Castool Community

The ARP plunger tip has been successfully and profitably used for a number of years, but the market for aluminum-castings is changing.  Castings are now being required, especially in the automotive sector, that are larger, more complex, and with closer tolerances than ever before. They also require a faster rate of production than previously thought possible.  Plunger tips used to seldom be larger than 150 mm.  Now, 200 mm tips and even larger, are not uncommon.

The demands on the plunger tip, particularly in strength and stability, outgrew the replaceable wear ring plunger.  This led to the development of the Allper high strength AMP plunger tip.

This high-strength modular plunger tip has been designed specifically for the production of large castings.  The beryllium copper body is longer, and it has a replaceable steel head.

The challenge to the Allper R&D engineers was to develop a plunger tip that would remain relatively stable so as to consistently maintain the required gap with the shot sleeve, but also be strong enough to withstand extreme pressures, as well as the impact of a short shot if the plunger contacts the die.  Their aim was to use as little copper as possible, primarily for the strength of steel, and also for economy.

The AMP plunger tip is longer than the ARP, and features a replaceable high-strength steel head.

As with the ARP, a steel holder screws onto the plunger rod.  The beryllium copper body with its steel head is similarly connected with a quick-release bayonet -fastener.

With the AMP, after a considerable period of incremental redesign and field-testing, the heat transfer to the coolant has become much more effective.  The tip is more dimensionally stable, and thermal control less dependent on the high coefficient of thermal expansion of copper.

Cycle times are reduced.  Cost of consumables is reduced.  Operating life of wear rings and tip bodies can now be estimated, and downtime for replacement scheduled, so production runs are never unexpectedly interrupted.

The AMP high strength plunger tip responds to the demands of an increasing and changing market.  It makes better castings.

The ARP plunger tip has been successfully and profitably used for a number of years, but the market for aluminum-castings is changing.  Castings are now being required, especially in the automotive sector, that are larger, more complex, and with closer tolerances than ever before. They also require a faster rate of production than previously thought possible.  Plunger tips used to seldom be larger than 150 mm.  Now, 200 mm tips and even larger, are not uncommon.

The demands on the plunger tip, particularly in strength and stability, outgrew the replaceable wear ring plunger.  This led to the development of the Allper high strength AMP plunger tip.

This high-strength modular plunger tip has been designed specifically for the production of large castings.  The beryllium copper body is longer, and it has a replaceable steel head.

The challenge to the Allper R&D engineers was to develop a plunger tip that would remain relatively stable so as to consistently maintain the required gap with the shot sleeve, but also be strong enough to withstand extreme pressures, as well as the impact of a short shot if the plunger contacts the die.  Their aim was to use as little copper as possible, primarily for the strength of steel, and also for economy.

The AMP plunger tip is longer than the ARP, and features a replaceable high-strength steel head.

As with the ARP, a steel holder screws onto the plunger rod.  The beryllium copper body with its steel head is similarly connected with a quick-release bayonet -fastener.

With the AMP, after a considerable period of incremental redesign and field-testing, the heat transfer to the coolant has become much more effective.  The tip is more dimensionally stable, and thermal control less dependent on the high coefficient of thermal expansion of copper.

Cycle times are reduced.  Cost of consumables is reduced.  Operating life of wear rings and tip bodies can now be estimated, and downtime for replacement scheduled, so production runs are never unexpectedly interrupted.

The AMP high strength plunger tip responds to the demands of an increasing and changing market.  It makes better castings.

The pour end of the shot sleeve is where the temperature is highest.  This is obviously where cooling is most necessary.  Accordingly, another method of temperature control is the pour-end cooling jacket.  This effective and economical device puts shot sleeve cooling where it is needed most, directly below the pour spout.  The cooling jacket can also be re-used when the sleeve is replaced.

If uncontrolled, the vertical temperature variance in the shot sleeve at the pour end will result in a distortion which may allow some of the alloy to enter part of the gap between the plunger and the sleeve.  This will cause premature wear, and inconsistent shot velocity.

As well, the alloy being poured into the sleeve is at about 700°C., while the annealing temperature of H-13 (1.2344), the usual shot sleeve material, is only 585°C.  If the shot sleeve is not adequately cooled, it will likely lose some of its hardness.  Wear will then more quickly result from the abrasive action of any alloy that penetrates the gap