DIANA DE LA FELD 迪安娜 1156371. * The chalkboard is a flat, vertical writing surface on which anything can be inscribed by means of chalk piece: it is widely.

*MANUFACTORING PROCESS of the CHALKBOARD

DIANA DE LA FELD迪安娜1156371

*THE PRODUCT: an OVERVIEW

*The chalkboard is a flat, vertical writing surface on which anything can be inscribed by means of chalk piece: it is widely used all over the word mostly for educational purposes.

*The modern chalkboard was first patented in 1823 by Samuel Reed Hall, a leading educator of the day.

*The earlier products were simple pine board painted black and than developed in a combination of lime, plaster of Paris and lampblack.

*RAW MATERIALS

*GALVANIZED STEEL: the front and the back surfaces of the chalkboard are formed of thin sheets of galvanized steel, that enter the manufacturing facility from an outside supplier in pre-cut standard sizes

*PAINT: it is a type of acrylic enamel designed specially for chalkboards to which a powdered mineral formulation is added to make the coating dry to a rougher texture

* SLIP: it is applied to the steel surface, it is made of SILICA, a crystalline compound derived from quartz or similar minerals (silicon and oxygen) the surface of the chalkboards is usually a blend of inorganic compounds as a powder glass opacifier and oxides

*CONTACT CEMENT: it is used as an adhesive for assembly

*ALLUMINUM MOLDING: used for the board frame

*PREPARATION of the STEEL

① COLD-ROLLING: the sheet sheets undergo a cold-rolling process in order to increases the strength (strain hardening) and the surface finish

② CHEMICAL WASHER: it blasts the sheets with acid to remove dirt that would prevent paint to inhale to the surface

③ DRYING: at the exit from the cleaner the sheets are cooled off by powerful fans

*COATING

① SLIP APPLICATION

*The steel sheets pass through a COATING CHAMBER where SPRAY GUNS apply a layer of slip of at least 0.026mm the slip is left to dry

*FIRING: the sheets enter a large furnace area where they are subject to a temperature of 218°C for 10’ this process softens the steel and allows fusion of the slip with the steel

The steel sheets are subject to a coating process that comprehends two major steps: SLIP APPLICATION & SURFACE COMPUNDS

* the surface is treated with a SURFACE-COATING COMPUND, usually derived from glass opacifiers and gives a smoother texture to the board (oxides for color can be added during this step)

* the surface is treated with a SURFACE-COATING COMPUND, usually derived from glass opacifiers and gives a smoother texture to the board (oxides for color can be added during this step)

*also this layer must be at least 0.062mm

* the sheets are completely cooled and dried

*COVER COAT FURNACE, the sheets go through a heating process (at least 649°C) to fuse the first ground coat with the surface coat

*COOLING CHAMBER the temperature is gradually reduced so that the flat sheets do not buckle or weaken

② SURFACE COMPUND

*BOARD ASSEMBLY*ASSEMBLY

contact cement is sprayed on the back of two painted sheets which are assembled with the CHALKBOARD CORE placed in between, usually a 12mm fiberboard

*HIGH PRESSURE ROLLER the tree layer assembly is fed into the roller in order to force out any trapped air and bonds the layers tightly

*FRAMING* the board frame is made out of one

long strip of aluminum molding, that has a stain proof satin finish

*a series of 45° angle cuts are made this enables the workers to bend the frame around the board perimeter, creating neat corner scenes

*The frame is finally fastened to the board, during this step other extra components, depending on the boars model, can be added

*QUALITY CONTROLL is made before the board can finally be introduced in the market