Below Francis Ward explain some of the more frequently used terms in the rotomoulding industry - from 'cross-linking' to 'kiss-off' and more. AIR FLOW AMPLIFIERS Used to increase the flow of air into difficult-to-heat areas on the surface of the mould by moving larger volumes of air with a compressed nozzle. Can be used effectively to control wall thickness on parts. ANTISTAT Chemical added to polymers to eliminate or reduce the effect of static electricity during moulding. BIAXIALE ROTATION Most common form of rotation used were moulds are rotated about two perpendicular axes simultaneously. BULK DENSITY A measurement of the weight per unit volume of powder standard units of measurement are g/cmᵌ and lbs/cuft. CALIBRATION Verification of equipment using known standards. An integral part of ISO9000 system wherein all equipment used to manufacture products must be periodically checked. CHEMICAL RESISTANCE The ability of the material to resist the presence of certain other chemicals. The effects of the chemicals are usually measured by weight loss physical properties or size. CROSSLINKING Describes the chemical reaction that connects polymer chains together during the moulding.This typically occurs at elevated temperature and creates an interconnected structure with improved physical properties. DIMENSIONAL STABILITY A property of the material to hold its exact shape after it has been moulded. Dimensional stab ability can be correlated to shrink factor and other material properties. FABRICATION Used to describe the technique for making sheet metal moulds. Usually made from hot or cold rolled steel, fabricated moulds tend to be lower cost than cast aluminium moulds and can be larger. IN MOULD GRAPHICS Graphics printed in reverse in transfer form that is applied to the mould surface prior to moulding. Polymer fuses over the graphic that migrates and penetrates below the outer surface of the finished part. INSERT Typically a metal (although other materials are used) component moulded into a part during processing. Common inserts include threaded nuts and bolts. The insert may also refer to a removable piece of a mould that creates an undercut in a part and must be removed prior to demoulding. KISS OFF Design feature in a moulded part used to connect or almost connect two surfaces. This technique can add considerable strength to the finished part. ROTATIONAL MOULDING A polymer moulding process used to make hollow parts. Polymer material is placed in a hollow mould cavity that is rotating in a two perpendicular axes. The mould is heated and rotated to melt and distribute the material evenly on the inner surface and form a part. The mould is then cooled to solidify the part for removal. ROTOLOG A radio based temperature-measuring device used to measure the temperature of the mould(s), oven air, polymer or internal air temperature during the complete moulding cycle.

1. Glossary of Rotomoulding Terms
Below we explain some of the more frequently used terms in the
rotomoulding industry - from 'cross-linking' to 'kiss-off' and more.
AIR FLOW AMPLIFIERS
Used to increase the flow of air into difficult-to-heat areas on the surface of the mould by moving
larger volumes of air with a compressed nozzle. Can be used effectively to control wall thickness on
parts.
ANTISTAT
Chemical added to polymers to eliminate or reduce the effect of static electricity during moulding.
BIAXIALE ROTATION
Most common form of rotation used were moulds are rotated about two perpendicular axes
simultaneously.
BULK DENSITY
A measurement of the weight per unit volume of powder standard units of measurement are g/cmᵌ
and lbs/cuft.
CALIBRATION
Verification of equipment using known standards. An integral part of ISO9000 system wherein all
equipment used to manufacture products must be periodically checked.
CHEMICAL RESISTANCE
The ability of the material to resist the presence of certain other chemicals. The effects of the
chemicals are usually measured by weight loss physical properties or size.
CROSSLINKING
Describes the chemical reaction that connects polymer chains together during the moulding.This
typically occurs at elevated temperature and creates an interconnected structure with improved
physical properties.
DIMENSIONAL STABILITY
A property of the material to hold its exact shape after it has been moulded. Dimensional stab ability
can be correlated to shrink factor and other material properties.
FABRICATION
Used to describe the technique for making sheet metal moulds. Usually made from hot or cold rolled
steel, fabricated moulds tend to be lower cost than cast aluminium moulds and can be larger.
IN MOULD GRAPHICS
Graphics printed in reverse in transfer form that is applied to the mould surface prior to moulding.
Polymer fuses over the graphic that migrates and penetrates below the outer surface of the finished
part.
INSERT
Typically a metal (although other materials are used) component moulded into a part during
processing. Common inserts include threaded nuts and bolts. The insert may also refer to a
removable piece of a mould that creates an undercut in a part and must be removed prior to
demoulding.

2. KISS OFF
Design feature in a moulded part used to connect or almost connect two surfaces. This technique can
add considerable strength to the finished part.
ROTATIONAL MOULDING
A polymer moulding process used to make hollow parts. Polymer material is placed in a hollow
mould cavity that is rotating in a two perpendicular axes. The mould is heated and rotated to melt
and distribute the material evenly on the inner surface and form a part. The mould is then cooled to
solidify the part for removal.
ROTOLOG
A radio based temperature-measuring device used to measure the temperature of the mould(s), oven
air, polymer or internal air temperature during the complete moulding cycle. Uses an insulated
container to protect the measuring electronics.
Francis Ward
http://contractmoulding.francisward.com
+ 44 (0) 1274 707030