Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/ je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky. Tutorial: Engineering Technology Topic: Plastic VIII. – Foaming Prepared by: Ing. Vladislav Zelinka

Engineering TECHNOLOGY Plastic Foaming

Briefly: The More gas bubbles in material is, the lighter it is and the more isolated it is against warm and cold. The lower density, the better material floats in water. The plastic is foamed as an intermediate material for further processing or directly for finished goods. Soft foamed plastics return into their original shape (for example mattress) after loading.

Foaming procedure: Guide track PUR belt cross section PUR folders Mixing head with slot jet Bearing separating foil Foaming PUR Production of polyurethane foam belt

Examples of polystyrene foam usage:  Model of electric motor stator (for exact casting by the method of burnable model)  Protective filler wrapping (for fragile or risky goods)  Filler of freezers/fridge walls (thermal insulation between inner and outer environment)  Insulation of domestic houses (increase of thermal comfort inside buildings)

Examples of foam usage (+ similar plastic):  Seats (motorcycle, cars, armchairs, bicycle, chairs…)  Handrails, handles, steering wheels, inner car lining,…  Bed mattresses  Anechoic sound insulation of studios  Filler of winter sport clothes  Sport landing area (pole jumping,…)

Summary: The More gas bubbles in material is, the lighter it is and the more isolated it is against warm and cold. The lower density, the better material floats in water. The plastic is foamed as an intermediate material for further processing or directly for finished goods. Soft foamed plastics return into their original shape (for example mattress) after loading.

ACTIVITY I.: Decide and choose the best solution of the problem: 1.) One of the workers lights his pipe while manufacturing foam polystyrene. Is there a threat of fire? Yes / No / It isn´t easy to determine 2.) Shape of seat filler in a car has very complicated anatomic shape. Do we use foam? Yes / No / It isn´t easy to determine

ACTIVITY II.: Decide and choose the best solution of the problem : 3.) Outer shape of stator of big electric motor is very complicated due to cooling fins. We want to manufacture burnable model for exact casting. Do we use form polystyrene? Yes / No / It isn´t easy to determine 4.) In the welding plant there is very closely placed wall thermal insulation made of foam polystyrene. Is it safe? Yes / No / It isn´t easy to determine

VOCABULARY Density Měrná hmotnost Frothing (ingredient) Napěňovací (přísada) Hot steam Horká pára Mold filler Vyplnění formy Solidification Tuhnutí Gas bubbles Bublinky plynu Welding (of bullets) Svaření (kuliček) Insulation boards Izolační desky Mattress Matrace seats sedadla

Resources: * Wikipedie – internetová encyklopedie (cs.wikipedia.org) * Technická Univerzita Liberec ( * ENGEL CZ s.r.o. ( * Dillinger, J. a kol. Moderní strojírenství pro školu a praxi. Praha: EUROPA SOBOTÁLES, ISBN * Mužík, J. Management ve vzdělávání dospělých. Praha: EUROLEX BOHEMIA, ISBN * Operační program Vzdělávání pro konkurenceschopnost, ESF 2007 – * Dostupné na: k-op-vzdelavani-pro-konkurenceschopnost