Joining processes

Joining processes design and technology revision cards.

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  • Created by: miguel
  • Created on: 14-05-12 14:14

Choosing a method joint

Temporary: This joint doesnt damage the materials when being undone.(Figure 1)  include wood screws and self-tapping screws. 

Permanent:dismantling this joints will damage the materials.(spot welding used on car body panels that last lifetime of the car)

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/072_nut_and_bolt.jpg)(Figure 1)

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Joining metals

Metals: can be joint using nuts, bolts screws.

Other methods: Folding, crimping = forming of a metal to provide a joint

HEAT joints: soldering, brazing and welding 

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/074a_seam_joint.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/074b_crimped_joint.jpg)

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Soldering

-Soldering-lowest temperature, including soft and hard solders.                                   -Soft solder-joining electronic components to circuit boards (200°C)                         -Hard solder-products that need addition strength (600-800°C)                                   -Solder nowadays contain 96%tin, 3.5%silver, 0.5%copper more expensive as lead free. Traditionally 60%tin and 40% lead.

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/075_soldering.jpg)1-remove grease/dust and kept clean with flux                 2-no large gaps and must be held securely while being heated up.                         3-Blowtorch heat the material, heat both evenly, heat material and melt the solder in capillary action.                                                                                                                    4-then allowed to cool.

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Brazing

Higher temperatures than soldering-materials that can be joint copper and steel (in particular mild steel)

Filler rod melts at (880°C)- brass alloy

Borax to clean the joint held together will being heated

Brazing rod melts like capillary action, then allowed to cool before having excess flux and braze removed.


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Welding

Material being joint must be the same.

Oxy-acetylene welding=2500°C mixture of oxygen and acetylene sufficient to meld mild steel.

Electric arc welding

MIG and TIG welding= Gas jet around the filler wire to prevent  oxidation of the material, different gases with different materials -argon with aluminium.

Spot and seam welding=electric current as heat source spot heat that fuse metal together- car body shell + drink /food cans 

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processes involving heat

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/076_oxyacetylene.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/078_spot_welding.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/077_electric_arcweld.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/079_resist_spot_welding.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/080_seam_welding.jpg)

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Joining processes for wood

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/082_wood_joints.jpg)

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Self- assembly furniture

High volume- being supplied to consumer flat packed

Self assembly with (KD) knock down fittings.

Along side their be hinges and especially drilled holes

Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/083_nut_and_bolt_joints.jpg)Click to view full size (http://www.quarrydale.notts.sch.uk/subjects/technology/ALevelProductDesign/gallery2/9_joiningprocesses/156_selftapping_screws.jpg)

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Joining polymers and ceramics

Joining polymers- can be joint using mechanical means 

Tensol 10, 12- joining Acrylics dissolving the components together

Adhesives in packaging -layer of adhesive is melted on rim of the container creating a seal between the two components and making packaging more hygienic 

Ultrasonic welding - very high frequency vibrations introduced through the clamps generate heat .

ceramics- use slip liquid clay then its fired

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Adhesives

Natural adhesive-Animal and vegetable based glues like gum arabic

Synthetic resins-epoxy resins manufactured adhesives silicon based adhesives

NATURAL ADHESIVES  

Animal glues-Animal hide ,bones,hooves-glue woods 

Natural resins-Gum arabic-papers and watercolour paints 

Inoganic cements -Portland cement-bonding bricks and blocks building industry

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SYNTHETIC ADHESIVES

SYNTHETIC ADHESIVES

Epoxy resins-araldite two part hardener and resin-joins most materials 

Synthetic resins-cascamite-woods+ waterproof can fill slight gaps

PVA-poly vinyl acetate-gluing woods

Contact adhesives-Evo sticks-bonding sheet material

Hot glue sticks -heat- papers and card 

Acrylic cement -tensol- acrylics

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Advantages of using adhesives

When using adhesives surfaces have to be cleaned of dust, grease and any previous coatings

Able to join dissimilar materials 

Prevent corrosion through electrochemical action of dissimilar metals act as sealants. 

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Joining polymers and ceramics

Joining polymers- can be joint using mechanical means 

Tensol 10, 12- joining Acrylics dissolving the components together

Adhesives in packaging -layer of adhesive is melted on rim of the container creating a seal between the two components and making packaging more hygienic 

Ultrasonic welding - very high frequency vibrations introduced through the clamps generate heat .

ceramics- use slip liquid clay then its fired

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Adhesives

Natural adhesive-Animal and vegetable based glues like gum arabic

Synthetic resins-epoxy resins manufactured adhesives silicon based adhesives

NATURAL ADHESIVES  

Animal glues-Animal hide ,bones,hooves-glue woods 

Natural resins-Gum arabic-papers and watercolour paints 

Inoganic cements -Portland cement-bonding bricks and blocks building industry

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SYNTHETIC ADHESIVES

SYNTHETIC ADHESIVES

Epoxy resins-araldite two part hardener and resin-joins most materials 

Synthetic resins-cascamite-woods+ waterproof can fill slight gaps

PVA-poly vinyl acetate-gluing woods

Contact adhesives-Evo sticks-bonding sheet material

Hot glue sticks -heat- papers and card 

Acrylic cement -tensol- acrylics

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Advantages of using adhesives

When using adhesives surfaces have to be cleaned of dust, grease and any previous coatings

Able to join dissimilar materials 

Prevent corrosion through electrochemical action of dissimilar metals act as sealants. 

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