Joining processes
Joining processes design and technology revision cards.
- 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)
(Figure 1)
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
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.
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.
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.
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
processes involving heat
Joining processes for wood
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
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
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
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
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.
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
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
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
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.
Comments
No comments have yet been made