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Don’t let the guidelines manipulate your understanding of H&S responsibility

Whilst it is believed that CE marking shows that a product meets EU safety, health and environmental requirements, in the case of equipment that is part of a larger cell – set of equipment from various manufacturers – it is open to interpretation and it is vital that the customer understands the difference of a partly completed machine and how to operate this within a safe environment, says engineering expert Clansman Dynamics.

Speaking to Foundry Trade Journal to warn of the confusion, Clansman’s sales director Derek Muir says: “A manipulator is not a fully completed machine, it’s a partly completed machine as it sits within a larger set of machines as a cell. This is because, on its own a manipulator doesn’t perform a function – it needs a moulding machine, shakeout / vibrating conveyor, shotblasting etc. to be able to process anything.” In effect it is the assembly of components (moulding line, shakeout, manipulator, shot-blast) that can be defined as the ‘completed machine’ – or just ‘machine’.

“The welfare of any personnel involved with the ‘machine’ is fundamental and forms the basis of the risk assessments generated for each installation. It is important that the customer understands that whilst a CE mark means that the equipment meets a standard in itself, the operation of said equipment still has inherent risks that need to be mitigated as part of a wider undertaking.

“It is down to interpretation and in terms of a new foundry it is usual for the main supplier, frequently the supplier of the moulding line, to be responsible for CE marking and the safety aspects of the whole cell. With an existing foundry when a manipulator or piece of equipment is being installed into an existing line, it is the responsibility of either the lead supplier or the foundry themselves to CE mark the ‘machine’ or cell.”

The Machinery Directive states: “The person constituting an assembly of machinery is considered as the manufacturer of the assembly of machinery and is responsible for ensuring that the assembly as a whole complies with the health and safety requirements of the Machinery Directive.”

It’s easy to see why Muir is concerned about this, as the implications for operators could be extreme. He says the confusion often happens because of the installation of a combination of different machines from different experts, resulting in individual partly completed machines being incorporated into a much wider range of equipment – something that needs to be managed with close attention to health and safety matters.

 

Correct Operation

“The manipulator, though manual, is not too different to a fully robotised cell,” he says. “In terms of the person in the cab, there is safe entry and exit and there is guarding. It is manually driven but any machine is only as good as the operator. There is always the possibility that things can happen like valves jamming due to contamination in the oil.”

All Clansman manipulators are supplied with a safety circuit which can be integrated and linked with the other machines (from other suppliers) in the equipment cell to create a safety ring. The failsafe is an e-stop facility should anything happen with the machine itself or if links are broken in the chain of equipment forming the cell. However, it is the foundry’s responsibility to operate the machine and the whole system correctly, which would include the control and awareness of other operations, such as forklift trucks manoeuvring around the manipulator. Muir continues: “We must remember that however safe the manipulator is, it is surrounded by other moving parts. Forklift trucks are moving boxes around, scrap metal, parts etc. and are thus coming in and out of the area where the manipulator is sited. We must ensure that these processes can function with minimal risk, and to avoid people walking into the area too.”

 

Guarding Solutions

One such project in a foundry with a confined area for the manipulator, conveyor and shot-blast trees involved the installation of a fence system, which Clansman advised the customer on. The solution is a fenced area around the larger cell that houses the manipulators, with a personal access door on the fence for each machine and a traffic light system for access. A request access button can be pressed on the fence door by an individual which alerts the manipulator cab driver. The same applies for forklift drivers who also have a request access button and a light barrier. The manipulator operator can give approval for forklift entry when a series of conditions are met: the light barrier is then muted. If the forklift attempts unauthorised entry, the manipulator e-stops as the light barrier is broken……. breaking the safety ring.

This was a particularly challenging job for Clansman as, whilst their recommendation was that the only completely safe solution equipment interaction was to stop the manipulator, the customer was adamant that production could not be halted every time a forklift needed access. Muir describes the solution: “The only way to ensure safety was the implementation of a third rotational stop, which is controlled electronically so that the manipulator can continue to operate but its rotational area is minimised while the forklift is in its so-called ‘red’ area. This is by means of a retractable stop function. When personnel request access into the area, the operator of the manipulator can activate this third rotational stop. The third stop will only engage once the operator has manoeuvred into a safe position.”

There is a reset button once the forklift has left the area to enable normal service to be resumed.

 

Increased Connectivity for Integrated Production

This adaptation can be enhanced thanks to the PLC based control system developed by Clansman enabling increased connectivity for integrated production across the shopfloor, Muir says this has offered a more flexible way of handling such requests in ever more complicated layouts. “At the end of the day we can’t rely on a hydraulic system. A valve could jam if the customer doesn’t maintain clean oil and we have to assume the worst-case situation happening. No personnel should be in the working area of the manipulator when it is live, so any interaction has to be managed in a safe way”.

Whilst this is a solution to the problem, it should also be remembered that it is a collaborative one and doesn’t detract from the need to remind customers that the overall health and safety aspects must be considered as part of the larger cell requirements, which comes back to the misinterpretation of CE marking on individual partly completed machines that form part of the equipment in a larger cell.

Muir says that Clansman has to be “very proactive” because of interpretation issues concerning the rules. “We undertake a risk assessment of each manipulator and liaise with the customer or lead supplier about levels of safety to mitigate risks, but it is important that there is an appreciation that the manipulator is a partly completed machine, operating within a larger cell.”

Thankfully, Clansman has developed strong working relationships with moulding equipment suppliers and other protagonists in the foundry industry and works hard to mitigate risks. However, all those involved need to fully understand the difference between machine safety, and safe operation in situ to maintain a safe working environment for all.

Contact: Derek Muir, sales director, Clansman Dynamics, Tel: +44 (0) 1355 579 900. Email: [email protected] web: www.clansmandynamics.com

 

The letters ‘CE’ appear on many products that are traded on the single market in the European Economic Area (EEA).

The CE marking is required for many products and it:

  • Shows that the manufacturer has checked that these products meet EU safety, health or environmental requirements.
  • Is an indicator of a product’s compliance with EU legislation.
  • Allows the free movement of products within the European market.