Fabricate - To work a material into a finished form by machining, forming, or other operation or to make flexible film or sheeting into end products by sewing, cutting, sealing, or other operation.

Family mold (injection) - A multi-cavity mold where each of the cavities forms one of the component parts of the assembled finished object.

Fiber - This term usually refers to relatively short lengths of very small cross-sections of various materials. Fibers can be made by chopping filaments (converting). Staple fibers may be 1/2 to a few in length and usually 1 to 5 denier (1/2 to 1 in diameter in Marlex polyethylene).

Fiber Show - Strands or bundles of fibers that are not covered by resin and that are at or above the surface of a reinforced plastic.

Filament - A variety of fiber characterized by extreme length, which permits its use in yarn with little or no twist and usually without the spinning operation required for fibers.

Filament Winding - Roving or single strands of glass, metal, or other reinforcement are wound in a predetermined pattern onto a suitable mandrel. The pattern is so designed as to give maximum strength in the directions required. The strands can either be run from a creel through a resin bath before winding or preimpregnated materials can be used. When the right number of layers have been applied, the wound mandrel is cured at room temperature or in an oven.

Fill Point - The level to which a container must be filled to furnish a designated quantity of the content.

Fill-and-wipe - Parts are molded with depressed designs; after application of paint, surplus is wiped off, leaving paint remaining only in the depressed areas.

Filler - A cheap, inert substance added to a plastic to make it less costly. Fillers may also improve physical properties, particularly hardness, stiffness, and impact strength. The particles are usually small, in contrast to those of reinforcements but there is some overlap between the function of the two.

Fillet - A rounded filling of the internal angle between two surfaces of a plastic molding.

Film - An optional term for sheeting having a nominal thickness not greater than 0.010 inch.

Fin - The web of material remaining in holes or openings in a molded part which must be removed in finishing.

Finish - The plastic forming the opening of a container shaped to accommodate a specific closure. Also, the ultimate surface of an article.

Finish Insert - A removable part of a blow mold to form a specific neck of a plastic bottle. Sometimes called Neck Insert.

Fish Eye - A fault in transparent or translucent plastics materials, such as film or sheet, appearing as a small globular mass and caused by incomplete blending of the mass with surrounding materials.

Flake - Used to denote the dry, unplasticized base of cellulosic plastics.

Flame Retardant Resin - A resin which is compounded with certain chemicals to reduce or eliminate its tendency to burn. For polyethylene and similar resins, chemicals such as antimony trioxide and chlorinated paraffins are useful.

Flame Spraying - Method of applying a plastic coating in which finely powdered fragments of plastic, together with suitable fluxes, are projected through a cone of flame onto a surface.

Flame Treating - A method of rendering inert thermoplastic objects receptive to inks, lacquers, paints, adhesives, etc. in which the object is bathed in an open flame to promote oxidation of the surface of the article.

Flammability - Measure of the extent to which a material will support combustion.

Flash - Extra plastic attached to a molding along the parting line; it must be removed before the part can be considered finished.

Flash Gate - A long, shallow rectangular gate.

Flash Line - A raised line appearing on the surface of a molding and formed at the junction of mold faces.

Flash mold - A mold designed to permit excess molding material to escape during closing.

Flash Point - The lowest temperature at which a combustible liquid will give off a flammable vapor that will burn momentarily.

Flexible Molds - molds made of rubber or elastomeric plastics used for casting plastics. They can be stretched to remove cured pieces with undercuts.

Flexural Modulus - A measure of the strain imposed in the outermost fibers of a bent specimen.

Flexural Strength - The strength of a material in blending, expressed as the tensile stress of the outermost fibers of a bent test sample at the instant of failure. With plastics, this value is usually higher than the straight tensile strength.

Flock - Short fibers of cotton, etc., used as fillers for molding materials.

Flocking - A method of coating by spraying finely dispersed powders or fibers.

Flow Line - A mark on a molded piece made by the meeting of two flow fronts during molding.

Flow Marks - Wavy surface appearance of an object molded from thermoplastic resins caused by improper flow of the resin into the mold.

Fluidized Bed Coating - A method of applying a coating of a thermoplastic resin to an article in which the heated article is immersed in a dense-phase fluidized bed of powdered resin and thereafter heated in an oven to provide a smooth, pin-hole-free coating.

Fluorescent Pigments - By absorbing unwanted wavelengths of light and converting them into light of desire wavelengths, these colors seem to have an actual glow of their own.

Fluorine - The most reactive non-metallic element. A pale yellow gas which is both corrosive and poisonous, it reacts vigorously with most oxidizable substances at room temperature, and forms fluorides. It is used in the production of metallic and other fluorides, some of which are used to introduce fluorine into organic compounds, i.e., the fluorocarbons.

Fluorocarbon Plastics - Plastics based on polymers made with monomers composed of fluorine and carbon only.

Fluorocarbons - The family of plastics including polytetrafluoroethylene (PTFE); polychlorotrifluoroethylene (PCTFE); polyvinylidene and fluorinated ethylene propylene (FEP). They are characterized by properties including good thermal and chemical resistance and nonadhesiveness, and possess a low dielectric constant. Depending upon which of the fluorocarbons are used, they are available as molding materials, extrusion materials, dispersions, film or tape.

Fluoroplastics - Plastics based on polymer with monomers containing one or more atoms of fluorine or copolymers of such monomers with other monomers, the fluorine containing monomer(s) being in greatest amount by mass.

Foaming Agents - Chemicals added to plastics and rubbers that generate inert gases on heating, causing the resin to assume a cellular structure.

Foil Decorating - molding paper, textile, or plastic foils printed with compatible inks directly into a plastic part so that the foil is visible below the surface of the part as integral decoration.

Force Plate - The plate that carries the plunger of force plug of a mold and guide pins and bushings. Since it is usually drilled for steam or water lines, it is also called the Steam Plate.

Force Plug - The portion of a mold that enters the cavity block and exerts pressure on the molding compound, designated as Top Force or Bottom Force by position in the assembly; also called Plunger or Piston.

Formaldehyde - A colorless gas (usually employed as a solution in water) which possesses a suffocating, pungent odor. It is derived from the oxidation of methanol or low-boiling petroleum gases such as methane, ethane, propane, and butane. It is widely used in the production of phenol formaldehyde (phenolic), urea formaldehyde (urea), and melamine formaldehyde (melamine) resins.

Friction Coefficient - A number expressing the amount of frictional effect.

Friction Welding - A method of welding thermoplastics materials whereby the heat necessary to soften the components is provided by friction.

Furan Resins - Dark colored, thermosetting resins available primarily as liquids ranging from low-viscosity polymers to thick, heavy syrups.