment.

The number of components, product complexity and volume of production will determine the type of machinery used for manufacture.

Prep 56

Revision Notes

You will ultimately be responsible for your own safety in the workshop so it is important that you discuss methods of manufacture with your teacher and follow all safety protocols.

Your prototype outcome will ultimately be a ‘one-off’ due to the time constraints and assessment criteria being applied, but it is good practice to acknowledge how your product might be produced in an industrial setting using batch or mass-production techniques.

A sound knowledge of selecting the appropriate tools, equipment and processes will apply to an industrial setting and the manufacture of our own practical work.

Make reference to scales of production covered in Unit 1.5 and other considerations such as materials, processes, unit cost etc.

L56-selecting-tools-and-processes.ppsx

Relevant process for scale etc.

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