Design For Manufacture · Design For Manufacture Part1: The brief for the first part of the design...

Design For Manufacture


Part1:

The brief for the first part of the design for manufacture mod-ule is to understand the fundamental principles of manufac-turing in an industry setting, understanding the many pro-cesses available and understanding the importance of the link between designing and manufacturing. Many factors have to be taken into consideration when designing a product as this can affect which process is used, the material required to create the product and its necessary finish.

By receiving the process of Rotational moulding it allows the group to research the process in which a material becomes a component or a product, what materials are suitable, most commonly used within this process, what products are availa-ble from this process and the strengths and weaknesses are.

Part2:

The second part of the module is a client based project, re-de-signing an existing mouse using the same key components such as the circuit board and the original optical tracking sys-tem. Updating the original design and shape to create a new modern and ergonomic mouse.

The design constraints are to not include new buttons and features as they will not be able to be used with the existing circuit board. The second and most important constraint is that the product has to be injection moulded and so this will have to be taken into account. The design will have to be carefully thought through as injection moulding comes with significant problems such as mould design and how the main body will be moulded to allow the battery and components will be accessed.

Brief

Design For ManufactureThermoforming

Thermoforming describes the process of heating a material until it is pliable enough to form a specific shape around a mould.

Process

The process begins with a mould which is typically machined alu-minium or cast.

1.The mould is fitted to the machine so that the required shape can be created.

2.The material is then heated up to a point where it is at its most flex-ible before becoming damaged. The plastic is then stretched around the mould. This is done by using a tool which is either made out of aluminium, nylon, wood or epoxy.

3.Once cooled the waste material is cut from the product.

Types:Pressure formingVacuum formingPlug assited forming.

Fig1: Pressure Forming

Fig2: Vacuum Forming Fig3: Plug Assited Forming

Materials

Amorphous thermoforming plastics.Semi Crystalline thermoforming plastics.Other materials include, ABS, PVC, Acrylic, Polycarbonate, Polystyrene, PPS, PET, HDPE, UHMW-PE.

Applications

Fig4: Plastic Containers Fig5: Thermoformed pond

Design For ManufactureSand Casting

70% of the products produced by casting are done using sand.There are five steps in total.

Process

1. Create the mould required.2. Fill both halves with sand and pack neatly.3. Place the two halves of the mould together so they are aligned.4. Pour the hot molten metal into the mould.5. Leave the mould to cool and once cooled remove the product.

Fig6: Sand Casting process

Materials

The materials available to sand cast are aluminium, magnesium, steel, grey iron and ductile iron.

Tools

The tools that are required within this process are;The molten material, tongs, protective clothing, crucible, crucible ring, furnace and a hammer.

Applications

A widely used process that allows a vast amount of products to be manufac-tured. Thes include engine parts, gears, signs, small or large ornaments.

Fig8: Ornaments and sand casted partsFig7: Engine parts

Design For ManufactureRotational Moulding

Rotational moulding is the process of placing a plastic powder into a mould and spinning the mould on the x and y axis whilst the mould is being heated.

Process

There is one basic process that is applied to rotational moulding, however there are slight changes depending on the type of machine that is used.1. The plastic powder is placed within the mould2. The mould is then heated.3. The mould is then spun on an axis and then spun in the op-posite direction on the opposite axis.4. The mould is then removed from the oven and left out to cool.5. The product is then removed from the mould.

There are several types of machines:1. Rock and Roll machine2. Leonardo machine3. Clamshell machine4. Shuttle machine5. Carousel machine

Tooling

The moulds and tools are created either using cast aluminium, fabri-cated steel or are CNC machined.

Fig9: Carousel machine layout and processMaterials

95% of all products are manufactured from Polyethylene. However, others are used as their properties differ slightly such as; Polypropylene, Polyvinylchloride, Polycarbonate and Nylon.

Applications

A vast amount of products can be rotational moulded and some of those are Kayaks, boats, hospital equipment, bollards, sign posts and many others.

Design For ManufactureRotational Moulding

Advantages

-Almost any size and shape can be created.

-Wall thickness can be selected.

-Mouldings are relatively cheap.

-Experimentation.

-Many colours and textures available.

-Little or no waste is achieved from each product.

-Virtually stress free products are manufactured.

-Plastic or metal inserts can be placed into the mould be manufacture.

-No secondary process needed.

Disadvantages

-Time for each product differs, slowing down production.

-Experimentation.

-Materials are limited to thermoplastics.

-Creating right angles can be difficult.

-Some shapes can be difficult to manufacture requiring changes to the design.

Rototek Visit

-Based in Newark.

-6million turnover a year.

-Second largest output of rotational moulding products in the UK.

-Own another sporting company called Teksport.

Achieving multi-coloured products:

-Multi-coloured patterns can be gained prior to the moulding- No pattern is ever the same- Can sometimes feel a different texture

Mould is heated Different colour is applied Process continues

Design For ManufactureAdvantages

-Almost any size and shape can be created.

-Wall thickness can be selected.

-Mouldings are relatively cheap.

-Experimentation.

-Many colours and textures available.

-Little or no waste is achieved from each product.

-Virtually stress free products are manufactured.

-Plastic or metal inserts can be placed into the mould be manufacture.

-No secondary process needed.

Metal CastingThere are three types of metal casting;

1. Die casting using a hot chamber.2. Die casting using a cold chamber.3. Investment castings.

Process

The hot chamber is used when a metal has a low melting point and the cold chamber is used when the metal has a high melting point.

1. The die is cleaned and then clamped to the machine.2. The molten metal is placed into the machine.3. High pressure push the molten metal into the die until it solidifies.

Fig10: Investment Casting

Materials

Almost any metal can be cast, however many manufacturers choose to use steel as it is cheaper, but a very useful material with many application.

Applications

As many materials can be used a vast amount of products can be manufactured. Those include car parts, a variety of different orna-ments and small components such as nuts and bolts.

Fig11: Engine

Fig12: Engine parts

Fig13: Gears

Fig14: Lost wax casting

Design For ManufactureMetal Pressing and Stamping

This is the process of placing large sheets of metal into a machine which contains a stamping die to cut through the metal and create the product or component required.

Process

There are many types of smaller processes within metal stamping and pressing such as,1. Embossing2. Bending3. Flanging4. Coining5. Blanking6. Punching7. Stamping

Materials

The materials available for this process are Brass, Stainless Steel, Carbon Steel, Aluminium and other steel based alloys.

Fig15: Metal Stamping Process

Applications

As there are a large amount of processes that can be done within metal stamping and pressing this allows a large amount of products and parts to be manufactured. Some of these products include;

1. Medals2. Gears3. Car doors4. Cutlery5. Door hinges

Fig16: Metal Stamped Products

Fig17: Hinges and Brackets Fig18: Car Body

Design For ManufactureMetal Milling

Metal Milling is the process of using rotary cutter to remove waste material so that the required part and detail can be gained.

Process

The machine is controlled using numerical control and so it is pro-grammed to do the required job. When started the head of the mill scrapes away the waste material to create the required part.

There are several steps to this process;

1. Load the preferred material.2. Load the tool.3. Start the mill.4. Unload the finished product.

Fig19: Flat Bed Mill

Materials

The materials typically used within this process are;

1. Titanium2. Aluminium3. Brass4. Magnesium5. Steel

Other items/ materials that can be milled include;

1. Metal bars2. Metal sheets3. Beams4. Metal tubes5. Metal Extrusions

Applications

A wide variety of products can be metal milled, some of these include, metal bolts, engine parts, car parts and metal ash trays.

Fig20: Metal Milling Machine Fig21: Milled ash trayFig22: Milled bolt

Design For Manufacture3/5 Axis Milling

3 and 5 axis machining simply describes how many axis the product and the tool can move on. 5 axis machining allows a much more accurate product to be manufactured as it is able to cut and remove material from areas that may not be accessible on a machine with only 3 axis’. This process is usually done by using CNC this allows a highly accurate products to be achieved.

Process

The chosen material is placed into the machine on a bed which rotates. A CNC file is then uploaded to the machine after being pre-made using a CAD software. The machine is then started and the machine copies the file and creates the product required.

Materials

Typically it is metals such as stainless steel, titanium and aluminium that are used on a 3/5 axis machines as much more accurate parts can be formed in a much shorter time than if you were to carve the metal by hand.

Fig23: 3/5 Axis Machin-ing

Applications

Many accurate and detailed parts can be created using this process. The most common application would be car parts such as engines and fixings. The product is only limited to the size of the machine. Large scale axis ma-chine can produce wind turbines and propellers.

Advantages:

-Highly accurate-Reduced manual labour-Fast process-Can be used for batch, mass and one-off productions.

Disadvantages;

-High cost set up-Specialised tools may need to be bought for specific jobs-Using a 3 axis machine limits the applications than using a 5 axis machine.

Design For ManufactureLaser Cutting

Lasercutting is another process that involves using CNC to perform the process. The machine converts the CAD file into a code and the Laser then follows the code creating the product required. Gases are used to create the laser beam which is then focused using lenses and mirrors. The laser reaches a temperature which is then able to cut through a variety of differ-ent materials.

Gases used;

-Hydrogen -Compressed oxygen-Carbon Dioxide-Nitrogen-Helium

Laser cutting can be done on both a massive scale and a very small scale such as school laser cutters. This is another process that is only limited to the size of the cutting bed. However, there are levels of laser cutters as some are much more power for industry than others and can cutter much thicker sheets of materials. Blocks of materials or tubes cannot be used within this process which limits the applications.

Fig24: Industria Lasercutter Fig25: Lasercutter

Materials:

-MDF-Plywood-Fabrics-Acrylic-Steel-Aluminium-Mild steels

Many other materials can be used within this process. It is one of the most common processes industry due to how many materials can be cut. This in turn provides more products and applications.

Advantages:

-Speed-Variety of materials- Machines can be relatively cheap depending on sizes.-Both large and small scale machines can be bought-Highly accurate

Disadvantages:

-Industrial machines can be very expensive-The beds have to be replaced over time-The product or component requires a finishing process due to the laser leaving behind a slightly burnt edge.-No mirrored materials can be used-Only 2D products can be manufactured

Design For ManufactureInjection Moulding

Injection moulding is the process of creating plastic products by heating up plastic granules until they form a liquid then forcing the plastic into the mould and creating the specified product.

Process

The process of injection moulding consists of 5 stages

1. The plastic granules which are pre-coloured and pre-weighed are placed into the hopper of the machine.

2. The polymer is then heated up until it becomes a liquid consistency.

3. A hydraulic ram then pushes the polymer through the machine and into the mould. It is forced through until the mould is full.

4. The mould is then left to cool otherwise warping may occur.

5. The mould is removed from the machine and opened allowing the final product to be achieved.

Materials

Plastics that are available for injection moulding:

-ABS-Nylon-Polypropylene-Polycarbonate-Polystyrene-PET-HIPS

Tooling:

Moulds for injection moulding have a very high cost. Moulds can be created in both two parts and four parts depending on what product is required and how much detail is necessary. Moulds are tested using a process called ‘flow analysis’ this determines if the material can freely flow through the mould and cover all surfaces.

Certain features have to be taken into account:

-Ribbing for strength-Drafts so the product can be removed from the mould.-Wall thickness-Bosses -Sharpness of corners-Webbing

Advantages:- Complex shapes can be made- Relatively fast process time.- Variety of colours- Lots of materials available.- Can be used for mass production

Disadvantages:-Initial set up can be expensive-Moulds are very expensive-Many materials cannot be recycled- A lot of experimentation may be needed to get the mould and product right.


ExtrusionThe basic type of extrusion is a very similar process to injection moulding how-ever instead of a mould a die with a continuous cross section is used.

Process

The process of extrusion consists of 4 stages

1. The plastic granules which are pre-coloured and pre-weighed are placed into the hopper of the machine.

2. The polymer is then heated up until it becomes a liquid consistency.

3. A hydraulic ram then pushes the polymer through the machine and into the mould. It is forced through a die.

4. It is then cut to the necessary size.

There are several types of extrusion all which differ slightly:

-Blow film extrusion-Co-extrusion-Over jacketing extrusion- Tubing extrusion-Sheet/ Film extrusion-Metal extrusion

Materials

This process allows thermoplastics metals and elastomers to be used.

Other types of Extrusion

Other types:

-Hot extrusion-Cold extrusion-Indirect extrusion-Direct extrusion

Hot extrusion consists of working with the material whilst its temper-ature is above the recrystallisation level. This allows the material to be worked with much easier as well as improve mechanical properties and allows more complex shapes to be created. However, it does affect the surface finish and so components that are manufactured using this pro-cess are usually used for structural purposes or will require a finishing process.

Cold extrusion is the process of applying no heat to the material whilst the process of extrusion is taking place. This provides a much higher quality finish as no oxidation layer is created.

Fig26: Extruded Metal Fig27: Extruded Plastic


Forging

Forging is the process of using a tool such as a hammer or using a die and using a high impact force, altering the shape of the metal into the required shape.

Types of forging:

-Hot forging-Cold forging-Rolling ring forging-Drop forging-Closed die forging-Open die forging

Hot forging is when the material is heated past the recrystalisation tempera-ture to reduce work hardening.

Cold Forging is done at room temperature which causes the material to harden, but lowers the finish.

Drop forging is the process of forcing a ram onto the material which causes it to spread and fill the die to create the required shape.

During open die forging, the material is not constrained and is worked into shape by the use of ‘flat faced’ dies.

Rolling ring forging can be done when the material is cold or heated. Ex-treme forces are used to push the material into a specific shape.

Advantages

Typically components that are manufactured using this process are much more durable than that of those that are cast or machined.

Disadvantages

-A very expensive process to set up-Tools and dies are very expensive to buy.-Not a cost effective process if used for one off production or batch production.

Applications

Many different industries use forging as a manufacturing process due to the increased strength of the products gained from it. Typically car parts, parts for military vehicles, bridge components, tubing and many others.

Fig28: Metal Forging Fig29: Rolling ring forging

Design For ManufactureBlow Moulding

Blow moulding is the process of forcing air into a parison which is then forced into the shape of the chosen mould.

Types of blow moulding:

-Injection blow moulding-Extrusion blow moulding-Injection stretch blow moulding

Injection stretch moulding involves placing an already formed bottle neck into the mould. Where as in ordinary injection blow moulding and extru-sion moulding the neck is formed at the same time as the bottle.

Advantages

-Cost effective in both mass and batch production.- Low pressures are used and so moulds are typically cheaper than those of injection moulding.- Fast production cycle-Many materials can be used.

Disadvantages

-Initial costs for set-up are high-Oil based plastics are used which aren’t environmentally friendly.

Fig30: Extrusion blow moulding

Fig31: Injection blow moulding

Fig32: Blow mould tooling

Design For ManufactureMetal Surface Coating

The process of metal surface coating is done to apply a layer that is either for aesthetic purposes or to improve specific mechanical properties.

Types of metal surface coating:

-Electroplating-Anodising-Nickle plating-Zinc and manganese plating-Thermospraying-Electropolishing

Advantages:

There are many advantages to each individual process such as making the material more durable, wear resistance or just improving the aesthetics.

-Metal surface coating makes the material much more wear resistant.-Improves friction performance.-Can improve corrosion/oxidation resistance.-Improved thermal protection.-A large variety of materials can have surface coating finishes.

Disadvantages:

Each process has its own disadvantages, as many of the processes can be expensive.

-Process is usually expensive-Time consuming-It’s a finishing process which is expensive as the part will have to be manu-factured first.

Examples of anodising:

Fig33:Anodised metal Fig34:Anodised tubing

Examples of electroplating:

Fig35: Electroplated metal part Fig36: Electroplated products

Design For ManufactureMetal Spinning

Metal spinning is the process of turning a piece of metal on a lathe and forming a new component over a mandrel. It is the process of transforming a metal sheet without removing material and creating wastage.

Typically this process can be done either manually by hand or using a CNC lathe. Both of which have their advantages and disadvantages.

As the material is spun only certain shapes can be manufactured:

-Spheres-Cones-Funnels-Flanged covers

Tools:

The mandrel or chuck is one of the key components in metal spinning as this is the shape that the sheet of metal will become. Mandrels can be manufac-tured out of wood, steel alloys or synthetic materials. Each provide slightly different properties. Metal mandrels provide the best quality finish to the product.

The burnisher is another main tool used for spinning. This is the tool in which shapes the material around the mandrel. There are many types of mandrels available, some manufacturers choose to make their own for very specific jobs.

Advantages of manual spinning:

-Bespoke on-off pieces-Higher quality finish

Materials:

Many metals can be used for this process however some are much easier to work with than others.

-Copper-Stainless steel-Aluminium-Brass

Advantages of Industrial spinning:

-Mass production-One continuous process- Lower levels of training needed -Speed of production is improved

Fig37: CNC metal spinning

Design For ManufactureGRP

Glass reinforced plastic is the process of layering up with several materials and adhesives to create a strong durable product.

Process:

1. A mould is initially created, it is checked for any imperfections that may affect the outcome of the product.

2. A wax coat is applied in order to create a polished shiny finish to the product.3. A releasing agent is applied to stop the glass becoming stuck to the mould.

4. A layer of resin is added to the mould to stick to bond the glass layers, this included the chosen coloured pigment that the buyer wishes to have on the outside of the product.

5. Using a roller the reinforcing material is smoothed into place.

6. The process of adding adhesive and reinforcing material is done until the product reaches the required thickness or strength.

7. Once dried the product is removed from the mould with the coloured pigment showing.

Moulds can be manufactured from almost any material as long as it provides the strength and support needed and also contains the required amount of detail.

Advantages:

-Great strength to weight ratio-Durable-Can be moulded into almost any shape-Can be coloured

Disadvantages:

-There has to be up-keep on the product every few years

Fig38: GRP process


Lamination

Lamination is the process of bonding two or more layers of a flexible material together using an adhesive and gradually bending the wood into shape using clamps which are slowly being tightened.

Process:

1. Each layer of wood has a thick layer of adhesive applied to it.2. The second layer is then applied to the first.3. The adhesive is then given time to dry. It dries clear so the finish of the final is not ruined.4. Once the layers are glued together they pieces are then cut evenly as there may have been movement whilst the adhesive was dry-ing.5. Finally wood is then applied to a pre made guide mould which the wood will be clamped to. The clamps will be gradually tighten until the correct curvature or shape is achieved.

Fig39: Wood Lamination

Advantages:

-The process is quite simple therefore will not cost a lot to set up.-Many woods can be laminated however some are easier than others.-A variety of shapes and products can be created.- The wood can then be varnished in a fireproof coat or coloured if necessary.

Disadvantages:

-Time consuming- Wood can split or become damaged.-Some woods are harder to work with.-The adhesive can sometimes come unstuck.

Fig40: Wood Laminated arches


Research Plan

Existing Products

Ergonomics

Reverse Engineering

Injection Moulding

Research Plan

Design For ManufactureExisting Products

By researching existing products this gave an insight into the price, shape, colour and the manufacturing process. It showed what other designers have used in order to hide split lines or make them become a part of the design. Typically many computer mice have a contrast of matte black and a gloss black to create a sophisticated finish. Some had chosen to use silicone over moulds in order to create the grips and hide the split lines.


Ergonomics

Fig41: Mouse ergonomics

Researching the ergonomic and anthropometric data allows an insight into what hand positions are most comfortable to the user and which can cause discomfort and possibly future health issues. Typically a user is sat at a computer desk for several hours especially if the user has a computer based career. Finding the correct position that the hand and wrist should be in will influence the design of the mouse so that it will also be comfortable.

Fig42: Theory of computer mice


Fig42: Theory of computer mice

ErgonomicsFig42: Theory of computer mice

This research explores the different shapes and styles available and how each affects ergonomics and comfort. This has highlighted areas that can be designed in and what can be explored in much more detail.


Reverse Engineering 2This is the mouse in which the client has given us to re-design. It is the standard size and shape for a computer mouse. The design constraints are that the circuit board, mouse wheel and LED light housing must be in-corporated into the new mouse so that these components can be placed inside and will create a fully functioning computer mouse.

It is evident that the design for this mouse has been influ-enced heavily by ergonomics and anthropometric data. The curvature of the mouse fits into the palm of the hand to allow the most comfort possible when sat at a computer. The curvature reduces the angle the wrist is at, to eliminate cramp and discomfort.

The curvature of the side of the body al-lows comfort for both left and right handed people as it creates grooves that form rests so it is comfortable either way it is held. This is a key part of the design as it allows the product to reach a much larger target mar-ket whilst still keeping its comfort levels for everyone.

A simple housing has been placed to maintain the switch. It is simple and has been placed on the base of the product so that it does not interfere with the design and also whilst some-one is holding the computer mouse.

A hollow section has been added to the base of the mouse to allow the tracking system to work and to allow the LED light to shine through. This is a key element within the design of the product as without this feature the mouse would not have the ability to work and so the product would be useless.

Four feet have been added to add a certain level of grip between the surface and the computer whilst still allowing it to move. This allows the user to have more control over the movement of the mouse. It allows raises the mouse slightly so that the plastic surface of the mouse does not become damaged or scratched.


Reverse Engineering 1

Reverse engineering is a key element in understanding products, how they work, what makes them unique and how designers has overcome issues to create a fully functioning product. It gives an insight into the inner workings of the product to then give a basis to start updating the design of the product or completely re-de-signing it.

By reverse engineering this mouse it gave the group an insight into the key components of a mouse and how each component is linked. It shows how the body of the mouse has been designed so that once it is injection moulded it houses all the components whilst creat-ing an ergonomic shape to hold. It showed how injection moulding


Reverse Engineering 3The mouse consists of three main com-ponents that form the outer shell of the product. The top layer has a reduced amount of material which forms the controls. The gap between the top layer and the main body towards the con-trol end is greater than that near the rear, this is both a design and a man-ufacturing feature as it creates a long flowing curve through the product. The manufacturing feature is that the gap increases to allow the top component to flex allowing the buttons to be pressed without damaging the material.

As this mouse has been designed to be wireless it needs a form of power supply. The designer has chosen to power this mouse using two AAA batteries. This requires a battery cradle to be attached to the product somehow. As evident by reverse engineering the main body of the computer mouse splits into 3 main com-ponents. The middle section is injection moulded, this allows the battery cradle to be built into the mould creating a suitable ledge for the batteries. This cradle also forms the main support of the USB so that once the mouse is finished with the USB can be removed from the computer, the top component of the mouse can be removed and then it can be placed inside ready for the next use.

The front of the top component has been split and also contains a housing for the wheel. The housing allows the scroll wheel to move freely whilst the com-puter mouse is in use. As it is not attached to the wheel it also allows the top component to be whole and so the user does not need to remove several pieces in order to place the batteries inside the mouse.

This mouse has a split line that runs through the scroll wheel and half way through the top component. This is a manufacturing feature as this mouse is most likely to be injection moulded out of ABS which is a strong material. However, reducing the material to cre-ate a much thinner layer of plastic and adding the split line it transforms the plastic and makes it much more flexi-ble allowing users to press the controls with ease.


Reverse Engineering 4

The main body of the mouse provides the most support. Without the internal structure of the body the product would not be stable and would not house the other component properly. The battery cradle has added feature such as the boss extrusions which a screw can be placed inside to link the base and the main body together so that it does not fall apart during use.

The base being the key part in the assembly as it holds all the electronic compo-nents and keeps them in position. However, one of the most important features being the cradle that both supports the scroll wheel whilst still allowing it to move to be used as a button.

The top component holds three main features. One being the extruded sec-tions that link to the circuit board so once the mouse button has been pressed this extrusion presses down on the button performing the required action.

The two final features of the top com-ponent are the hook that connects the main body and the top together and the clips that allow the top piece to slide on and off with ease allowing access to the batteries and the USB.


Injection Moulding

There are several rules and concepts that need to be taken into account when injection moulding otherwise the product that is desired will not be manufactured. The first rule of preventing issues arising is designing with the principles of injection moulding in mind. By keeping these rules in mind will allow a fully working computer mouse to be designed that will have the structural sup-port as well as the high level finish required.

Most injection moulds are created in two have which forms one split line down the centre of the product or component. In order to manufacture this mouse it may be necessary to use a four part mould that way a more complex shape can be created and the prod-uct will be of a better quality.

Rules:

1. Wall thickness must be taken into account when designing as if the walls are too thin they will break easily, however if they are too thick then the product will not mould properly. This could also affect the size of the computer mouse as if the wall thickness is too large then there may not be enough space to it the PCB and the battery holster.

2. Wall thickness should not be used in order to strengthen a product instead ribs should be added to the design as these will increase the strength as well as reduce the weight.

3. A tapered edge should be applied to the design to allow the product or component to be released from the mould without damaging it.

4. Too much material in one area should be avoided as this can cause sink marks to arise on the outside of the product which can affect its durability as well as affect its overall aesthetic appeal.

5. Extruded bosses should meet to allow the screw or pin to locate easily without damaging the screw or the components. This will apply when attaching the battery holster and the bottom component as extruded bosses can be applied to each component and once the components are slotted together the bosses will line up allowing the pieces to be fixed together permanently.


Initial Ideas

Here are some initial sketches using the same principle of one edge being straight to create a sleek, geometric modern design. The sketches are the start of an exploration into the different shapes, colours, textures, ergonomic grips and sizes.


Initial Ideas Further exploration taking a different approach of a much more ergonomic shape. Exploring how the different heights and the curvature of the top of the mouse can affect the comfort levels for users.


Modelling

For the first initial models three different approaches were taken. The first being a curved ergonomic mouse that fits comfortably in the palm of the hand, the second being a flatter more sleek prod-uct and the third being a geometric shaped computer mouse. . This process explores a variety of different style of computer mice to see which route is more effective and the highest quality and comfortable mouse can be designed.

Having the large curve at the back allows the mouse to sit comfortably within the palm of the hand. By adding the in-dents in the side of the mouse this provides finger rests and as both are equal on each side it allows both left and right hand-ers to use the mouse with ease. This makes the mouse design much more inclusive. However the issue with this design is that it is similar to that of the original design and so it would need to be further developed if the design is taken further.

Design For ManufactureModelling

This model is much flatter and has more of a sleek design. The idea behind this is that there is a cut out in the centre of the product, this would reduce weight as well as create an aesthetically pleasing design. However this may be also become an issue as the PCB cannot be altered meaning it would be difficult to fit inside the mouse. One other issue is that the angle at which the wrist is at, after a while it becomes uncomfortable because the mouse is too low.

One positive for this model is the flowing curve that flows through the product and down and joins the base. This would lower the visibility of the split that as it would still look like one component than the several it will be.


Modelling

The third model is a very geometric mouse. It is the correct height for the wrist, but due to the geometric shape it is still uncomfortable to hold for a long period of time. Overall mod-els one and two are the most effective design which can be explored further.


Development


Development

These are a few further explorations into how the circuit board will fit inside the product and how this will affect the overall design. By taking the measurements from the circuit board and forming the first part of the CAD this allowed a template to be created and used to form more shapes and products. The height of the wheel affected the curve and so finding a balance so the wheel is visible as well creating a shape that is comfortable for the user will be difficult.


Modelling

After the first initial models and exploring different shapes more another model was required to see what else needed to be devel-oped and if the design was going in the right direction. By combining elements of both models one and two a better product was developed.

By taking the long curved edge from the second model, but raising the curve to the height of the first model a much more comfortable product was achieved. The wrist sits at the appropriate height so it will not cause discomfort when being used for long periods of time. It also creates a more appealing design.

Further development will need to be done to explore how the product will be split, how each part will be moulded, if there will be indents, grips or different textured features on the product.


Development

Injection moulding requires certain elements to be taken into consideration, such as how the product will be split into separate parts to allow it to be moulded correctly. This sheet is an ex-ploration of how the product can be assembled and how the user can dismantle the product to gain access to the battery and other compo-nents.

It explores where split lines can be placed to avoid ruining the aesthetics of the product as well as allowing it to be injection moulded.


Development

These are side profiles to explore possible grips and textured surfaces to make the product much more mould-ed to the users hand and to improve the grip so the computer mouse is much easier to control. The top left sketch shows a long flowing grip that mirrors the curve of the surface of the mouse. The grip could become indented slightly so users can have somewhere to rest their fingers.


Modelling

By using the meas-urements gained from reverse engineering the staples mouse a final model was able to be created. The shaded area represents an indent that will form a finger rest. This will be equal on ei-ther side to include both left and right handed people.


Development

Some initial ideas as to the fin-ish of the top component were done. However the bottom right idea flows more with the design, it would also allow a texture to be added to the surface. This can be added to the mould so that only one section is textured providing more grip and the other can have a gloss finish to improve the visual appeal of the product.

Design For ManufactureDevelopment

With almost a finalised idea more development into how the product would split was done. It was decided that there would be three components. The top com-ponent that can be slid off to gain access to the batter-ies and the USB. The second component that forms the main body and houses the battery holster and the main structure and the bottom component that holds the circuit board, switch and light reflector.


Development

A problem arose when forming the final design. Having used many people to test the comfort lev-els of the computer mouse, many chose the front wheel to be at the lower sloping edge than that of the higher section of the mouse. It was decided that the position of the wheel would change from the original position to the lower section of the mouse. Many people believed that it was much more comfortable.

Design For ManufactureFinal Design

This is the final design that will be followed whilst using CAD. These will be the three separate components that will allow the mouse to be taken apart and to access all the components and then have the ability to be put back together. Hooks will be applied to each component to allow them to slot to-gether with ease. There will be grooves along the outer edge to make the mouse much more comfortable to hold and work with over a long period of time.

Design For ManufactureCAD Development

These are the three components that the product will be split into. The top section will be detachable to allow the user to unclip it and gain access to the battery cradle as well as the USB holder. There will be a split line down the centre of the top piece to allow the material to flex so that the controls can be pressed. The middle section will form the structure and support of the product as well as being a holster for the batteries and USB. Finally the bottom section will be removable to allow access to the circuit board, LED light and switch.


CAD Development

In order to manufacture a working mouse an internal structure had to be placed to support the circuit board and house the switch and LED. Using boss extrusions this forms a locator for the screws so that the compo-nents can be fixed together to form a solid product. Four other extrusions were placed as these slot into the circuit board to create a fixed position so that it does not move whilst in use. A cradle also had to be added to fix the scroll wheel in place.

The circuit board houses all the key com-ponents to allow the product to work. It also contains 4 holes in the main board that provide locators so that it can be fixed to the base components of the product.

Design For ManufactureCAD Development

The main body was shelled out to allow the housing for the battery to be created as well as make sure that the circuit board does not interfere with any of the components. Finding a balance with the wall thickness was difficult as it has to allow the batteries to fit whilst not affecting or cutting into the curved surface that forms the grip on the side of the mouse.

By inserting the circuit board into the fin-ished bas this provided a template to create the structure for the batteries and the sup-porting frame for the mouse.


CAD Development

The battery and the battery holster were then added to the product. There was no need for more of an internal structure as the other components such as the wheel are already supported by the circuit board and the top component so they stay in place. The lack of internal structure also reduces weight as it reduc-es the amount of material used. This also makes the product require a mould which is much simpler and will cost less.

The USB holster was added so that the top component can be removed and the USB can be accessed easily. The USB rests on four hooks to again remove material and weight whilst still providing the necessary support.


CAD Development

A section was cut out to expose the wheel as well as keep it in place while in use. A small section was also removed from the front to allow the top compo-nent to flex and so the buttons can be pressed individually.

To finish the computer mouse several hooks and clips were added to all three components to hold the product together as well as allow the user to take it apart when necessary. Two extrusions were also added to the front of the mouse as this allows the mouse to work correctly. Once the button has been pressed the extrusions are forced down onto the controls on the circuit board which performs the command.

FINAL PRODUCT

EXPLODED

DRAWING

Product in Context


OrthographicNot to scale

39mm

65.5mm

33mm

65.5mm


Orthographic

95mm

58mm

95mm 58mm

Not to scale

Design For ManufactureEvaluation

Overall the project went to plan, the brief for the first part of the project was to research and understand the fun-damental principles of the design process that make up the design industry. Understanding how they influence the choices made during the design process and how certain factors have to be taken into account. Taking into account the process, how long the production time is, how the process can affect the finish of the product and how this may affect your design. Also taking into account which materials are available for each process so this can be taken into account and also what the advantages and disadvantages are as this can affect the outcome and the overall quality of the finished product.

The second part of the brief was to re-design a wireless staples mouse using the same components which were in the pre-existing one. Using solidworks to form the finished product cause difficulties as it is a long process and un-foreseen circumstances arise which cannot be foreseen on paper, which sends the project backwards and forwards from development.

The module on the whole allowed valuable skills to be gained and a wider understanding of how many elements about processes and how this can really affect the design. Elements from injection moulding such as a standard wall thickness, using ribs to provide strength, creating bosses to locate screws to hold the shape of the mouse and others that may affect the outcome.

There are several improvements that would be made if the project were to be done again. By exploring a wider range of products this can give a better insight into what is available and further detail into how each individual mouse is manufactured. This will also help provide an insight into how designers have overcome problems with injection moulding and what tricks are used to hide split lines.

Time management would be another aspect to improve as more time could be spent in the development stage by exploring certain features of the mouse further to resolve the design to the best of its ability. By doing more devel-opment sketches it provides more detail as well as providing more options and paths to take with the mouse.

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Design For Manufacture · Design For Manufacture Part1: The brief for the first part of the design...

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