Control Static on Winding Rolls

Transcription

1 Control Static on Winding Rolls Kelly Robinson, E, hd Control Static on Winding Rolls 1/19

2 Speaker Introduction Kelly Robinson, E, hd, Owner Electrostatic Answers LLC 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 Engineer US Nat l Fire rotection Assoc. (NFA), Member - Static Electricity Committee IEEE Fellow - for contributions to electrostatic performance of mfg. processes Electrostatics Society of America - Distinguished Service Award AIMCAL - John Matteucci Award, excellence in technical presentations hd 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, aper Film & Foil Converter, author of Static Beat column on static control. Control Static on Winding Rolls 2/19

3 Control Static on Winding Rolls Agenda 1. Introduction Static sparks: 1) ignite flammable solvents, 2) shock people and machine control systems, 3) cause sheets to stick and jam, and 4) damage products. 2. Net Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3. Balanced Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3) Diagnosing balanced charge 4. Summary Control Static on Winding Rolls 3/19

4 1. Introduction 1. Eliminate ignitions. 2. revent shocks to operators. 3. revent static problems in customer applications (sheet sticking, process jams). Control Static on Winding Rolls 4/19

5 1.4 Introduction Static sparks can damage the silicone release liner causing release failure (SA label sticks to support). roduct Application SA Label Image courtesy of Release liner Control Static on Winding Rolls 5/19

6 Control Static on Winding Rolls Agenda 1. Introduction Static sparks: 1) ignite flammable solvents, 2) shock people and machine control systems, 3) cause sheets to stick and jam, and 4) damage products. 2. Net Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3. Balanced Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3) Diagnosing balanced charge 4. Summary Control Static on Winding Rolls 6/19

7 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. Incoming web is charge-free Top Dancer / Float Roller M E SAN Winding roll E ROLL Bottom Tension control nip Lay-on roller 2 electrostatic fieldmeter measurements characterize winder static performance: (1) E SAN & (2) E ROLL Control Static on Winding Rolls 7/19

8 2.1 Net Charge Static charges from tension control nip (top ) Incoming web is charge-free Top Dancer / Float Roller E SAN = 3 KV/cm M Winding roll E ROLL = 15 KV/cm Bottom Tension control nip Gapped roller The winding roll accumulates all of the static charges on the web entering the winding roll. Control Static on Winding Rolls 8/19

9 2.2 Best ractice Charge Control Dancer / Float Roller E SAN = 0 KV/cm Incoming web is charge-free Top Bottom SB1 M Tension control nip Gapped roller SB2? Winding roll E ROLL 0 KV/cm Could we skip SB1 & just install static bar SB2 on the winding roll? Best ractice: Install active static bar SB1 on the web span exiting the tension control nip facing the web surface that touched the polymer nip roller. Control Static on Winding Rolls 9/19

10 Static charges from tension control nip (top ) Incoming web is charge-free 2.2 oor Charge Control Top Bottom Dancer / Float Roller M Tension control nip E SAN = 3 KV/cm Gapped roller 3 Winding roll stores large amounts of static! E ROLL 0 KV/cm Control Static on Winding Rolls 10/19 The winding roll accumulates all of the static charges on the web entering the winding roll. 1 Static charges from tension control nip (in surface) SB2 (Bad!) 2 Neutralizing charges (out surface)

11 2.1 Net Charge Dancer / Float Roller E SAN = 0 KV/cm Incoming web is charge-free Top SB1 M Winding roll E ROLL = 15 KV/cm Bottom Tension control nip Lay-on roller The lay-on roller deposits static charges on the out surface of the winding roll. Static charges from lay-on roller (bot ) Control Static on Winding Rolls 11/19

12 2.2 Best ractice Charge Control Dancer / Float Roller E SAN = 0 KV/cm Incoming web is charge-free Top SB1 M Lay-on roller SB2 Winding roll E ROLL = 0 KV/cm Bottom Tension control nip Best ractice: Install active static bar SB2 to dissipate static on the out surface of the winding roll. Control Static on Winding Rolls 12/19

13 Control Static on Winding Rolls Agenda 1. Introduction Static sparks: 1) ignite flammable solvents, 2) shock people and machine control systems, 3) cause sheets to stick and jam, and 4) damage products. 2. Net Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3. Balanced Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3) Diagnosing balanced charge 4. Summary Control Static on Winding Rolls 13/19

14 3.1 Balanced Charge Static charges from tension control nip (top ) Incoming web is charge-free Top Dancer / Float Roller E SAN = 3 KV/cm M Winding roll E ROLL = 15 KV/cm Bottom Tension control nip Gapped roller The winding roll accumulates all of the static charges on the web entering the winding roll. Control Static on Winding Rolls 14/19

15 3.1 Balanced Charge Static charges from tension control nip (top ) Incoming web is charge-free Top Dancer / Float Roller M SB1 (wrong!) E SAN = 0 KV/cm Winding roll E ROLL = 15 KV/cm Bottom Tension control nip Gapped roller Diagnose balanced charge by measuring E SAN and E ROLL with the lay-on roller gapped away from the winding roll. Control Static on Winding Rolls 15/19

16 3.2 Best ractice Charge Control Dancer / Float Roller E SAN = 0 KV/cm Incoming web is charge-free Top SB1 M Winding roll E ROLL = 0 KV/cm Bottom Tension control nip Gapped roller Best ractice: Install active static bar SB1 on the web span exiting the tension control nip facing the web surface that touched the polymer nip roller. Control Static on Winding Rolls 16/19

17 3.3 Diagnosing Balanced Charge Dancer / Float Roller E SAN = 0 KV/cm Incoming web has balanced charge Top SB1 M Winding roll E ROLL = 10 KV/cm Bottom Tension control nip Gapped roller SB1 is correctly installed. E SAN is nearly 0. E ROLL is high. The incoming web has balanced charge. An upstream static dissipator is likely installed facing the wrong web surface. Control Static on Winding Rolls 17/19

18 Control Static on Winding Rolls Summary 1. Introduction Static sparks: 1) ignite flammable solvents, 2) shock people and machine control systems, 3) cause sheets to stick and jam, and 4) damage products. 2. Net Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3. Balanced Charge 1) High Static on winding rolls. 2) Best ractice Charge Control 3) Diagnosing balanced charge Control Static on Winding Rolls 18/19

19 THANK-YOU! Questions? Comments? Kelly Robinson, E, hd, IEEE Fellow Owner, Electrostatic Answers Tel: Control Static on Winding Rolls 19/19

20 Triboelectric Series Control Static on Winding Rolls 20/19

21 Triboelectric Series Control Static on Winding Rolls 21/19

22 Tribocharging Chemical structure of poly dimthyl siloxane (DMS), the repeat unit of silicone rubber By Sei This vector image was created with Inkscape. - Own work, CC BY-SA 3.0, Control Static on Winding Rolls 22/19

23 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) Control Static on Winding Rolls 23/19

24 Electrostatic Fieldmeter (work horse for diagnosing and solving static problems) Web Fieldmeter Gap G #1 #2 Center of a sphere that expands to just touch your hand. For reliable readings, all nearby conducting objects must be out the sphere. 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 out the sphere. Control Static on Winding Rolls 24/19

25 Measure Static - Fieldmeter σ TO Coulombs m 2 Control Volume σ BOTTOM Coulombs m 2 Floor Electric Field E A5 The electrostatic fieldmeter responds to the total amount of charge in the control volume. E α ( σ TO σ BOTTOM ) Control Static on Winding Rolls 25/19

26 Measure Static - Fieldmeter σ TO Coulombs m 2 Surface Area A σ BOTTOM Coulombs m 2 Control Volume Floor Electric Field E ε ( σ ) ε 0 E ds = CV Surface 0 E A = Top q Enclosed ( σ σ )A ( σ ) Bottom σ Bottom ε 0E Top = μc 2 m KV E cm σtop Bottom 2 Control Static on Winding Rolls 26/19

27 Measure Static - Voltmeter V (Volts) Range: ± 3,000 V Response time: 50 µs V (Volts) Range: ± 3,000 V Response time: 3 ms Surface voltage are typically in the range ±200 V = ±0.2 KV. Control Static on Winding Rolls 27/19

28 Electrostatic Voltmeter (Use to verify which web surface is charged.) Charged surface Web Charged surface Static charge Electrostatic voltmeter Measures balanced charge A1 Control Static on Winding Rolls 28/19

29 Measure Static - Voltmeter Q = CV SURFACE V SURFACE Q A = σ C = A S V SURFACE How much charge is on the surface of this sheet? non-contacting electrostatic voltmeter probe σ ε = d S V SURFACE lastic or insulating paper sheet d permittivity ε material property Control Static on Winding Rolls 29/19

30 Static Dissipators A static dissipater is located to neutralize a charged web. Ions generated by static dissipater Charged surface Web Machine frame Electric field Static dissipater Static charge A6 Neutral surface Control Static on Winding Rolls 30/19

31 Static Dissipators Neutralization is complete after the motion of the ions stops. Ions generated by static dissipater reviously charged surface Web Machine frame Static dissipater Neutral surface Control Static on Winding Rolls 31/19

32 Static Dissipators A static dissipater is located to neutralize a charged web. Ions generated by static dissipater Machine frame Static dissipater Neutral surface Electric field A6 Charged surface Web Static charges Control Static on Winding Rolls 32/19

33 Static Dissipators Neutralization is incomplete because the web is electrically insulating. Ions generated by static dissipater Machine frame Static dissipater Neutral surface Web Electric field Charged surface Static charges Control Static on Winding Rolls 33/19