EN 847-2:2017
(Main)Tools for woodworking - Safety requirements - Part 2: Requirements for the shank of shank mounted milling tools/circular saw blades
Tools for woodworking - Safety requirements - Part 2: Requirements for the shank of shank mounted milling tools/circular saw blades
This European Standard specifies the determination of the maximum speed for given eccentricity at clamping devices for the shank strength of milling tools with cylindrical and taper shank. It also specifies the marking of the tool. Bore mounted tools which are mounted on an arbor shall be considered as a shank mounted tool.
Maschinen-Werkzeuge für Holzbearbeitung - Sicherheitstechnische Anforderungen - Teil 2: Anforderungen für den Schaft von Fräswerkzeugen/Kreissägeblätter
Outils pour le travail du bois - Prescriptions de sécurité - Partie 2 : Prescriptions pour les queues des fraises à queue
Orodja za obdelavo lesa - Varnostne zahteve - 2. del: Zahteve za držalo rezkalnih orodij
Ta evropski standard določa največje hitrosti za dano ekscentričnost pri vpenjalnih napravah za moč stojala frezal s cilindričnim in stožčastim stojalom. Prav tako določa označevanje orodja. Orodja, ki se pritrdijo v izvrtino in so pritrjena na stojalo, naj bi bila obravnavana kot orodja, pritrjena na stojalo.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2018
1DGRPHãþD
SIST EN 847-2:2014
Orodja za obdelavo lesa - Varnostne zahteve - 2. del: Zahteve za držalo rezkalnih
orodij
Tools for woodworking - Safety requirements - Part 2: Requirements for the shank of
shank mounted milling
Maschinen-Werkzeuge für Holzbearbeitung - Sicherheitstechnische Anforderungen - Teil
2: Anforderungen für den Schaft von Fräswerkzeugen/Kreissägeblätter
Outils pour le travail du bois - Prescriptions de sécurité - Partie 2 : Prescriptions pour les
queues des fraises à queue
Ta slovenski standard je istoveten z: EN 847-2:2017
ICS:
25.100.20 Orodja za frezanje Milling tools
79.120.10 Lesnoobdelovalni stroji Woodworking machines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 847-2
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2017
EUROPÄISCHE NORM
ICS 79.120.10 Supersedes EN 847-2:2013
English Version
Tools for woodworking - Safety requirements - Part 2:
Requirements for the shank of shank mounted milling
tools/circular saw blades
Outils pour le travail du bois - Prescriptions de sécurité Maschinen-Werkzeuge für Holzbearbeitung -
- Partie 2 : Prescriptions pour les queues des fraises à Sicherheitstechnische Anforderungen - Teil 2:
queue Anforderungen für den Schaft von
Fräswerkzeugen/Kreissägeblätter
This European Standard was approved by CEN on 21 August 2017.
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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 847-2:2017 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 List of significant hazards . 6
5 Safety requirements . 6
5.1 General requirements for cylindrical shank . 6
5.2 Stability of the shank of shank mounted tools . 7
5.3 Stability of HSK mounted tools . 13
6 Marking of tools with cylindrical shank . 15
Annex A (informative) Examples of calculation . 17
A.1 Example of calculation of n . 17
shank
A.2 Examples of calculations of n . 18
HSK
Annex B (normative) Method of measuring the eccentricity at clamping devices . 19
Annex C (informative) Recommended minimum clamping forces . 20
Bibliography . 21
European foreword
This document (EN 847-2:2017) has been prepared by Technical Committee CEN/TC 142
“Woodworking machines - Safety”, the secretariat of which is held by UNI.
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 May 2018, and conflicting national standards shall be
withdrawn at the latest by May 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 847-2:2013.
According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Introduction
The content of this European Standard is aimed at eliminating hazards which can lead to overloading of
the shank of shank mounted milling tools for woodworking by excessive rotational speeds.
1 Scope
This European Standard specifies the determination of the maximum speed for given eccentricity at
clamping devices for the shank strength of milling tools with cylindrical and taper shank. It also
specifies the marking of the tool. Bore mounted tools e.g. milling tools, circular saw blades which are
mounted on an arbor should be considered as a shank mounted tool.
This European Standard complements EN 847-1:2017 and applies also for shank tools with a cutting
diameter of less than 16 mm.
This European Standard is not applicable for shanks of tools according to this scope, which are
manufactured before the date of its publication.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 847-1:2017, Tools for woodworking — Safety requirements — Part 1: Milling tools, circular saw
blades
EN ISO 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk
reduction (ISO 12100:2010)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 847-1:2017 and the following
apply.
3.1
7/24 shank
SK
type of tool holder with a 7/24 cone ratio taper
3.2
hollow taper shank
HSK
type of tool holder with a short hollow taper with high positioning accuracy and high grade of rigidity
that contacts the spindle on two surfaces
3.3
arbor
device to be mounted on the machine spindle interface and which is designed to carry bore type cutting
tools
4 List of significant hazards
Table 1 shows the list of significant hazards.
Table 1 — List of significant hazards
Hazard according to Condition or causes of Corresponding clause of
hazard related to the tool EN 847–2
EN ISO 12100:2010
Mechanical hazards due to:
Breaking of the tool 5
Inadequacy of mechanical strength
Vibration Dynamic unbalance of tool 5
Variations in the rotational speed of
Breaking of the tool 5
tools
5 Safety requirements
5.1 General requirements for cylindrical shank
The minimum value for the clamping length l shall be as given in Table 2.
e min
Table 2 — Minimum clamping length l
e min
d ≤ 10 mm 10 mm < d < 25 mm d ≥ 25 mm
2 2 2
l = 20 mm l = 2 ⋅ d (mm) l = 1,8 ⋅ d (mm)
e min e min 2 e min 2
The tolerance of the shank diameter d shall be h6 for d ≥ 12 mm and h8 for d < 12 mm.
2 2 2
5.2 Stability of the shank of shank mounted tools
5.2.1 General
For descriptions of symbols for the stability of the shank of shank mounted tools, see Table 3.
Table 3 — Stability of the shank of shank mounted tools — Symbols and units
Symbol Description Unit
diameter
a) shank diameter d
d mm
b) cone diameter d
c) with axial force: d (calculated); without axial force: d
4 arbor
d maximum diameter of the cutting part mm
cut
shank diameter, see Figure 2 mm
d
d cone diameter, see Figure 3 mm
calculated hub diameter, see Figure 4 mm
d
d shank diameter of the arbor, see Figure 4 mm
arbor
− 2
E modulus of elasticity of the shank material N mm
maximum permissible eccentricity at clamping device mm
e
sp
f form factor —
f safety factor (f = 4) —
s s
axial clamping force, see Figure 4 N
F
a
balance quality grade of the tool set (individual tools, arbor, spacers, HSK):
− 1
G product of the permissible eccentricity and the angular velocity according to EN 847– mm s
1:2017
I second moment of area mm
height of cutting part mm
l
cut
l free shank length mm
l , l , l , . axial distance of the gravity centre of the mass m , m , m , . mm
1 2 3 1 2 3
axial distance of gravity centre, see Figure 1 mm
l
s
l clamping length mm
e
total length of shank mm
l
g
m , m , m , . mass of the parts of the tool set, see Figure 1 g
1 2 3
m mass of the cutting part in the area of l , see Figure 2 g
cut cut
m* mass of the tool in the area (l + l ) g
0 cut
m * reduced mass of the cutting part, see Figure 2 g
cut
− 1
n operational speed min
− 1
n maximum permissible rotational speed with regard to shank strength min
shank
S centre of gravity —
W section modulus mm
− 2
σ fatigue strength under reversed bending stresses of shank material N mm
w
− 3
ρ density of material (e.g. shank, tool body, spacers) g mm
The maximum permissible rotational speed of shank mounted tools n shall be calculated referring
shank
to the shank strength.
For calculation of n with a given e the following formula applies:
shank sp
W ⋅ W ⋅ ⋅ l
σ σ
s
2 w w 6
− G + + ⋅ + ⋅
G e 10
sp
*
3 ⋅ E ⋅ I
⋅ l
m
s
(1)
= ⋅
n
shank
f ⋅ π
l
s W ⋅ ⋅
σ
s
w
+
e
sp
3 ⋅ E ⋅ I
with
d
I = π⋅ (2)
d
W π⋅ (3)
For balance quality, see EN 847-1:2017.
Better balance quality grades for tools or tool sets may be applied, if these can be permanently
maintained due to the tool design.
NOTE 1 The safety requirements for the shank strength are fulfilled when, using the given tool sizes and
material characteristics with defined free shank length l , gravity centre displacement e and eccentricity at
0 per
clamping device e , the maximum permissible rotational speed for the shank n is not exceeded during
sp shank
operation. The cutting force is not significant in comparison with the centrifugal force. Therefore, the cutting force
has not been taken into account.
For the determination of the maximum rotational speed n of shank mounted tools the lower value of
max
either
- n (maximum speed value for the shank strength) and
shank
- n (strength against centrifugal force in accordance with EN 847-1:2017)
max
shall be considered.
NOTE 2 If the value of the axial distance of gravity centre l is unknown, l can be determined approximately
s s
according to the example as shown in Figure 1 and Formula (4).
=
Figure 1 — Distances of the gravity centres of the tool components
m ⋅ l + m ⋅ l + m ⋅ l + m ⋅ l + m ⋅ l + m ⋅ l + m ⋅ l
1 1 2 2 3 3 4 4 5 5 6 6 7 7
l = (4)
s
m + m + m + m + m + m + m
1 2 3 4 5 6 7
5.2.2 Cutting tools with cylindrical shank
For cutting tools with cylindrical shank the maximum permissible rotational speed n shall be
shank
calculated referring to the shank strength in the mounted position in a clamping device with quantities
and units as shown in Figure 2 and Table 3.
Key
a axis of rotation
Figure 2 — Quantities for calculation of n referring to the shank strength
shank
NOTE 1 d = d2 (see Formula (2) and 3)
e = 0,06 mm for clamping devices in CNC machines.
sp
e = 0,1 mm for clamping devices in hand-held power tools.
sp
Smaller values for e than 0,06 mm are possible, if the determined value (according to Annex B)
sp
maintains throughout the service life of the clamping device.
If the value of m* is unknown, for those tools using material of the same density for shank and body of
the cutting part m* can be determined a
...
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