HSE WARNS OF MACHINERY DANGER

HSE press release: E143:03 - 23 July 2003

Workers in the engineering sectors run the risk of serious or fatal injuries because guards on turning machines (lathes) are not being properly maintained, says the Health and Safety Executive (HSE).

This follows a survey of CNC turning machines carried out by HSE inspectors during 2002/03. They looked at the condition of machine guards, including vision panels, which are fitted into guard doors to allow operators to view the machining process. Inspectors found evidence of cracked or damaged panels. These parts can also deteriorate over time due to the effects of metalworking fluid and lose a substantial amount of their impact resistance. These safety critical parts of the machine need to be properly maintained.

At about two thirds of the visits inspectors also found that users had not assessed the arrangements needed to maintain the machine so that it was safe to use.

There is a history of incidents at this type of machine where parts have been ejected and operators seriously injured, fatally in some cases, because vision panels have failed to contain the projectile. Modern computer controlled lathes are normally fully enclosed and interlocked and the risk of entanglement has largely been eliminated. However, enclosure panels need to be maintained in good condition to prevent injuries from ejected parts.

The survey follows on from guidance issued by the HSE nearly two years ago. Engineering Information Sheet (EIS) 33 "CNC Turning machines - controlling risks from ejected parts" , warned about the hazard of parts being ejected from machines and the need to ensure that vision panels are properly constructed and maintained. HSE worked with a number of organisations including the Manufacturing Technologies Association (MTA) and the Engineering Employers Federation (EEF) to produce this practical guidance.

Research has shown that some materials used in the construction of vision panels, particularly the polycarbonate window, deteriorate over time and may not protect operators from parts that can be ejected with very high energy.

Nick Hitchcott from the HSE Manufacturing Sector explained:

"Vision panels constructed of plain, unprotected polycarbonate need to be assessed periodically to ensure that they will continue to provide adequate protection against ejected parts. This needs to be done even on machines where there is no obvious evidence of damage to the panel. In over half of the premises visited during the survey employers admitted that ejections had occurred or inspectors saw, first hand, evidence of cracked or damaged panels. Machines over two years old need to be assessed unless they are fitted with a specially manufactured, fully protected laminated vision panel where all the layers are bonded together. The HSE guidance gives advice on what to look for and the options for improving the guards."

"The risks do vary according to the type of work being done and the work-holding methods that are used but, by following the guidance, employers can ensure that if any improvements are needed they are cost effective and proportional to the risk. Machine manufacturers and suppliers should be aware of the potential problems and can offer advice on the kind of remedial action that needs to be taken or supply upgraded parts."

A copy of EIS 33 'CNC Turning machines - controlling risks from ejected parts' can be obtained from HSE's website:http://www.hse.gov.uk click on 'free leaflets' and then 'engineering'.

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