Glass quality assessment. Glass packaging and labeling.
Finished glass products should have a smooth surface and polished edges. The outer surface of the bottom of the cookware must be balanced. Lids and stoppers should be carefully selected to match the shape and color of the glass. Additionally, crystal glass products should make a clear sound.
Check with quality acceptance:
- the condition of the packaging and the correctness of labeling,
- correctness of shape,
- the color of the glass,
- pay attention to possible defects,
- careful decoration,
- careful finishing, np. use your finger to check the edge of the product. When assessing the quality of thermos flasks, the tightness of the gaskets is additionally checked, traffic jams, thermal resistance of the cartridge (by pouring hot water) and thermal insulation (measuring the time of heat preservation).
Depending on the number of acceptable quality defects, found in glass tableware, they are classified into two species, marked with Roman numerals I and II.
Defects can arise as a result of disturbances in the melting and annealing processes, reducing the value in use of finished products.
The most common disadvantages of glass mass are:
- heterogeneity, which entails non-uniformity of physical properties in different areas of the glass,
- foreign bodies - stones and scale,
- blisters,
- wrong viscosity,
- colored streaks,
- improper state of stress.
Unfortunately, defects can also arise in the forming and finishing process:
- shape: deviations in the form of curvatures, twists, uneven wall and bottom thickness,
- surface: stains, raids, features, scratches,
- decorations,
- finishes.
Defects of glass products may also arise during transport and storage due to transport injuries. These are usually gaps on the edges and edges of the bottom.
Brittleness is a great disadvantage of glassware, therefore to avoid losses, arising during transport and storage, they must be properly packaged.
The unit packaging is wrapping paper, which should at least protect the most vulnerable parts. Glass products can also be wrapped in heat-shrinkable foil. The package should contain tableware of one type, selected in terms of size and shape. Individual items must be wrapped in paper and wrapped in wood wool or hay (shock-absorbing materials), then they are placed in collective packaging, np. cardboard boxes, cassettes, rolled, profiled packaging made of corrugated cardboard, and then in transport packaging (crates and containers). The number of products in collective and transport packaging is specified in the relevant standard. Collective packages should bear the following markings: product name, manufacturer, size determination, the number of items, type, in the case of decorated cookware, the description of the decorations. Crystalline products should bear a sticker, which, in addition to the company, should also include the content of lead oxide (PbO) in the glass mass, np. 18%, 21%, 24%, 30%. Transport packaging should also have a permanently affixed inscription "glass carefully" and a handling sign - carefully fragile. Glass tableware and kitchenware with high thermal resistance must be accompanied by instructions for use.
Glassware storage rooms must be dry and airy, because moisture causes the products to become dull after some time. Basic storage rules should be followed, arranging and arranging glassware.
Glass is one of the most valuable, man-made materials, which is constantly being improved, also in the household glassware group. Recently, the so-called. French crystals, ie products with lead oxide content over 24% and additionally hardened. They are appreciated for their excellent optical properties and much greater mechanical strength. It is also classified as safe glass.