Design For Manufacturing And Assembly Engineering Essay

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A design process that focuses on meeting customer requirements meanwhile balancing the important aspects such as cost, quality and performance is Dfma.

DFMA is an abbreviation for "Design for manufacturing and assembly". It a software comprised of various principles or methods when used properly will improve the ability of design to be easily manufactured and assembled thereby decreasing the costs. This system can be divided into three major sections. The first is the raw material. Choosing the right material is the foundation of a good design. Second is the machines and processes used to work the raw material. The right process is essential for creating finished parts that will meet your design requirements. Third is the assembly of the product. It is during the assembly of the finished product that provides the greatest opportunity to apply DFMA principles. The proper use of DFMA principles will allow one to design a quality product.

  • DFMA follows an exacting design review method
  • It identifies the following features:

-Optimal part design of the product.

-Material choice.

-Assembly and fabrication operations to produce an efficient and cost effective product

  • It reveals that initial ideas may not be the most efficient in all the cases.
  • It is a structured catalyst methodology used to analyze a design and generate ideas for further improvement.
  • DFMA encourages concurrent engineering during product design so that product qualities exist in with both the designers and other members of the production team.
  • It is a communication tool for the team.
  • It is a bench marking tool.
  • It defines the design and manufacturing capabilities of self and competitor
  • It provides a non-threatening way to get people talking about a design without feeling like others are encroaching on their territory
  • Einstein said “ the best design is the simplest one that works “. DFMA provides the cheapest way to that goal.

Customer requirements and product specifications are useful for guiding the concept phase of product development. But during the later stages product design teams often have difficulty linking needs and specifications to the specific design issues. Due to this, many product design and development teams practice ‘Design for X' (DFX) methodologies .The most common of these methodologies is Design for Manufacturing and Assembly (DFMA), which is an engineering philosophy used generally by design and manufacturing engineers that promotes simplifying parts and product designs to reduce production costs. Other (DFX) methodologies are

  • DFD Design for Disassembly
  • DFEMC Design for Electro Magnetic Compatibility
  • DFR Design for Recycling
  • DFE Design for the Environment
  • DFS Design for Safety
  • DFT Design for Test

DESIGN FOR MANUFACTURE:

Design for manufacturing software follows a simple rule which states one can improve the efficiency of a product by minimizing the number of parts that have to be assembled so the cost of the product is efficient and easy to manufacture. This manufacturing approach is different from the traditional approach where a huge project is broken down in smaller parts (steps) and then these steps are assigned to various departments. These departments then work independently most of the time. The traditional approach enhances the specialization and functional job focus of the product devolpment. But the main drawback with the traditional approach is the market time plus various difficulties that arise in the manufacturing process.

While designing a product lots of parameters have to be kept in mind ot of which that most important one which manufactures ask is can we build the product now that they have the product designed. A way to design a particular product is to make sure that the product maintenance is less, its reliable, time factor, its simple. Maintenance of a particular product shold be less or else it could cost a huge amount for maintenance. Reliability of a product is also a key factor because if the product fails consistently it makes little sense and thereby it's a huge money waste to the organization. Speed is the another key factor in designing, if it take too long to make the product then it will have more and more competitors. Competitors control the market by releasing their product faster than fellow counterparts. Using few parts also increase the simplicity and saves money as well, more parts for a product increases the rate of complexity which can lead to malfunctioning of a product. The simpler the product is the fewer are its problems.

Over the wall syndrome process was used before the use of DFMA process. Over the wall syndrome is a process where if an idea was generated in a company it would first have to be approved by the president of the company. It would then go then go to the manger of the process deign to be devolved into a product. If any problems would arise it would then be asked to redesign and then brought into the notice of the manager. The resolved problem would then be sent to the engineers where the work would continue where they left from. This process was a huge time consuming process because everyone is not situated in the same location and it would also take a lots of time to solve the problems. The total process sometimes could take year or more. The concept of design for manufacture was used to break these barriers and thereby reducing the time spent on designing the products.

DESIGN FOR MANUCTURING

has some advantages and disadvantages just like any other software. Firstly dfma tools don't take into consideration many manufacturing capabilities or tolerance. DFM has many computer based tools which nearly complete the design but when we analyze the design finally there are number of barriers which prevent substantial modification of the design.DFM use's too many tools which can increase the manufacturing costs of a product, its also gives very little feedback upon which to base the design modifications.

One advantage with DFM it suggests the optimal assembly and the degree of automation. DFM can produce higher products yields through manufacturing. It also increases the performance and the predictability of the product yields.DFM analysis helps us to compare various materials and manufacturing process for the parts of the components. There is an increase in the performance and the cycle time is reduced enormously.

DESIGN FOR ASSEMBLY SOFTWARE

Design for assembly can be defined as a analysis for improving the product design for a simplified and low cast assembly. Design for assembly main aim is to simplify the product so that the cost of assembly is reduced. By applying dfa we can also improve quality, reliability in the production equipment and the part inventory.

G. boothroyd was the person who promoted the usage of DFA in the industry. The practice of dfma is a relatively recent development, but many companies have been following this process form a long time. For example, a company called general electric published its own internal manufacturing handbook as a set of guidelines for its engineers to follow. These guidelines had the same set of principle of DFA without actually distinguishing it from the rest of the product development process.

Assembly methods can be divided into three different groups

Manual assembly

Automatic assembly

Robotic assembly

In manual assembly the work is mainly done manually parts are transferred from one work bench to another. Worker use different types of hand tools. This is one of the most flexible and the adaptable of the assembly methods methods.

Automatic assembly follows a process where it consists of a custom built machine that assembles one and only a specific kind of a product. In this assembly large amount of investment is needed and as the production increases the total manufacturing costs decreases. These types of assembly can be only beneficial when a product is produced in bulk.

Robotic assembly in this the assembly we use robotic systems. The robotic systems can take the form of a single robot or a multi station robot. Robotic assembly also involves huge capital costs. In robotic assembly the robots are normally controlled by computers, one company can have huge flexibility on different types of products in robot assembly

Assembly methods are chosen by a company keeping two important parameters in mind ie time and costs.

Relative costs of different assembly methods by type and production volume.

Design for Assembly

Vincent Chan and Filippo A. Salustri

http://deed.ryerson.ca/~fil/t/dfmdfa.html

Design for assembly is an experimental way to identify the unnecessary parts in a product and to determine its assembly time and costs. DFA is a software which gives the design engineers more tools to analyse various design concepts and therby creating innovative products with few and simpler parts.

Using DFA software helps engineers to assess the costs of each part and then modify the product through part reduction concepts. The outcome of a DFA based design is a much well designed product with fewer parts which is both efficient and also easy to assemble. The benefits of a DFA based design are reduced part costs, improved quality and reliability, and shorter development cycles.

DESIGN FOR ENVIORMENT:

Design for environment is an idea of implementing various environmental friendly aspects to create a product. Design for environment helps a company to minimize the waste and also decrease the pollution thereby saving some money which can be used for other processes.

Design for environment helps engineers at various stages of the manufacturing process. While selecting a manufacturing process for a product an engineer should also keep in mind various aspects such as amount of energy used, amount of energy released, process should be non toxic. These are all the various aspects an engineer also has to keep in mind other than manufacturing and assembly of the product. Dfma 2009 gives the design engineers an extra option in which they could conduct a environmental assessment during the concept stage.

The analysis helps the designers to select a suitable material from the DFMA library that they prefer to use. Then the software reveals the various proportions of those materials in a particular product. It also estimates various other proportions like reuse, recycle, end of life destinations and landfill. All these measure help the company meet the requirements set up by ROHS.

DESIGN FOR RECYCLING:

Design for recycling en-cooperates methods such as recycling and recyclability of products to obtain recyclable products. Recycling is a process where a product or a raw material is recovered from waste stream and is reused as a raw material in the manufacturing process of a new product. When a part is recycled it does not affect or change the properties or the price of a particular product. Design for recyclability helps a manufacturing process to reduce the environmental impact of a material and by following design for recyclability large number of parts can be reused this thereby decrease the cost for raw material and thus decreasing the overall costs for manufacturing a product.

DESIGN FOR SAFETY:

Many companies use safety standards purely as guidelines. Although some safety equipments are costly the future savings make up for the cost invested. Safety production also helps the company in producing more. Safety also improves the morale of the worker which helps in the increase of production.

The main aspects or the principles on which DFMA focus are:

  • Raw materials
  • Minimize the number of parts
  • Minimize the number of fasteners
  • Standardize
  • Avoid difficult components
  • Use modular subassemblies
  • Use multifunctional parts
  • Minimize reorientation
  • Use self-locating features
  • Avoid special tooling/test equipment
  • Eliminate Interfaces
  • Minimize operations & process steps
  • Part Interchangeability
  • Design Tolerances to Meet Process Capability
  • Determine Capabilities of each Process Step
  • Design for Ease of Part Orientation for Assembly
  • Eliminate Multiple Solder and Cleaning Steps
  • Eliminate Adjustments

DFMA Raw materials:

Choosing the best raw material for the design is the first step in designing a world class product. There are many factors that need to be considered when choosing the best material for a design. At first the material must have the correct mechanical and chemical properties to meet the design criteria. Secondly when possible one should choose a standard material that is readily available. Using special materials may increase purchase price and lengthen deliveries. Third use near net parts whenever possible. The raw material's profile should be as close to finished parts as possible to reduce processing.

DFMA Minimize the number of parts:

Minimizing the number of parts directly affects the final cost of the product. By minimizing the number of parts Product quality, flexibility and reliability of the product is increased. The fewer parts a product has the fewer chances of misalignment.

DFMA Minimize the number of fasteners:

Fasteners increase the complexity of a particular product, thereby increasing its weight and cost. Dfma main aim is to eliminate the fasteners and include self aligning features into a part. If fasteners are needed in a part then its better off using self tapping screws

DFMA standardize:

Standardization is a phenomenon which requires increase in communication between different design teams working on a complex product. The more standard products an engineer uses for manufacturing of a product the less number of tools are required and it gradually decreases the cost for production. The best method is to create a list of various standard parts available for each project. In order to smooth the progress of the standard parts, the design and manufacturing team should make the most of the different resources such as trade magazines, various vender catalogs and various part manuals.

DFMA modular sub-assemblies:

With the help of modular designs, the identification of problems becomes easier by reducing the number of parts. Maintenance and serviceability of a product also increases by using modular assemblies. By designing parts as independent modules times for disassembly are reduced thereby decreasing the overall repair time.

DFMA Using stack assemblies:

Stack assembly is stacking up the components of an assembly from bottom to top. The main purpose of using stack assemblies is it requires less reorientation of parts which leads to speeding up the assembly process, which thereby decreases the cost for assembly.

DFMA self locating features:

The use of Self aligning parts speeds up the assembly process. Self aligning parts don't need any kind of adjustment or re-orientation. The more the self aligning parts present in a product assembly the much easier it is for an assembly worker to assemble the product. Different types of self aligning parts are washers, ball bearings, roller bearings.

DFMA simplifies and optimizes the manufacturing process :

Minimization of manufacturing process reduces the direct and overhead costs. While designing a production process a designer's main aim should be on various factors like

Smooth flowing of materials.

Using various processes than can easily be controlled.

Separating different operation (like manual and automated )

DFMA Eliminate Interfaces:

Eliminating of interfaces is an important phenomenon while assembling of a product. The amount of interfaces increases the cost of an assembly. Each interface present on the part increases the time for assembly as it requires double the amount of information.

DFMA Part Interchangeability:

Interchangeability is a phenomenon where similar parts are used for manufacturing of a product that can be interchanged. This phenomenon reduces the number of parts used for an assembly which leads to a decrease in assembly time and costs. While using interchangeability left and right handed parts should be avoided because they create confusion which directly leads to increase in time.

DFMA Design Tolerances to Meet Process Capability:

Tolerances are such parameters of a part which tend to complicate the design. If a tight tolerance has been specified for a particular part, other process such as inspection or fixturing has to be done. Which gradually increase the overall cost of a product and also time is wasted. They fore a designer during the design process should understand the manufacturing and suppler capacity while specifying different tolerance to make sure that tight tolerances are necessary

DFMA Minimizes parts for interconnections:

Interconnected parts are flexible parts which are used to connect two parts in an assembly. Interconnected parts are prone to get damaged when compared to other parts. When harnesses are used in an assembly of a product always ensures that we are using distinctive connectors for a simple reason to avoid the connectors being misaligned

DFMA Determines Capabilities of each Process Step:

Process capability can be defined as an ability of an process to produce within a suitable specification. When the correct process capabilities of a particular deign are determined, it also helps the design team by giving them some valuable information from which they could choose a simple technology and a simple sequence. Which directly decreases the costs for assembly and gradually the time for production is also decreased.

Eliminate multiple solder and cleaning steps:

The more processes one uses in manufacturing of a product the more are its risks, costs and potential for delays. Production engineers use DFMA to minimize the processing technologies used in the manufacturing process. The more the number of technologies the greater are the chances for various errors and part malfunction.

Eliminating adjustments:

Minor adjustments only affects the look of the product, but it does not affect the functionally of the product whereas the major adjustments have a major affect on the functioning process of the product. Adjustments are normally complicated process which involves huge costs. Elimination adjustments could also include replacement of parts in the assembly.

WHY DFMA

  • Dfma can be used as the basis for engineering studies and thereby provide a guidance for the design team to simplify the existing product, reduce its manufacturing and assembly costs.
  • It can also be used as a benchmarking tool to study competitors and to quantify manufacturing and the difficulties that arise during assemblies
  • One can also use Dfma as it “should-cost” tool to help validate design concepts, provide cost predictions, and to negotiate suppliers bids and contracts.

The main purpose to use dfma is

Dfma also helps us to keep various aspects in mind during the manufacturing and assembling a product.

Materials

  • Is material that we are going to use available in standard stock configuration.
  • Is material well-suited with the most desirable manufacturing process.
  • Is the material available from reliable sources.
  • Do material prices fluctuate widely over time.
  • Are special alloys and exotic materials used only for environmental or functional demands.

Product Assembly

  • Are tolerance dimensions realistic.
  • Is marking and stenciling defined and visible.
  • Are assembly notes complete and definitive.
  • Is internal wiring layout critical? If so, is the location and routing specified?
  • Is harness development required? If so, can the harness be fabricated outside the unit and installed as a subassembly.
  • Does the design lend itself to automated assembly.
  • Are component parts accessible for assembly.
  • Can testing be performed without disassembling the unit.
  • Are standard connectors and assembly hardware used.
  • Are circuit cards, if used, designed to plug in.
  • Has the assembly been analyzed to meet electrical, thermal, vibration, and shock Specifications.
  • Can printed circuit flex cable or moulded ribbon be used in place of hard wiring.
  • Can plastic tie-wraps be used in place of lacing or spot ties.

HOW DFMA

Designers do not enter a new design situation as newcomers or novices. Through education and practice they have acquired a vast repertoire of design solutions, which they will carry over the design task at hand (PASMAN, 2003).All these experiences are due to the result of several situation mistakes, improvement opportunities or just real good new ideas acquired due to development and research on design area.

A good engineer must know what happens in his factory in a detail level that can permit an assembly to be done and an injected part to be extracted and also must know were the assembled parts are and the injected material should be in the correct geometry. These means two different conflicting conditions. The designer cannot stay in his area ignoring what is happening around and the designer must know his tasks perfectly to justify his work position.

The question remains, is it possible to be in simultaneously in the factory and in the design office? FERREIRA and TOLEDO (2002) say so and suggested how using the technique of Design for Manufacture and Assembly is possible to “hear the voice of the production line” and been virtually near to the information. BUSS et al. (2001) agreed with this point of view, saying that the DFMA allows bring to the project area the considerations related to the assembly and manufacturability of the product. Finally FAGADE and KAZMER (1998) defended that the most significant advantage of DFMA is the encouragement of the teamwork between project and production, improving the reliability of the final product and generating the possibility of cost/time to deliver reductions due decreasing in the parts number and/or more productive parts that can accelerate processes.

WHAT TO HAVE DFMA:

First of all we need to understand the project with DFMA techniques. For this is important to define the product conception as a task of multiple responsibility, from the conceptual sketch to the packed assembly delivered there are many operations and actions that need to be considered. Thus in accordance with the key points the total chain of the process is to be defined in an clear form from one (process) to another to provide or receive services/pre-processes

Also is essential to let all teams warned that the project is designed for manufacture and assembly - and this means that all attention is focused in a development for that condition and this means that the manufacture must be heard all time.

To achieve all this, there should be efficient communication, efficient information, translation of data is the basic requirements on a DFMA driven development.

WHEN DFMA:

What's the correct time to carry on a Dfma driven project?

CAPUCHO et al. (1997) adopted after observe the behaviour of multidisciplinary teams that the local rework caused by an activity with adverse results is much smaller then a global restructuring of a project - also, a global reproject may be impossible due costs (according to HARTLEY and OKAMOTO (1992)) the inclusion of a change in a running project is more expansive as more is close to the project end or due other factors as time and market expectations.

So, once the projects main activities are defined the doing them is a good option irrespective of their order of development. Mistakes, adverse results and budget can less compromise the project running timetable.

Which technology:

According to BOOTHROYD (2001) the rising sophistication in the use of moulded injection plastics. Injection moulding is an important tool to win the battle of reduces parts to save costs and creates an elegant design.

Based on the literature present and other articles researched by the groups of teams on plastic injection acquired by work and development in other lines (refrigerators and washing machines), where plastics are used in a very large scale,It was decided to try a solution using injection of thermoplastics.

This was a risky decision. First of all the temperature limitations on a plastic material are more severe than in a metal - limits also include the possibility of deformations, flowing and resistance downgrade. After that, a running and deployed solution give some comfort to the project designers and all of other teams: the new idea was offering a possibility of assembly improvement and a bundled possibility of fail, this means that for some parts of the workgroup the manufacturability advantages were not good enough to release the change - in short words that was to develop a substitute part to improve a good working assembly to give some help to line and to reduce costs, with a low, but existent, possibility of further problem.

Case studies of companies that used DFMA software

Product: Motorcycles

Company: Harley Davidson

General goals:

Identify the total costs (make design, material, process) and by making some substitutions to have an impact on cost.

Improve the overall cost predictability of the product to meet the desired revenue and costs targets

Method:

Engineers of Harley and the suppliers team up and the cad models of each part are loaded into the dfma software. Dfma software generates cost information that gives rise to various discusiions on cost, labour rate , process materials etc.

A motorcycle frame was designed which was to cut down the costs by 70 dollars . before the manufacturing of the new frame Harley Davidson analysed various departments in DFMA like material cost , operating efficiency, plant cost. The software predicted that the current frame costs within 0.5%.

Frame of Harley Davidson motorcycle

Then the new frame was analysed in DFMA software, the company found out that the new frame would cost 7 dollars more than the old frame (not dollars 70 less as they had anticipated). Harley Davidson was glad to discover this before they went into production and they researched various other areas for cost savings, before the bike was launched.

Product: Microwave

Company: whirlpool

General goals :

To reduce the costs inside the plant

Generate a good slim design.

Simplify or eliminate assembly processes.

Method:

Teams were developed which consisted of all types of engineers (mechanical, electrical, technicians, air ventilation designers. The teams closely observed all the video tapes of the assembly line of the current microwave to spot the different weak or awkward operations. Teams structured a bill of materials and saw how the product was assembled or in what order it would assemble before crating a prototype of the model.

Engineers used DFMA and prepared a performance matrix in which they could evaluate the easiest and the awkward assembly operations.

In the original design, the worker had to turn the chassis over to install the door spring, and then turn it back over to do the rest of the operation. With the help of dfma the engineers can to a conclusion to have the spring in the front of the oven, so that there was no need to turn the chassis to install the spring.

With the help of DFMA analysis whirlpool had the following results.

  • 29% part reduction was achieved .
  • 106 parts for the new oven, versus 150, this was more than expected.
  • Many of the reduced parts were fasteners, cutting assembly time 26%
  • Standardized cabling across product lines, creating immediate assembly and part savings
  • Payback time was 6 months

Product: Gourmet coffeemaker

Goals:

High standards of coffe tate

Uniform coffe saturation

Temperature control

Weight of the design is less'

Efficient design for best retail price.

Company

Access group is one of the leading distributor and manufactures of a comprehensive range of durable products, which include water treatment and air filtration systems and most importantly an award winning coffee maker. Which we are going to discuss in this case study.

Two years ago access business group wanted to design an high end coffee maker to support their own line of water filters and gourmet coffees. According to access business group their main was to build a coffee maker which is stream lined and an efficient machine and they achieved their objectives with the help of design for manufacture and assembly software.

Using DFMA analysis:

The major aim of DFMA analysis was to determine the minimum number of parts for this design.

With the help of DFMA the design engineers could reposition the motor much closer to the power and a bit higher on the machine. This phenomenon was achieved due to the reduction in the number of parts. Most companies now a days gives higher priority to the look of a product, designers of gourmet decided to replace the existing motor with a new sleek and a less power motor thereby saving the costs.

Manufacturing of the coffe maker using DFMA involves three stage

  • Bill of materials
  • Middle product development
  • Fine tuning of the design

Design for assembly consists of an index Colum which shows the results or the rating of the design. As the time taken for assembly, costs for the assembly and when the parts are consolidated or omitted the index number rises. The table present below indicates how DFMA software helped kahve coffee maker to reduce the part count, cost and assembly time.

Kahve coffee maker

DFMA Round 1

DFMA Round 2

DFMA Round 3

DFMA Index

18.6

21.5

24.8

Part Count

122

90

81

Cost of Assembly

$3.20

$2.12

$1.93

Assembly Time

721.08 seconds

477.35 seconds

433.74 seconds

Source (http://dfma.com/news/abgcoffee.htm)

Engineers firstly recognized that by using special filters and temperature controlled water in a coffee make was one way towards a better coffee.

In design of a filter DFMA was precisely used to decrease the part count and thereby decreasing the assembly time of the filter. Dfma analysis suggested that the two piece carbon block which is called as a pressure vessel is to be combined into one part. Engineers also eliminated some parts to reduce the production costs, designers used a UV- lamp combined with an inductive coupling which is an wireless equipment which would then eliminate the use of connectors and lead wires in the UV-lamp sub- assembly. The primary and secondary coils present in the lamp which are in the shape of a donut create a wireless field of electric action which powers the lamp. The table presented below shows the results of five rounds of DFMA that improved the system.

Water Filter

DFMA Round 1

DFMA Round 5

DFMA Results

DFMA Index

8.9

14.8

65% increase

Part Count

25

21

20% reduction

Cost of Assembly

?

?

?

Assembly Time

602 seconds

393 seconds

35% reduction

Source (http://dfma.com/news/abgcoffee.htm)

Results achieved using DFMA:

Positioned the motor assembly higher on the machine, closer to the power destination

Designers could then use a smaller motor—uses less power and makes the unit more sleek

Only machine of its kind endorsed by the Society of Specialty Coffee Association, the industry's major trade group

Product: Spectrometers

Company: MDS SCIEX

Company goals:

  • To grow in the market with the help of various quadruple designs.
  • To achieve high standards in quality, cost -competitive
  • Should not have an onsite assembly or a technician to install.

Method used:

The huge development team which consisted of 75 members who used DFMA software in the form of a catalyst to guide the technical analysis of a design. The team used DFMA software to analyze the existing design and then the parts were consolidated and then the difficulties in assembly were eliminated.

The figure shown below shows the top view of an flight tube. An ion detector and an accelerator Assemblies were designed to be self locating so that they can be inserted in vacuum only one way.

The modular nature of the flight tube design aids in shipping and servicing the Qstar .

Results achieved using DFMA

  • Cut materials cost by $35,000 per unit
  • Reduced opportunities for design and manufacturing corrections, by more than half the number per part
  • Product to market in 14 months
  • Captured one-fifth of the global market in the first year of sales
  • Increased revenue by $20 million

Company: dell

Situation

Dell computer promise their customer a 5 day delivery of a computer. They have their own industries in United States, Ireland and china. Dell wanted to increase their own customers. The main problem is that they wanted to know how a customer configurated their own computer and how does their own factory configure their computers. They wanted to match both the customers and factory picks.

Method used:

The first method they used was to add u the components such as the mother board and the chassis before they arrive at the factory.

They also worked on various functional areas and with the offshore manufacturing partners to evaluate various factors like productivity, quality and inventory issues.

The main concern for dell was:

Quality events: Anything that can affect the experience of a customer can have a huge affects on the company and must be carefully managed.

Forecast accuracy:

Dell is a company which takes orders and then builds the computer, but the supplier of dell needed an accurate demand rate at which they could supply the different parts as per the demand.

Demand Volatility:

Unpredictability is a large problem in dell. Unplanned large orders can affect commitment to ship configurated system within 5 business days and the 10 days of sales inventory at different supplier hubs.

With the help of DFMA software dell conducted a cost befit analysis, enabling the assessment of various other alternative design proposals to identify the highest level at which two different products could be combined. Compiled cases were presented to the top experts and then the CEO of dell cooperation approved it. The end product was dell not get their mother board and chassis as an assembly unit.

Results:

Assembly times was reduced by 30%

The basic need of immediate facility expansion was avoided.

Dell Company built new factories to keep up with the increase in demand.

Mother board and the chassis design were new treated as one design. They simplified the internal process.

History of the ball mouse and its parts:

“The history of the computer mouse is all owed to Douglas Carl Engelbart. His technical career started when he was a radar operator. He knew how information could be displayed on a screen, and he knew that things could be improved. Douglas Engelbart went to the Stanford Research Institute in 1957. There he received 12 patents relating to computers and magnetic components. His reputation and standing in the research and development community was good enough to get approval for doing his own research. His work in 1962 and in later years was titled Augmenting Human Intellect. His goal was to make it easier for man to approach, work, and solve problems. Creating a computer with user-graphic interface would multiply the demographics of potential computer users.

In 1963 Engelbart wrote a proposal to the Air Force to start his own research center. The proposal was granted, and he named his center the Augmentation Research Center. The Augmentation Research Center would be the setting for developments that would change then entire world. The Center eventually decided to focus on selection devices for computers. They developed light pens, which could be put directly on the monitor. Other devices were a knee brace, which was relatively usable. However, they knew they met success when they built the prototype for the computer mouse in 1964.“

Mouse Ball:

The first and the most important part of a ball mouse is the ball which is normally made up of a steel (low alloy steel ), and the manufacturing process that is used in manufacturing the solid ball is casting.

In casting process a mould is prepared first of the desired shape and then a molten material of choice is poured into the mould and then time is given for it to solidify. Preparation of the mould is important in casting process, the molten material should be able to flow to all parts of the mould. Molding of plastic materials is also a similar process

This process is primary shape forming process and is normally used to prepare materials in bulk form. Shrinkage is the most defects of casting its is caused if the mould is not built properly and the end product is not in proper shape. Shrinkage could also be caused if the metals shirk after they cool down.

Housing (top and bottom):

Housing of a ball mouse is normally made up of a thermoplastic. The most common process used in manufacturing of a plastic is injection moulding, other process such as polymer moulding can also be used in the manufacture of a mouse housing. As its made up of plastic its 100 % recycled and can be reused.

Injection molding is one of the prime processes various plastic articles. It's a fast process and is used to produce large number of similar products. Injection molding is a process which is used for producing parts of plastic materials (thermoplastic and thermo settings). The process requires an injection molding machine, raw plastic material, and a mold. The plastic is melted in the injection molding machine and then injected into the mold, where it cools down and solidifies into the desired part.

Internal wires:

The manufacturing process used in the manufacture of internal wires are rolling and forging. As the wire is an electrical material which obeys all the electrical properties the material used in manufacturing is copper.

Copper is used for manufacturing of wires because of the ease with which it can be drawn into a wire and also because of its excellent electrical properties. It's a material with high thermal and electrical conductivity. Although copper can be machined, to get good machine-ability characteristics copper is combined with other alloys to produce complex parts. Copper is supplied nearly with all metals for all types of used whether it be commercial or industrial use. It is supplied in the form of fine grained polycrystalline form. Polycrystalline metals have more strength than mono-crystalline.

Rolling is a metal forming process when a give material is passed through a pair of rolls to convert the material into desired form. Rolling is normally classified into two types based on the temperature of the metal rolled. If the temperature of the metal is below the re-crystallization temperature then we use cold rolling, if its higher than the re-crystallization temperature then we use hot rolling.

Forging is process where a metal is heat and brought into desired shape by plastic deformation by applying compressive force. Usually the compressive force is applied by using a power hammer or a press.

Forging is of many types such as press forgings, upset forgings roll forging and near net shape forging. For manufacturing of copper wires we use roll forging which is also called as draw forging.

Insulation wire:

Insulation wire is manufactured by a process called polymer extrusion and the material used in its manufacturing is polyvinyl chloride

Polyvinylchloride is a blueish material with a bit of transparency to it. It's a linear structure made out of polyethylene but chlorine replacing the hydrogen atom. The presence of plasticizers in PVC makes it soft and is ideally used for gloves and tubing manufacture process. Rigid form of PVC is used to produce tanks, trays and troughs. I can be used at a temperature of 80 Celsius for short periods of time but it's normally not recommended for the use above 70 Celsius.

Plastic extrusion is a process is mainly used for various thermo plastics, but some of the elastomers and thermo sets may also be extruded. Plastic extrusion is a process of producing long products with similar cross- section. Firstly in plastic extrusion a soft polymer is forced through a die with an small opening. Polymer material is fed into the extruder in the form of pellets. The material is then moved forward through a feeding screw and is forced out through a die which converts it into continuous polymer product. Heating elements soften and melt the polymer. Thermocouples are used to control the temperature.

A key advantage of plastic extrusion is its low cost.

Ball casing:

The ball casing is normally made up of a thermoplastic and it manufactured by a process called as polymer moulding.

Polymer moulding is a process where a molded polymer foam structure comprising expanding solvent imbibed polymer particles selected from the group consisting of a polyetherimide, a polycarbonate and a polyphenylene oxide-polystyrene blend and fusing the expanded particles together in a mold.

These are the parts of a computer ball mouse

Materials used in manufacturing of mouse ball using dfma

Material selection - mouse:

Several factors are to be considered before selecting materials for a product. Various parameters like strength, cost, durability, etc. each one of the parameters can affect the design both during the assembly or the manufacture of the product. If specific material with that has optimum manufacturability with a part many have assembly issues.

In order to achieve optimal overall costs, the costs for assembly and manufacture of the product should be considered early. A product that will be too costly as a result of poor planning will be out of the market. The product should have good durability and should be attractive (i.e. good shape and size) for today's consumer driven market. Environmental issues should also be kept in mind. Temperature, weather and some other factor can affect the design and also decrease the lifetime of the product. All these factors are to be kept in mind while selecting an apt material for a part or a product.

PART

MATERIAL USED IN DFMA

MANUFACTURING PROCESS

Mouse housing

Abs

Injection molding

Mouse ball

Low carbon Alloy steel

Investment Casting

Ball rubber casing

High density polyethylene

Blow molding

Internal wires

Copper

Casting process

Insulting wires

PVC

Plastic extrusion

Usb

Medium carbon steel

Automatic sand Casting

Usb casing

Abs

Blow molding

Spring

Low carbon steel

CNC machining

Wheel

Abs

Injection molding

Polyvinylchloride is a blueish material with a bit of transparency to it. It's a linear structure made out of polyethylene but chlorine replacing the hydrogen atom. The presence of plasticizers in PVC make it soft and is ideally used for gloves and tubing manufacture process . Rigid form of PVC is used to produce tanks, trays and troughs. I can be used at a temperature of 80 Celsius for short periods of time but it's normally not recommended for the use above 70 Celsius.

Properties:

  • It has a excellent resistance to dilute and concentrated acids , alcohols
  • PVC has good resistance against vegetable oils
  • PVC has a limited resistance against aldehydedes. (moderate attack only)
  • Shows bad resistance to ketones, esters and aldehydes

Acrylonitrile Butadiene Styrene is a combination of different monomers to form a single materials that has all the properties of the three materials. ABS has high impact strength and high mechanical strength. It also has good dimensional stability and electrical insulating properties. Commonly used for car components, TV casing, radios, controls panels.

Properties:

ABS can be blow moulded, sawed, drilled or even cold stamped .

ABS has a special characteristic that it can also be ultrasonic welded, thermo welded and chemically bonded.

ABS can be used in various manufacturing process like thermo welding and ultra- sonic welding.

ABS posses Good impact resistant.

Nylon (Polyamide) is the first thermoplastic and was invented by Wallace carothers. Nylon is created when a condensation occurs between amino acids, dibaic acids and diamines. Normally nylon is used when machined into of gears, rollers and thread guides.

Properties:

Good materials for machining

Tough strong and impact resistant material

Very low coefficient of friction

Abrasion resistant.

Alloy steel :

Steel is considered to be a carbon steel when no minimum content is required for any other element to be added to obtain a desired alloying effect. Plain carbon steel is a compound where the major constituent is carbon.

There are five major classifications of steels: carbon steel, alloy steel, high-strength low-alloy steel, stainless steel and tool steel. Low alloy steels are normally used to achieve better hardenability, which also improves its mechanical properties. They are also used to increase corrosion resistance in certain different environmental conditions.

Copper :

Copper is used for manufacturing of wires because of the ease with which it can be drawn into a wire and also because of its excellent electrical properties. It's a material with high thermal and electrical conductivity. Although copper can be machined, to get good machine-ability characteristics copper is combined with other alloys to produce complex parts. Copper is supplied nearly with all metals for all types of used whether it be commercial or industrial use. It is supplied in the form of fine grained polycrystalline form. Polycrystalline metals have more strength than mono-crystalline.

Different combinations of properties can be produced by varying the heat treatment of copper and its alloys--influencing strength, hardness, ductility, conductivity, impact resistance, and inelasticity.

Manufacturing process used in DFMA:

Housing of a ball mouse:

As the mouse was divided or broken into smaller parts, housing of a ball mouse comprises of three parts

Housing -one (top half of the mouse)

Housing-two(the click button of the mouse)

Base (base of the mouse)

The material used in the manufacturing process of the above parts is ABS and the manufacturing process used is injection moulding.

Acrylonitrile Butadiene Styrene is a combination of different monomers to form a single material that has all the properties of the three materials. ABS has high impact strength and high mechanical strength. It also has good dimensional stability and electrical insulating properties. Commonly used for car components, TV casing, radios, controls panels.

Properties:

ABS can be blow molded, sawed, drilled or even cold stamped.

ABS has a special characteristic that it can also be ultrasonic welded, thermo welded and chemically bonded.

Good impact resistant.

ABS was chosen keeping in mind the electrical nature of mouse. Its high impact strength and machinability characteristics made ABS an apt material for the housing of a mouse.

Injection molding is one of the prime processes various plastic articles. It's a fast process and is used to produce large number of similar products. Injection molding is a process which is used for producing parts of plastic materials (thermoplastic and thermo settings). The process requires an injection molding machine, raw plastic material, and a mold. The plastic is melted in the injection molding machine and then injected into the mold, where it cools down and solidifies into the desired part. According to BOOTHROYD (2001) the rising sophistication in the use of molded injection plastics. Injection molding is an important tool to win the battle of reduces parts to save costs and creates an elegant design.

  • Design flexibility.
  • Repeatability with different tolerances.
  • Low labor.
  • Minimum scrap loss.
  • Can produce wide range of materials.

All the above factors helps the manufacturing company to lower down their manufacturing costs, that the reason why injection molding manufacturing process is used.

Mouse ball:

As mouse ball is a major part of a mouse which has to have good surface finish with no parting lines. The manufacturing process used for a ball of a mouse is investment casting.

Investment casting is the oldest form of techniques. Investment casting process can be used with any metal. It is generally more expensive per unit when compared to sand and die casting but the equipment cost is low.

Advantages of investment casting:

Good accuracy

Repeatability

Gives excellent surface finish

Most importantly no parting lines.

The material used in manufacturing of a ball is low carbon alloy steel.

Steel is considered to be a carbon steel when no minimum content is required for any other element to be added to obtain a desired alloying effect. Plain carbon steel is a compound where the major constituent is carbon.

Carbon steel is a form of steel that is formed due to the comibination of two materials (ie carbon and steel). It also has other materials such as copper and silicon but in small quantities.

Steels are normally classified as three types:

  • Carbon steel
  • Alloy steel high-strength low-alloy steel
  • Stainless steel and tool steel.

Low alloy steels are normally used to achieve better hardenability, which also improves its mechanical properties. They are also used to increase corrosion resistance in certain different environmental conditions.

Ball casing:

Ball caseing acts as a sub-assembley to the ball. the materials used in manufacturing process of ball casing is High density polyethylene.

Blow molding is used as a manufacturing process. Blow molding is a very common type of plastic molding. In this process a plastic tubular form is used which is produced by extrusion molding which is generally used to form the part. The tubular form of plastic is called as a parsion, the parison is softened inside a mold and then air is injected into the parision which expands the parison against the sides of the mould cavity. A hollow part is formed with the size and shape of the molding general, there are three main types of blow molding.

  • Extrusion blow molding
  • Injection blow molding
  • Stretch blow molding.

Blow molding is especially used for hollow parts.

Copper wires:

The manufacturing process used in the manufacture of internal wires are wire drawing rolling and forging. As the wire is an electrical material which obeys all the electrical properties the material used in manufacturing is copper.

Copper is used for manufacturing of wires because of the ease with which it can be drawn into a wire and also because of its excellent electrical properties. It's a material with high thermal and electrical conductivity. Although copper can be machined, to get good machine-ability characteristics copper is combined with other alloys to produce complex parts. Copper is supplied nearly with all metals for all types of used whether it be commercial or industrial use. It is supplied in the form of fine grained polycrystalline form. Polycrystalline metals have more strength than mono-crystalline.

Rolling is a metal forming process when a give material is passed through a pair of rolls to convert the material into desired form. Rolling is normally classified into two types based on the temperature of the metal rolled. If the temperature of the metal is below the re-crystallization temperature then we use cold rolling, if its higher than the re-crystallization temperature then we use hot rolling.

Forging is process where a metal is heat and brought into desired shape by plastic deformation by applying compressive force. Usually the compressive force is applied by using a power hammer or a press.

Forging is of many types such as press forgings, upset forgings roll forging and near net shape forging. For manufacturing of copper wires we use roll forging which is also called as draw forging.

Insulation wire:

Insulation wire is manufactured by a process called polymer extrusion and the material used in its manufacturing is polyvinyl chloride

Polyvinylchloride is a blueish material with a bit of transparency to it. It's a linear structure made out of polyethylene but chlorine replacing the hydrogen atom. The presence of plasticizers in PVC makes it soft and is ideally used for gloves and tubing manufacture process. Rigid form of PVC is used to produce tanks, trays and troughs. I can be used at a temperature of 80 Celsius for short periods of time but it's normally not recommended for the use above 70 Celsius.

Plastic extrusion is a process is mainly used for various thermo plastics, but some of the elastomers and thermo sets may also be extruded. Plastic extrusion is a process of producing long products with similar cross- section. Firstly in plastic extrusion a soft polymer is forced through a die with an small opening. Polymer material is fed into the extruder in the form of pellets. The material is then moved forward through a feeding screw and is forced out through a die which converts it into continuous polymer product. Heating elements soften and melt the polymer. Thermocouples are used to control the temperature.

A key advantage of plastic extrusion is its low cost.

Spring :

A spring is a device which changes its shape when an external force is applied and when the force is removed returns to its original shape. The amount of change in shape of the spring is directly proportional to the amount of load or the force applied. Deformation of a spring occurs when too large load is applied.

The raw materials used in manufacture of springs are steel alloys. The most popular are low and high carbon steel alloys

Manufacture of coiled springs involves many steps

Coiling is the process where a wire is wound round a shaft(mandrel) . this process may be done on a spring winding machine or on a lathe. Alternatively the wire may also be coiled without the round shaft this is generally done using a computer CNC machine.

Hot winding is a process where the wire is coiled around a mandrel while its red hot. This process is done to make the spring much more flexible.

Hardening is a process where the spring is hardened through a heat treatment process at 260 C for one hour and then it is allowed to cool down slowly.

Grinding is a process which is used when the deign calls for flat ends on the spring. In this process the spring is mounted on a jig and is held against a rotating wheel till the desired flatness is obtained.

Setting of the spring is the last process of manufacturing a spring. Here the spring is completely compressed so that the coils touch each other, this is done to permanently fix the desired length and the pitch of the spring.

USB metal:

Sand casting is very old method even used in today's manufacturing process. In sand casting process the metal is put into a furnace and allowed to melt. Then the molten form is poured into a cavity or impression made by sand.

Automated sand casting has a slight variation from sand casting to produce parts with high speed, high volume and high repeatability. Benefits of automated casting include high rate of uniformity, reducing labor expenses, high output.

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Medium carbon steel is used for the manufacturing of a usb because of its special properties

machinabilty of 60 to 70%

its extremely popular because of numerous application.

Good toughness and ductility

Fair formability and is less in cost than high carbon steel.

USB casing:

Acrylonitrile Butadiene Styrene is a combination of different monomers to form a single materials that has all the properties of the three materials. ABS has high impact strength and high mechanical strength. It also has good dimensional stability and electrical insulating properties. Commonly used for car components, TV casing, radios, controls panels.

Properties:

ABS can be blow moulded, sawed, drilled or even cold stamped .

ABS has a special characteristic that it can also be ultrasonic welded, thermo welded and chemically bonded.

Good impact resistant

Blow molding is used as a manufacturing process. Blow molding is a very common type of plastic molding. In this process a plastic tubular form is used which is produced by extrusion molding which is generally used to form the part. The tubular form of plastic is called as a parsion, the parison is softened inside a mold and then air is injected into the parision which expands the parison against the sides of the mould cavity. A hollow part is formed with the size and shape of the molding general, there are three main types of blow molding.

Insulation wires:

Polyvinylchloride is a blueish material with a bit of transparency to it. It's a linear structure made out of polyethylene but chlorine replacing the hydrogen atom. The presence of plasticizers in PVC make it soft and is ideally used for gloves and tubing manufacture process . Rigid form of PVC is used to produce tanks, trays and troughs. I can be used at a temperature of 80 Celsius for short periods of time but it's normally not recommended for the use above 70 Celsius.

Properties:

It has a excellent resistance to dilute and concentrated acids , alcohols

Good resistance to vegetable oils

Limited resistance to aldehydes (moderate attack only)

Poor resistance to ketones, esters and aldehydes.

Plastic extrusion is a process is mainly used for various thermo plastics, but some of the elastomers and thermo sets may also be extruded. Plastic extrusion is a process of producing long products with similar cross- section. Firstly in plastic extrusion a soft polymer is forced through a die with an small opening. Polymer material is fed into the extruder in the form of pellets. The material is then moved forward through a feeding screw and is forced out through a die which converts it into continuous polymer product. Heating elements soften and melt the polymer. Thermocouples are used to control the temperature.

A key advantage of plastic extrusion is its low cost.

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Mouse housing

Abs

Injection moulding

Mouse ball

Low carbon Alloy steel

Investment Casting

Ball rubber casing

High density polyethylene

Blow moulding

Internal wires

Copper

Casting process

Insulting wires

PVC

Plastic extrusion

Usb

Medium carbon steel

Automatic sand Casting

Usb casing

Abs

Blow molding

Spring

Low carbon steel

CNC machining