Metal front contact sensor

This cavity sensor transmits a signal which is triggered by a metal butt joint with the melt during the mold filling process (see Mold filling phase).

When applied in die casting procedures, the metal position in the cavity can be determined in real time during the injection process by using a metal front contact sensor (MFCS). If several sensors are attached to the mold, the mold filling process can be exactly understood. This way, the following reasons and effects on the mold fillinf can be evaluated and verified:

1. Mold temperature variations
2. Metal temperature variations
3. Injection system changes
4. Lamellar or abrupt (too turbulent) mold filling
5. Separating agent changes
6. Check of the results from the numeric mold filling simulation

It is useful to use the sensor also for starting the second phase (see Changeover point), the third phase (pressure intensification phase) and for triggering the squeeze function. Independent of the metal quantity, a highly accurate repeatability is guaranteed. The advantages of the implementation of a metal front contact sensor are the following:

  • The casting process can be optimized if the second Phase (mold filling phase) is started by a metal front contact sensor since the injection process is independent of dosage variations.
  • Upon starting the third Phase (pressure intensification phase) through a metal front contact sensor, the final pressure can be independent of the mold filling. This way, the final pressure is even more effective since the metal has not yet solidified and included blow holes can be minimized in relation to the pressure change (see Fig. 2). Effective final pressure improves the heat penetration ability in the mold, inlcuding an increase in the cooling speed and shrinking deficits can better be balanced.
  • The sensor is also suitable to trigger a squeeze function. Thanks to the signal output, the exact position in lreation to the casting piston position can be displayed on the monitor through a dashed line.

To measure these functions, a high sampling rate of the measureing device is required, which is fulfilled with a 4 to 5kHz frequency. Therefore, the metal front contact sensor can be used to determine the following parameters:

Additional references:
Vacuum sensor
Multi airpipe sensor system
Mold filling control sensor
Mold cavity pressure sensor
Metal front temperature sensor
Air flow sensor
Humidity sensor
Residual gas sensor

  • Fig. 1: MFCS metal front contact sensor and measuring system by Electronics GmbH
  • Fig. 2: Change of the pore size due to the final pressure effect pN dF = Gas pore diameter at a mold filling pressure of pF dN = Gas pore diameter at a final pressure effect of pN