Position sensor in a cold-chamber die casting machine

• Application: Complete solution for monitoring the main process variables in a cold-chamber die casting machine with the highest safety standards
• Products: WPP-A Magnetostrictive transducer, KS and TPSA pressure transducers, QE1008-W and ML1018 strain transducers, TC6 thermocouple
• Results: Comprehensive portfolio of position, pressure, force and temperature transducers of Gefran enabled effective and complete monitoring of the cold-chamber die casting process

In a cold-chamber die casting process, the metal is initially melted in a separate furnace.

A precise amount of molten metal is then transferred to the die casting machine where it is ladled into a cold shot chamber (Figure 1); the metal is finally injected into the die by means of a ram driven by a compressed gas like nitrogen. Usually the cold-chamber process is employed for metals which have a high melting point (e.g. aluminium @ 660-700°C). When the workpiece is cold, the die cavity opens and the ejector pins make it fall out.

• This application requires a real-time control with excellent resolution and repeatability of several process variables such as the mould and workpiece ejector positions.
• The very fast injection system, stressing all the mechanical components of the machine requires high resistance to shocks and vibrations.
• Moreover, the forces impressed on the four columns supporting the moving die half (to avoid burrs in the die-cast part) must be balanced and constantly monitored at each cycle.
• Fractures in the mould or columns can raise serious safety concerns in addition to economic damage.

Hyperwave WPP Position Transducer

• The WPP-A Magnetostrictive transducers with a position sampling frequency of 2 kHz, equals to a reading update every 500 𝜇 This offers real-time position control of the main mechanical movements
• High resolution up to 0.5 𝜇m
• Position repeatability of 0.1 mm
• Resist shocks up to 100 g, vibrations up to 15 g

KS Pressure Transducer

SIL2 certification ensures high level of safety standards

TPSA Pressure Transducer

Innovative mechanical structure makes it insensitive towards tightening – most suitable for applications calling for robust structure and high accuracy.

QE 1008-W and ML1018 Strain Sensors

• Simultaneous strain measurement of four tie bars
• Direct display of strain value
• Wireless transmission
• Easy, fast and non-destructive mounting

Movable die half and ejector pins position control:

WPP-A Magnetostrictive position transducers – 2 Nos (Figure 2)

• Transducer stroke: 1500 and 150 mm respectively, aluminium profile
• Cursor: Floating PCUR210
• Repeatability: 0,01 mm
• Signal linearity (error): ≤ ±0,02% FS
• Shock Resistance: 100 g
• Vibrations Resistance: 15 g

Oil pressure of the hydraulic circuit (250 bar):

KS pressure transducer – 1 No (Figure 3)

Nitrogen injection pressure (1000 bar in 3-6 ms):

TPSA pressure transducer – 1 No (Figure 4)

Mould clamping force adjustment:

QE1008-W strain sensor with wireless transmission– 8 Nos (Figure 5)

Control of the forces applied to the four mould closing columns:

ML1018 strain sensors – 4 Nos (Figure 6)

Hydraulic circuit temperature control:

TC6 thermocouple – 1 No (Figure 7)