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Leuze Electronic has revealed that its Compact light curtain has been selected by BMW to improve machine safety during the die-casting of automotive engine components.

BMW’s 300,000m2 plant in Landshut near Munich develops and produces cylinder heads and other light-metal cast components, such as crank cases, plastic components and rebuilt engines for practically all BMW Group vehicles.

Thirty die-casting systems run in a three-shift pattern, where a 2m-high furnace for each system heats the melt on the ground floor of the production hall.

Above this, on the first floor, there is a 6m-high die-casting system with the inlet for the molten aluminium close to the floor.

Forklifts transport the ‘ladles’, each of which holds 600kg of liquid metal.

This melt is emptied into the inlet and flows down into the furnace beneath.

Compressed air at a fairly low pressure of 9lb/in/0.6 bar causes the liquid aluminium or other light metal to rise through the immersion pipe, which is located at the bottom end of the melt, rising to a chilled mould, which is a re-usable casting, where the metal solidifies.

The cast component can be removed after the sides of the chill mould have been driven out by the ejection cylinders.

A deflection arm removes the still hot cast component, which can weigh between 20kg to 40kg depending on the model, from the mould.

An operator uses special lifting grips to take the piece from the deflection arm, makes a visual inspection, and places it on a palette to be transported away.

The components are later tested 100 per cent for faults such as inclusions and cavities using X-ray analysis as part of an in-depth quality assurance procedure.

Two particular danger points during this process are the horizontal movement of the ejection cylinders when releasing the mould, which can crush the operator, and when the deflection arm swivels as it takes the cast component from the machine to the unload position, which could seriously injure the operator.

Therefore, the operator starts the casting process by pressing a ‘start’ button outside the die-casting area, which is guarded by Leuze Electronic’s Compact light curtains.

During the five-minute cycle time, no one is allowed into the casting system area.

Identifying such risks and inspecting to ensure physical or opto-electronic protection is in place to prevent such injuries is the purpose of Leuze Electronic’s machine safety inspections.

To ensure that no one can enter these danger areas during the cycle time because there is movement, especially during the automatic removal of the cast component, BMW relies on the Compact safety light curtain.

These light curtains, along with the machine safety inspections, provide an integrated safety solution that meets all relevant requirements and guarantees reliable protection, according to Leuze.

The entire die-casting area is now guarded with Compact safety light curtains, most of which have a resolution of 30mm and an 18mm range.

Horizontal danger zone guarding on welding and assembly lines or robot cells is widely used, plus 14mm resolution curtains, providing hand and finger protection on presses and punches, for example.

The Compact safety light curtains comply with type four in accordance with IEC/EN 61496.

In addition to reliable detection of protective field interruptions, they are also highly immune to interference ensuring high machine availability.

Additionally, their integrated auto-analysis system enables easy and efficient on-site diagnostics.

Safety-related considerations and manufacturing conditions such as transportation corridors or stillage loading positions resulted in the guarding floor plan for the chill mould being trapezoidal in shape.

Therefore, the solution was to use a Compact transmitter, a Compact receiver and two UMC deflecting mirror columns, with one having a reflection angle of more than 90-deg and the other having a reflection angle of less than 90-deg.

The mirrors guard the area between the chill mould and the transport lane across a distance of 3m.

Both the transmitter and the receiver are positioned 4m across from the mirrors on the other side of the casting system, close to the control cabinet, providing access guarding for the trapezoidal area.

On its way via the mirror to the receiver, the light beam must travel 12m and therefore to speed alignment over this distance when even a tiny deviation in the angle would cause the light beam to miss the receiver Leuze Electronic’s laser alignment aids were used.

The laser alignment aid is mounted directly on the transmitter and clearly marks the target point of the sensor beams with a red laser light, enabling just one person to commission the perimeter guard easily and efficiently.

Transmitters, receivers and deflecting mirrors are positioned in free-standing and sturdy UDC device columns, which are firmly anchored in the floor.

The UDC columns enable precise vertical and axial alignment and anti-vibration mounts in the base of the column provide isolation from the vibrations caused by forklifts driving past carrying 600kg ladles of metal.

The UDC device columns are enclosed again at the BMW plant by a solid steel column in order to guarantee reliable protection against melt splashes, even with a direct impact.

This enclosure is also anchored in the floor with shock absorbers to attenuate all tremors and vibrations.

By equipping the die-casting system with Compact safety light curtains, BMW has been able to manage the risks identified, achieve the relevant declaration of conformity, and benefit from the high availability of the machinery.

Leuze Electronic

Leuze electronic the ‘sensor people’ are committed to being the supplier of choice by providing the best customer service and products.

Leuze electronic the ‘sensor people’ are committed to being the supplier of choice by providing the best customer service and products.

DETECTIONOptical Sensors: An innovative range from economic standard sensors to feature-rich special solutions.

Barcode, 2D and RFID code readers; Smart cameras and Vision systems; Optical data transmission; Optical positioning.

PROTECTION – Machine safety light curtains and barriers; Safety laser scanners; Door and entry interlocks and switches.
Leuze electronic also offer a machine Safety Inspection Service to ensure the correct guarding of machines using any brand of safety light curtains & barriers.

Virtual online catalogues, industry specific brochures, and extensive guidance on machine safety are all available on our website.
Please call and talk to ‘the sensor people’ for technical information, samples and advice.

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