Better performance in roll systems by applying specific ... · Better performance in roll systems...

© PRÜFTECHNIK Group – A Company Profile Page 1

Pascal Locoge – PARALIGN and Machinery Service Manager at PRÜFTECHNIK Condition MonitoringDr. Edwin Becker – Head of Service Center at PRÜFTECHNIK Condition Monitoring

Better performance in roll systems by applying specific geometric measurement techniques

AIMCAL 2017 - München


PRÜFTECHNIK Condition Monitoring GmbH

Development and production of measurement systems for machine alignment, machine monitoring and service in the areas of industrial maintenance and quality assurance.Firmensitz: Ismaning bei München Laser - Vibration analyzer – Inertial devices

14 subsidiaries and over 70 distributors worldwide300 patents and 150 trademarks

Founded in 1972 by Dieter Busch

Member of the PRÜFTECHNIK group with over 550 employees worldwideHomepage: www.pruftechnik.com


Content

• Motivations and goals.• Failure mode and effects analysis (FMEA) Definition• FMEA Procedure• Applied an FMEA to metallizing, laminating and coating equipment − Structure analysis − Function analysis − Failure mode analysis − Risk assessment and risk reduction

• Practical example from the field.• Conclusions


Motivation and goals


Using Failure Mode and Effects and Criticality Analysis (FMEA) on laminating roller asset shows that application-specific procedure is required for the rolls / machines alignment.

It is by evaluating the possibilities/chances and the limits of each different measurement methods that the correct measurement technology for interventions can be determined.

Only with the right methodology / method we can increase not only the process qualities, but also reduce the vibration level and the stresses of the working rolls.

Motivations and goals


Definition of the FMEA


FME(C)A = Failure Mode Effects Analysis (and Criticality ). The FMEA is often the first step of a system reliability assessment.

FMEA is an analytical method used to systematically detect possible component failures and estimate of the associated risks and resultant effects on system operations, in order to reduce the risks or avoid errors.

The type of FMEA depends of the application field and the type of object to be analyzed. FMEA is used to analyzes processes and / or products.

Definition of the FME(C)A

Type System-FMEA

Focus FMEA for process FMEA for product

Goal Identification of potential weaknesses in processes and process flows

Identification of potential weaknesses in the interaction of subsystems within the overall system

Application E.g. Safety procedure in paper production

E.g. Uncertainties in product quality


FMEA Procedures


FMEA Procedures

1. Structure analysisDecomposition of the system to be analyzed, identification of subsystems to be considered

2. Function analysisDistribution of the functions and characteristics of each structural element

3. Failure mode analysisCause of failure – Failure identification (image) - effect of failure

4. Risk assessmentAssessment of the current system condition by experts

5. Risk reductionIdentify measures for improving the system condition


Applied an FMEA to a coating equipment for extremely thin foils made of copper, up to 6 µm


Dissolve the system structure into system elements and functionalities Level 1: Overall system Level 2: Foundations, upper strand, lower strand,

housing/structure Level 3: Rolls (components) Level 4: Elements of the components , bearing, cylinders, …

Step 1 : Structure analysis

Level 1

Level 2

Level 3

Level 4


Interaction of several system elements = Function structure Functions are assigned to each structure element Result: functional tree, function block diagrams Benefits: overview, selection of critical structures and interfaces, basis for the next failure

analysis, recognition of potential improvement

Step 2 : Function analysis


Interaction of several system elements = Function structure Functions are assigned to each structure element Result: functional tree, function block diagrams Benefits: overview, selection of critical structures and interfaces, basis for the next failure

analysis, recognition of potential improvement

Step 3 : Failure mode analysis

Failure causeRoll misalignment

Failure identificationWrong product displacementnon sysmetric product extension

Failure consequenceQuality problem with other

consequences ($)


Causes and risk assessment using Key figures : Key figures: Risk Priority Number RPZ = A * B * E A: Probability of the failure occurrence (Probability of occurrence or frequency). B: Severity of the failure (The worst consequences of a failure mode) E: Detection of the failure (Probability that the failure can be detect)

Step 4 : Risk assessment

Source: Book QM-Methoden, C. Brückner, TU-Berlin


Application-specific description and classification of the assessment variables:


Occurence / Probability

Severity Detection Lower limit Upper limit

Unlikely (No knownoccurrences )

Not Relevant Very high 1

Remote, isolatedcases– relativelyfew failures

Very minor, only consequences in a maintenance action

High 2 3

Often Lifetime impacted Ok 4 6

Regularly Lifetime reduced Low 7 8

Permanent , almost inevitable

Damage the asset Very low 9 10


Risk Priority Number RPN = A * B * E

Legende Risk Priority


Risk AssessmentRPN Classes

Lower limit Upper limitVery Low 1 60Low 61 90Middle 91 125High 126 200Very high > 200


Case study paper machine: Prevention action for band damage on the basis of tape skew by rolls misalignment.To define the E number, we considered the following parameters: Accuracy of the measurement, Operator educated required level, Measurement Speed, (how many rolls per hours with report) Rolls accessibility, visual access to the Rolls, possibility to measure all or part of the rolls.


System Function Failures causes

A Failureconsequences

B Detection method / Measurement systems

E RPN

Coating rollsasset (up to 6 µm)

Copper foil treatment

Tape skew because of rolls misalignment 3 Band damage in

a corrosive bath 8

Water level/measurementtape/cord/Visual Laser system 10 240

Theodolite / Total station 8 192

ProRoll 7 168

LEVALIGN Expert 6 144

Laser Tracker 4 96

PARALIGN 3 72

Rollalign (Combination of PARALIGN and LEVALIGN Expert)

1 24


The issues in this case studies are : The available time to measure and correct, The possibility to measure the rolls in the upper part, not

visible from outside and without any possibility to measure directly in horizontal and vertical.

If the metal foil machine is measured with theodolites, the RPN is 192

The risk number can be reduced from 192 to 72 if a Gyroscopic measurement method like PARALIGN is used.

Since the lower series of rollers with PARALIGN are not accessible/visible in coating systems, ROLLALIGN must be used in order to achieve further risk reduction up to 24.



ROLLALIGN is a new PRÜFTECHNIK method where the proven gyroscopic technology of PARALIGN is combined with the laser SENSALIGN (5 axes sensor) technology to achieve fast and precise roll parallelism even in complex assets.

This method combine the accuracy and measurement speed of the gyroscopic technology of PARALIGN with a 5 axes Sensor and a leveled rotating laser. This combination give the possibility to link an entire machine to a non Roll reference, like a reference line on a floor/wall, in a very short time (classical planned production stop 8h)

+

Practical example –what is the method ROLLALIGN


Step 1: Check the quality of the reference line with a self leveled rotating laser and select only the reliable points for measurement.

Step 2: Determine the position of one roll to the reference line with laser. Step 3: Optional, mostly used on new asset, measure the “parallelogram” failure by

measuring distance of the Roll (middle)/Frames difference to the reference line. Step 4: Measure the entire machine with gyroscopic method (PARALIGN), the

gyroscopic PARALIGN method allows a quick measurement of the rolls parallelism

Step 5: Provide the entire machine report to the reference line


60 to 120 Rolls /day depends of the machine and accessibility


Practical examples


Measure the parallelism of the rolls and correct the alignment within a planned downtime break (8 to 16 Hours). The lower rolls are not accessible with a gyroscopic or optical method. Only the rotating axes after the bearing can be measured with a 5 Axes sensors.

Practical example 1 – Laminated Copper treatment asset


A temporary reference line is create on the side of the machine. ( )

A gyroscopic method (PARALIGN) is used to measure the 21 upper rolls and the rewinder/winder within 90 minutes.The Rotating laser is used to measure the lower rolls and the rewinders to the temporary reference line (about 3 Hours).


Lower rolls, not visible

Upper rolls, all visible and directly accessible

Temporary reference line set up on the machine side

Rewinder rollWinder roll


In this case, the customer had his coating bloc align with a Theodolite, using the coating rolls as reference to the reference line on the floor. In the following weeks, he notice a strong tension on the operator side, a wave “design” on the machine side and the rubber roll shows an irregular wear (not more cylindrical).

The customer ask us to perform a control. Goal was to find any geometric failures and to check if the reference line is still representative for the asset or not, in a very short time. Here also is the FMEA helping us to choose the best measurement solution

Practical example 2 – Aluminium Coating Asset

System Function Failures causes

A Failureconsequences

B Detection method / Measurement systems

E RPN

Coating rollsasset

Aluminium foil coating

Rolls misalignment or bad reference line

3

Asymmetric (side) tension within the coating bloc. Irregular wear ofthe rubber roll.Lite waves were visible on the product on machines side

8

Water level/measurementtape/cord/Visual Laser system 10 240

Theodolit / Total station 8 192

ProRoll 7 168

LEVALIGN Expert 6 144

Laser Tracker 4 96

PARALIGN 3 72

Rollalign 1 24


PARALIGN is used to measure the asset rolls (3 Hours were enough to get the report)

As found : All rolls are aligned within the coating bloc. But the coating bloc is misaligned with the rest of the asset (about 4 mm over 2 m)

Practical example 2 – Coating Asset


LEVALIGN Expert and a 5 axes sensor are used to measure the position of the rolls to the reference line (15 minutes). One roll need to be measured. This definitively shows that the coating bloc is not aligned with the reference line (about 4 mm / 2 m) while the other rolls are aligned within about 0,5 mm / 2 m with the reference line.



After the correction of the coating bloc, the measurement of the upper coating roll with PARALIGN is enough to show that the entire machine is now aligned.In addition, the reference line is qualify for further alignment.

The main benefits of the ROLLALIGN method are: To give misalignment and correction values within a short time, To prove that the reference line is still a good reference for this machine.



The use of application-specific and suitable geometric measurement techniques improve the recognition of certain geometric failures. The benefit is a significant reduction in the risk priority numbers.

Conclusion


Thank you AIMCAL

Pascal [email protected]

www.pruftechnik.com

mailto:[email protected]

Date post:	04-Aug-2020
Category:	Documents
Upload:	others
View:	0 times
Download:	0 times

Better performance in roll systems by applying specific ... · Better performance in roll systems...

Documents