Product category:
Injection moulding
News Release from: Sandretto UK | Subject: Mould temperature control
Edited by the Manufacturingtalk Editorial
Team on 29 March 2004
Mould temperature control - don't skimp
on quality
Injection moulding requires careful control of numerous parameters -as understood by most - except that mould temperature control is often not fully understood, says Gordon Crouch.
Gordon Crouch, Manager, Processing at Rugby-based injection moulding machinery supplier Sandretto UK, argues for careful sourcing and trialling of prospective temperature control equipment Injection moulding is a process that requires the careful control of numerous parameters to obtain optimum component quality
This article was originally published on Manufacturingtalk on 27 May 2003 at 8.00am (UK)
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Quite often too little attention is paid to the original mould design, where many simply trust that the mould maker will correctly interpret the requirements of mould cooling.
Once the mould goes into production, it is most often just hooked up to the chilled water system, or piped to a water temperature controller, and left at that, often with very little thought into how well set up the cooling has been established.
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From there, injection machine process parameters are often used to overcome deficiencies in the mould temperature control, and any product faults are dealt with in the usual way, labelled as process faults, to be corrected by changing mould machine parameters.
This results in a less than ideal situation, often impacting on things like the cycle time, mechanical part strength, part dimensions, and surface finish, to name just a few.
The reality is that mould temperature control is a subject equally important to moulding, as any other.
In fact, temperature control can be the single most important processing parameter.
On top of less than ideal mould cooling design, the cooling system is the one that is likely to deteriorate more than most other factors.
And due to water being the preferred cooling medium, the steel water channels succumb to rust and scale, thus further reducing the chances of producing good mouldings.
Many users purchase their equipment without due consideration, thinking, for example, that as a unit is rated at, say 90 degrees C, that it will therefore do for the 80 degree C ABS-based job currently being run in the factory.
But the truth is, there is far more involved in just reaching a set temperature.
Even the set temperature is open for debate; some units measure return coolant temperature, while others measure the out going temperature.
Once the process is running, the heating requirement of the mould, most often turns to a cooling requirement.
Water flow rate, is another criteria, that has significant impact on how a unit can perform.
Cheaper control units use lower pump ratings or cheaper types of pump.
However, the more resistance the mould channels offer, the higher the pressure required for water to flow, and a higher flow rate drop off on a cheaper pump system.
Another area that the cheaper temperature control units cut corners on is in the cooling department.
By fitting smaller heat exchangers, the price of the unit comes down, but so does the performance.
And often the heat exchangers fitted are inadequate to function properly.
Next time you buy a mould temperature controller, ask how much cooling capacity the unit has, and compare this to others.
You'll be amazed at the differences between them.
As an injection moulding machinery supplier it is clearly in our best interest to offer the best kind of mould cooling possible.
This simply helps to bring out the best in our moulding machines.
At Sandretto UK we therefore ensure that we can offer a large range of water temperature control units, with a high specification level to accommodate even the more demanding applications.
All our temperature control units feature high capacity pumps, to ensure good water flow, even under high pressures.
Our units also deploy large heat exchangers, for better cooling, and two PID temperature controllers to ensure a very accurate temperature control.
The range includes both water and oil units, which offer temperature control up to 330 degree C.
Heater capacities range from 3Kw up to 150kW.
These units are also packed with additional features such as leak stopper modes, and quick circuit cooling.
It makes sense to protect a moulding investment with fault free temperature control.
Sensible choices and outlay at the start of a project help ensure smooth production for time to come.
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