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BRONDOLIN - Shot Sleeve - Made in Italy

Thermal Regulation is a technology
that is becoming more frequently utilized
for the HPDC process

In any new project development, it is very important for the customer to always consider thermally balancing the injection system regardless of the machine size. Controlling the temperature by removing excess heat, caused by the metal dosing process, is possible only by using the appropriate solution. Today’s market promotes several different types of equipment for these applications, such as pressurized water or diathermic oil, which are good solutions for a successful final result.

Overheating is normal and the most common problem, depending on the application, can cause a dangerous deformation of an otherwise high quality operating system. This deformation can also cause a misalignment between the rod and sleeve, generating excessive friction during injection. Premature sleeve erosion and plunger seizure are the resulting consequences. Operating temperatures are ordinarily high, so it is important to maintain the target in a safe and controlled limit.

Excessive heating of the shot sleeve, during the injection process, can be easily identified, measured and located by using a thermal camera. In the overheated area, the steel is severely stressed and starts losing its mechanical properties, especially under the pour hole. When the steel under the nitrided layer is compromised, the normal result is premature erosion of the shot sleeve.

Maintaining a balanced and controlled temperature is essential not only for the shot sleeve, but also significantly helps the plunger system function correctly. A round sleeve has lower friction, requires less lubricant, has less metal turbulence, all adding to the ability to properly thermally regulate the shot sleeve. The die side of the shot sleeve is heavily thermally stressed from the heat coming from the biscuit and is the most critical area of the thermal circuit layout design. For large shot sleeves, it is best to also have an independent circuit on the die side for proper thermal control.

SOLUTIONS

BRONDOLIN

The increasing demand for structural parts production requires the growing use of specific aluminum alloys, which aggressively attack tool steels used for shot sleeves. For such applications, it is extremely important to consider utilizing replacement inserts that can be replaced when eroded. This solution results in longer shot sleeve life and improved plunger performance (RPH EVO™). Running structural parts usually requires longer shot sleeves to be successful. In this case, it is mandatory to use a dual zone thermal circuit design for optimal thermal control.
Depending on the shot sleeve size and relative wall thickness, we can offer different thermal circuit solutions:
• Only with a back circuit
• Integral circuit
• Dual zone circuit
The shot sleeve replacement insert solution has been proven to increase service life many times over. However, an adequate shot sleeve wall thickness is necessary to take advantage of this beneficial design feature. A convenient tool is supplied to replace the used insert with a new one, even while the sleeve is in the machine.