Zusammenfassung der Ressource
VACUUM FORMING
- Materials used
- Acrylonitrile Butadiene Styrene (ABS)
- Polyester Copolymer (PETG)
- Polystyrene (PS)
- Polycarbonate (PC)
- Polypropylene (PP)
- Polyethylene (sheet and foamed sheet) PE
- Polyvinyl Chloride PVC
- Acrylic PMMA
- Products
produced
- Baths
- Yoghurt Pots
- Boat Hulls
- Machinery Guards
- Vehicle door liners
- Refrigerator liners
- Sandwich Boxes
- Parts of vehicle cabs
- Exterior shop signs
- Nature of Use and Limitation
- Use and Advantages
- Low Cost: Low forming pressures
- Inexpensive moulds/less time manufacturing
- Prototypes, low quantity of large parts,
medium size runs are therefore economical
- For more continuous production of high volume:
more sophisticated moulds+machines used
- Yoghurt Pots
- Disposable cups
- Limitations
- Requires a mould and extruded plastic sheets
- Secondary process may be needed to trim formed sheet
- trimmed waste can be re-ground + recycled
- Process
- Clamping
- clamp frame to be powerful enough to
hold plastic sheet during forming
- Hold from 6mm to 10mm
- Guarded + interlocked for automation
- Heating
- Uniformly located infra-red elements w/
aluminium reflective plate
- Twin heaters and precise temperature readout
are available for precision and speed
- For higher temperatures use quarts heaters
- Sheet Level
- To stop sagging of plastic a photo
electric beam scans just below
and pumps air if it's broken
- Pre stretch
- Pre stretch after forming temp. reached
- Done by making a 'bubble' of the plastic
- Helps with minimum draft angles and
high detail + even thickness
- Vacuum
- Vacuum sucks air from 'bubble'
- Plug assist
- A male plug tool that forces material into holes
- Good for deep-draw moulds + no webbing
- Made from resign (smooth and not conductor)
- Cooling and release
- Fans to speed up cooling (+spray)
- Speed up by 30%
- Temp controls
- Release by reverse pressure form vacuum system
- Trimming and finishing
- Excess removed
- Holes, slots and cut-outs drilled into part
- Can also be painted/decorated and strengthened