Latest Developments in Feeding Technology
Over recent years, the foundry industry has been increasingly challenged by changes in the methods used to make castings in the drive to save material and improve mechanical properties. This has made the task of ensuring efficient feeding of these castings more and more complex. To meet these challenges, we are constantly updating our product portfolio with new and improved feeding solutions for a wide variety of casting processes and alloy types.
Our latest innovations include:
What is feeding?
During the cooling and solidification of most metals and alloys, there is a reduction in the metal volume known as shrinkage. Unless measures are taken which recognise this phenomenon, the solidified casting will exhibit gross shrinkage porosity which can make it unsuitable for the purpose for which it was designed. To avoid shrinkage porosity, it is necessary to ensure that there is a sufficient supply of additional molten metal, available as the casting is solidifying, to fill the cavities that would otherwise form. This is known as ‘feeding the casting’ and the reservoir that supplies the feed metal is known as a ‘feeder’, ‘feeder head’ or a ‘riser’. The feeder must be designed so that the feed metal is liquid at the time that it is needed, which means that the feeder must freeze later than the casting itself. The feeder must also contain sufficient volume of metal, liquid at the time it is required, to satisfy the shrinkage demands of the casting. Finally, since liquid metal from the feeder cannot reach for an indefinite distance into the casting, it follows that one feeder may only be capable of feeding part of the whole casting. The feeding distance must therefore be calculated to determine the number of feeders required to feed any given casting. The application of the theory of heat transfer and solidification allows the calculation of minimum feeder dimensions for castings which ensures sound castings and maximum metal utilisation.
FEEDEX SCK Sleeves
FEEDEX SCK Sleeves are a set of modular insulating and exothermic components designed to optimise yield and reduce fettling costs on large iron and steel castings. By using the individual components in different combinations, the foundryman can customise the modulus of the feeder to suit the needs of the specific casting.
THE NEW FEEDEX SCK SLEEVES SYSTEM FOR HAND MOULDING APPLICATIONS
The development of Foseco feeding technology
- In the early days, foundries made their own feeder sleeves from sacks of FEEDEX powder.
- In the 1960s, the first preformed KALMIN (insulating) and KALMINEX (insulating-exothermic) sleeves were developed.
- In the late 1960’s KALMINEX S highly exothermic-insulating sleeves were developed for application on high production moulding machines.
- The 1970s saw the launch of insert sleeves for application on automatic moulding machines.
- In the 1980s, the increased use of customised breaker cores improved feed performance and reduced fettling costs.
- During the 1990s, we developed the FEEDEX V sleeves range of exothermic feeders, enabling spot feeding of difficult sections.