Dfm 7 Forming

Design for ManufactureDesign for Manufacture

Forming ProcessesForming Processes

Jonathan MarshJonathan Marsh

Lecture 6Lecture 6 -- RecapRecap

Machining Machining Design ConsiderationsDesign Considerations ToleranceTolerance Material PropertyMaterial Property Tool TypesTool Types Surface FinishSurface Finish

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Surface FinishSurface FinishMachining Machining Turning Turning Boring Boring MillingMilling BroachingBroaching

MachinesMachines CNCCNC Machine CentreMachine Centre

IntroductionIntroduction

FormingForming IntroductionIntroduction

Fundamentals of FormingFundamentals of FormingTheoryTheory

Design Considerations in FormingDesign Considerations in Forming

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Design Considerations in FormingDesign Considerations in FormingMaterialsMaterials

Draft anglesDraft angles

Types of formingTypes of formingForgingForging

Vacuum formingVacuum forming

FiringFiring

IntroductionIntroduction

What does forming involve?What does forming involve? Deforming a work piece to a desired shapeDeforming a work piece to a desired shape

Can be performed as a Hot / Cold ProcessCan be performed as a Hot / Cold Process

Uses materials ability to flow plasticallyUses materials ability to flow plastically

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Design ConsiderationsDesign Considerations

Design ConsiderationsDesign Considerations The main consideration in forming processes are The main consideration in forming processes are

centred on the work piece material.centred on the work piece material.Forming a WP will effect the material properties in the Forming a WP will effect the material properties in the formed region.formed region.

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formed region.formed region.

This can add significant strength to the final unit that This can add significant strength to the final unit that other processes can notother processes can not

Cast PieceCrystals form randomly Cracks can propagate

between crystal regions

Machined PieceCrystals remain in

original alignment. Shear cracks can develop along

regions

Formed PieceCrystals form with the

piece keeping strength of original billet


Design ConsiderationsDesign Considerations Does process/material require Hot / Cold working.Does process/material require Hot / Cold working.

Cold working is not actually cold, but colderCold working is not actually cold, but colder

Used to create a fine grain structure and finish on Used to create a fine grain structure and finish on formed WP previously hot formedformed WP previously hot formed

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formed WP previously hot formedformed WP previously hot formed

NB: Can add around 20% to the costNB: Can add around 20% to the cost


Design ConsiderationsDesign Considerations Chose a material that allows a significant amount Chose a material that allows a significant amount

of plastic deformationof plastic deformation e.g. Aluminium, Copper, Thermoplasticse.g. Aluminium, Copper, Thermoplastics

Available billet sizes and shapesAvailable billet sizes and shapes

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Available billet sizes and shapesAvailable billet sizes and shapesi.e. Vacuum Formingi.e. Vacuum Forming

Tool Size, Shape and complexityTool Size, Shape and complexity

Are draft angles required?Are draft angles required?

Surface FinishSurface Finish

Tolerance Tolerance

Forming ProcessesForming ProcessesPlastic State Forming

Forging Rolling Drawn Extrusion

Hammer Hot Direct Deep

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Hammer

Drop

Press

Swaging

Hot

Cold

Direct

Impact

Deep

Wire


RollingRolling Continuous manufactureContinuous manufacture

Can be performed hot/coldCan be performed hot/cold

Used to produce Plate, Rail, TubeUsed to produce Plate, Rail, Tube

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Tool must be rotationally symmetricalTool must be rotationally symmetrical

Medium Tolerances 0.05 Medium Tolerances 0.05 –– 1 mm 1 mm

Good Surface finish 0.5 Good Surface finish 0.5 –– 66mmm Rm Raa

Very economical for continuous manufacture of Very economical for continuous manufacture of certain shapescertain shapes


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ForgingForging Forging is plastic forming of metal by localised Forging is plastic forming of metal by localised

compressioncompression“Bashing with huge hammer” “Bashing with huge hammer”

Types: Hammer, Open die, drop forging, press Types: Hammer, Open die, drop forging, press

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Types: Hammer, Open die, drop forging, press Types: Hammer, Open die, drop forging, press forging etc.forging etc.

Very quick Very quick –– Automated Automated

Tolerances Typically Tolerances Typically 1mm can be 0.1mm1mm can be 0.1mm

Surface finish 5 Surface finish 5 –– 25 25 mmm Rm Raa

Used on most metalsUsed on most metals

Limit to the complexity of shapeLimit to the complexity of shape

Hammer

Open


ForgingForging

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ExtrusionExtrusion Extrusion is plastic forming of material forcing it Extrusion is plastic forming of material forcing it

through a diethrough a die“Like squeezing toothpaste” “Like squeezing toothpaste”

Tolerances Typically 0.25mm Tolerances Typically 0.25mm –– 2.5mm2.5mm

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Tolerances Typically 0.25mm Tolerances Typically 0.25mm –– 2.5mm2.5mm

Surface finish 1 Surface finish 1 –– 3 3 mmm Rm Raa


Pressing / Deep DrawingPressing / Deep Drawing Formation of 3D parts by plastically stretching material.Formation of 3D parts by plastically stretching material.

Design must take account thinning of materialDesign must take account thinning of material

Very quick 2000/minVery quick 2000/min

Use adequate radii to prevent tearing/sheeringUse adequate radii to prevent tearing/sheering

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Use adequate radii to prevent tearing/sheeringUse adequate radii to prevent tearing/sheering

Highly dependant on material propertiesHighly dependant on material properties

Tolerances 0.2 Tolerances 0.2 –– 5 mm 5 mm

Surface finish 0.5 Surface finish 0.5 -- 25 25 mmm Rm Raa


SwagingSwaging Repeatedly hammering tube or bar to form a 3D profile Repeatedly hammering tube or bar to form a 3D profile

Requires ductile material usually metalRequires ductile material usually metal

Production around 400 parts/hrProduction around 400 parts/hr

Tolerances 0.05 Tolerances 0.05 –– 5 mm5 mm

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Tolerances 0.05 Tolerances 0.05 –– 5 mm5 mm

Surface finish 0.2 Surface finish 0.2 –– 2 2 mmm Rm Raa

Used for creating necks in tube splines etcUsed for creating necks in tube splines etc


Blanking / Punching / SheeringBlanking / Punching / Sheering Creating form buy cutting punching shapes.Creating form buy cutting punching shapes.

From Scissors to large presses…From Scissors to large presses…

Very quick 1Very quick 1--5 sec/part5 sec/part

Used for sheet material 0Used for sheet material 0--100mm thick100mm thick

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Used for sheet material 0Used for sheet material 0--100mm thick100mm thick

Tolerance depends on thickness Tolerance depends on thickness 0.05 0.05 –– 10mm10mm

Edge roughness 0.8 Edge roughness 0.8 –– 25 25 mmm Rm Raa


SpinningSpinning Creating a shape from sheet material formed over a Creating a shape from sheet material formed over a

spinning mandrelspinning mandrel

Can be done on a lathe.Can be done on a lathe.

Production rates 200 parts /hrProduction rates 200 parts /hr

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Production rates 200 parts /hrProduction rates 200 parts /hr

Tolerances 0.1 Tolerances 0.1 –– 2mm2mm

Surface finish 0.2 Surface finish 0.2 -- 6 6 mmm Rm Raa

Used for axisymmetric shapes,Used for axisymmetric shapes,

e.g. reflectors, light shades, trumpet bellse.g. reflectors, light shades, trumpet bells


Vacuum formingVacuum forming Used to produce shapes by sucking material over a patternUsed to produce shapes by sucking material over a pattern

Widely used to from plastic sheetWidely used to from plastic sheet

Thickness 1Thickness 1--10mm thick10mm thick

Tolerances dependant on size 1Tolerances dependant on size 1-- 10mm10mm

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Tolerances dependant on size 1Tolerances dependant on size 1-- 10mm10mm

Surface finish as originalSurface finish as original

Used for plastic containers, packaging etcUsed for plastic containers, packaging etc


Vacuum formingVacuum forming

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Other Forming ProcessesOther Forming Processes BendingBending

Bending of sheet or bar into desired shape can be done Bending of sheet or bar into desired shape can be done hot / cold depending on material properties.hot / cold depending on material properties.

Types: Angle, Roll, Draw, SeamingTypes: Angle, Roll, Draw, Seaming

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Types: Angle, Roll, Draw, SeamingTypes: Angle, Roll, Draw, Seaming

EmbossingEmbossingPressing of shapes into sheet or surfaces to form Pressing of shapes into sheet or surfaces to form desired shape e.g. Credit carddesired shape e.g. Credit card

HydroformingHydroformingFluid Pressure used to expand material into dieFluid Pressure used to expand material into die

Wire Drawing Wire Drawing Like extrusion but pulling the material through the dieLike extrusion but pulling the material through the die


CeramicsCeramics Have some very good properties including Have some very good properties including

resistance to temperature and wear resistanceresistance to temperature and wear resistance

Long used in the electrical industry for resistance Long used in the electrical industry for resistance properties now more commonly in engineering.properties now more commonly in engineering.

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properties now more commonly in engineering.properties now more commonly in engineering.

In general ceramics are a hard, brittle material In general ceramics are a hard, brittle material with high compressive strength.with high compressive strength.

Compounds of metallic and non metallic materials Compounds of metallic and non metallic materials normally in crystalline form.normally in crystalline form.

Ceramics are formed from paste/powder (Pottery) Ceramics are formed from paste/powder (Pottery) or Viscous hot material (Glass)or Viscous hot material (Glass)


Ceramics Ceramics –– Glass Glass Glass is usually formed from a molten Glass is usually formed from a molten

viscous liquid molded into a 3D Solidviscous liquid molded into a 3D Solid

Used from bottles, windows, vases etcUsed from bottles, windows, vases etc

Glass ManufacturingGlass Manufacturing

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Glass ManufacturingGlass ManufacturingPlate rolled or floated on molten tin.Plate rolled or floated on molten tin.

Molded into many forms, casting, blow Molded into many forms, casting, blow molding, Pressing etcmolding, Pressing etc

Largely Automated Largely Automated Can be hand crafted Can be hand crafted


Ceramics Ceramics –– Crystalline CeramicsCrystalline Ceramics Ceramics are from formed aggregates shaped as Ceramics are from formed aggregates shaped as

moist paste/powder and solidified.moist paste/powder and solidified.

Used from pottery to semi conductorsUsed from pottery to semi conductors

Usually brittle material not good for post Usually brittle material not good for post

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Usually brittle material not good for post Usually brittle material not good for post processing some can be machinedprocessing some can be machined

Ceramic ManufacturingCeramic ManufacturingPlastic forming Plastic forming –– blend of ceramic and additives to make blend of ceramic and additives to make a formable mixture by Pressure heat, injection molding. a formable mixture by Pressure heat, injection molding. Additive is then removed.Additive is then removed.

Slip Casting Slip Casting -- Slurry is cast into a porous mold and the Slurry is cast into a porous mold and the liquid reduces by capillary action. liquid reduces by capillary action.


Ceramics Ceramics –– CastingCasting

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Questions?Questions?

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Dfm 7 Forming

Design

Transcript of Dfm 7 Forming