New Machinery Directive
An MTA seminar presentation in May tackled issues associated with revisions to EU legislation on machinery safety; we highlight some of the main changes likely to affect the production engineering sector.
Machine tool builders and importers must address issues concerning partly completed machinery, foreseeable misuse/manual intervention, fixing systems for fixed guards, and the language of instruction manuals.
The message from the EC and others is that, mostly, the technical aspects of machinery meeting the requirements of the old directive (98/37/EC) will also meet the new one (2006/42/EC). But how true is this for the machine tool and related machinery sectors? And what about relaxations and derogations?
PARTLY COMPLETED MACHINERY
Old directive Article 4 Cl 2: ‘Member States shall not prohibit, restrict or impede the placing on the market of machinery...intended to be incorporated into machinery or assembled with other machinery to constitute machinery covered by this Directive, except where it can function independently.’
New directive Article 1 (Scope): ‘This Directive applies to......(a) machinery...(g) partly completed machinery.’ Article 2 (a): ‘machinery’ means: ‘an assembly...fitted with or intended to be fitted with a drive system...or missing only the components to connect it on site or to sources of energy...’ Article 2 (g): ‘partly completed machinery’ means: ‘...an assembly which is almost machinery but which cannot in itself perform a specific application...’ The old Article 4 statement apparently limits coverage of functioning but incomplete machinery to that for incorporation with other machinery.Partly completed machinery requiring the addition of safeguarding equipment is therefore not fully covered in the old directive.
Large engineering manufacturers are quite used to working closely with their production machinery supply chain. Historically they have been able to specify and purchase machines without some guarding so that self-specified or customised guarding can be fitted on installation - and then assume responsibilities as manufacturers for the purposes of final CE-marking of the machine.
The new Articles 1 & 2 definitions for ‘machinery’ and ‘partly completed machinery'’ in the scope of the new directive effectively eliminate this possibility. An unguarded machine which is capable of working will no longer be legally sold with an Annex IIB certificate of incorporation, for CEmarking when the guarding is installed subsequently by a competent installer.
Similar principles would apply to all safeguarding systems, including those for acoustic noise, gas/mist emissions and optical or electromagnetic radiation; and under the new definition of machinery, simply removing the drive system components and connections will make no difference.
For such supply and manufacturing chain options to continue, the new definition means that machinery will have to be supplied to the customer ‘disassembled’ ie incapable of working.
Although this evidently means more than disconnecting or removing drive system components such as axis motors or controls, current Orgalime discussions are aiming at interpretations to reduce this newly introduced level of rigidity.
FORESEEABLE MISUSE AND MANUAL INTERVENTION
Old directive Annex I Cl 1.2.2.(a): ‘..The aim ...must be to eliminate any risk of accident...even where risks of accident arise from foreseeable abnormal situations.’ Annex I Cl 1.2.2.( c): ‘The machinery must be designed to prevent abnormal use if such use would engender a risk...’
New directive Annex I Cl 1.1.2.(a): ‘Machinery must be designed and constructed...without putting persons at risk...taking into account any reasonably foreseeable misuse...’ Annex I Cl 1.1.1.(i): ‘reasonably foreseeable misuse’ means the use of machinery in a way...which may result from readily predictable human behaviour.’ The changes of wording point to a new definition of ‘reasonably foreseeable misuse’.
The new directive permits greater flexibility for machine designers and users to take account of important factors when preventing the possible misuse of machinery ie the training, skill level and competence of machine users, as well as ergonomic considerations and the use of personal protective equipment.
As a direct consequence of this perceived relaxation in the new directive, an opportunity is created for machine tool designers and users to achieve greater machining flexibility with potential for higher productivity (especially when skilled operators need to carry out precision machining ops with manual intervention in the work zones of CNC machines, running under restricted conditions with the guard doors open).
The new directive completes the legal detail for this extended flexibility, by adding a specific derogation to the existing conditions for machinery operating mode selection. The new wording effectively extends the existing conditions, but in a non-specific way...
Manual intervention operating mode Annex I Cl 1.2.5. (Selection of control or operating modes): ‘If, for certain operations, the machinery must be able to operate with a guard displaced or removed and/or a protective device disabled, the control or operating mode selector must simultaneously:
• disable all other control or operating modes,
• permit operation of hazardous functions only by control devices requiring sustained action,
• permit the operation of hazardous functions only in reduced risk conditions while preventing hazards from linked sequences,
• prevent any operation of hazardous functions by voluntary or involuntary action on the machine’s sensors.
New directive ‘If these four conditions cannot be fulfilled simultaneously, the control or operating mode selector must activate other protective measures designed and constructed to ensure a safe intervention zone...’ This is given more detail in relevant harmonised European standards as ‘Extended Operating Mode 3’ for machines such as CNC milling machines and machining centres (not to be confused with the so-called ‘Mode 4’ operating mode which has been applied for some time on certain machines used in Germany). Under the old directive, for applications requiring manual intervention (mainly setting and maintenance activities but also limited machining operations) guard-open running is permitted only under the operating conditions bullet-pointed above. The usual way of achieving this, satisfying the 2rd bullet point, is with the use of a hold-to-run or pendant control.
Following intensive lobbying by German car manufacturers worried about Far East competition, it’s been established that for fine finish machining with manual intervention such as in mould and die milling, it’s not ergonomically sustainable to enable machining operations with the hold-torun control whilst making the necessary delicate manual adjustments and visual inspections. The harmonised European ‘C’-type safety standards for these machines were amended last year, reflecting the new wording.
Justification for the Extended Mode 3 EN12417:2001A1 Machining Centres & EN13127:2001A1 Milling Machines Cl 1.1.6.4.
Mode 3 - Optional mode for manual intervention under restricted operating conditions ‘Where ergonomic considerations in the application of Mode 3 make the use of an enabling device impractical (eg because the duration of necessary process observation/intervention exceeds an acceptable fatigue time for the machine operator to actuate the enabling device or the manipulation of multiple parameter control devices prevents the sustained operation of an enabling device) then a combination of alternative engineering control measures, to reduce entanglement and crushing risks, shall be substituted for the enabling device.’
Examples of accepted alternative engineering control measure combinations:
A safe standing position for the operator that is monitored by an active optical protection device (AOPD) (e.g. a scanning device or light curtain) or other approved safety monitoring device, but excluding the use of a pressure sensitive mat or similar easily defeated device, together with:
• A readily accessible emergency stop control device shall be provided plus
• Safe edge emergency stop arrangements shall be applied to all moving machine elements that pose a crushing risk plus,
• The monitoring for reduced spindle and axes speeds shall satisfy the requirements of EN 954 (1996) Part 1 Category 3, and
• Identification of appropriate personnel protective equipment (PPE) shall be provided in the Instructions for Use (See clauses 7.2 n) and 7.2 o) of this standard).
As an alternative to this we can have: Protection against entanglement risk by means of a fixed guard enclosing the rotating spindle and cutter or an AOPD (light curtain) around (or in front of) the rotating spindle and cutter, together with ‘Other engineering control measures that provide the equivalent level of risk reduction’ ie to those identified above.
This corresponds directly with the Cl 1.2.5. additional wording (or derogation) given in the new directive and allows for technical progress.
FIXING SYSTEMS OF FIXED GUARDS
New requirement Annex 1 Cl.1.4.2.1. Fixed guards: ‘...Their fixing systems must remain attached to the guards or to the machinery when the guards are removed.’ This new requirement is likely to cause significant design issues for the larger machine categories, for which further guidance and interpretation on types of fixings will be needed.
LANGUAGE OF INSTRUCTION MANUALS
Language translations can be a real headache especially with the EU expansion to 27 member states. The new directive still requires that CE-marked machinery sold and used in the EU must be accompanied by the instructions in the language(s) of use and of origin. It is sometimes thought that it is acceptable to supply without the customer’s local language if their agreement is obtained, and that a ‘confirmation letter’ can be used by the manufacturer to pass responsibility to the customer.
This is dealt with in the EC’s ‘Useful Facts’ document (in relation to 98/37/EC available at the EC’s Europa website): Q10 - Can manufacturer (or seller) and user agree that the instruction manual will be written only in the language of the manufacturer? A10 - A private agreement.... cannot take the place of legislation. In the event of accident due to lack of comprehension on the operator’s part, the manufacturer or representative might be liable.’
However, the existing directive allows that maintenance instructions for use by specialised personnel employed by the manufacturer/representative may be in only one of the Community languages understood by that personnel.
Annex 1 Cl.1.7.4 Instructions: ‘By way of exception, the maintenance instructions intended for use by specialised personnel mandated by the manufacturer or his authorised representative may be supplied in only one Community language which the specialised personnel understand.’ The new directive extends this derogation by using the word ‘mandated’ instead of ‘employed’.
It may be presumed, therefore, that any suitably qualified persons including the user companies’ own programmers and maintenance engineers could be mandated as specialised personnel for this purpose. In such circumstances it would be necessary to make a clear distinction between specialized instructions such as the CNC programming and maintenance instructions and the more general instructions for use.
It would also, of course, be necessary to confirm in writing any arrangement with the user, as well as to confirm the language abilities of the mandated specialised personnel.
