DD-DOC 0111 - General Guidelines for Screen Printing on Flat Glass

8/21/2019 DD-DOC 0111 - General Guidelines for Screen Printing on Flat Glass

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General Guidelines for Screen Printing On Flat Glass

Typical appl icat ions cover appl iance, automotive and architectural glass

KeyElements

Variables Characteristics Guidelines Comments

ARTWORK Film PositiveQuality

Film must be clean, void of marks, greasystains, scratches or other blemishes suchas ‘static spots’

Poor artwork is the single largest cause ofpoor print quality

Image

Image output must be solid of the correctdensity, complete image(s) intact,geometrically accurate in representationwith no appearance of distortion, moiré orbanding

Printing can never better the original—onlyequal it at best

EdgeResolution

If necessary, re-output the film at a higher

DPI if edge quality of image is not smoothor there is evidence of moiré/banding (seeabove)

Check with imagesetter supplier for furtherresolution and density recommendations

Accuracy

If printing more than one color, checkregistration accuracy between the set offilms

Films shrink due to environment changeswhich can cause registration problems later

ALTERNATIVE

IMAGING

TECHNIQUES

Computerization

CTS and Direct

Projection

A variety of Computer-To-Screen andDirect Projection systems offer alternativeimaging techniques that do not require filmpositives and perhaps other processing

steps employed in conventional screenmaking. Follow system’s guidelines closelyfor optimal error-free results.

Check image for unacceptable serratededges, as well as moiré with monotone or

process work and banding with vignettes(dot gradations).

SCREEN Frame

Type

‘Stretch & Glue’ and ‘Self -tensioning’ arethe two main types of frame systemscommonly used for glass printing

Stretch and glue frames are lighter, morecost effective and practical forauto/architectural glass

Self-tensioning frames are a more practicalconsideration for appliance/white goodsdue to close-tolerance multicolorregistration requirements


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KeyElements


SCREEN

(Continued)

Frame(Continued)

Size

Image size should ideally not exceed 65%of the inside of the frame for architecturalglass

50% for automotive glass

40% for appliance and other smaller formatsizes

Percentage recommendations may not bepossible in all situations

Allow as much space as possible fromsqueegee to inside frame for good ink well

(see separate entry)Consider equipment and other possiblelimitations

Ink Well

Ensure there is a healthy space largeenough for the squeegee and floodbar toclear the image at either end to prevent inkfrom seeping back into the open imagearea

Ink seepage due to insufficient clearancewill cause potential rejects particularly withetched or frosted coatings

Tubing

Tubing/section size should be based onoverall frame size and desired tension

levels

Consult with fabric and screen supplier for

optimum recommendations

Construction

For extra large screens for architecturalapplications, consider having cornergussets and prebowed

Gussets reduce corner warpage andprevents cracking

Prebow reduces inward deflection underhigh tensions and helps maintain tension

Flatness All four corners should lay flat on the printtable without any signs of warpage

Do not use if the frame doesn’t clamp downflat as the image may distort as well asother problems

Squareness Corners squared 90º An out of square frame can potentially leadto registration and distortion problems


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KeyElements


SCREEN

(Cont inued) Frame(Cont inued)

Standardization

Keep frame sizes to a minimum to reduceadjustments and set up times, particularlywith architectural applications

Consider a universal master frame holderto accept various frame sizes forarchitectural applications

Determine one frame size (maximum) forappliance and automotive jobs and nomore than three for architectural (S, M andL for example)

A master frame holder can significantlyreduce setup/changeover times (havingtwo sets: one on press and the otherprepared offline for next job)

Fabric / MeshType

Monofilament polyester

Stainless steel

Nylon

Low elongation polyester is the mostcommon mesh type used for glass printing

Stainless steel is good for conductivitypurposes

Mesh Count

Effects ink consumption, ink deposit,opacity, screen tension, screen life amongother factors

Consider particle size when selecting,particularly for fine line images andcharacters (see Aperture on next page)

Higher mesh counts (TPI/TPC) providesbetter image detail to be reproduced

Typical mesh counts used for glass printingwith inorganic enamels are:

- Appliances: 86 – 380 Threads Per Inch(TPI)/34 – 150 Threads Per Centimeter(TPC)

- Automotive: 140 – 305 TPI/55 – 120 TPC

- Architectural: 74 – 255 TPI/29 – 100 TPC

Printing mediums other than ceramic frit,

such as other types of inorganic, organic,

elastomeric, solvent-/water-based or UV

(ultra-violet) may require different meshcounts, processing and handling—refer

specifically to supplier’s mesh

recommendations and processing

procedures as well as those of the ink

coating manufacturer


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KeyElements


SCREEN

(Cont inued) Fabric / Mesh(Cont inued)

ThreadDiameter

Effects how ink flows to edge of stencil

Best to use thinnest thread possible forsmall dots, fine lines and graduations

Thinner thread results in less resistance toprint

Thicker thread is prevalent for glassprinting due to the aggressiveness of theceramic frit

Thinner threads typically deposit more

enamel and provide better resolution andoverall print detail

Aperture

Aperture or physical opening size shouldideally be at least 3 – 4 times greater insize than the largest particles contained inthe ink

Aperture can be increased or decreased insize by selecting a thinner or thicker threaddiameter

POA(Percentage Open

Area)

POA is a useful guide to determine howreceptive ink will transfer to the glasssurface in comparison to other fabricgrades

Higher POA requires less squeegeepressure and wear while permitting higherprinting speed

POA is determined by thread count anddiameter

Mesh Color(dyed)

As opposed to white, dyed mesh impactsquality and edge sharpness of the stencilimage

Yellow or orange mesh provides betterresolution and definition than white

White mesh is cost effective for non-demanding applications such as f lood/openscreens

Dyed fabrics are best to use for allphotographically reproduced imagesregardless of pattern


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KeyElements


SCREEN


Tension

Screens should have enough tension toallow for a clean separation from the glasssurface immediately behind the squeegee

during the print stroke with minimum off-contact

Follow fabric supplier’s recommendedtension level for each fabric grade, usuallyaround level I for automotive andarchitectural and level II for whitegoods/small format intricate jobs

Smaller screens withstand higher tensionlevels than their larger cousins

Tension should be uniform within theimage area, checked in five places (center

and four corners) in both directions withsmall screens, and consider up to nineplaces for very large architectural screens

While each fabric grade has its owndesirable tension level, how straightforwardor demanding the job is needs to be takeninto consideration too

Higher tension screens will increaseproductivity, quality and yield

If screen making is outsourced, establishminimum ‘shipping’ tension for each fabrictype based on recommendations, asopposed to when it is received, sometimesreferred to as ‘shipping’ or ‘transit loss’

Consistent print results and superiorcoating uniformity can only come about

with close tension consistency regardlessof tension level or screen size

Stretching

Follow stretching equipment’s proceduresfor rapid tension

Fabric stretched at a bias angle for glassprinting is generally not required so fabric

ought to be glued linearly better than 1%angle to the screen frame

Fabric should ideally be held pneumaticallyat the desired tension level consistently for30 minutes prior to gluing

If stretching is outsourced, discussmethodology to gain best results forassured quality and consistency

Methodology behind the 30-minute rule isto prevent screens from weakening tooquickly from repeated use, therebyextending their durability and useful life


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KeyElements


SCREEN


Preparation

All newly stretched fabric needs to bedegreased so that it’s surface is clean andslightly abraded to promote better adhesionof the stencil

Cleaned screen should ideally be dried inan enclosed area or cabinet void ofcollecting dust particles and must becompletely dried/moisture-free beforebeing coated

Procedure and treatment techniquesinvolved are according to film or emulsionused

If stretching screens for storage purposes,clean and degrease screens within 24hours of coating and exposing

TestScreens

Screens made for samples and testingpurposes should have the exact samefabric grade and tension level that is usedin actual production regardless of whatthey may be

Production can better match printedsamples, deposit thickness, color andopacity/translucency when both screensare made to the same specifications exceptfor size

Emulsion or

Rest Period

When stretching has been completed,allow at least 24 hours - 48 hours beforecoating for reorientation of the fibers (this iswhen the long side of large screens areforced to bow in the center)

Rest period will help to prevent lines ordots at the outer edge of the imagedeveloping a curve, if the frame bowsalong its length, as well as improving close-tolerance registration

Stencil Film

Type

While there are numerous types available,they basically comprise of two groupsaccording to enamel’s chemistry: solvent-resistant or water-resistant

Select emulsion type based on type of inksystem to be used, being mindful that thescreen may not be used with all types ofprinting ink

Application

For capillary film application, followmanufacturer’s processingrecommendations

For emulsion coating, one or more coatingstrokes are required to encapsulate themesh

Full encapsulation is necessary to provideintegrity for maximum durability


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SCREEN

(Cont inued) Emulsion orStencil Film(Continued)

Thickness

EOM (emulsion over mesh) on thesubstrate side should be kept below 10

microns with coating recipes pre-programmed if using an automatic coatingmachine

Following supplier’s recommendation toattain mesh encapsulation, which mayrequire several test screens to achieve theobjective

For superior quality image detail, EOMshould ideally be between 4 – 8 microns

depending on emulsion type

Thinner EOM is recommended for fine dotsand lines as it reduces the unsightly ‘thick-edge’ appearance

Thickness has no effect on ink deposit inopen areas except at the outer edges

Surface Roughness

Substrate side of screen should provide agood gasket for ink transfer and imageintegrity

If there are any doubts about obtaining themost desirable Rz value (measure ofroughness) with fine images, have testscreens made to determine optimal value

Screens with a Rz value of 8 – 12 isrecommended for glass surfaces

If stencil is too smooth (lower than 8 R z),static may damage the printed image asthe screen separates

If Rz value is too high, edge resolution willbe lost

Drying

Screens coated with emulsion or capillaryfilm applied should be dried horizontallywith squeegee side uppermost in a cleandust-free environment

Allowing screens to dry in a verticalposition will render coating or stencil to beuneven and will lead to print quality issues


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KeyElements


SCREEN

(Cont inued) Emulsion orStencil Film(Continued)

Exposure

Determine correct distance of light sourceaccording to screen/image size

Determine correct exposure time, via a

light integrator, with the aid of an exposurecalculator

Each fabric grade and emulsion thicknesswill have its own unique exposure t ime thatshould be programmed into the proceduresfor consistency

For very fine line resolution requirements,consider the ‘secondary-exposing’technique to improve definition and coatingintegrity—more prevalent for applianceapplications

Keep exposure glass, top and bottom,continuously clean of particle matter, tapeand greasy finger marks

Suppliers will recommend optimum lampsystem according to screen/image size but

higher Kw lamps provides superior imagereproduction

Obtain a full vacuum seal between blanketand exposure glass as it is critical toprevent image distortion and loss of detail

Change lamps at the recommended life,usually 1000 hours regardless of a lightintegrator employed

Keep a record of each screen made,emulsion applied, image (job #) andexposure time for tracking potentialproblems

Washout

Establish acceptable procedures towashout the emulsion, including sprayconsistency and warm water temperature95º - 113º F (35º - 45º C), if used andhighly recommended

Do not overly washout as it will irreparablydamage the emulsion/stencil properties

Blockoutand Tape

Blockout areas outside the emulsion/stenciland tape according to set procedures

It is better for screen makers to finish thescreen completely and have ready forprinting than to allow printers to do this partof the job


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KeyElements


SCREEN

(Cont inued) Emulsion orStencil Film(Cont inued)

Final QC

If outsourced, check maker’s QCinspection sheet upon receiving screensand keep on file

Prior to placing into production, inspect thewhole screen to ensure stated tension is

correct, the complete image is in tact (suchas half a dot missing), line integrity, edgeresolution acceptable (with the aid of aloupe) and no appearance of banding,moiré, etc

If necessary, keep a log of screensrecording tension of fabric each time it hasbeen used – before and after

Proper documentation will map longevity ofscreens and may indicate potentialproblems from reoccurring

Custom Taping

Mark up screen prior to production,indicating where the tape will go whenprocessing various custom sizes with thesame screen/image

Pre-marking will significantly improveaccuracy and productivity

Cleaning Washbooth

For professional-looking clean screens,use a backlite washbooth designed for thispurpose including a high-pressure washerwith suitable PSI

Remove tape, adhesive residuals and anyparticles of ink, including those at inneredges of the frame

Consider two separate systems, or acombination, when processing water andsolvent-based inks

Consult washbooth suppliers as well asstate, city and local ordinances regardingdrainage and waste disposal

PRINT TAB LE

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PRESS SETUP

Squeegee

Material

Urethane is the most common squeegeematerial and make sure the grade selectedholds up to aggressive frit and solventsused

Single durometer – straight edgesqueegees (90º corners) are the mostcommonly used for glass printing

Dual-durometer blades are gaining inpopularity for fine detail applications,particularly for smaller format printing anddemanding results

High quality, more expensive squeegeeblades are generally more cost-effective asthey do a better job of printing, have moreresistance to aggressive frit/solventcleaning and last much longer


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KeyElements


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PRESS SETUP (Continued)

Squeegee(Cont inued)

Durometer(hardness)

Affects ink deposit and edge resolution

Durometer ranging from 65º – 85º arewidely used for glass printing

Continuous cleaning as well as wear andtear will increase durometer over time andthose increasing in hardness by 5º shouldbe discarded for demanding print quality

Softer squeegees yield more deposit butreduce edge definition while the reverseoccurs with harder blades

Check durometer periodically to insurehardness has not changed due to solvents

or when incrementally wearing down

Always refer to durometer by its hardnessnumber —not by color - whentroubleshooting since a common color-code system does not exist betweenmanufacturers

Edge Quality

Most critical variable of the squeegee: keepclean and sharp, let it rest after cleaningand sharpening (see separate entry)

Solvents and chemicals weaken the edge;so does printing too soon after sharpening(see separate entry)

Follow manufacturer ’s recommendation forproper squeegee handling and care

For long production runs, rotate squeegeesfrequently, as determined by experience, toallow their edges to regain integrity (reduceswelling)

Mechanical Angle

Set mechanically fixed angle on thesqueegee assembly bridge 10º - 15º fromthe vertical position

Large depth squeegee blades will requireless of a fixed angle as opposed to thoseshorter in depth

Never preset more than 20º anglemechanically under any circumstances forglass printing

Print Angle

Actual print angle is an important variablethat needs to be constantly attended to inorder to render suitable print performance

Angle decided by several variables:durometer, mechanical fixed angle, depthof squeegee from holder, pressure, off-contact and peel-off settings, mesh, imageand more

Print angle should not vary more than 5º – 10º from fixed mechanical angle and backoff pressure slightly when reducing angleor print speed

Less angle improves edge quality/thinnerdeposit while the opposite occurs with agreater angle


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KeyElements


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Pressure

Pressure needed is in direct relation toscreen tension, fabric grade, off contact,peel-off, image size, copy characteristics,durometer and frit size to complete ink

transferThe least amount of force is ideallyrequired to transfer ink through the screen,which under suitable conditions, will reduceoverall stress in the process

Keep pressure at a minimum to reduceunnecessary squeegee and screen wearas well as image distortion and possiblyregistration problems

Best way to keep pressure low is by usinghigher screen tension and lower off-contactdistance

Speed

Ideal speed is determined by transferabilityof ink (ink flow) and shear rate according tomesh grade and reproduction of imagedetail

Lower viscosity generally permits fasterprint speed

Speed should ideally be fixed with thesame ink type and viscosity range for all

jobs

Length

Probably the most overlooked variable forconsistency in deposit uniformity

Fit the squeegee to suit the image, not theframe

Squeegee length should be no longer than1” (25 mm) past the image width on eitherside

A blade that is too long will collapse in thecenter, resulting in excessive pressure,premature screen wear, image distortionand uneven ink deposit

Snowplow

Consider snowplowing the squeegee a few

degrees, on either axis when printing linesand halftones

Snowplow helps to improve edge definition

of lines by reducing the ‘sawtoothing’ effectas well as helping to eliminate moiré

Dripless

Use feature when printing acid-etchcoatings or any ultra thin/transparent-typecoatings

The anti-drip device prevents ink drippingoff the squeegee blade onto the openscreen during the flood cycle, which willruin the next print


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Sharpening

A good quality squeegee sharpener isimperative as the number one support toolfor screen printing onto any clear substrate,such as glass and in particular for largesizes

Prepare a detailed procedure to ensuresharpening is regularly carried out aftersqueegees have been printing andcleaned, rested before sharpening andthen rested again before reuse

Frequent sharpening is perhaps the mostcritical pre-press process on the productionfloor but about the least considered

Follow sharpener’s recommended

procedures very carefully and modify themto suit as required

Ideally cross-train in its operation, rotatebut designate one person per shift/permonth to handle the job to yield consistentresults

Management Care

Uncoil material when received, cut to size ifpractical, lay flat, store away from inks,solvents and bright lights at 68º – 77º F(20º – 25º C)

Clean only with water or ‘press-wash’ forsolvent-based inks and do not leave ink todry on them

With solvent-based inks and aggressivecleaning solvents, rest blades ideally for 24hours or overnight before reuse orsharpening

Rest again for 24 hours or overnight aftersharpening (see comments)

Have several sets of squeegees in the loopof the same size so they can be rotatedduring production

Squeegee blades are the cheapest item forprinting yet they can be the most expensivein the process if they are not treatedproperly

Superior blade material will always lastlonger, resist solvents better andsignificantly improve overall printperformance

Some sophisticated sharpeners createhardly any heat from friction if usedcorrectly, so squeegees could be reusedimmediately after sharpening

Using aggressive solvents for cleaning willunnecessarily make the edges swell andbe completely unusable until properly

rested

Variables

Variables listed in this section are some ofthe more critical operational variables.Please be aware that there are many morevariables associated with the squeegee

Consult your supplier


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PRESS SETUP

(Continued)

Floodbar

Role

The real purpose of the floodbar(floodcoater or scraper blade) is not toreturn the ink back to commence the nextprint cycle but to determine how much thesqueegee will deposit

Squeegee can only transfer what thefloodbar has left in and on the screenregardless of its conditions

Type

Those that are mechanically angled at 0ºfrom vertical are ideal for applying heavydeposits—and are sometimes referred toas a ‘standard’ floodbar

Those pre-angled at 25º - 45º degrees arebetter for obtaining thinner deposits andimproved image resolution/edge quality.Sometimes are referred to as a ‘halftone’ or‘special’ floodbar

If the dynamics of the screen permittedmore ink coating to be transferred thandesirable, switch to an angle (halftone)floodbar

If ink deposit is insufficient due to thedynamics of the screen, switch to astandard floodbar

Set Up

Should have enough pressure to leave aneven amount of ink across the surfacealong its entire length

Floodbar adjustments are independent ofthe squeegees’, which can be veryadvantageous

Adjust floodbar pressure for controlling inkdeposit before changing other variables

EdgeEdge must be straight, level, nick and burr-

free

Any nicks will print as an unsightly line

Never lay a floodbar on its edge but rather

on its back and place a protective coverover the edge

ControlsKeep control settings consistent, such asspeed, angles, pressure, etc.

Oftentimes, the flooding action has moreinfluence on the print than the squeegee sobe mindful of its formidable power


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KeyElements


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PRESS SETUP

(Continued)

Floodbar(Continued) Length

Extremely important that its length shouldbe ‘paired’ with the squeegee

A floodbar that is too long will leave moreink coating in the middle of the screen thuspermitting the squeegee to print an unevendeposit

Print Modes

Should ink dry too quickly in the screenbetween print cycles, consider using the‘flood/print’ mode, if available, as it keepsthe screen flooded during the pausebetween cycles

Conversely, if too much ink seeps throughthe screen between print cycles, switch tothe ‘print/flood’ mode of operating, which isgenerally considered the normal way ofoperating

Variables

Variables listed in this section are some ofthe more critical operational variables.Please be aware that there are many more

variables associated with the floodbar

Consult your supplier

Make-Ready

Before setting up a press, check that it is ina useable state from the last job and safeto commence make-ready - especially atthe start of a shift and in particular when aformal handshake (handover) was notconducted between the previous operator

Sometimes the most simplest thingsforgotten create unnecessarily longdowntimes between changeovers

Mechanical Off-Contact

Screen tension alone determines distance

to use

Set as low as possible to allow for a cleanrelease of screen from the substrate duringthe printing stroke

Since larger screens typically have lowertension, they would require higher off-contact

Too much off contact will result in

excessive squeegee pressure, imagedistortion, poor registration, reducedscreen life, loss of image detail andinconsistent ink deposit

Higher tension screens will always allow alower off-contact distance correspondingwith less squeegee pressure; setting up theideal rheology for successful printing


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KeyElements


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Mechanical(Continued)

Peel-Off

Shear rate of ink determines the amount ofpeel-off to use, if required, to prevent alarge area of the fabric to remain in contactwith the glass behind the squeegee

Peel should be set high enough to allowthe screen to release from the substrate toprovide a clean looking print

Increase peel-off rather than off-contact ifhigh tension screens do not create a cleanseparation from the glass surface

High tension screens will always reduce

the dependence of peel-off and excessivesqueegee pressure

Nesting

To reduce wear on the screen and yield abetter-looking print, consider using nestingsupports to prevent the squeegee from

jumping when it runs on and off from theglass surface

May also be used to register the glasspanel

In many instances where good printingtechniques are used, nesting is not alwaysrequired – but generally used to provide a‘safety net’

Nesting material should be the samethickness as the substrate

Teardown

Upon finishing a production run, it is a goodworking practice to leave the printingmachine in a ‘neutral safe state’ – that iszero back registration adjustments andcancel any excessive settings oradjustments

On the last print of a job, set the machineso the print cycle finishes at the end of theprint stroke, thereby making it easier toclean the screen

As screen printing equipment can be rathercomplex, insist on having handshakes (anupdate of the printing machine’s state andcurrent/finished job) when switchingoperators

Drying orCuring

Ensure heat settings configuration iscorrect for the ink type, color, depositthickness and conveyor speed

Ensure correct lamp configuration, voltagepower settings and conveyor speed withUV curing

If cooling is used, ensure the air is notrestricted, too warm and that the exhaust isworking properly

In general terms, water- or solvent-basedinks require the longest possible residenttime in the heating section that will keep upwith productivity, which will then afford thelowest temperature setting – for a moreefficient way of operating and reducingglass exit temperature

Usually the reverse with UV, ink is exposedfor the shortest possible time to crosslinkand not over cure


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KeyElements


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Mechanical(Continued)

SOP

Each of the printing equipment’s settingsand conditions should be properly recordedfor each type of print need and ink mediumused (standard and transparency etch) sothat they can be repeated by any operator

Generate a full working set of operatingprocedures (SOPs) according to practicesand techniques employed when resultsproduce good-looking prints with minimalhassle in make-ready and production

Some form of standardized proceduresbecome necessity when mechanizing an

artistic printing process into one that ismore controllable, repeatable andmanageable by everyone involved

ENVIRONMENT Conditions Print roomConsider building a separate room aroundthe printing operation to keep factory dustand dirt away

To keep the print room continuously clean,minimize traffic by making it ‘AuthorizedPersonnel Only’ and, as necessary, supplyoperators with cleanroom outerwear (coats,hats, bootees, etc)

Consistency to maintain actual or practicalworking conditions, regardless of what theyare, is more important than the ideal valuesstated if they cannot be continuously met

Cost to provide some form of a separateprint room is greatly outweighed byspectacular print results and superiorproduction performance

Temperature Ideal range 68º – 72º F (20º – 22º C)Consider using an industry-recognizedviscometer

Consistency in viscosity promotes quickerchangeovers for short custom jobs andmakes it easier to track problems as theyarise

HumidityIdeal range throughout the year 50% - 60%R/H

Pressure Atmosphere slight over pressure, 1¾ in (45mm) over water column

Air Quality

Quality filtered air with at least fourchanges/hour although six should beconsidered


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KeyElements

Variables Characteristics Guidelines

ENVIRONMENT

(Cont inued)

Conditions(Continued) Static

Reduce the effects of static electricity byusing antistatic mats and coats as well asconsider separately grounding equipmentas necessary

Access Ensure access doors open outwards toprevent dragging factory dust particles fromentering

Enamel (ink)

Viscosity

Enamels, referred to as ink or paint, shouldbe thinned and/or mixed prior to use withinthe supplier’s viscosity range

Establishing a workable range will enableoperators to use the same machinesettings

Recovery

Always filter the ink before used,

particularly if ink recovery is practiced, toprevent hard dried pieces from beingprinted

Dried up, hard ink can not only ruin anotherwise good print, but can also pop thescreen

Material Storage

Screens As above

If materials cannot be stored in this type ofenvironment, they should be brought intothe printing environment at least 24 hoursprior to being used and allowed toacclimate to the print room-type conditions

Enamels As above As above, but recommend 48 hours prior to

use

Squeegee andFloodbar

Consider hanging them on the wall orprovide a rack for each size includingpaired floodbars

As with floodbars, squeegees should neverbe rested on their edges but left laying ontheir backs blade uppermost

Others

Air SideUse a tin side meter to ensure the glass’ airside surface is uppermost for architecturaland appliance glass printing

When printing on the tin side of glass, theceramic frit will react with the tin and maycause discoloration or mottling. This couldgive the appearance of a defect or poorprint quality

Comments


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ENVIRONMENT

(Cont inued)

Others(Continued)

Tin SideUse a tin side meter to ensure the glass’ tinside surface is uppermost for automotiveglass printing

The tin side is desirable for automotiveapplications, due to the reaction with the tinand the silver conductive ceramic enamel

AntistaticConsider using antistatic devicesparticularly as the glass enters the printroom from the washer

Refer to suppliers’ recommendations

Ink Feeding

Consider suitable access for operators topour ink into the screen at the floodbarend, according to size of the press andlayout

Work with OEM initial recommendations

InspectionConsider need to inspect print immediatelyafter printing before it enters the dryer

Highly recommended to allocate space forsuch checking since it will enable operatorsto make print adjustments as necessary

For information on additional reference resources including the GANA Glazing Manual and other Glass Informational Bulletins visit GANA

website: www.glasswebsite.com.

The Glass Association of North America (GANA) has produced this document solely to provide general information as to general guidelines for

screen printing on flat glass. The document does not purport to state that any one particular type of screen printing process or procedure should

be used in all applications or even in any specific application. The user of this document has the responsibility to ensure that architectural glass

constructions meet building code and other specific project requirements, GANA disclaims any responsibility for any specific results related to the

use of this document, for any errors or omissions contained in the document, and for any liability for loss or damage of any kind arising out of the

use of this document.

This document was developed and approved by the GANA Decorative Division – Printing on Glass Task Group and approved by the Decorative Division membership and GANA Board of

Directors. This is the original version of the document as approved and published in January 2011.

DD-DOC 0111 - General Guidelines for Screen Printing on Flat Glass

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Transcript of DD-DOC 0111 - General Guidelines for Screen Printing on Flat Glass