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Low cost, high specification coreshooters

Well known for its comprehensive range of no-bake moulding equipment and coreshooters, Omega Foundry Machinery Ltd appreciates that there is also a need for a low cost option to its jobbing machine range. 

To answer the need, the company has manufactured a new range of coreshooters starting with a very basic ‘entry level’ machine that can be added to with increased functionality and sophistication depending upon customer requirements. The result is the CB series coreshooter.

The ‘entry level’ CB Coreshooter already has the following features as standard:

  • Compact space saving design
  • Hydraulic clamping
  • Suitable for vertical coreboxes
  • Slide fitted as standard
  • Vertical hydraulic movement of the shoot head

Optional extras that can be added are:

  • Vacuum clamping for quick change of tooling (optional)
  • Touchscreen control with up to 500 recipes storage
  • Air-flow fluidising chamber for intricate cores
  • Heated gassing plate
  • All movements are hydraulic
  • Shoot pressure, purge pressure and liquid gas are controlled electronically from the main touchscreen interface
  • Linear transducers on all hydraulic cylinders for precise and repeatable movement
  • Suitability for vertical and horizontal coreboxes

Omega built the first of the new range in 2013 and has sold many machines worldwide since then. 

The introduction of electronically controlled sand shoot pressure, gassing and purging pressures from the operator interface is a revolutionary departure from the conventional manually adjusted pressure regulators. It is now much easier and faster for the operator to make these pressure adjustments from his workstation HMI. With a conventional manually adjusted pressure regulator, fine adjustments are not carried out as often as they should be which leads to the same pressures being used for almost every core box – this results in poor core quality and wastage of gas due to leakages from an over pressurised core box! 

Longer life and lower pressures

The CB series coreshooter moves the shoot head up and down hydraulically instead of the conventional table lift – this means less hydraulic force is required to achieve the correct clamping pressures therefore leading to a longer life for the hydraulic system as well as lower hydraulic system costs.

The CB series also has the option of a fluidised shoot head, which aerates the sand just prior to shooting, leading to a much greater compaction with lower shoot pressures. This has the immediate effect of reduced core finning plus the added longer-term effect of less sand erosion inside the corebox.

The gassing plate is also heated; in the case of methyl formate where condensation is a major problem in cold ambient conditions, this feature is a must.  There are also added benefits when using the CO2 hardened phenolic resin process.

The integral gas generator has a separate heater for the liquid gas and the carrier/purge air. The liquid pump uses a positive displacement gear pump with variable speed controls (via the operator interface). The airflow through the heater is controlled by a proportional valve, which is in turn controlled from the operator interface. The considered best practice for gassing requires an initial air/vapour pressure of approximately 0.1 to 0.4 bar – measured at the corebox. The proportional valve is then ramped up to a value of typically one to four bar during the purging part of the cycle. The operator can set the final purging pressure or absolute value via the operator interface.

This data, along with the relevant corebox gassing parameters, is then stored as a recipe for that particular corebox.

A liquid calibration feature allows the amount of liquid gas to be easily checked as it leaves the pump. The pump output can be varied via a variable speed pump motor, which is in turn controlled from the operator interface.

A major problem with jobbing and low series core production is the time and effort taken when carrying out a tooling change. Omega can offer a vacuum clamping option to the CB series so that pattern change times can be drastically cut.

Touchscreen control

The CB series of coreshooter has a colour touchscreen interface with storage for up to 500 recipes. Each recipe consists of corebox identification, corebox left half and right half positions (useful when the shoot entry into the corebox is off-centre), number of shoots, gassing time/pump, output/gassing pressure, purge time/pressure and finally whether slide or side clamps are to be included in the cycle or excluded. The interface also has auto/manual controls, real time status for all components as well as full fault diagnosis with alarms. All of these features can be password protected to ensure changes can only be made by authorised personnel. 

Mixed sand is provided separately via either continuous mixer or high-speed batch mixer with multiple recipes and auto fill facility.

At the moment the CB range has three models – 10 litre, 30 litre and 60 litre capacity; the intention is to further extend this range based on demand.

For more information contact: sales@ofml.net