Unformatted text preview: used for low
quality items such as disposable packaging or cheap children’s
Terms in Injection moulding Short Weight: The Shot Weight of a machine is
defined as the weight of plastic produced at the
nozzle in a normal cycle (without a mould) in PS
(specific gravity 1.05).
This is the pressure in the barrel at the point of
injection, expressed in kg/cm2 or kbar. A higher
L/D ratio produces greater Injection Pressure.
The greater the Injection Pressure the better the the
better the quality of product produced. Terms
Terms in Injection moulding INJECTION STROKE
The distance that the screw travels during an
injection stroke, up to 4 * diameter.
Theoretically, the injection volume is the
length of the injection stroke multiplied by the
cross sectional area of the screw.
only around 90% of that Injection Volume gets
injected. INJECTION SPEED
INJECTION RATE :This is the volume of
melt produced by the screw, expressed in cm3
SCREW ROTARY SPEED CLAMP FORCE The melt is injected into the mould under very
great pressure, which the mould halves, and any
other components or cores, must be able to resist
in order to maintain their shape and to avoid any
seepage. The larger a component is, the greater
the pressure and so, the greater the Clamp Force
required. MOULD OPENING STROKE This is the distance that the moving mould half
moves from mould closed to mould open. MOULD HEIGHT
This should be called Mould Thickness, Moulding
• Moulding refers to shaping of plastic
melt inside the mould. INJECTION MOULDING MACHINE FOR PREFORMS 1987 HUSKY XL
225 P THREE
THREE BALANCING TRICKS I can summarize the successful and
consistent moulding to three balancing
Flow balancing – part geometry dependent.
Heat balancing in one cycle time- dependent
on design of cooling in the mould and
cooling water supply system.
Uniform freezing of melt in the mould. –
Dependent on cooling design and supply
Any unbalancing on the above three
View Full Document
- Spring '14
- Plastics industry, Blow molding, injection moulding