DESIGN FOR MANUFACTURING & ASSEMBLY (DFMA)

DESIGN FOR MANUFACTURING & ASSEMBLY (DFMA)SUBMITTED BY:-TARUN BHATIATARUN GUPTAYASH JAINSWATI MENDIRATTADesign for manufacturing (DFM) is design based on minimizing the cost of production and/or time to market for a product, while maintaining an appropriate level of quality. The strategy in DFM involves minimizing the number of parts in a product and selecting the appropriate manufacturing process.

Design For Assembly (DFA) involves making attachment directions and methods simpler.

WHAT IS DFMA?It reduces part count thereby reducing cost. If a design is easier to produce and assemble, it can be done in less time, so it is less expensive. Design for manufacturing and assembly should be used for that reason if no other.

It increases reliability, because if the production process is simplified, then there is less opportunity for errors.

It generally increases the quality of the product for the same reason as why it increases the reliability.

DFADFMDFMADFEDFSDFDDFSSDFA = DESIGN FOR ASSEMBLYDFM = DESIGN FOR MANUFACTUREDFE = DESIGN FOR ENVIRONMENTDFD = DESIGN FOR DISASSEMBLYDFS = DESIGN FOR SERVICEDFSS = DESIGN FOR SIX SIGMADFX = DESIGN FOR XDEVELOPMENT OF DFMADFXsOBJECTIVES OF DFMA1) Material and Process selection and understanding theirimpact on design.2) Process planning avoiding expensive and timely processes.3) Simplification (reducing number of processes of manufacturingand number of parts in an assembly).4) Cost estimating of manufacturing and assembly.5) Time estimating of manufacturing and assembly.6) Taking into account product maintainability (adequate access and unrestricted vision).7) Considering product packaging and handling.(a) Shorter processing time to manufacture/assemble.(b) Reducing Cost of manufacturing and assembly, and(c) Reproducibility of parts and product(d) Increase quality(e) Improve reliabilityADVANTAGES OF DFMAIn a survey of 89 industries that used DFMA it was found that the following reductions were achieved, on average.

100%From the BDI websiteBoothroyd & Dewhurst Institute websiteDFM & DFADFM and DFA starts with the formation of the design team which tends to be multi-disciplinary, including engineers, manufacturing managers, cost accountants, and marketing and sales professionals. The most basic approach to design for manufacturing and assembly is to apply design guidelines. You should use design guidelines with an understanding of design goals. Make sure that the application of a guideline improves the design concept on those goal.DFMA GUIDELINES

1) Simplify design (minimize the number of parts): this results in cheaperproduct, fewer assemblies , part manufacturing, inspection, inventory, etc.2) Use Modular design: this leads to simplifiesthe manufacturing process, use of standardcomponents, tests of modules operation.

3) Use Standard components: it provides lessexpensive and proven component and no needfor development.4) Design parts for Multi-functional: this leads to reduction of parts,manufacturing time, inventory cost.5) Design part for Multi use: the part is used for the same or different operationsmultiple times in a product. This leads to reduce the number of parts that need to bedeveloped.6) Design to allow assembly in open spaces,this leads to that important components notconfined or buried, and easing maintainability

7) Design Parts indicating orientation for insertion. Parts should have self-locking features so that the precise alignment during assembly is not required. Or,provide marks (indentation) to make orientation easier.8) Integrate design: integration/combination of parts depends on the need ofmovement relative to others, use of different materials, need to separate to allowassembly access, or repair and need not tangle or stick to each other.

9) Differentiate between similar parts: Distinguishdifferent parts that are shaped similarly by non-geometric means, such as color coding.10) Design parts to prevent nesting.Nesting is when parts are stacked on top ofone another clamp to one another, forexample, cups and coffee lids

11) Maximize the ease of insertingparts: Design the mating parts foreasy insertion. Provide allowance oneach part to compensate for variationin part dimensions.12) Design for stability. Design the firstpart large and wide to be stable and thenassemble the smaller parts on top of itsequentially.

13) Design for alignment/orientation: Design partswith orienting features to make alignment easier.14) Minimize Assembly Directions:Optimal assembly of a product occursin one direction (Preferred direction isfrom above using gravity to assist inassembly). If you cannot assembleparts from the top down exclusively,then minimize the number of insertiondirection. Never require the assemblyto be turned over.

15) Avoid Separate Fasteners: design fasteners appropriately. Joining parts can bedone with fasteners (screws, nuts and bolts, rivets), snap fits, welds or adhesives.16) Maximize compliance: this leads to reduce Errors in insertion due to positioningand dimensional variability cause damage to parts. Use tapers, chamfers andmoderate radii to ease insertion.17) Maximize the ease of handling parts: this results in reducing time and costof Positioning, orienting, and fixing a part. Use external guiding features to orientthe part and Ideally the part should be placed one time.18) Design part eliminate unnecessary process steps; this reduces the numberof steps of the production process resulting usually in reduce costs. Usesubstitution steps, where applicable. Analysis Tool Process Flow Chart andValue Stream Mapping.

19) Design and simplify process for ease of manufacturing: This concernswith design of products ability to be easily manufactured. This differ fromprocess to other. For example:a) For injection molding:

19) Design and simplify process for ease of manufacturing: This concernswith design of products ability to be easily manufactured. This differ fromprocess to other. For example:b) For casting process:

19) Design and simplify process for ease of manufacturing: This concernswith design of products ability to be easily manufactured. This differ fromprocess to other. For example:c) For sheet metal processing:

19) Design and simplify process for ease of manufacturing: This concernswith design of products ability to be easily manufactured. This differ fromprocess to other. For example:d) For machining processing:CROSS FUNCTIONAL TEAMS

DESIGN RULES: SPECIALIZED BY FIRM

CAD TOOLS: BOOTHROYD DEWHURST SOFTWARE (USED BY FORTUNE 1000 COMPANIES)METHODS TO IMPLEMENT DFMADFM METHOD1) Estimate the manufacturingcosts.2) Reduce the costs ofcomponents.3) Reduce the costs of assembly.4) Reduce the costs ofsupporting production.5) Consider the impact of DFMdecisions on other factors.

1. ESTIMATE THE MANUFACTURING COSTS

1. ESTIMATE THE MANUFACTURING COSTS

Manufacturing Cost = Sum of all the expenditures for the inputs of the system(i.e. purchased components, energy, raw materials, etc.) and for disposal of thewastes produced by the system.1. ESTIMATE THE MANUFACTURING COSTSManufacturing Costs: Fixed costs & Variable Costs Fixed Costs : It is the cost incurred in a predetermined amount, regardless of number of units produced (i.e. setting up the factory work area or cost of an injection mold). Variable Costs: It is incurred in direct proportion to the number ofunits produced (i.e. cost of raw materials, labor costs).Cost estimating is based on the use of bill of material added tothe cost information for each component.2. REDUCING THE COST OF COMPONENTS By Understanding the Process Constraints and Cost Drivers Redesign costly parts with the same performance while avoidinghigh manufacturing costs.Work closely with design engineersraise awareness of difficultoperations and high costs. By Redesigning Components Eliminate Processing StepsBy Choosing the Appropriate Economic Scale for the Part Process The unit cost of a component decreases as the productionvolume increases.2. REDUCING THE COST OF COMPONENTSBy Standardizing Components and ProcessesThis leads to be common to more than one product. Useanalysis tools , suchas group technology and mass customization. By Adhering to Black Box Component Procurement Successful black box design requires clear definitions of the functions, interfaces, and interactions of each component based on the description of what the component has to do, not how to achieve it.

3. REDUCING THE COST OF ASSEMBLYBy Design for Assembly (DFA) index Compute Assembly Time = Handling Time + Insertion Time DFA index = (Theoretical minimum number of parts) x(3 seconds)/(Estimated total assembly time) The Theoretical minimum number of parts is determined based on partneed to move relative to the rest of the assembly, made of a differentmaterial from the rest of the assembly for fundamental physical reasons,and has to be separated from the assembly for assembly access,replacement, or repair. By Integrated Parts (Advantages and Disadvantages) This results if no assembly is required; less expensive to fabricate;allowing control of critical geometric features to be controlled by thepart fabrication process versus a similar assembly process. However, it may conflict with other sound approaches to minimizecosts and is not always a wise strategy.3. REDUCING THE COST OF ASSEMBLY By Maximizing Ease of AssemblyoInsert part from the top of the assemblyoAssemble the part in a single, linear motionoSelf-aligning partoSecuring the part immediately upon insertionoPart does not need to be orientedoPart requires only one hand for assemblyoPart requires no tools By Considering Customer Assemblyo Customers acceptance some assemblyo Design product so that customers can easily assemble partscorrectlyo Customers will likely ignore directions4. REDUCING THE COST OF SUPPORTING PRODUCTION Minimize Systemic Complexity (inputs, outputs, andtransforming processes) Use smart design decisions Error Proofing Anticipate possible failure modes Take appropriate corrective actions in the early stages Use color coding to easily identify similar looking, but differentparts5. CONSIDER THE IMPACT OF DFM DECISIONS ON OTHER FACTORS1. Impact of DFM on Development Time2. Impact of DFM on Development Cost3. Impact of DFM on Product Quality4. Impact of DFM on External FactorsComponent reuse Life cycle costsTHANK YOU