Mingzhi - Sand Core System

As part of our ongoing investment into new facilities for our sites, MAT Foundry Group have just purchased a new sand core system for our Eurac Hradec foundry in Czech Republic. Manufactured by Mingzhi, the new sand core system includes a sand preparation system, that treats the core sand and mixes binding agents. Additionally, the Core Machine MP 40 is included in the new system, which utilises the cold box core method.

Sand Core – Cold Box Method

In the cold-box method for creating sand cores, a resin coated sand is blown into a room-temperature box which is sealed, and a gas catalyst is then passed through holes in the pattern to harden the core. Amine Gas is used to cure the core instantly to a relatively strong state.

This is the most effective method for mass production of cores, allowing Eurac Hradec to machine and cast brake discs on an industrial scale.

Process

Usually stored in a hopper, the core sand is first transported and treated in the preparation system, where a heavy-duty mixer ensures optimum blending and homogeneity of the core sand. The preparation system also includes an automatic binders dosing device, that injects both agents on a timed system to help increase the rigidity of the cores.

Once treated and mixed correctly, the core sand enters the discharge chute via a pneumatic vibrator tray and enters a vertical hopper, situated above the core shooter.

The MP40 core shooting machine at Eurac Hradec will be used to make gassing cold box cores in horizontal parted core boxes. The shooting volume is approx. 40 dm³, however, the shooting volume can be increased by double shooting.

Once the hopper is full of sand mixture, the front entrance will shut, and the lower section and upper section of the shooting machine form the core shape. These sections are then compressed against the gassing unit and a seal is created ready for the core to be created. Once in position and a seal has been created, the shoot machine will blow compressed air and the sand will enter the core box.

Now the core box has been created the gassing stage occurs, hardening the sand core box. This is where the cold box process receives its name, instead of using massive amounts of heat to harden a core, gas is used as a catalyst to rapidly harden the sand. The gas used is Triethylamine and it is a hazardous gas, hence why all operators are recommended to wear respirators.

Once the process has finished, an ejection system will remove the cores for inspection by the machine operator, prior to storage and finally production.

MFG – Reusing Used Core Sand

At MAT Foundry Group we believe we’re the best in the world at what we do, and we also believe that we have a responsibility to pioneer new and inventive green methods of reducing our waste. One of these new methods currently under testing at our Eurac Poole plant, is reusing used or ‘old’ green sand from our Disa casting line, for the creation of new sand cores.

Historically we have treated our used Green Sand in an Eirich sand mixer, prior to being repurposed for moulding on the Disa casting line. The Green Sand can only be repurposed and treated a finite amount of times, before it needs to be disposed of as waste. The new method Eurac Poole is testing, reuses the used Green Sand as part of the core sand structure.

If successful not only would this reduce the amount of core sand required, thus lowering our supply chain carbon footprint, but also reduce our waste and disposal needs and the emissions associated.

GIFA 2019

Mingzhi Technology will attend GIFA 2019 this year, specifically in the core making machine product category.

The MP series that MFG have just purchased will make up their three-part stall, coupled with their offerings in the A+ series and the D series. The A+ series has been designed to offer significant precision of movement, flexible core production and high reliability due to its low maintenance design.

Conversely the D series was designed to offer a quick dry cycle time, a heavy-duty frame and a pit-free design, that was suitable for inorganic, hot box and cold box processes.