Casting on horizontal cold chamber machines
Numerous studies in casting laboratories relate to horizontal cold chamber diecasting machines. One of the problematic areas here is the interaction between casting chamber, plunger and formfilling. The processes are extremely difficult to measure and record and it is practically impossible to avoid problems - at best they can be minimised.
Problematic areas include:
- The changed geometry of the casting chamber during the casting process with considerable casting chamber movements due to thermal and mechanical pressure.
- The inclusion of air and casting gases in the molten mass due to the setting of the plunger movement in the pre-filling stage.
- The cooling down and in some cases solidification of the molten mass in the casting chamber because of heat dissipation into the casting chamber and plunger.
- Molten mass which has solidified in the casting chamber cannot be used for mould filling. Pre-solidified areas close parts of the ingate so that only part of the ingate is effective for filling the mould.
- In particular, the solidified part of the molten mass in the casting chamber is not available for feeding the shrinking volume as the mass cools down in the die cavity and during the transition from liquid to solid. The result is shrinkage cavities in the cast part.
The FFCS sensor
The sensor uses the liquid metal column to measure the forces that counteract the injection and that arise through wave formation, passing the ingate and the distribution and filling of the mould. If the machine works with constant casting parameters, the graphs produced by the FFCS can be used like a fingerprint as a template for a good die-cast part. The data collected by the FFCS contributes to a better understanding of the processes during the whole injection process.
Deployment of the FFCS sensor
The aim is to be able to measure, register and analyse faults that occur in a certain area with the FFCS sensor and, if need be, to correct the problem by resetting the plunger.