EN ISO 28881:2013

SLOVENSKI STANDARD
01-november-2013
1DGRPHãþD
SIST EN 12957:2002+A1:2009
Obdelovalni stroji - Varnost - Elektroerozijski stroji (EDM) (ISO 28881:2013)
Machine tools - Safety - Electro discharge machines (ISO 28881:2013)
Werkzeugmaschinen - Sicherheit - Funkenerodiermaschinen (ISO 28881:2013)
Machines-outils - Sécurité - Machines d'électro-érosion (ISO 28881:2013)
Ta slovenski standard je istoveten z: EN ISO 28881:2013
ICS:
25.120.40 Elektrokemijski stroji Electrochemical machines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 28881
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2013
ICS 25.080.01 Supersedes EN 12957:2001+A1:2009
English Version
Machine tools - Safety - Electro-discharge machines (ISO
28881:2013)
Machines-outils - Sécurité - Machines d'électro-érosion Werkzeugmaschinen - Sicherheit -
(ISO 28881:2013) Funkenerodiermaschinen (ISO 28881:2013)
This European Standard was approved by CEN on 14 March 2013.

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-CENELEC 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-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2013 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 28881:2013: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .4

Foreword
This document (EN ISO 28881:2013) has been prepared by Technical Committee ISO/TC 39 "Machine tools"
in collaboration with 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 February 2014, and conflicting national standards shall be withdrawn
at the latest by February 2014.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12957:2001+A1:2009.
This document 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.
For relationship with EU Directive, see informative Annex ZA, which is an integral part 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, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 28881:2013 has been approved by CEN as EN ISO 28881:2013 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 2006/42/EC on machinery.
Once this standard is cited in the Official Journal of the European Union under that Directive and has been
implemented as a national standard in at least one Member State, compliance with the normative clauses of
this standard confers, within the limits of the scope of this standard, a presumption of conformity with the
relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling
within the scope of this standard.

INTERNATIONAL ISO
STANDARD 28881
First edition
2013-08-01
Machine tools — Safety — Electro-
discharge machines
Machines-outils — Sécurité — Machines d’électro-érosion
Reference number
ISO 28881:2013(E)
©
ISO 2013
ISO 28881:2013(E)
© ISO 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

ISO 28881:2013(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 3
4 List of significant hazards . 7
5 Safety requirements and/or protective measures . 9
5.1 General requirements . 9
5.2 Safety-related parts of control systems for EDM equipment and EDM systems .10
5.3 Operating modes .11
5.4 Stop functions .13
5.5 Specific requirements .14
6 Information for use .22
6.1 General .22
6.2 Marking, signs and written warnings .22
6.3 Instruction handbook .22
Annex A (informative) Examples and schematic diagrams .28
Annex B (normative) Noise-emission measurements .37
Annex C (informative) Fire protection codes for special regional cases .38
Annex D (informative) Guidelines for risk assessment on EDM equipment and EDM systems to
identify the required performance level and, if necessary, category .48
Bibliography .51
ISO 28881:2013(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 28881 was prepared by Technical Committee ISO/TC 39, Machine tools, Subcommittee SC 10, Safety.
iv © ISO 2013 – All rights reserved

ISO 28881:2013(E)
Introduction
This International Standard has been prepared to be a Harmonized Standard to provide one means of
conforming to the Essential Safety Requirements of the Machinery Directive of the European Union and
associated EFTA regulations.
This document is a type-C standard as defined in ISO 12100:2010.
The machinery concerned and the extent to which hazards, hazardous situations and events are covered
are indicated in the Scope of this International Standard. In addition, electro-discharge machining (EDM)
equipment and EDM systems are intended to be designed according to the principles of ISO 12100 for
hazards which are not dealt with in this International Standard.
When requirements of this type-C standard are different from those which are stated in type-A or
-B standards, the requirements of this type-C standard take precedence over the requirements of
other standards for machines that have been designed and built according to the requirements of this
type-C standard.
This International Standard defines performance level and safety categories of the safety-related parts
of the control system for EDM equipment and EDM systems as defined in ISO 13849-1:2006.
The requirements of this International Standard concern designers, manufacturers, suppliers and
importers of machines described in the Scope.
This International Standard also includes a list of informative items intended to be provided by the
manufacturer to the user.
INTERNATIONAL STANDARD ISO 28881:2013(E)
Machine tools — Safety — Electro-discharge machines
1 Scope
This International Standard specifies safety requirements and/or protective measures, applicable to
EDM equipment and EDM systems, such as
— manually controlled EDM die sinking or EDM drilling machines,
— numerically controlled EDM die sinking or EDM drilling machines, and
— numerically controlled EDM wire cutting machines
intended to be adopted by persons undertaking the design, construction, installation and/or supply
of such equipment. This International Standard also includes information to be provided by the
manufacturer to the user.
This International Standard is not applicable to arc eroding and electro-chemical machining equipment.
This International Standard takes account of the precondition of the intended use as well as the
reasonably foreseeable misuse, in normal workshop environments and non-explosive atmospheres,
including transportation, installation, setting, maintenance, repair and dismantling for removal or
disposal of EDM equipment and EDM systems.
This International Standard is also applicable to auxiliary devices essential for EDM processing.
This International Standard deals with all significant hazards, hazardous situations or hazardous events
relevant to EDM equipment and EDM systems, where they are used as intended and under conditions of
misuse which are reasonably foreseeable by the manufacturer (see Clause 4).
This International Standard is intended to apply to machines manufactured after the date of publication
of this International Standard.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 3746, Acoustics — Determination of sound power levels and sound energy levels of noise sources using
sound pressure — Survey method using an enveloping measurement surface over a reflecting plane
ISO 4413, Hydraulic fluid power — General rules and safety requirements for systems and their components
ISO 4414, Pneumatic fluid power — General rules and safety requirements for systems and their components
ISO 4871, Acoustics — Declaration and verification of noise emission values of machinery and equipment
ISO 11202, Acoustics — Noise emitted by machinery and equipment — Determination of emission sound pressure
levels at a work station and at other specified positions applying approximate environmental corrections
ISO/TR 11688-1, Acoustics — Recommended practice for the design of low-noise machinery and equipment —
Part 1: Planning
ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction
ISO 28881:2013(E)
ISO 13849-1:2006, Safety of machinery — Safety-related parts of control systems — Part 1: General
principles for design
ISO 13849-2:2003, Safety of machinery — Safety-related parts of control systems — Part 2: Validation
ISO 13850, Safety of machinery — Emergency stop — Principles for design
ISO 13855, Safety of machinery — Positioning of safeguards with respect to the approach speeds of parts
of the human body
ISO 13857:2008, Safety of machinery — Safety distances to prevent hazard zones being reached by upper
and lower limbs
ISO 14118, Safety of machinery — Prevention of unexpected start-up
ISO 14122-1, Safety of machinery — Permanent means of access to machinery — Part 1: Choice of fixed
means of access between two levels
ISO 14122-2, Safety of machinery – Permanent means of access to machinery — Part 2: Working
platforms and walkways
ISO 14122-3, Safety of machinery — Permanent means of access to machinery — Part 3: Stairs, stepladders
and guard-rails
IEC 60204-1:2009, Safety of machinery — Electrical equipment of machines — Part 1: General requirements
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 61000-6-2, Electromagnetic compatibility (EMC) — Part 6-2: Generic standards — Immunity for
industrial environments
IEC 61000-6-4, Electromagnetic compatibility (EMC) — Part 6-4: Generic standards — Emission standard
for industrial environments
IEC 61310-1, Safety of machinery — Indication, marking and actuation — Part 1: Requirements for visual,
acoustic and tactile signals
IEC 61310-2, Safety of machinery — Indication, marking and actuation — Part 2: Requirements for marking
IEC 61558-1, Safety of power transformers, power supplies, reactors and similar products — Part 1: General
requirements and tests
IEC 61800-5-2:2007, Adjustable speed electrical power drive systems — Part 5-2: Safety requirements —
Functional
EN 2, Classification of fires
EN 54-1, Fire detection and fire alarm systems — Part 1: Introduction
EN 349, Safety of machinery — Minimum gaps to avoid crushing of parts of the human body
EN 614-1, Safety of machinery — Ergonomic design principles — Part 1: Terminology and general principles
EN 614-2, Safety of machinery — Ergonomic design principles — Part 2: Interactions between the design of
machinery and work tasks
EN 626-1, Safety of machinery — Reduction of risks to health from hazardous substances emitted by
machinery — Part 1: Principles and specifications for machinery manufacturers
EN 953:2009, Safety of machinery — Guards — General requirements for the design and construction of
fixed and movable guards
EN 1037:2008, Safety of machinery — Prevention of unexpected start-up
2 © ISO 2013 – All rights reserved

ISO 28881:2013(E)
EN 1088, Safety of machinery — Interlocking devices associated with guards — Principles for design and selection
EN 12198-1, Safety of machinery — Assessment and reduction of risks arising from radiation emitted by
machinery — Part 1: General principles
EN 12198-2, Safety of machinery — Assessment and reduction of risks arising from radiation emitted by
machinery — Part 2: Radiation emission measurement procedures
EN 12198-3, Safety of machinery — Assessment and reduction of risks arising from radiation emitted by
machinery — Part 3: Reduction of radiation by attenuation or screening
EN 62226-1, Exposure to electric or magnetic fields in the low and intermediate frequency range — Methods
for calculating the current density and internal electric field induced in the human body — Part 1: General
EN 62226-2-1, Exposure to electric or magnetic fields in the low and intermediate frequency range —
Methods for calculating the current density and internal electric field induced in the human body— Part 2-1:
Exposure to magnetic fields — 2D models
EN 62226-3-1, Exposure to electric or magnetic fields in the low and intermediate frequency range —
Methods for calculating the current density and internal electric field induced in the human body — Part
3-1: Exposure to electric fields — Analytical and 2D numerical models
EN 62311, Assessment of electronic and electrical equipment related to human exposure restrictions for
electromagnetic fields (0 Hz – 300 GHz)
CISPR 11, Industrial, scientific and medical equipment — Radio-frequency disturbance characteristics —
Limits and methods of measurement
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12100:2010 and
ISO 13849-1:2006 and the following apply.
3.1
control circuit
circuit used for the control, including monitoring, of the machine
Note 1 to entry: For electrical equipment, see IEC 60204-1:2009, 3.8.
3.2
machine control system
system that responds to input signals from parts of machine elements, operators, external control
equipment or any combination of these, and generates output signals causing a machine to behave in the
intended manner, as specified in ISO 13849-1:2006, 3.1.32
3.3
dielectric fluid
non-conductive medium to improve the discharge effect, evacuate debris and cool the
workpiece/electrode
3.4
dielectric fluid container
tank system to keep the dielectric fluid in a condition suitable for EDM
EXAMPLE Filtering and cooling.
3.5
EDM equipment
machine tool that includes all the necessary units for the process of electro-discharge machining
EXAMPLE Generator, control circuits and dielectric fluid container.
ISO 28881:2013(E)
3.6
EDM system
assembly of EDM equipment and other machines or devices, which are arranged, linked and controlled
to function as an integrated whole
3.7
electrode changer
mechanism integrated with the machine to supply a previously loaded electrode in
exchange for another electrode
Note 1 to entry: The changing device is expected to enable an operator to load/unload electrodes from outside of
the work area.
3.8
electro-discharge machining
EDM
any machining process based on spark erosion
Note 1 to entry: Electro-discharge machining is generally abbreviated as “EDM”.
3.9
electro-magnetic compatibility
ability of EDM equipment and EDM systems to function satisfactorily in their electro-magnetic environment
without introducing intolerable electro-magnetic disturbances to anything in that environment
Note 1 to entry: Electro-magnetic compatibility is generally abbreviated as “EMC”.
3.10
electronic handwheel
manually operated control device that initiates and maintains an axis movement by pulse generation
input to the numerical control during its rotation
3.11
enabling device
additional manually operated device used in conjunction with a start control and which, where
continuously actuated, allows a machine to function
[SOURCE: ISO 12100:2010, 3.28.2 — modified.]
3.12
flammable dielectric fluid
dielectric fluid used in EDM, characterized by its relative ease of ignition and relative ability to
sustain combustion
3.13
flash point
minimum temperature at which the dielectric fluid used in die sinking electro-discharge machining
gives off sufficient combustible gas or vapour to ignite and sustain combustion
3.14
generator
unit to convert the electrical power supplied to the EDM equipment and EDM system for the purpose of
being used for spark erosion processing
3.15
hazardous electric discharge power
electrical energy used to perform machining by electro-thermal material removal, which exceeds a
permitted level of voltage for contact with persons
4 © ISO 2013 – All rights reserved

ISO 28881:2013(E)
3.16
hold-to-run control device
control device that initiates and maintains hazardous machine functions only as long as the manual
control (actuator) is actuated
[SOURCE: ISO 12100:2010, 3.28.3 — modified.]
3.17
electric machining power
electrical power supplied to the EDM equipment and EDM system transformed by the generator in
specific electric energy, supplied as a tool to the sinker/wire electrode and the workpiece, to perform
machining by electro-thermal material removal
3.18
mean time to dangerous failure
MTTF
d
expectation of the mean time to dangerous failure
[SOURCE: ISO 13849-1:2006, 3.1.25 — modified.]
3.19
numerical control
NC
computerized numerical control
CNC
automatic control of a process performed by a device, which makes use of numerical data introduced
while the operation is in progress
[SOURCE: ISO/IEC 2806:1994, definition 2.1.1 — modified.]
3.20
operating mode
possible mode for use of the machine
3.20.1
automatic mode
mode for use under numerical control to achieve programmed sequential operation with the guards
closed, until stopped by a program or an operator
Note 1 to entry: This term is equivalent to machining mode.
Note 2 to entry: For machinery having automatic setting programs, such operations are considered automatic mode.
3.20.2
setting mode
mode for use without electric machining power, for operations in which adjustments for the subsequent
machining are performed by the operator
Note 1 to entry: Measuring cycles (e.g. touching of the workpiece with a probe or electrode), checking the
movement of the workpiece and/or electrode using the electrode and/or workpiece changer, checking/optimizing
the injection or suction flushing, a dry run for checking the NC program, etc. are procedures forming part of the
setting mode (see 5.3.2.2).
3.20.3
discharge alignment mode
mode for the use for specific alignment with the discharge power on and with the guards of EDM
equipment temporarily open and alternative safety measures activated
EXAMPLE Exhaust air extraction adjustment, e.g. vertical wire alignment, dielectric flushing adjustment and
visual machining inspection.
ISO 28881:2013(E)
3.21
performance level
PL
discrete level to specify the ability of safety-related parts of control systems to perform a safety function
under reasonably foreseeable conditions
[SOURCE: ISO 13849-1:2006, 3.1.23 — modified.]
3.22
shielding
mechanical barrier or enclosure of conductive material intended to attenuate the emission/penetration
of a varying electro-magnetic field into an assigned region
3.23
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, and where the energy in the
discharge is controlled
Note 1 to entry: The two electrically conductive electrodes are the tool electrode and the workpiece electrode.
3.24
EDM die sinking
removal of material by spark erosion to produce various shapes in the workpiece
Note 1 to entry: Shapes in the workpiece may be concave, convex and prismatic holes.
3.25
EDM drilling
removal of material by spark erosion with a tubular electrode to produce straight holes in the workpiece
3.26
EDM wire cutting
removal of material by spark erosion with a wire electrode to produce prismatic shapes in the workpiece
3.27
work area
space within the envelope of the machine where the EDM process can take place
3.28
workpiece changer
mechanism forming part of the machine to load a workpiece or pallet in exchange for
another workpiece or palette previously unloaded
Note 1 to entry: The workpiece changer/palette changer is designed to enable an operator to load/unload the
workpiece or palette from outside of the work area.
3.29
work tank
unit surrounding the work area to contain the dielectric fluid for EDM processes
6 © ISO 2013 – All rights reserved

ISO 28881:2013(E)
4 List of significant hazards
This clause lists all the significant hazards, hazardous situations and events, as far as they are dealt with
in this International Standard, identified by risk assessment as significant for this type of machinery,
and which require action to eliminate or reduce the risk.
NOTE 1 The purpose of risk assessment is to identify hazards and estimate and evaluate risk to be reduced
and to transfer the remaining risk to the user (see Clause 6). There are many methods and tools available for this
purpose and several are described in this International Standard. The method or tool chosen is largely a matter
of industry, company or personal preference. The choice of a specific method or tool is less important than the
process itself. The benefits of risk assessment come from the discipline of the process rather than the precision
of the results: as long as a systematic approach is taken to get from hazard identification to risk reduction, all the
elements of risk are considered (see ISO/TR 14121-2).
The list of hazards given in Table 1 is the result of a risk assessment carried out for all EDM equipment
covered by this International Standard. The technical measures and information for use in Clauses 5 and
6 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.
NOTE 2 The designer’s attention is focused on hazards which can occur during the life of the machine. The risk
assessment assumes risks to both the operator(s) and other person(s) who can have access to the hazard zone(s)
for conditions of intended use, including reasonably foreseeable misuse of the machine (see ISO 12100:2010,
3.22 and 3.23) for both spark erosion with automatic mode and operations requiring intervention (e.g. setting,
maintenance and repair).
The significant hazards covered by this International Standard are listed in Table 1.
Particular attention is paid to hazards dealing with:
— electrical hazards (electrode voltage);
— flammable dielectric fluid (level, temperature, fire detection);
— hazardous substances (waste disposal, filters, used dielectric fluid, electrodes and sludges);
— electro-magnetic emissions (radiated and conducted); see IEC 61000-6-2 EMC for immunity and
IEC 61000-6-4 EMC for emission.

Table 1 — List of significant hazards and major sources of these hazards
associated with electro-discharge machines
Hazardous
Reference to
a
No. Hazard type situation Activity Danger zone
Table 3
action
1 Mechanical hazards:
Acceleration, decel- A3 to A5
eration (kinetic
energy of elements Movements of machine ele-
Setting, machining At and near the
1.1 in controlled or ments, failure of the control
and maintenance machine
uncontrolled circuit
motion): being run
over, impact
ISO 28881:2013(E)
Table 1 (continued)
Hazardous
Reference to
a
No. Hazard type situation Activity Danger zone
Table 3
action
Loading/unloading, Between clamps and A1, A2, A3
1.2.1 Workpiece clamping
reorienting workpiece
Power-operated, Envelope of work- A1, A2, A3
Cutting parts, sharp 1.2.2 Automatic workpiece/
workpiece/ elec- piece/electrode
1.2 edges: crushing and electrode changing
trode change motion
shearing
1.2.3 Moving parts (e.g. Manual operation/ Between workpiece/ A1, A2, A3, B4
axes, rolling elements), fail- workpiece/electrode electrode and machine
ure of the control circuit change parts
Manual or automatic work- A1, A2, A3, B4
Manual or power-
Moving and/or piece/electrode changing, Between workpiece/
operated workpiece/
1.3 rotating elements: spindle rotation and wire electrode and machine
electrode changing
entanglement rollers rotation, failure of parts
and spindle rotation
the control circuit
Hydraulic/pneumatic A4
High-pressure: fluid systems ejection, leakage, Setting, machining At and near the
1.4
injection or ejection flushing and residual pres- and maintenance machine
sure
Work tanks where A6
Rough, slippery
Ejection or spillage of fluids whole-body access is
surface: slipping, During and after
and lubricants; trailing possible, slippery floor
1.5 tripping and falling machining and main-
floor-mounted or loose con- and high working posi-
of persons (related tenance
nection cables tions; area surround-
to machinery)
ing the machine
Loss of stability: A9
— unbalanced
machine or parts
— inappropri- Machine assembly,
Impact, trapping and/or
ately fixed part of transportation, At and near the
1.6 crushing by inclination
machine installation and machine
and/or falling of machine
commissioning
— lifted machine or
parts by crane
— transportation
with overload
2 Electrical hazards:
Live parts (direct B1, B2
Contact with workpiece/
contact): electrical Process control,
electrode, wire/wire-path Workpiece, electrode,
2.1 shocks to persons, setting and mainte-
and contact with unpro- tooling fixture
effect on medical nance
tected circuits
implants, shock
Parts that become B1, B3
live under fault
Maintenance and At and near the
conditions (indirect Contact with parts of the
service on the gen- machine, insulation of
2.2 contact): electro- machine which are not live
erator and/or the electrical cables and
cution of persons, during normal operation
machine equipment
effect on medical
implants, shock
3 Thermal hazards (not relevant to EDM):
4 Noise hazards:
Manufacturing pro- C1
cess (fluid pumps,
moving and/or Emission of hazard- During operation,
At and in the vicinity
rotating parts, whis- ous noise from the EDM setting, cleaning,
4.1 of the machine or the
tling pneumatics): equipment or its auxiliary maintenance and
auxiliary devices
hearing damage loss devices repair activities
or other physiologi-
cal disturbances
8 © ISO 2013 – All rights reserved

ISO 28881:2013(E)
Table 1 (continued)
Hazardous
Reference to
a
No. Hazard type situation Activity Danger zone
Table 3
action
5 Vibration hazards (not relevant to EDM):
6 Radiation hazards:
Electro-magnetic B4, B5, B6
radiation: effect on
In the vicinity of the
failure of safety- Hazardous radiation imme- During operation of
6.1 machine or the auxil-
related parts of the diately near the work area machine and setting
iary devices
control circuit and
medical implants
7 Materials/substances hazards:
Contact with or Conditions near the During the EDM pro- D1 to D4
inhalation of harm- machine caused by ejection cess, setting, main- At and near the
7.1
ful fluids, gases, of dielectric fluid, droplets tenance and disposal machine
mists and dust or evaporation, mists, etc. of the machine
Fire hazard originated by D4 to D12
flammable gas bubbles or
mist generation, long-
In the work tank, the
lasting arcing condition, During the EDM
7.2 Fire or explosion work area and near
loss of dielectric fluid, fault process
the machine
of electrical or hydraulic
power supply, failure of the
control circuit, etc.
8 Ergonomic hazards:
During loading EN 614-1
Unhealthy posture or
Specific require- and unloading of EN 614-2
excessive effort including
ments resulting electrode or work-
8.1 the design of machines in At operator’s position
from neglect of ergo- piece on the EDM
accordance with ergonomic
nomic principles equipment and EDM
principles
system
9 Hazards associated with the environment in which the machine is used:
Malfunction of the machine B4
itself or electrical equip-
Electro-magnetic
Machine in opera-
ment due to electro-mag-
disturbances: exter- At and in the vicinity
9.1 tion, setting and
netic disturbances, failure
nal influences on of the machine
maintenance
of the control circuit
electrical equipment
10 Combination of hazards:
Malfunction resulting from E1, E2, E3
power loss on the machine
Failure of the exter-
itself and/or electrical/
nal power supply
pneumatic equipment, At the machine and all
and restoration of All activities at the
10.1 powered clamping failures moving elements of
the energy supply machine
and machine elements mov- the machine
after an interrup-
ing and/or rotating under
tion
residual forces (e.g. inertia,
gravity)
a
This list is derived from ISO 12100:2010, Table B.1.
5 Safety requirements and/or protective measures
5.1 General requirements
EDM equipment and EDM systems shall comply with the safety requirements and/or protective measures
and be verified in accordance with this clause. In addition, the equipment and systems shall be designed
ISO 28881:2013(E)
in accordance with the principles of ISO 12100:2010 for relevant, but not significant, hazards, which are
not dealt with by this International Standard.
An analysis of failure of machine components, including failure in the control system(s), is part of the
risk assessment and guidance on this subject is given in ISO 13849-1. Therefore, reliability requirements
for safety functions are defined as performance levels in accordance with ISO 13849-1 (see 5.2).
5.2 Safety-related parts of control systems for EDM equipment and EDM systems
a) Safety-related hardware and software: for the purposes of this International Standard, the safety-
related parts of the control system are the parts of a control system which respond to safety-related
input signals and generate safety-related output signals. The safety-related parts of a control
system start at the point where the safety-related input signals are initiated (including, for example,
the actuator and the actuating system of the position switch) and end at the output of the power
control elements (including, for example, the main contacts of a contactor). Safety functions of
control systems shall be implemented using safety-related parts designed, constructed and applied
in accordance with ISO 13849-1. If the safety function, when activated, initiates a category 2 stop in
accordance with IEC 60204-1:2009, 9.2.2, an automatic monitoring of the category 2 stop is required
to prevent unexpected start-up or axis movement in accordance with ISO 14118.
b) Safety functions: safety-related parts of control systems implementing the safety functions shall
meet the requirements for the performance level and category of ISO 13849-1, as listed in Table 2.
Additional information is given in Annex D.
10 © ISO 2013 – All rights reserved

ISO 28881:2013(E)
Table 2 — Required performance level (PL ) of safety-related parts of
r
the control system for EDM equipment and EDM systems
Reference Required perfor-
[(sub) mance
Reference to Table
Safety functions clause] level,
PL
r
ISO 13849-1:2006
— Movement control by means of hold-to-run control device or 5.3.2.2
PL b A3
r
electronic handwheel
— Movement control with safely monitored reduced speed 5.3.2.2 PL c A3
r
— Interlocking function of movable guards of tool changer/ 5.3.2.2
Cat. 3, PL c A1, A2, A3, B2
r
magazine
— Safe operational stop (SOS) function in accordance with 5.4.1
PL c B6
r
IEC 61800-5-2
— Start, stop and automatic restart function of machining 5.4.1 PL b E3
r
a
— Interlocking function of movable guards of the EDM equip-
Cat. 3, PL c A1, A2, A3, B2
r
ment
5.3.2.2
— Movement control and/or electric machining power control
Cat. 3, PL c A3
r
by means of enabling device
5.3.2.3
— Time limit function for discharge alignment mode 5.3.2.3 PL c A1, A2, A3, B2
r
— Mode selection function 5.3.1 PL c
r
— Emergency stop function 5.4.2 Cat. 3, PL c
r
5.3.2.2
— Enabling device function Cat. 3, PL c A3
r
5.3.2.3
b
— Monitoring function of level and temperature of flammable
PL c D6, D7, D8
r
dielectric fluid
b
— Fire detection function PL c D10
r
a
Interlocking function of movable guards, electro-sensitive protective equipment (ESPE) or other safety equipment of
EDM equipment with hazardous movements and electrical discharge power > 25 V-a.c. or > 60 V-d.c. (using a safety source
in accordance with IEC 61558-1).
b
The fire detection device is a protective measure, complementary to the level and temperature monitoring of flammable
dielectric fluid, to prevent ignition due to human error.
The function of safety-related parts, as specified above, shall be validated by examination of circuit
diagrams and practical checks (see ISO 13849-2).
5.3 Operating modes
5.3.1 Operating mode selection
The selection of the operating mode shall be carried out either using a key switch or equivalent means,
which restrict the use of certain modes to certain operators. If a restriction for operators is required,
an admission code to access the setting mode shall be available (see 6.3.3). 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 and the provision of an indicating light
or visual display indication). Mode changes shall ensure that only one mode is active at any one time in
accordance with ISO 12100:2010, 6.2.11.10, and IEC 60204-1:2009, 9.2.3.
ISO 28881:2013(E)
5.3.2 Protective measures relating to operating modes
5.3.2.1 Automatic mode
Before starting automatic operation, the mode selector shall be in the automatic mode position, the
guard shall be closed and other safety devices shall be in protective conditions (e.g. guard lock and fire
detection device ready where flammable dielectric fluids are used).
5.3.2.2 Setting mode
In the setting mode, the electrical discharge power of parts, which can be touched, shall be limited
to ≤ 25 V a.c. or ≤ 60 V d.c., in accordance with IEC 60204-1:2009, 9.2.4 (using a safety source in accordance
with IEC 61558-1).
The axis movement speed shall be monitored for setting operations (e.g. measuring cycles by touching
the workpiece with a probe or electrode, checking the movement of the workpiece and/or electrode
using the electrode changer and/or workpiece changer, checking/optimizing the injection or suction
flushing and performing a dry run to check the NC program).
With the guards open, the axis speed shall not exceed 2 m/min and shall be monitored (see Table 2). The
axis movement shall be controlled through:
— (hand-operated) hold-to-run control, or
— (hand-operated) enabling device, together with a start button, or
— electronic handwheel.
For movements with axis speed > 2 m/min and ≤ 15 m/min and the guards open, protective measures
shall be available to prevent the operator or other persons having access to the EDM equipment, from
entering with the upper limbs in the work area by:
— hold-to-run control device in conjunction with an enabling device (see Table 2), or
— electronic handwheel, together with an enabling device (see Table 2), or
— means to prevent reaching the danger zone (e.g. light curtain, laser scanner, two-hand control device).
The stop resulting from the release of the enabling device shall be a safe operational stop (SOS) in
accordance with 4.2.3.1 of IEC 61800-5-2:2007. The minimum distance in accordance with ISO 13855
shall be maintained.
For rotating axes with speed up to 50 U/min and
...