molding

 

in architecture, furniture, and decorative objects, a surface or group of surfaces of projecting or receding contours. A molding may serve as a defining element, terminating a unit or an entire composition (e.g., in the cap of a column or the crowning cornice of a building) or establishing a boundary or transition between portions of a design. One of the primary considerations in the design of a molding is the type of shadow it will cast. The shape of a molding is termed its profile or section. Moldings formed an important part of most past styles; in Babylonia, Assyria, and Persia, however, their place was taken by flat ceramic enrichments in color. In Egypt, moldings were limited to the cove, or cavetto, and the half round, or torus, which, used together, formed the cornices for the walls of temple or pylon. Moldings were an essential feature of Greek orders and buildings. The Greek profiles form the basic molding vocabulary for classic types such as the fillet and the fascia, flat vertical surfaces; the ovolo, of an egglike convex outline; the bead and the torus, both convex, three fourths of a circle and one half, respectively; the cavetto, a quarter circle, and the scotia, of elliptical curvature, both concave; and the cyma recta and the cyma reversa, both of compound curvature, being half concave and half convex. The ovolo was carved with the alternating egg and dart; the acanthus leaf and the anthemion were used for the cyma recta, or ogee, and the water leaf for the cyma reversa. Roman designers, substituting simple segments of circles for the elliptical and parabolic curvatures, never attained the beauty of Greek forms, although in ornament they added numberless innovations. In Byzantine architecture the tendency was to flatten the classic outlines, transforming them into bands of pierced enrichment. Romanesque moldings were chiefly simple segments of a circle, as in the especially characteristic boltel, or three-quarter round. Moldings changed with the development of Gothic architecture. Cornices, jambs, archivolts, and capitals show a richly varied interplay between projecting rounds and deep concavities. In the late Gothic (15th cent.) of France and Germany there were ingenious combinations of differing elements to produce broken, merging, and interpenetrating moldings. In developed Gothic a rich assortment of naturalistic forms appeared, e.g., flowers and intertwining vines. The Renaissance return to purely Roman forms was followed in the baroque by heavier, projecting moldings, which cast dramatic shadows. Later a wide variety of styles was employed, but since the 19th cent., decorative molding has been little used in modern architecture.

Molding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a mold.

A mold or mould is a hollowed-out block that is filled with a liquid like plastic, glass, metal, or ceramic raw materials. The liquid hardens or sets inside the mold, adopting its shape. A mold is the opposite of a cast (see casting). The manufacturer who makes the molds is called moldmaker. A release agent is typically used to make removal of the hardened/set substance from the mold easier.

Types of molding include:

• Powder metallurgy and ceramics
  • Compaction plus sintering
• Plastics
  • Injection molding
  • Compression molding
  • Transfer molding
  • Extrusion molding
  • Blow molding
  • Rotational molding
  • Thermoforming
    • Vacuum forming, a simplified version of thermoforming
  • Reaction Injection Molding
  • Laminating
  • Expandable bead molding
  • Foam molding
  • Rotomolding
  • Vacuum plug assist molding
  • Pressure plug assist molding
  • Matched mold

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