The center of activity in every foundry is the melt department. Regardless of the alloys poured or molding method adopted, there is metal to be melted – and the efficiency of the melt shop is fundamental to the foundry’s success.
In almost all casting processes, gates and sprue are separated from the cast parts and returned to the melt furnaces, with a typical casting yield of 50 to 60%. This ‘return’ material, gates and sprues, are directed back to the melt center for remelting.
In most operations the returns become tangled, low-density messes – a barrel of monkeys comes to mind. Handling these returns is a logistic nightmare. Charge material that is in a denser form can be loaded more quickly and efficiently into a furnace, so it is advantageous to break the returns down to smaller pieces.
Even in some U.S. foundries the returns are simply piled up so the operators can break them with heavy weights. This not very efficient practice is also dangerous to the workers, with metal shrapnel flying both high and low.
Now consider the Yuatsuki “Crocodile” – a gate and sprue crusher specially designed to break returns in a safe and controlled manner, and to densify the metal by three to four times and sometimes up to five times denser than the starting state.
Denser material also will mean less traffic in the foundry, as forklift trucks move the returns to the scrap yard, and wear and tear is reduced on both man and machine. And a further benefit will be that the charge yard magnet can lift three to five times more material, so the transfer of crushed material to the charge bucket (or charge car) is done more quickly, reducing the preparation time for the next charge.
Faster furnace loading will have a direct effect on the amount of energy that will be lost while the furnace lid is open.
With the denser returns and faster furnace loading, foundries see one to two extra melt cycles per shift.
And a dense load melts more efficiently too. Energy savings of 900,000 kWh per year have been reported using one mid-sized ALP 1200 machine. In this installation, the before and after energy saving qualified for power-charge rebates of about $60,000 in 2024 dollars.
The Crocodile is built from a robust design, with jaws consisting of “tooth plates” formed from high manganese castings. One plate is stationary, while the other moves by means of a hydraulic cylinder that provides the force needed to crush the returns. Thanks to the high-manganese material, the plates are work-hardened from use and will show little wear – even after a decade of service (and with no missing teeth.)
The Crocodile has a machined (not welded) design, allowing for the tight tolerances necessary to withstand the high crush forces. While the Crocodile hardware is manufactured in Japan, the hydraulic units and controls are designed and manufactured in the US. More than 300 Yuatsuki crushers have been delivered for use worldwide, with many repeat customers – which is a testament to their excellent performance.