Bsi bs en 12957 2001 + a1 2009

BRITISH STANDARD BS EN 12957 2001 Machine tools — Safety — Electro discharge machines ICS 25 120 40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW +A1 2009 BS EN 12957 2001 Thi[.]

Machine tools —

Safety — Electro

discharge machines

ICS 25.120.40

This British Standard was

published under the authority

of the Standards Policy and

The UK participation in its preparation was entrusted to Technical Committee

A list of organizations represented on this committee can be obtained on request to its secretary

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

Compliance with a British Standard cannot confer immunity from legal obligations.

Amendments/corrigenda issued since publication

NORME EUROPÉENNE

English Version

Machine tools - Safety - Electro discharge machines

Machine-outils - Sécurité - Machines d'électroérosion Werkzeugmaschinen - Sicherheit -

Funkenerodiermaschinen

This European Standard was approved by CEN on 9 May 2001 and includes Amendment 1 approved by CEN on 29 December 2008 CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E FÜ R N O R M U N G

Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2009 CEN All rights of exploitation in any form and by any means reserved

worldwide for CEN national Members

Ref No EN 12957:2001+A1:2009: E

Contents

Foreword 3

Introduction 4

1 Scope 4

2 Normative references 4

3 Terms and definitions 6

4 List of hazards 9

5 Safety requirements and/or measures 12

5.1 General requirements 12

5.2 Operating modes 12

5.3 Stop functions 13

5.4 Safety related parts of control systems for EDM equipment or EDM systems 13

5.5 Specific requirements 14

6 Verification of safety requirements and/or measures 23

7 Information for use 23

7.1 General 23

7.2 Markings, signs, written warnings 23

7.3 Instruction handbook 23

Annex A (informative) Examples and schematic pictures 27

Annex B (normative) Noise emission measurements 36

Annex ZA (informative) !!Relationship between this European Standard and the Essential Requirements of EU Directive 98/37/EC, amended by Directive 98/79/EC"" 37

Annex ZB (informative) !!Relationship between this European Standard and the Essential Requirements of EU Directive 2006/42/EC"" 38

Foreword

This document (EN 12957:2001+A1:2009) has been prepared by Technical Committee CEN/TC 143

"Machine tools - Safety", the secretariat of which is held by SNV

This European Standard shall be given the status of a national standard, either by publication of an identical

text or by endorsement, at the latest by August 2009, and conflicting national standards shall be withdrawn at

the latest by December 2009

This document includes Amendment 1, approved by CEN on 2008-12-29

This document supersedes EN 12957:2001

The start and finish of text introduced or altered by amendment is indicated in the text by tags ! "

This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s)

!Annexes A, ZA and ZB of this standard are informative, Annex B is normative."

!For relationship with EU Directive(s), see informative Annexes ZA and ZB, which are integral parts of this document."

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom

Introduction

This standard applies to equipment using the process of Electro Discharge Machining (EDM) as defined in

clause 3 This European Standard is a type C Standard as stated in EN 1070

The machinery concerned and the extent to which hazards, hazardous situations and events are covered are

indicated in the scope of this standard

Complementary guidance is given in type A and B Standards to which reference is made in the text

When provisions of this type C Standard are different from those which are stated in type A or B Standards,

the provisions of this type C Standard take precedence over the provisions of the other standards, for

machines that have been designed and built according to the provisions of this type C Standard It provides

one means of conforming with the Essential Health and Safety Requirements (EHSR’s) of the "Machinery

Directive" (98/37/EC)

1 Scope

1.1 This standard specifies technical safety requirements and measures, applicable to EDM equipment and

EDM system (e.g for spark erosion-sinking, spark erosion-wire cutting), to be adopted by persons undertaking

the design, construction, installation and/or supply of such equipment This standard also includes information

to be provided by the manufacturer to the user

1.2 The design requirements of this standard shall not apply to arc eroding and electro chemical machining

equipment

1.3 This standard takes account of the intended use in normal workshop environment and non explosive

atmospheres including installation, setting, maintenance, repair and dismantling for removal or disposal of

EDM equipment

1.4 This standard also applies to auxiliary devices essential for EDM processing

1.5 This standard deals with specific hazards defined in clause 4, Table 1, and the measures of prevention in

clause 5, Table 2

1.6 This standard applies to machines built after its date of issue

NOTE Directive 94/9/EC concerning equipment and protective systems intended for use in potentially explosive

atmospheres can be applicable to the type of machine or equipment covered by this European Standard The present

standard is not intended to provide means of complying with the essential health and safety requirements of Directive

94/9/EC

This European Standard contains dated or not dated references on provisions from other publications These

normative references are cited at the appropriate places in the text and the publications are listed hereafter

For dated references, subsequent amendments to or revisions of any of these publications apply to this

European Standard only when incorporated in it by amendment or revision For undated references the latest

edition of the publication referred to applies (including amendments)

EN 2:1992, Classification of fires

EN 54-1:1996, Fire detection and fire alarm systems – Part 1: Introduction

EN 292-1:1991, Safety of machinery - Basic concepts, general principles for design – Part 1: Basic terminology, methodology

EN 292-2:1991, Safety of machinery - Basic concepts, general principles for design – Part 2: Technical principles and specifications

EN 292-2:1991/A1:1995, Safety of machinery - Basic concepts, general principles for design – Part 2: Technical principles and specifications, (Amendment A.1)

EN 294:1992, Safety of machinery - Safety distances to prevent danger zones being reached by the upper limbs

EN 349:1993, Safety of machinery - Minimum gaps to avoid crushing of parts of the human body

EN 418:1992, Safety of machinery - Emergency stop equipment, functional aspects - Principles for design

EN 626-1:1994, Safety of machinery - Reduction of risks to health from hazardous substances emitted by machinery – Part 1: Principles and specifications for machinery manufacturers

EN 775:1992, Manipulating industrial robots - Safety (ISO 10218:1992 modified)

EN 811:1996, Safety of machinery - Safety distances to prevent danger zones being reached by the lower limbs

EN 953:1997, Safety of machinery - Guards - General requirements for the design and construction of fixed and movable guards

EN 954-1:1996, Safety of machinery - Safety related parts of control systems – Part 1: General principles for

EN 999:1998, Safety of machinery - The positioning of protective equipment in respect of approach speeds of

parts of the human body

EN 1037:1995, Safety of machinery - Prevention of unexpected start-up

EN 1050:1996, Safety of machinery - Principles for risk assessment

EN 1070:1998, Safety of machinery - Terminology

EN 1088:1995, Safety of machinery - Interlocking devices associated with guards - Principles for design and

prEN 12437-3:1996, Safety of machinery - Permanent means of access to machines and industrial plants –

Part 3: Stairways, stepladders and guard-rails

prEN 12437-4:1996, Safety of machinery - Permanent means of access to machines and industrial plants –

Part 4: Fixed ladders

EN 55011:1998, Industrial, scientific and medical (ISM) radio frequency equipment - Radio disturbance

characteristics - Limits and methods of measurement (CISPR 11:1997, modified)

EN 60204-1:1997, Safety of machinery - Electrical equipment of machines – Part 1: General requirements

(IEC 60204-1:1997)

EN 60529:1991, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989)

EN 60742:1995, Isolating transformers and safety isolating transformers - Requirements (IEC 60742:1983 +

A1:1992, modified)

EN 61000-6-2:1999, Electromagnetic compatibility (EMC) Part 6-2: Generic standards - Immunity for industrial

environments (IEC 61000-6-2:1999)

EN 61310-1:1995, Safety of machinery - Indication, marking and actuation – Part 1: Requirements for visual,

auditory and tactile signals (IEC 61310-1:1995)

EN 61310-2:1995, Safety of machinery - Indication, marking and actuation – Part 2: Requirements for marking

(IEC 61310-2:1995)

EN ISO 3746: 1995, Acoustics – Determination of sound power levels of noise sources using sound pressure

- Survey method using an enveloping measurement surface over a reflecting plane (ISO 3746:1995)

EN ISO 4871:1996, Acoustics – Declaration and verification of noise emission values of machinery and

equipment

EN ISO 11202:1995, Acoustics - Noise emitted by machinery and equipment - Measurement method of

emission sound pressure levels at the workstation and at other specified positions - Survey method in situ

EN ISO 11688-1:1998, Acoustics – Recommended practice for the design of low noise machinery and

equipment – Part 1: Planning

3 Terms and definitions

For the purposes of this standard, the definitions given in EN 1070:1998 apply together with definitions listed

below

Other general definitions (e.g hazard, risk, safeguarding) are mentioned in corresponding type A and type B

Standards and in the annex A of EN 292-2:1991

3.1

arc erosion; arc eroding; arc machining

the removal of material by constant (non pulsed) electro discharges, performed in a dielectric medium The

discharges are initiated by periodical contact of the electrode with the work piece interrupted by axial

movement of the electrode

3.2

arc erosion equipment

all the necessary units for the process of arc machining

3.3

control system for EDM equipment or EDM system

the system from the initial actuator or sensor to the point of input to the final actuator or element (e.g motor,

cylinders)

3.6

dielectric fluid (for EDM processes)

non-conductive medium to improve the discharge effect, evacuate debris and to cool the work piece/electrode

3.7

dielectric fluid container

unit and/or systems used to keep the dielectric fluid in a condition suitable for EDM (e.g filter unit/dielectric system)

an assembly of EDM equipment and other machines or devices which are arranged, linked and controlled to

function as an integral whole

3.10

electro chemical equipment

all the necessary units for the process of electro chemical machining

3.11

electro chemical machining; ECM

any machining process based on electrolysis

3.12

electro discharge machining; EDM

any machining process based on spark erosion

3.13

electromagnetic compatibility; EMC

the ability of the EDM equipment/system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment

3.14

flammable dielectric fluid

dielectric fluid used in EDM, characterised by its relative ease of ignition and relative ability to sustain combustion

3.15

flash point

minimum temperature at which, under specified test conditions, a liquid gives off sufficient combustible gas or

vapour to ignite momentarily on application of an effective ignition source

3.16

generator (for EDM equipment)

device to convert electrical power supplied to the machine for the purpose of being used for spark erosion

processing

3.17

operator of an EDM equipment and/or system

person or persons given the task of programming, setting, adjusting, operating, maintaining and cleaning the

setting mode (simulation mode)

use of the machine under numerical control, without machining power, to check/optimise the NC-programme

and allowing manual interventions

3.20

shielding of EDM equipment

mechanical barrier or enclosure of conductive material intended to attenuate the emission/penetration of a

varying electromagnetic field into an assigned region

3.21

spark erosion; spark eroding; spark machining; EDM process

removal of material in a dielectric fluid by electro discharges, which are separated in time and randomly

distributed in space, between two electrically conductive electrodes (the tool electrode and the work piece

electrode), and where the energy in the discharge is controlled

spark erosion-wire cutting

removal of material by spark erosion with a wire electrode to produce prismatic shapes in the work piece

3.24

tool changer (for EDM equipment); electrode changing device

mechanism integrated with the machine to supply a previously loaded electrode in exchange for another

electrode The electrode changing device is expected to enable an operator to load/unload electrodes from

outside the work area

3.25

work area (on EDM equipment)

space within the envelope of the machine where the EDM process can take place

3.26

work piece changing device (for EDM equipment)

mechanism integrated with the machine to supply a previously loaded work piece in exchange for another

work piece The work piece changing device is designed to enable an operator to load/unload work pieces

from outside the work area

3.27

work tank (for EDM equipment)

unit surrounding the work area to contain the dielectric fluid for EDM processes

4 List of hazards

The list of hazards contained in Table 1 is the result of a risk assessment, carried out as described by

EN 1050:1996 for all EDM equipment covered by the scope of this standard The technical measures and information for use contained in clause 5 and 7 are based on the risk assessment and deal with the identified hazards by either eliminating them or reducing the effects of the risks they generate

The significant hazards covered by this standard are listed in Table 1

Particular attention is given to hazards dealing with:

⎯ Electrical hazards (electrode voltage);

⎯ Flammable dielectric fluid (level, temperature, fire detection);

⎯ Hazardous substances (waste disposal, filters, used dielectric fluid, fume extraction, electrodes and sludges);

⎯ Electromagnetic emissions (radiated and conducted)

NOTE The designer’s attention is focused on hazards which can occur during the life of the machine to both operator and other persons who have access to the danger zone/s for conditions of intended use including reasonably foreseeable misuse of the machine (see EN 292-1:1991, 3.12) for both spark erosion with automatic mode and operations requiring intervention (e.g setting, maintenance, repair).Although acoustic noise is not considered to be a significant hazard for EDM equipment, the manufacturer of the equipment is not absolved from reducing noise and making noise declaration The designer is cautioned to verify whether the list of hazards in Table 1 is exhaustive and applicable and, if there are other hazardous situations, not listed in Table 1, which are related to the specific equipment in question

Table 1 — List of significant hazards and major sources of these hazards associated with Electro

Discharge Machines

* Description Hazardous situation

action Activity Danger zone Reference to Table 2

1 Mechanical hazards due to:

setting, machining and maintenance

at and near the machine

loading/unloading, reorienting power operated, work piece/

electrode changemanual

operation/work

piece/electrode change

between clamps and work piece envelope of work piece/electrode motion

between work piece/electrode and machine parts

A1, A2, A3 A1, A2, A3

A1, A2, A3

1.4 Entanglement manual or automatic

work piece/electrode changing, spindle rotation and wire rollers

manual or power operated work piece/electrode changing and spindle rotation

between work piece/electrode and machine parts

setting, machining and maintenance

at and near the machine A4

(continued)

Table 1 (continued)

* Description Hazardous situation

action Activity Danger zone Reference to Table 2

2 Electrical hazards due to:

process control, setting and maintenance

work piece, electrode, tooling fixture, generator and electrical enclosure

B1, B2

2.2 Contact of

per-sons with parts

which have

be-come live under

faulty conditions

(indirect contact)

contact with parts of the machine which are not live during normal operation

maintenance and service of the machine

at and near the machine, insulation

of electrical cables and equipment

B1, B3

7 Hazards generated by materials and substances (and their constituent elements) processed or

used by the machinery

7.1 Contact with or

inhalation of

harmful fluids,

gases, mists,

fumes, and dust

conditions near the machine caused by ejection of dielectric fluid, droplets or evaporation, mists, fumes, etc

during the EDM process, setting, maintenance and disposal of the machine

at and near the machine

D1 - D5

7.2 Fire or explosion fire hazard originated

by flammable mist generation, long lasting arcing condition, loss of dielectric fluid, fault of electrical or hydraulic power supply, etc

during the EDM process near the machine and the work tank D5 - D12

10 Unexpected start-up, unexpected overrun/overspeed (or any similar malfunction) from:

ma-of the energy supply

after energy restoration at the machine E3

machine in operation, setting and maintenance

at and in the vicinity of the machine

C1

13 Failure of the

power supply malfunction resulting from power loss,

powered clamping failures and machine elements moving under residual forces (e.g

Table 1 (concluded)

* Description Hazardous situation

action Activity Danger zone Reference to Table 2

14 Failure of the

control circuit mechanical hazards associated with

ma-chine movements, trical hazard and/or fire

elec-during operation, setting, cleaning, maintenance and repair activities

trailing floor-mounted or loose connection cables

during and after machining and maintenance

large work tanks, slippery floor and high working positions; area surrounding the machine

during operation, setting, cleaning, maintenance and repair activities

at and in the vicinity of the machine or the auxiliary devices

H1

* This list is derived from EN 1050:1996, annex A

5 Safety requirements and/or measures

5.1 General requirements

Machinery shall comply with the safety requirements and/or protective measures as indicated in Table 2 of this clause In addition the equipment shall be designed according to the principles of EN 292 for hazards relevant, but not significant, which are not dealt with by this standard (e.g sharp edges)

5.2 Operating modes

5.2.1 Operating mode selection

Based on 1.2.5 of EN 292-2:1991/A1:1995 and 9.2.3 of EN 60204-1:1997, the selection of the mode shall be either a key operated switch, or equally lockable means Mode selection shall be permitted only from outside the work area and shall not initiate start-up The indication of the selected operating mode shall be provided (e.g the position of the selector, the provision of an indicating light or visual display indication) Mode changes shall ensure, that only one mode is active at any one time

Mode selection shall be category 1 according to EN 954-1:1996

5.2.2 Protecting measures relating to operating modes

5.2.2.1 Automatic mode

Starting the automatic mode shall be possible only if guards are closed and other safety devices are in protective condition (e.g guard lock, fire detection device ready when flammable dielectric fluids are used and fume extraction activated)

5.2.2.2 Setting mode

Suspension of safeguarding under setting mode has to be in accordance with 9.2.4 of EN 60204-1:1997 Linear movements shall be limited at a maximum rate of 2 m/min under hold-to-run control, or incremental movements at a maximum increment of 6 mm The stop resulting from hold-to-run control release or end of the incremental movement shall be a controlled stop category 2, according to 9.2.2 of EN 60204-1:1997 Rotating motions shall be limited to a rotation not exceeding 50 min-1

Speed limit control shall be category B according to EN 954-1:1996, combined with either:

⎯ hold-to-run control together with an enabling device, or

⎯ manual data input (MDI) followed by a cycle start together with an enabling device, or

⎯ electronic hand-wheel together with an enabling device

to achieve category 3 according to EN 954-1:1996

The enabling device shall be in accordance with 9.2.5.8 of EN 60204-1:1997

5.3 Stop functions

5.3.1 Operational stop

An operational stop-function which is initiated by a stop device shall be provided for each mode of operation When the operational stop function is activated, the energy supply to axes drive motors, work piece holding device and NC equipment, need not be cut off, see A.1.2.4 of EN 292-2:1991/A1:1995 and annex A, Figure A.5 of this standard

5.3.2 Emergency stop

The EDM equipment or system shall be provided with one or more emergency stop control devices according

to EN 418:1992 and 6.1.1 of EN 292-2:1991

The emergency stop function/s shall be category 1 according to 9.2.2 of EN 60204-1:1997

For EDM equipment or systems without NC controlled axes (e.g EDM equipment with single working axis including electromechanical planetary motion devices or Electro Discharge Drilling machines), stop function category 0 according to 9.2.2 of EN 60204-1:1997, may be applied

Emergency stop shall be category 3 according to EN 954-1:1996

Emergency stop device/s shall be provided at each working station but at least at:

⎯ the main control panel,

⎯ the portable control panel, if quick access to another emergency stop device is not possible,

⎯ the work piece/electrode loading and unloading station if separated from the main operator’s position,

⎯ a location quickly accessible from inside of an enclosure and/or work tank where whole body access is possible

5.4 Safety related parts of control systems for EDM equipment or EDM systems

Safety related parts of control systems comprise parts concerning the following functions and shall fulfil the requirements of the categories given below according to EN 954-1:1996

Functions EN 954-1:1996

category see ref Table 2

• Machining voltage and electrical sensing for positioning of

• Start, stop and automatic restart of machining B E3

Specific safety measures as needed for EDM equipment and/or EDM systems to prevent hazards identified in

clause 4 of this standard, are described in Table 2

Table 2 — List of safety requirements and/or protective measures and their verification procedures

** Hazards Safety requirement and/or

EDM equipment shall be designed

as to avoid foreseeable mechanical hazards during intended use and reasonable foreseeable misuse

Where hazardous situations cannot

be prevented, fixed guards shall be used where no access to danger zones is necessary during intended use

Where access to wire transportation system (rollers) is required, crushing

or entanglement prevention devices shall be provided, preventing access

by hand As a schematic example, see annex A, Figure A.9

Where frequent (more than once per day) access to the work area is required, hazardous situations shall

be prevented with interlocking guards

In automatic mode opening of interlocking guards shall stop all current operations in order to remove all risks within the area under protection

As long as the interlocking guards remain open, unexpected start-up shall be prevented in all modes

No other hazardous machine movements shall arise from the actuation of any sensor

By visual inspection and/or practical checks

By visual inspection and/or practical checks

By visual inspection and/or practical checks

By visual inspection and/or practical checks

By visual inspection and practical checks, examination of circuit diagrams

By visual inspection and practical checks, examination of circuit diagrams

By visual inspection and practical checks, examination of circuit diagrams

piece/electrode cleaning, inspection

of work progress) a device which prevents inadvertent closing of the door/s, shall be provided in order to inhibit any hazardous movements and/or actions (e.g filling of work tank)

By examination

of circuit diagrams and practical checks

EN 1088:1995, 3.2

EN 60204-1:1997, 5.4, 9.3.1

EN 775:1992, 7.3.1.2a

(continued)

Table 2 (continued)

** Hazards Safety requirement and/or

measure Verification Reference to relevant standards

Opening the guard of the tool changer, shall prevent automatic tool changing movement, or magazine movement As a schematic example, see annex A, Figure A.7 and A.8

Any movement of the tool - or work piece changer with the guards open shall be initiated only under the control of a hold-to-run control device in combination with an enabling device Such equipment shall be positioned outside the reach

of hazardous movements

If the speed of the movement exceeds 2 m/min, only step - by - step function of maximum increment

of 6 mm (singular incremental movements) is permitted

While tool changing or magazine movement is in progress, opening of the door shall be inhibited by

interlocking with guard locking

Access to other remaining hazards shall be prevented

By visual inspection and practical checks

By visual inspection and practical checks

By visual inspection and practical checks

By visual inspection and practical checks

EN 292-2:1991, 4.1, 4.2

EN 953:1997

EN 999:1998

EN 1088:1995, 7 and Annexes

EN 294:1992

EN 60204-1:1997, 9.2.4, 9.2.5.6

Hydraulic and pneumatic systems shall be designed in accordance with the appropriate standard

By calculation and/or tests and visual inspection

Examination of circuit diagrams, data sheets and

by visual inspections

EN 292-2:1991/A1:1995

EN 60204-1:1997

(continued)

Table 2 (continued)

** Hazards Safety requirement and/or

measure Verification Reference to relevant standards

be at least IP2X or IPXXB, according to EN 60529:1991

Enclosures including control devices (e.g keyboards, portable control stations) shall be protected against foreseeable external influences or environmental conditions where the equipment or system is intended to operate (e.g machining residuals, dielectric fluid) Protection degree provided by enclosures or control devices shall be at least IP22, according to EN 60529:1991

The enclosures shall be located and mounted to facilitate accessibility and life parts inside the enclosures shall be protected to prevent direct contact Protection degree provided

by enclosures shall be at least IP1X

or IPXXA, according to EN 60529:1991

The work area on the EDM equipment or system, where electrical energy is used as a working tool (excluded from EN 60204-1:1997) shall be protected with interlocking guards, as specified

in clause 5.4 of this standard, to prevent accidental or inadvertent contact

The opening of interlocking guards protecting live parts, shall cut off the machining electrical power in automatic mode, using hard-wired electromechanical components to prevent unexpected return of the machining electrical power

On EDM equipment or systems where electrical power is used in the work area for position pick-up by contact sensing, such operations shall only be possible with interlocking guards closed

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and practical test

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

small size electrodes, fine wire), auxiliary devices shall be provided for the setting mode (see clause 5.2.2.2 of this standard), to inhibit hazardous contact with electrical power inside the work area, such as:

− Access detection barriers (e.g

light beam sensors or equally safe operating systems), combined with hard-wired electromechanical components,

to switch off the electrical power

to the work area in case of accidental or inadvertent entrance;

− Sensing voltage, between electrode/sensing tool and work piece, supplied by a safety source in accordance with EN 60742:1995, not exceeding 25 V

AC or 60 V DC;

− Any other suitable devices to prevent hazardous contact with electrical energy inside the work area in setting mode with suspended safeguarding

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

Examination of circuits, diagrams and/or test

By examination

of the equipment and testing

EN 60204-1:1997, 5.2, 6.3.3, 8.2, 19.2

C Electro Magnetic Compatibility (EMC)

in accordance with EMC regulations for industrial equipment As a schematic example see annex A, Figures A.1 and A.2

By measurements according to the standards

EN 61000-6-2:1999

EN 55011:1998

EN 60204-1:1997, 4.4.1

(continued)

Table 2 (continued)

** Hazards Safety requirement and/or

measure Verification Reference to relevant standards

D Hazards generated by materials and substances (and their constituent elements) processed, or used by the machinery

D1 General

requirements EDM equipment shall be designed to prevent leakage in order to allow

the safe handling of materials in process and/or removal of dielectric fluid, filters, process residuals, sludge or any other waste

By inspection and practical checks

EDM equipment shall be designed

to avoid contact with harmful dielectric fluid Means to collect fumes (to be installed as part of the EDM equipment or EDM system) shall be designed so that

connections can be made to equipment (to be provided by the user) to complete the local exhaust ventilation system As a schematic example see annex A, Figure A.3

Check of the interface specification for the customer, by practical checks

by the EDM equipment manufacturer As a schematic example see annex A, Figure A.3

By examination

of the circuit diagrams and practical checks

EN 626-1:1994

D5 Formation of

gases EDM dielectric fluid containers shall incorporate devices to prevent

concentration of hazardous gases, (e.g natural ventilation through venting openings or forced ventilation)

Provision shall be made to cool the dielectric fluid in relation to the maximum power supplied by the EDM equipment

By practical check, (e.g

concentration measuring according to the supplier’s specification of the dielectric fluid) and by inspection of the instruction handbook

Check specification of dielectric fluid and instruction manual (continued)