Control Static on Winding Rolls - AIMCAL · Control Static on Winding Rolls 24/19 In your “mind’s eye,” draw a dot the web below the fieldmeter. The dot becomes the center of

Control Static on Winding Rolls 1/19

Control Static on Winding Rolls

Kelly Robinson, PE, PhD


Speaker IntroductionKelly Robinson, PE, PhD, Owner – Electrostatic Answers LLC

[email protected] • www.ElectrostaticAnswers.com

• Business Owner - Founded Electrostatic Answers, an engineering consulting company dedicated to eliminating injury and waste from static electricity.

• Industrial Experience – working over 25 years solving static problems in web conveyance and solvent handling manufacturing operations.

• Award Winning EngineerUS Nat’l Fire Protection Assoc. (NFPA), Member - Static Electricity CommitteeIEEE Fellow - “for contributions to electrostatic performance of mfg. processes” Electrostatics Society of America - Distinguished Service AwardAIMCAL - John Matteucci Award, excellence in technical presentationsPhD Electrical Engineering - Colorado State University

• Inventor with 14 US patents.

• Associate Editor for the Journal of Electrostatics, a leading peer reviewed technical journal (Elsevier publication)

• Contributing Editor, Paper Film & Foil Converter, author of “Static Beat” column on static control.

mailto:[email protected]

http://www.electrostaticanswers.com/


Agenda1. Introduction – Static sparks:

1) ignite flammable solvents,2) shock people and machine control systems,3) cause sheets to stick and jam, and4) damage products.

2. Net Charge1) High Static on winding rolls.2) Best Practice Charge Control

3. Balanced Charge1) High Static on winding rolls.2) Best Practice Charge Control3) Diagnosing balanced charge

4. Summary



1. Introduction

2. Prevent shocks to operators.1. Eliminate ignitions.

3. Prevent static problemsin customer applications(sheet sticking, process jams).


Release liner

PSA Label

Product Application

Static sparks can damage the silicone release liner causing release failure

(PSA label sticks to support).

1.4 Introduction

Image courtesy of






4. Summary



2.1 Net Charge

This typical winder has:(1) tension control nip(2) a dancer to control

the winder motor, &(3) a lay-on roller.

Dancer / Float Roller

Tension control nip

Lay-on roller

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN

EROLL

2 electrostatic fieldmeter measurements characterize winder static performance: (1) ESPAN & (2) EROLL

MP

P


2.1 Net Charge


Tension control nip

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = +3 KV/cm

EROLL =+15 KV/cm

MP

P

+

+

+

+ +

+

++

+

+

+

+

Static charges from tension control nip (top side)

+

The winding roll accumulates all of the static charges on the web entering the winding roll.

Gapped roller


2.2 Best Practice Charge Control


Tension control nip

Gapped roller

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = 0 KV/cm

EROLL ≅0 KV/cm

MP

P+

Best Practice: Install active static bar SB1 on the web span exiting the tension control nip facing the web surface that touched the polymer nip roller.

SB1

SB2?

Could we skip SB1

& just install static bar SB2

on the winding roll?


2.2 Poor Charge Control


Tension control nip

Top side

Bottom side

3 Winding roll stores large

amounts of static!

Incoming web is

charge-free

ESPAN = +3 KV/cm

EROLL ≅0 KV/cm

MP

P

+

+

+

+ +

+

++

+

+

+

+


+


Gapped roller

SB2(Bad!)

‒

1 Static charges from tension control nip

(inside surface)

‒

2 Neutralizing charges

(outside surface)

‒

‒+‒

+‒

+‒


2.1 Net Charge


Tension control nip

Lay-on roller

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = 0 KV/cm

EROLL =‒15 KV/cm

MP

P+

The lay-on roller deposits static charges on the outside surface of the winding roll.

‒‒ ‒

‒

‒

‒‒

‒

Static charges from lay-on roller

(bot side)

SB1




Tension control nip

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = 0 KV/cm

EROLL =0 KV/cm

MP

+

‒

SB1

SB2

Best Practice: Install active static bar SB2 to dissipate static on the outside surface of the winding roll.

Lay-on roller






4. Summary



3.1 Balanced Charge


Tension control nip

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = +3 KV/cm

EROLL =+15 KV/cm

MP

P

+

+

+

+ +

+

++

+

+

+

+


+


Gapped roller


3.1 Balanced Charge


Tension control nip

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = 0 KV/cm

EROLL =‒15 KV/cm

MP

P

+

+

+

+ +

++ +

+

+


+

Diagnose balanced charge by measuring ESPAN and EROLL with the lay-on roller gapped away from the winding roll.

SB1

‒

‒‒‒

‒

‒‒‒

‒

‒

‒

‒‒

+++

‒‒

+‒‒

Gapped roller

(wrong side!)




Tension control nip

Gapped roller

Top side

Bottom side

Winding roll

Incoming web is

charge-free

ESPAN = 0 KV/cm

EROLL =0 KV/cm

MP

P+

Best Practice: Install active static bar SB1 on the web span exiting the tension control nip facing the web surface that touched the polymer nip roller.

SB1


3.3 Diagnosing Balanced Charge


Tension control nip

Gapped roller

Top side

Bottom side

Winding roll

Incoming web has balanced charge

ESPAN = 0 KV/cm

EROLL =‒10 KV/cm

MP

P+

SB1 is correctly installed. ESPAN is nearly 0. EROLL is high.The incoming web has balanced charge. An upstream static dissipator

is likely installed facing the wrong web surface.

SB1

+‒

+‒

+‒

+‒

++ +

+++

‒

‒‒

‒

‒

‒


Summary

1. Introduction – Static sparks:1) ignite flammable solvents,2) shock people and machine control systems,3) cause sheets to stick and jam, and4) damage products.





Questions?Kelly Robinson, PE, PhD, IEEE Fellow

Owner, Electrostatic AnswersTel: 585-425-8158

[email protected]

THANK-YOU!Comments?


Triboelectric Series


Triboelectric Series


Tribocharging

By Sei This vector image was created with Inkscape. - Own work, CC BY-SA 3.0,https://commons.wikimedia.org/w/index.php?curid=5505464

Chemical structure of poly dimthyl siloxane (PDMS),the repeat unit of silicone rubber


Measure Static - Fieldmeter

Common industry

standard for acceptably low static:

KV/cm KV/in KV/10 cm

E < ±2 (KV/cm) = ± 5 (KV/in) = ± 20 KV/(10 cm)


In your “mind’s eye,” draw a dot the web below the fieldmeter. The dot becomes the center of a sphere that expands to just touch your hand.

For reliable readings, all nearby conducting objects must be outside the sphere.

Web

Gap G

Center of a sphere that expands to just touch your hand.

#1 #2

For reliable readings, all nearby conducting

objects must be outside the sphere.

Fieldmeter

Electrostatic Fieldmeter (work horse for diagnosing and solving static problems)


ElectricField

+ + + + + + ++ + + + + + + +

2TOP mCoulombsσ

2BOTTOM mCoulombsσ

Control Volume

EFloor


The electrostatic fieldmeter responds to the total amount of charge in the control volume.

E α ( σTOP + σBOTTOM )A5


ElectricField

+ + + + + + ++ + + + + + + +

2TOP mCoulombsσ

2BOTTOM mCoulombsσ

Control Volume

SurfaceArea A

EFloor

qsdEε Enclosed

SurfaceCV

0 =⋅∫∫

( )AσσA Eε BottomTop0 +=

( ) Eεσσ 0BottomTop =+

( ) cmKVE

mμCσσ 22BottomTop

≈

+



Measure Static - Voltmeter

Surface voltage are typically in the range ±200 V = ±0.2 KV.

V (Volts) Range: ± 3,000 V

Response time: 3 mS

V (Volts) Range: ± 3,000 V

Response time: 50 µS


Electrostatic Voltmeter (Use to verify which web surface is charged.)

Web

Chargedsurface

Chargedsurface

– – –

Staticcharge

+ +

Electrostatic voltmeter

Measures balanced charge

A1

+–

–

–

–

+

+

+

+


Plastic or insulating paper sheet+ + + + + + + + + + +

How much chargeis on the surfaceof this sheet?

VSURFACE

non-contacting electrostaticvoltmeter probe

SURFACES VACσ

AQ

==

SURFACES Vdεσ

=

SURFACECVQ =

d

permittivity εmaterial property

Measure Static - Voltmeter


– – – ––

+

+ + + +

A6

Machine frame

Web

Neutralsurface

Chargedsurface

– – – – –

Staticcharge

Electricfield

Staticdissipater

– ––

–+–

+++ +

Ions generated by static dissipater

A static dissipater is located to neutralize a charged web.

Static Dissipators


Neutralization is complete after the motion of the ions stops.

Machine frame

Web

Neutralsurface

Previously chargedsurface

Staticdissipater

– ––

–+–

+++ +

Ions generated by static dissipater

– –– – +–+ ++ +

Static Dissipators

Control Static on Winding Rolls 32/19A6

Machine frame

Web

Chargedsurface

Neutralsurface

– – – – –Static

charges

Static dissipater

– ––

–+–

+++ +

Ions generated by staticdissipater

– – – ––

+

+ + + +

Electricfield

A static dissipater is located to neutralize a charged web.

Static Dissipators


Neutralization is incomplete because the web is electrically insulating.

Machine frame

Web

Chargedsurface

Neutralsurface

– – – – –

Staticcharges

Staticdissipater

– ––

–+–

+++ +

Ions generated by staticdissipater

++ + + +

Electricfield

Static Dissipators

Documents

Control Static on Winding Rolls - AIMCAL · Control Static on Winding Rolls 24/19 In your “mind’s eye,” draw a dot the web below the fieldmeter. The dot becomes the center of