Abab Ink jet in the PCB industry An introduction

ab

Ink jet

in the PCB industry

An introduction

Eric Janssens May 2013

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Inkjet: definition

Inkjet:

generation of images by propelling droplets of

a functional material onto a substrate


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Inkjet: thermal propelling

An ink is pumped in the pressure chamberAn electrical heater generates steamThe increased pressure jets a droplet from the chamber onto

the substrate

Cheap, slow, difficult to control well, need of aqueous inksUsed in consumer printers


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Inkjet: piezo-electical propelling

A piezoelectric crystal generates a shock wave in an ink chamber, jetting a droplet out of the chamber onto the substrate

Ink is to be cured by UV light (UV inks) or by cooling down (phase shift inks)

More expensive, fast, good control, wide variety of inks

Used in commercial and industrial printers


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Inkjet: continous propelling

A high pressure pump generates a constant flow of charged ink droplets. The droplets can be deflected from the substrate by a electrical field

Matured technology, long traveling distance, no nozzle clogging

Used in industrial printers (marking).


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Inkjet: functional material

1 Aqueous inks:Water, glycol and dye or pigment

Dye: cheap, colors fadePigment: long term, UV resistant

Cheap, receiving layer needed on substrate

2 Solvent inks (hard and mild or eco)Volatile organic compounds (VOCs) and pigmentsCan print on vinyl

3 UV inksAcrylic monomers and initiatorAfter printing ink is cured by UV-light (pinning the droplet)Can be applied on uncoated substrates, very robust imageExpensive, require expensive curing moduleImage may crack


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Inkjet: substrate

The right propelling technology with the right functional material can print on:• Paper• Paper (with micro porous layer)• Wall paper• Coated paper• Card board• Textile (canvas, T-shirts)• Stone and tiles• Packaging materials• Plastics (vinyl)• Aluminum (cans, blisters)• Copper (PCB)• ………


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Inkjet: Heads: Good to know

Nozzle:• Pipe, channel that directs an ink droplet• Also called: droplet generation unit, propelling unit, orifice

Resolution• Figure indicating the number of nozzles per inch• Typical: 360, 720, 1440 DPI

Drop size• Figure indicating the content of one droplet expressed in pL (pico

liter)• 1 liter = 1 000 000 000 000 (1012) pL• 1 000 000 pl weights 1 mg, • Typical: 80, 40, 14, 4, 1 pL


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Inkjet: Heads: Good to know

Dots per droplet• One droplet can be formed by several dots (shots)• These dots conglomerate during flight to form one

droplet• Typical: 1 to 8

ManufacturesBrother, Cannon, Dimatix (ex Spectra) (part of

Fujifilm), Epson, Konica Minolta, Kyocera, Ricoh, Toshiba-Tech, Xaar


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Inkjet: UV Inks: Good to know

Dynamic viscosity (jetability):• Resistance of a fluid to be deformed• Also "thickness“

- water is "thin“, low viscosity- honey is "thick", high viscosity.

• The study of viscosity is known as rheology• Expressed in Pas (Pascal sec) / mPas or cPoise• Typical: 5 – 15 mPas

Static surface tension (line sharpness)• Measurement of the capacity of a liquid to form a ball

when in contact with another surface• Expressed in N/m (Newton per meter) / mN/m• Typical: 20-25 mPas

The Dynamic viscosity is varying with changing temperature


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Specific weight• Weight per volume unit• Expressed in kg/m3 / g/cm3

• Typical: 1 – 1,25 g/cm3

Average particel size:• Size of the particles in the ink• Expressed in m / nm• Typical: 250 – 500 nm

Latency:• Time a nozzle can be idle without getting clogged


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Adhesion

Scratch resistance

Shelf life

Color and color fading• Dyes - pigments

Price (per liter, per cassette)

….

Manufactures:HP,Sun Chemicals, Cabot, Avecia, Agfa, Sericol,Taiyo,

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Inkjet: Printers: Good to know

Print quality Resolution Repeatability Speed Foot print Flat bed / drum Price (purchase, operation, maintenance, … ) ….Manufactures:

Agfa, Canon, First EIE, Epson, HP Kodak, Lexmark, Microcraft, Orbotech, Ricoh, Xerox, ….


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Inkjet: Wave form

Piezoelectric.avi


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Inkjet: Cleaning mechanisms

The primary cause of problems:

when ink sedimentates, hardens or particles size grows in the print head's nozzles they get blocked (clogging)

Solutions:

Covering the print head nozzles with a rubber cap

Suction pump

A mechanism to reapply moisture to the print head.

Frequent spraying and wipe print head

The frequent cleaning can consume quite a bit of ink

and has an impact on the cost


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Traditional Workflow

PatterningResist (IL & OL)

Solder mask

Legend print


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Workflow Inner Layer

Traditional

InkJetProvisional

InkJetFinal

LDI & PI


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Workflow Outer Layer

Traditional

InkJet Provisional

InkJet Final


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Workflow Solder Mask

Traditional

InkJet Provisional

InkJet Final


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Workflow Legend

Design

Plotter film

Dev & fix film

Produce Screen

Screen print

Clean screen

Design

Print

Traditional

InkJet Final


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Long term

Inkjet:

conductors, insulators, solder mask, legend ink,

hole filler, conformal coatings,

optical conductor, surface finishing, solder paste,

…..

reel to reel


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And

ab


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Agfa holds good cards

Agfa Materials:• Market leader AgX phototooling

- Good in-road in the PCB industry

- WW sales & application organization

- WW logistical organization

Agfa Graphics• Strong in Ink Jet technology and inks

Agfa Materials Technology Center:• Top lab that creates functional fluids

Agfa Material Operations• World class functional fluid production facilities


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Printer Coatings

Test platforms(multi color)

INKS

Your application

and printing system

Jetting lab(single color)

Agfa Materials Technology Centre Functional fluid development


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Agfa Materials Technology Centre Functional fluid development

Jetting performanceJetting reliabilityLatency

Shelf life

Physical Properties- adhesion- flexibility- scratch resistance- tackiness- ……

Pigment dispersion

Photo initiationAcrylates

Wetting agent

Image qualityCure speedImage permanence

Compatible with: - printer components - production facility - packaging - safety & environment regulations - patent situation

…..Raw material costManufacturability


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Agfa Materials Technology Centre

Functional fluid development


Agfa

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Agfa Materials Operations


Agfa

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Agfa Materials Operations


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Inkjet & the PCB industry

Inkjet technology reached a level

it is applicable

in the production of PCB’s

a competitive way with good yields

ab is dedicated to transform

from #1 in phototooling

to # 1 in patterning

Documents

Abab Ink jet in the PCB industry An introduction