Plunger lubricant

In high-pressure die-casting the molten metal is injected into the die cavity through a cylindrical sleeve by a piston (or plunger) that forces the molten metal through a narrow orifice at high speed and pressure. Proper lubrication of the plunger (e. g. Chem-Trend, Geiger + Co. Schmierstoff-Chemie GmbH, Tribo-Chemie GmbH) is essential to provide smooth filling of the cavity, reduce energy consumption during the shot and extend the life of the plunger tip and sleeve.

Movie 1:Tribo-Chemie GmbH – Isolat® 80 G

Solid plunger lubes are most frequently supplied as small pellets that are introduced by an automated device through the pour hole into the shot sleeve. Practical experience with Isolat 80 G and a competitive product shows both videos (Tribo-Chemie).

The carrier is designed to melt and then assist in the distribution of additives over the surface of the tip and shot sleeve. Oil-borne plunger lubricants are similar in function but, as they are liquids, they may be applied with or without atomization to enhance surface coverage.

Graphite is a key functional material in many plunger lubricants. It can be supplied in a variety of carriers including oil, water and waxes. The carrier serves not only as a lubricant itself, but also to help distribute the additives over the surface of the shot sleeve, and, depending on the method of application, to hold the additives in place once applied.

Additional references:
Die casting release agent
Separating agent

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