Please enable JavaScript.
Coggle requires JavaScript to display documents.
Plastic Forming Technique, Methods
continuous rovings of the…
-
Methods
- continuous rovings of the reinforcement are impregnaated with th resins
- then,pulled through the heated die
- curing takes place in the heated die & oven
- puller used to pull the whole system with certain speed
-
Methods
- the fibers are passed through the resin bath
- then, continuously wound onto the mandrel
- after number of layers, curing is carried out in an oven or room temperature
- mandrel is removed
-
Methods
- heat a thermoplastic sheet until it softens
- force the hot & pliable material against the
countours af amold by using either mechanical,air or vacumm pressure
- Held against mold and allow to cool, and plastics
retains its shape
-
Methods
- a predetermined amount of polymer powder is loaded into the cavity of a split mold
- the mold is then heated & simultaneously rotated on 2 perpendicular axes
- while still rotating, the mold is cooled so
that the plastic skin solidifies
- the mold is openend & the part is unloaded.Rotational speeds used in the process are slow so it is causes uniform coating of the mold surfaces
-
Methods
- in this process,the extrudate is extruded directly into the nip area between two rolls
- the rollers have small gap between them & plastic is forced through this gaps by the counterrotatting of the rollers between two rolls
-
Methods
- the mould is held between the heated platens of the hydraulic press
- a prepared quantity of molding compound is placed in the mould
- the platen closes with sufficient pressure to minimize flash at mould parts line
- the compound softens & flows to shape,chemical cure then occurs as the internal mould temperature becomes high enough
- the press is opened and the molding removed.
-
-
Methods
- the mould is closed when a short of melt is ready in the injection unit
- injection occurs when the valve opens and the screw acting as a plunger forces the melt through the nozzle into the mold
- the valves closes and screw rotation starts
- the molding in the mould has continue to cool when ready the press & the molud open and the molding is removed
- the mould closes again and the cycle repeats
-
Methods
- the extruded materials flow through a tubular die
- the melt flow around a mandrel & exits the die as a tube
- a cooling ring is placed at the exit of the die to give the tube some dimensional stability
- air is introduced through the back of the die and flow upwards inside the middle of the tube of materials
- the tube or bubble, continues to expand, cool and crystallize until the radial (tensile) strength of the plastics equals the pressure of the air inside
- the bubble is then forced into a flat sheet by the collapsing guides, and moved into the nips rolls
- then it travels down over some rollers and it was sealed
-
Methods
- melting the resin- done in extruder
- form the molten resin into a cylinder or tube
(this tube is called parison)
- the parison is placed inside a mold & inflated so that the plastic is pushed outward against the cavity wall
- the part is allowed to cool in the mold and is
then ejected
- the part is trimmed
-
Methods
- materials fed into hopper, falls through a hole in the top the extruder (feed throat) onto the screw
- the screw moves the molten plastic forward until the end of the extruder barrel to which die has been attached
- die gives shape to molten plastics,
cooled in water tank
-
