Standardisation of Ink Transfer for converting corrugated paper board

Measuring Ink Transfer according to FCO305 and understanding how this impacts on your print performance and ink costs

By David Parr

Pamarco

5-11-2015

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What Corrugated Convertors want?

Consistent print quality Reduction of defects, downtime &

costs Global Standardisation of print

performance

GOOD INK TRANSFER IS ESSENTIAL

TO ACHEIVE THESE GOALS

WHY IS INK TRANSFER IMPORTANT

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Defects caused by Ink transfer problems:

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Transferring the correct amount of ink

WHY IS INK TRANSFER IMPORTANT

Eliminates Defects Controls print consistency

Improves press performance Reduces Waste, Controls costs

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Press Variables:

INKING SYSTEM, 2 roll or doctor bladed

PRESS SPEED, 3000 or 22000 SPH

IMPRESSION, kiss or heavy pressure

Print component Variables:

ANILOX, specification & cell profile

PLATES, hardness, thickness, cushioning

INKS, density, viscosity, water addition

PAPER: Roughness and absorbancy

VARIABLES AFFECTING INK TRANSFER

Test variables to understand

biggest impact on INK TRANSFER

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PRINTING PLATE

ANILOX

PAPER BOARD

DOCTOR ROLL

INK

More Ink transferred, less controllable

Lower Ink transferred, more consistent

FLEXO PRINTED

BOARD

PRINTING PLATE

DOCTOR BLADE

PAPER BOARD

ANILOX INK

FLEXO PRINTED BOARD

10 µm

10 µm

Y µm ?

FEFCO FC 0305: INK TRANSFER

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Ink transfer:

Weight of ink applied to board, every print repeat

Relative Ink Transfer:

How much ink at start of print process vs how much Ink on board surface

Ink film thickness on board substrate/Anilox Ink film thickness

% IFT = IFT on Paper board x 100% IFT on Anilox

Anilox Cell Volume (cm3/m2) = IFT on Anilox (µm) Weight of ink on board (grams) = IFT on Paper Board (µm)

MEASURING INK TRANSFER

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Accurate weigh scale:

Weigh ink loss after every print repeat

20.000 Kg

FLEXO PRINTED

BOARD

19.995 Kg

MEASURING INK TRANSFER

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1: Press with known anilox and ink weights

10 µm

Weight of ink

5000 g

2000 boards

FLEXO PRINTED

BOARD

IFT BOARD

2.5 µm

IFT BOARD: 2.5 µm

IFT ANILOX: 10 µm

Ink Transfer = 25%

IFT ANILOX

2: Print and measure ink per board

3: Calculate ink transfer for known variables

20.000 Kg 15.000 Kg

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VARIABLES ASSESSED

3 PRINT UNITS: All Doctor blade chamber

60 degree

Hexagonal

75 degree

EFlo

ANILOX, Screens 100, 160 & 320 L/cm, IFT 5 & 10 um

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PRESS SPEED: 3500 & 7000 SPH

IMPRESSION: Kiss pressure only

VARIABLES ASSESSED

PLATES: full & half tone,

single col & wet-on-wet

INKS: high & low density,

0, 10 & 20% water

PAPER BOARD: Kraft & Semi-coated

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ANALYSING INK TRANSFER (FC0305)

Ink to fill

chamber

Print run

Water added

to ink

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6 print tests, 40 variables

10,000 sheets of board

60,000 data measurements

SUMMARY

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Press Speed & Inks:

HIGH DENSITY INKS: Press speed has little impact on ink transfer

LOW DENSITY INKS: Higher speeds = reduced ink transfer

WATER ADDITION: Increases ink transfer but massive reduction in colour

Anilox & Paper Board:

ANILOX: Extended EFlo cells give best Ink Transfer

PAPER BOARD: Has highest impact in relation to all other variables

INK TRANSFER RESULTS

Ink transfer:

Values stayed in range 12 to 35% for all tests

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Ink transfer:

12 to 35% of ink is transferred to the paper

65 to 88% stays in the inking system

Paper Board:

The minimum amount of ink to be transferred is dictated by THE PAPER BOARD

Anilox:

Choosing the wrong anilox specification for the paper, will result in either

OVER inking = waste of ink & print defects

UNDER inking = poor print coverage, defects & waste

INK TRANSFER CONCLUSIONS

Select Anilox for the Paper Board

Control the unused Ink

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Test/Recycled

Kraft Liners Coated Liners

Anilox to Paper Standards

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CONTROLLING THE UNUSED INK

Cost annually €24,000 - €40,000

Ink loss during Colour Changes (FC 0306):

8,000 per year per press

Cost of ink €1.5 to €2.5 per kg

Average Ink lost on colour change: 2 kg

Back doctoring / Blade, End seal & pipe leakage:

Wrong doctor angle, dirty anilox

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CONTROLLING THE UN-USED INK

ASYMMETRIC CHAMBERS Control Back Doctoring & Leakage

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CONTROLLING THE UNUSED INK

INK-SAVE Returns 80% of Ink during changes

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What Corrugated Convertors want?

Consistent print quality Reduction of defects, downtime &

costs Global Standardisation of print

performance

UNDERSTAND & OPTIMISE

INK TRANSFER

THANK YOU

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