The operating
temperature for a particular mould will depend on a number of factors which
include the following: type and grade of material to be molded; length of flow
within the impression; wall section of the molding; length of the feed system
and so on. It is good to use a slightly higher temperature than is required
just to fill the impression, as this tends to improve the surface finish of the
molding by minimizing weld lines, flow marks and other blemishes.
To maintain the
required temperature differential between the mould and plastic material, water
is circulated through holes or channels wihthin the mould. These holes or
channels are termed flow-ways or water-ways and the complete system of flow
ways is termed the circult.
During thr
impression filling stage the hottest material will be in the vicinity of the
entry point, that is gate, the coolest material will be at the point farthest
from the entry. The teperature of the coolant fluid, howerve, increases as it
passes through the mould. Therefore, to achieve an even cooling rate over the
molding surface, it is necessary to locate the incoming coolant fluid adjacent
to hot molding surface and to locate the channels containing heated coolant
fluid adjacent to cool molding surface. However, it is not always practicable
to adopt the idealized approach and the designer must use a fair amount of
common sense when laying out coolant circuits if unnecessarily expensive moulds
are to be avoided.
In general, the
simplest systems are those in which holes are bored longitudinally through the
mould plates. However, this is not necessarily the most efficient method for a
particular mould.
When using
drillings for the circulation of the coolant, however, these must not be
positioned too close to the impression (closer than 16mm) as this is likely to
cause a marked temperature variation across the impression, with resultant
molding problems.
All in all, waterchannel is very important for a mould, like water for fish. So if you want to
learn more about water channel, pls kindly contact me, Ima glad to reply you.
 |
Post by Miss Mandy
Email: auto@sinomould.com
Skype: sino.mould
Whatsapp: +8615757610702
