Glossary - Glass containers

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z


ACL (Applied Ceramic Labeling) – colored lettering or design of a ceramic nature fused onto bottles.
Amber – A brown color of glass that absorbs nearly all radiation with wavelengths shorter than 450mm.  Amber glass offers excellent protection from ultraviolet radiation.  This is critical for products such as beer and certain drugs.

Annealing – A controlled heating and cooling process designed to relieve internal stresses introduced in a glass container during and immediately after glass container formation.

Annealing Point – The specific temperature in which internal stresses built up during glass container formation are substantially relieved in 15 minutes.

Batch – A properly proportioned mix of raw materials melted to produce glass.
Blanks – The mold parts used in all glass container machines for preliminary formation of glass in preparation for the most efficient completion of glass containers in the finish molds where bottles are blown.  The blank forms the parison.  The parison itself is at times referred to as the blank.

Blank Mold – The metal mold in which the parison is formed.

Blow Blow Process – A method of glass container manufacturing of narrow finish containers in which the parison is formed by compressed air.

Bottom Plate – A piece of mold equipment used to shape the bottom of the glass container.  It can have depressions in where letters and symbols are formed in the glass to indicate the cavity number and/or manufacturer of the particular container.

Borosilicate Glass – A high silicate glass with at least 5% boron oxide.

Caps – A term used for metal or molded closures.
Chemical Durability – The resistance of glass to attack by solvents or product.

Closure – Any structure or device which is designed to close off the opening of a container and prevent loss of its contents.

Continuous Thread (CT) – A continuous spiral projecting glass ridge on the finish of a container intended to mesh with the thread of a screw type closure.

Cullet – Waste or broken glass intended to be remelted.  Cullet can be plant generated or recycled from the marketplace.

Density – Weight per unit volume normally reported as grams per cubic centimeter.  Typical container glasses range from 2.48 to 2.52 gm/cc.  One of the physical properties used to monitor composition. 

Ear – The name given to the finger grip of pressed glass between the shoulder and finish of a 1 gallon, gallon, or other glass jug.  The ear is used to facilitate holding the jug. 

Fill Point – The level to which a container must be filled to furnish designated quantity of contents.
Finish – The specifically shaped formation of glass surrounding the container opening which will eventually accept a cap.

Flint - A glass color or lack of color.  Flint is perfectly clear transparent glass, like window glass, used for all types of containers.

Forming Mold (Also "finish mold") – The forming mold, sometimes referred to as the bottle mold, is the mold in which the bottle is blown into its final shape after being preformed in a blank mold.

Gob – A lump of molten glass with a specific shape, temperature, viscosity, and weight.  The gob will be processed by the IS Machine into a glass container.
GPI – Glass Packaging Institute.  An organization composed of glass container producers.  GPI establishes policies, such as standardization and develops industry advertising programs.

Grossage – A quantity in terms of gross.  Grossage is the usual denomination used in glass container terminology.

Head Space – The space between the level of the contents in the neck of a container and the closure.  Head space is intended to furnish room for expansion of product due to heat or other action after packing. 

IS Machine – A term is short version of "Individual Section Machine".  The IS machine is used for the formation of glass containers.  It has the ability to have one or more sections taken out of production for maintenance purposes while the remaining sections continue making containers. 

Lehr – The long heated oven through which glass containers move on a conveyor belt so gradual cooling will properly anneal and remove stress from glass.
Lug Finish – A glass container finish identified by horizontal tapering protruding ridges of glass that permit the specially shaped edges of the closure to slide between the protruding lugs and fasten securely with a partial turn.

Meniscus – The curved surface of the liquid at the fill point of a bottle where the fluid level next to the glass is higher than in the center.
Mold – A set of iron forms fastened on a bottle machine to provide a means of shaping a glass container.  Parts of the set are tips, neck rings, blank molds, finish molds, and bottom plates with a plunger used in producing wide mouth containers.

Narrow Mouth – The finish of a glass container in which the diameter is small relative to the diameter of the body.
Neck – The portion of a glass container in which the shoulder cross sectional area decreases to join the finish.

Neck Bead – A small protruding circle of glass on a glass container at the point where the neck meets the finish of the container.

Neck Bead Ring (Or Band) – A protruding ring just above the neck ring parting line necessary in the manufacture of glass containers and specifically in transferring containers from blank to mold.

Neck Ring – A piece of mold equipment used to form the finish of the glass container.

Overflow Capacity – The capacity to the top of the finish or to the point of overflow. 

Parison – The preliminary shaped red hot glass that hangs from the neck rings as the blank molds open.  The parison is also called "pattern" or "blank."
Parting Line (glass) – The slight horizontal ridge formed by a surplus of glass blown into a worn crevice or joint between two parts of the mold equipment.  These lines may occur on various areas of the container, such as between the neck ring and the plunger tip or guide ring, between the neck ring and blank or mold, and between the mold and bottom plate. The vertical line formed by the joint between two halves of the same mold part is called a "seam".

Pour Out Finish – A glass container finish, with an undercut immediately below the top, designed to facilitate pouring without dripping.  The pour out finish is used principally for prescription and other drug and chemical containers.

Press & Blow Process – A method of glass container manufacturing of large diameter finish containers in which the parison is shaped by pressing the glass against a blank mold with a metal plunger.

Sealing Surface – The lip portion of the finish which makes contact with the sealing gasket or liner and forms a seal.
Shoulder – The portion of a glass container in which the maximum cross section or body area decreases to join the neck of the container.

Softening Point – The specific temperature in which glass is just barely able to maintain its shape and not flow like a liquid.

Tolerance – The allowable variation from actual specifications permitted in the manufacturing operation.
Type I Glass – Containers made of Type I Borosilicate glass are generally used for preparations that are intended for parenteral administration.  Highly resistant borosilicate glass.

Type II Glass – Treated soda lime glass.

Type III Glass – Soda lime glass.

Type NP Glass – General purpose soda lime glass.

Weathering – The attack on glass surface by atmospheric elements.
Wide Mouth – The finish of a glass container in which the diameter is large relative to the diameter of the body.