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DFM
| Term | Definition |
|---|---|
| value | innovators, brand manager, price minimisers, simplifiers, technological integrators, socialisers |
| weld lines | Convergent and Divergent material flowing past hole and rejoining controlled by runner dimensions |
| How injection Injection Moulding works (principle) | polymer granules inserted into a cylinder melt transferred by rotation of a screw injected into mould where it solidifies |
| Key Drivers | Cost - less waste Quality - constant checks Time - predictable |
| Manufacturing Principles | Avoid tight tolerances Modular parts Minimise number of parts Standardised parts Avoid secondary operations Ease of assembly Capabilities of each process |
| Defects of Micro-injection Moulding | Part warping thin walls non-uniform shrinkage gas trapped in the mould |
| Moulds for Micro-injection moulding | Part thickness Features scaled correctly Laser and electrons Temp controlled by cooling |
| Advantages of rapid prototyping | quicker costs less complex geometries wide range of materials direct from CAD |
| Factors that affect shrinkage | crystallisation low cooling times molten part gates |
| Defects in IM | Flash Ejector pin mark Weld lines Gatemarks Shrinkage |
| Micro-machining Guidelines | Round Corners Stiff Design Correct Grade and Geometry lower thickness = lower stiffness multiple tools= more complex |
| Assembly | Cost and Quality dependent on number of operations =layout, form, production type storing, handling, positioning, joining, adjusting |
| What is Manufacturing | converting raw materials into high quality products competitively right cost and time |
| Design Guidelines for IM | Undercuts Thread Holes Metal Inserts Ribs Wall thickness Round Corners Draft angle Part lines |
| Features of MIM | clamping unit plasticisation unit handling module inspection |
| Problems with DFA | Costly Takes to long Only looks at amount of parts |
| Design for assembly | easy less costly higher quality more reliable case studies: lamp reflector Methodologies: Boothroyd, Hitachi, Lucas |
| Types of Prototypes | Form study: ergonomic, inexpensive, internal (styrofoam) Visual: aesthetic, internal, consumer (clay) Proof of principle: prove aspects, no visual Functional: final design, tests and proves design |
| Machinability | tool access paths identify datum planes minimise area to be machined non-value time parts |
| What are Prototypes | Representation - test new theories what to test? -consumer interest -functionality -assembly -performance |
| Types of Fixtures | conformable - foam pucks modular - prototype tooling Flexible Dedicated - automotive casting |
| 3D Representations | Prototypes - looks into how the product works Appearance model - looks into visuals - not functional Appearance prototype - mix of both |
| Differences between prototype and production | cheaper materials low fidelity more flexible manufacturing methods |
| VAT Polymerisation (SLA) | resin types provide properties layer thickness 25-100 micrometers placed in UV for complete curing small parts are ideal complex parts built in supports |
| Jetting Base 3D printing | deposit liquid to build no post printing curing multiple print heads case study: adidas football boot |
| Direct and Indirect cost | Direct- raw materials, tool Indirect - admin, operational managers |
| Fitting Analysis | Total Fitting index/ A less than or equal to 2.5 |
| lucas method | made in 1980s 1.specification 2.design 3.functional analysis 4. feeding analysis 5. filling analysis 6.assessment |
| Functional Analysis | tests components for function A/(A+B) x 100 =m design efficiency > or equal to 60% |
| Applications and advs of Injection Moulding | Food Container -complex shapes -uniform thickness -variety of dimensions -surface finish -high economic batch size |
| Cast-ability and guidlines | ease of producing casting with minimum defects potential defects radii constant sections avoid solid areas machining & shrinkage allowance draft angles |
| Different uses of capabilities | surface finish and tolerance achievable wide range of capabilities complex tooling requirements dimensional accuracy |
| Micro-injection moulding | weight = 1g dimension = 1mm tolerances = 10 -100 micrometers similar steps to IM applications: printer heads, sensors Thermoplastics: PP, PE, PS |
| Materials for Injection Moulding | Thermoplastics : ABS (heated cylinder, cool die) Thermosets: epoxies (heated both) Elastomers: Rubber |
| Micro-extrusion (FDM) | Pressure to move material move nozzle to moving table thermoplastic filaments price range:£2K- 50K e.g. materials ASA, ABS, PLA |
| Binder jetting | Adhesive bonding used between molten material ideal for: prototypes, low volume, good properties application: healthcare, automotive |
| Rapid Tooling | used to make 3D printing tools makes soft(polymers x100 & cheaper) and hard (hardened steel x1000) e.g. silicone rubber tooling |
| Feeding/ Handling analysis | tests parts handling and insertion timers are examined Total Index/A |
| Complex Designs | Cost more Takes longer - late delivery complex manufacturing and holding methods |
| 3 basic components | locators clamps supports |
| Why do we use polymers | -low density -electrical &thermal conductivity -good process-ability complex forms little investment for mass production reduced need for surface finish |
Created by:
annabelheath
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