Calibracion par dinamico

8/9/2019 Calibracion par dinamico

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Calibration of torque tools


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1 INTRODUCTION ................................................................................2

2 WHAT IS CALIBRATION? ........................................................... 3-5

2.1 Why do we need calibration and determining of capability? ......3

2.2 How does calibration differ from service? ..................................5

3 CREDIBILITY OF RESULTS ........................................................ 6-9

3.1 Traceability of measuring equipment ..........................................6

3.2 Conditions for performing calibration .........................................7 3.3 Measurement uncertainty .............................................................8

3.4 Calibration certicate.................................................................. 9

4 ACCREDITED AND NON-ACCREDITED CALIBRATION ... 10-12

4.1 Why use accredited calibration? ................................................10

4.2 Rules for performing calibration ..........................................11-12

5 ADVANTAGES OF THE ATLAS COPCO LABORATORY ......13-17

5.1 Who are Atlas Copco? ......................................................... 13-14

5.2 Services provided ................................................................. 14-16

5.3 Contact ....................................................................................... 17

6 APPENDIXES .............................................................................. 18-22

Atlas Copco s.r.o. accreditation certicate and appendix ......... 18-19 Sample calibration certicate

3-point calibration of a rise-and-fall pendant ..................................20

ISO 9001, ISO 14001 certicates...............................................21-22

Contents

CALIBRATION OF HAND TORQUE TOOLS 1


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Using calibration services for torque tools, torque transducers

and torque measuring tools (collectively torque measuringequipment) signicantly contributes to compliance with

prescribed parameters in all technical activities that require

reliable tightening results. Increasing product safety requirements

for are especially important in the automotive industry, but are

also applied in assembly and other industrial elds.

The purpose of this publication is to provide information onthe importance of accredited calibration services for torque

measuring equipment. It presents the work provided by

calibration laboratories and the range of information provided

on calibrated devices to their users. The publication also explains

important concepts associated with the work of calibration

laboratories.

1. Introduction

Fig. 1 Sample use of a hand

torque tool.

2 CALIBRATION OF HAND TORQUE TOOLS


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2.1 Why do we need calibration and

determining of capability?

Services for torque measuring equipment include maintenance

and repair, as well as equipment adjustment. These services are

needed wherever it is necessary to monitor the parameters of tight-

ening tools. A good service organization will provide adjustments

to meet the users requirements (and according the knowledge of

its employees). However, this service is no substitute for independ-

ent, impartial assessment of the equipments ability to achieve the

required results.

A direct request for independent accredited calibration and deter-

mining of capability may arise from a customers quality manage-

ment system certication. Chapter 7.6 of ISO 9001 refers to cali-

bration of measuring equipment according to standards associated

with national or international standards. The stricter ISO/TS 16949

standard, in chapter 7.6.3.2, demands that a calibration laboratory

be directly accredited according to ISO/IEC 17025 (although it

also allows for other forms of verication of a laboratorys capa-

bilities).

2. What is calibration?

Fig. 2 Mobile equipment for testing

hand torque tools.



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The quality cost of badly performing tools

Badly

performing

tool reported

by the

employee

Quality control

detects that the

joint is wrong

10

???

???

1000

100

Final inspection

detects that theassembly is wrong

Expense of

warranty repairCustomer detects that

the assembly is wrong

Losses mounttenfold

Lets hope that the

rest are OK!

On a properly working tool, a sensor measures tightening torque at 25 Nm,where ~24.8 Nm is the set torque and ~0.2 Nm is the friction on the gearsand joints.

During work, the set torque gradually changes, but the sensor still shows25 Nm. If internal friction reaches 5 Nm, the tool will tighten only to 20 Nm.

Are your tools really adjusted right?

25Nm or 20Nm?

SensorGears

Bearings

What problems can calibration detect?

Electric and pneumatic wrenchesand screwdrivers (Gear wear)

Variance

(3)

Number of tightenings (Worn angle and planetary gears)

Tools live longer with regular preventative maintenance.

x x

70% max. tightening torque

Tool set to maximum

tightening torque

Gear replacement needed

Failure


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2.2 How does calibration differ from service?

Torque tools, torque transducers and torque measuring devices

are calibrated by a calibration laboratory within the scope

specied in a valid accreditation certicate, or more precisely

in its appendix. For accredited calibration (see chapter 4), the

calibration laboratory is bound by specic rules, and violation of

them can result in revocation of the laboratorys accreditation. The

calibration laboratorys customer can be sure that an auditor and

a professional expert conduct strict inspections of the laboratory

employees activities. The customer can also submit a complaint

regarding the laboratorys activities, and complaint resolution is

the object of special attention by the supervisory authority.

A calibration laboratorys management system involves a

number of monitoring instruments. These include upgrading

employees qualications, inspection of the technical equipment

used, managing disputes and taking systematic measures, all

the way to internal audits conducted by a qualied employee.

The basic difference between adjustment in a service context

and calibration of torque tools is the reliability and credibility

of the parameters required when using the tools.

Fig. 3 Sample equipment for

testing dynamic torque tools.



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3.2 Conditions for performing calibration

A laboratorys activities include calibration conducted under

laboratory conditions and calibration conducted externally on

the customers premises. Monitored values include the ambient

temperature and humidity. For this monitoring, the laboratory has

barometers and thermometers calibrated at accredited calibration

laboratories. The standard environmental condition for obtaining

proper measuring results is a temperature between 18C and 28C

(preferably between 20C and 22C) and a maximum of 90%

humidity. The temperature during calibration must be recorded.

If, during measurement, there is a deviation of more than 1C,

measurement must be repeated. If the customer denes different

temperature conditions for using calibrated measuring equipment,

the uncertainty must be adjusted. Based on the manufacturers

data, the uncertainty caused by the temperature difference during

calibration and ordinary use must also be added.

To obtain reliable results, treatment of the calibrated equipment is also

essential.

In laboratory calibration, equipment is inspected upon receipt. (An

ineligible equipment cannot be accepted for calibration and is sent for

service or returned to the customer.) Throughout the process, thorough

marking and monitoring of the course of the activities are ensured.

For calibration on the customers premises, the equipment is inspected

and accepted for calibration, but the customer is responsible for its

condition.

If there is any damage to the tool, the situation is recorded, the

customer is immediately informed, and after evaluation, corrective

action is taken.



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3.3 Measurement uncertainty

The appendix to the laboratory accreditation certicate species

the BMC value (Best Measurement Capability). Why is this data

important? It gives the minimum percentage of the measured

value by which a calibration result can vary under standard

conditions.

For judging the level of the laboratory, it is also essential to

take into account the contribution of the standard (wtcm) to the

uncertainty. In such a case, during calibration the calculation

methodology allows assessment not only of deviations in the

equipment themselves, but in the entire chain (from the torque

converter to the imaging unit). It also allows assessment of

the equipment ability to work within the context of deviations

ascertained.

Data on measurement uncertainty (also including deviations in

the standard) are included on the calibration certicate.

To achieve reliable calibration results, it is best to use specialized

calculation software, which undergoes annual testing and

inspection by the accreditation authority.


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3.4 Calibration certifcate

A calibration certicate is a list of results of calibration performed.

It guarantees adherence to the approach and accreditation rules

during calibration. The data on the calibration certicate provide

specically achieved values, but it does not assess whether a

customers required parameters have been achieved. Calibration

laboratory employees cannot monitor the conditions under which

the calibrated equipment is used, and in many cases they dont know

the customers specications. The information in the calibration

certicate must allow the customer to make a qualied judgement

as to whether the equipment used fulls his requirements.

Upon customer request, a professionally qualied laboratory

employee can provide an expert opinion on the calibration results.

This statement is not a product of the accredited laboratorys

activities.

Fig. 5 Sample calibration

certifcate.



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4.1 Why use accredited calibration?

What are the main differences between accredited and non-

accredited calibration?

The procedures for conducting accredited calibration and for

calculating the deviation and uncertainty of measurement are

regularly veried by auditors and specialists of the accreditation

authority. The laboratorys employees must pass repeated training

in torque measuring equipment calibration and metrological

regulations. However, also important is the system of equipment

traceability for verifying a calibrated tools compliance with

the dened parameters, or standards. The customer delivers the

torque measuring equipment to the calibration laboratory trusting

that the stability and precision of the tightening processs results

will be reliably veried. How is the reliability of non-accredited

calibration ensured? It is based on the customers trust in the

reliability of the equipment at the laboratory he uses. However,

this reliability is not independently veried and is not based on

4. Accredited andnon-accredited calibration

Fig. 6 Calibration of precise

equipment (torque transducers), as

dynamic also stationary.


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a rm methodology for implementing the calibration conditions,

for evaluating measurement or determining uncertainty.

Accreditation cannot be replaced with any form of certication

or other calibration laboratory authorization. Certication

according to ISO 9001, for example, shows a laboratorys ability

to meet its obligations, but it is no indication of technological

reliability. Certication especially does not verify the correctness

of the approach for calculating the reliability and precision of the

results of measurements conducted in the laboratory. It does not

even include the procedures for testing a laboratorys capabilities,

or so-called inter-laboratory comparison (comparing the results

achieved by various accredited calibration labs).

Credibility is enhanced by direct monitoring of the calibration

labs activities by auditors from the accreditation authority in

the labs place of operation and by evaluation of calibrations

conducted in operation (called witness auditing), for external

calibrations, on the laboratory customers premises.

4.2 Rules for performing calibration

The difference between service adjustments to torque tools and

calibration is dened procedures and parameters - standardiza-

tion. The basic standard for assessing conformity - the capabilities

of the accredited calibration laboratory - is international standard

EN ISO/IEC 17025. Technical requirements for calibrating hand

torque tools are dened by standard EN ISO 6789. Methods of

determining, calculating and expressing measurement uncer-

tainty are dened by EA 4/02. EA 10/14 is a manual published

by European Accreditation for calibrating torque measurement

equipment. International standard ISO 5393 describes Perform-

ance test method of Rotary tools for threaded fasteners.



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The entire calibration eld is also subject to the requirements of

national laws on metrology. When providing services abroad,

a calibration laboratory must provide its employees with the

metrological legislation of the country where the customer

operates. In some countries, the national metrological authorities

make information on legal requirements available on the

Internet.

To get the right results when conducting calibration (even for non-

accredited calibration), it is essential to have proper calibration

procedures and internal methodologies that are maintained in

practice. Step by step, calibration procedures for specic types

of equipment determine the approach to performing calibration.

They start with stabilizing the equipments temperature, and

continue with inspecting it, actual measurement and recording

the calibration and labelling the equioment. The calibration

methodology is an essential internal document specifying the

conditions for performing calibration, the general principles for

all calibration procedures, the method for evaluating measurement

and determining measurement uncertainty, and the calibration

certicate requirements.

All documents must be accessible to the customer on demand.

The right calibration procedure is chosen during the actual

ordering phase for calibration services. For this reason even the

qualications of sales employees are essential. They must be

informed enough to support the customer in choosing the right

calibration procedure.


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5.1 Who are Atlas Copco?

Atlas Copco is a group of industrial companies with worldwide

leadership in the eld of compressors, construction and mining

vehicles, pneumatic tools and assembly systems. In industrial

tools, it is a world leader, setting trends in the eld.

The Atlas Copco group delivers sustainable solutions for

increasing its customers productivity through innovative

products and services. The company was founded in 1873 and

is headquartered in Stockholm, Sweden. Around the world, Atlas

Copco is represented in more than 170 countries and had 30,000

employees in 2009. In industrial tool calibration, it can therefore

use its knowledge from production. It has access to precise

technical information and specications and the latest ndings

from research and development.

Atlas Copcos accredited calibration laboratory operates in several

countries of Europe, and North and South America. This allows

international knowledge exchange among laboratories accredited

under the same accreditation standards, ISO/IEC 17025. However,

their experience and national conditions differ. The groups

organizational structure allows clear establishment of independent

calibration laboratories, emphasizing the monitoring mechanisms

of the companys information system.

The Atlas Copco calibration laboratory is accredited by the

Czech Accreditation Institute, o.p.s. It has offered its services

since 2007 and operates in Central and Eastern Europe. Inclusion

5. Advantages of theAtlas Copco laboratory



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of accreditation approval under international agreements on

recognizing accreditation (EA MLA and ILAC MRA) allows

publication of calibration certicate without regard to workshop

location.

The range of activities is not tied only to Atlas Copco brand tools.

We also use our calibration experience with tools of other brands.

The important thing is to comply with the scope of calibration

specied in the appendix to the accreditation certicate.

Atlas Copco also provides its customers with Internet access to

its specialized calibration database. There anyone can check

the calibration dates of their tools, and the associated data. If

the customer is connected to this database, he is automatically

informed ahead of time of his tools calibration deadline.

5.2 Services provided

Angle calibration

For equipment capable of measuring the angle of screw rotation

during tightening, ITS can conduct inspection and non-accredited

calibration of the rotation angle, including settings.

Other Atlas Copco services

Atlas Copco and its sister service company Industrial Tools Service

(ITS) can provide you with a full range of services for industrial

tools of various brands and assembly applications.

You can choose from one of our various service programs. They

can be further adapted to your needs and requirements.

ITS service representatives (see paragraph 5.3) can discuss and

propose optimal service programs based on the customers own

needs.


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More than 60 specialists in industrial tool and application services

in all regions of Eastern Europe are then ready to full the

customers requests.

Full Coverage Service

You can delegate all your service needs to ITS, who will choose

the best preventive maintenance plan and provide a full range of

services (repairs, calibration) for your tools for xed costs.

This program provides the following advantages:

- less production downtime, higher productivity

- consistently high production quality

- a xed service budget with no surprise expenses - lower administrative and production costs

- less need for investment in inventories of replacement parts

and backup equipments

It allows customers to concentrate fully on increasing production

efciency.

ToolScan RCM Reliability Centered Maintenance

This program establishes an optimal system of preventive or

predictive maintenance tailored to the customers needs and

requirements. It can be part of Full Service Coverage. The

program ensures that the systems user can be sure that it will

work the way its user demands it to, without irregular, unexpected

interruptions and breakdowns. It allows the customer to optimize

production processes and minimize manufacturing interruptions

or slowdowns while lowering administrative costs.

Preventive maintenance

This program allows users to keep their industrial tools at top

performance. As a service partner, ITS can provide preventive

maintenance that ensures maximum reliability while maintaining

tools stable high performance. The program allows users to plan a



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large portion of their necessary service activities for manufacturing

downtimes, thus minimizing production line breakdowns.

Fixed-price repairs

This program allows fast repairs while decreasing administrative

costs. Tools receive priority repair service based on a system

previously agreed upon between the user and ITS. Transport to

the service centre and back is handled with special service boxes.

Full-service repairs at ITS ensure maximal life and performance

for repaired tools. After repair, the tools are tested according to

ITS global standards.

Training, consulting services and installation of assembly

systems

ITS provides a full range of training and consulting services

for tightening technology, ergonomics and pneumatic and

electronically operated industrial tools and systems. ITS also

performs installation (including all necessary documentation) and

modication of industrial applications.

Advantages of Atlas Copco calibration and ITS maintenanceservices

- Preventive maintenance is performed along with tool and

equipment calibration.

- Part of calibration of ordinary tools is their adjustment

according manufacturer specications.

- ITS and Atlas Copco perform services during customer

downtime (such as weekends).

- Calibration services can be part of a Full Service Program

that includes a complete range of services.

- ITS is a part of the worldwide Atlas Copco network and

is therefore integrated into the supply system of all important

industrial manufacturers.


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5.3 Contact

For more information about offerings from the Atlas Copco s.r.o.

accredited calibration laboratory and other ITS-services, please,

contact your local from the following representatives:

Tomasz Biernat...............................................western Poland

Tel: +48 510 025 974, email: [email protected]

Krzysztof Karolak........................................... eastern Poland


David Tydlitat................................................Czech Republic


Martin Krynsk......................................Moravia & Slovakia


Csongor Tomos ..........................................................Hungary


Remus Cosmin Stangu............................ Romania, Bulgaria


For more information, visit www.its-ee.com.



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6. Appendixes

original

translation of original


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NOTES


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NOTES


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CustomerCentreEasternEurope2011

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