glass manufacture

GLASSINPACKAGINGC.S.Purushothaman*CSP TRG AIDS - AUG 2008

CSP TRG AIDS - AUG 2008

BASICSMANUFACTURE DESIGN FEATURES TYPES & PROPERTIESPERFORMANCE & TESTING*CSP TRG AIDS - AUG 2008SCOPE


BASICS


What is Glass?*CSP TRG AIDS - AUG 2008SUPERCOOLED LIQUIDLIQUID WHICH IS COOLED TO A STAGE WHERE ITS VISCOSITY IS SO GREAT THAT THE MOLECULES DO NOT MOVE FREELY ENOUGH TO FORM CRYSTALS


What is glass made of?Sand 70%Soda Ash 15% Limestone 10%

*CSP TRG AIDS - AUG 2008

Three of most common rock forming minerals on earth. Chemically named: quartz sand / rock crystalProperties: Extremely heat durable Chemical stack resistance


Naturally:Mechanical & chemical weathering of quartz-bearing igneous & metamorphic rocksChemically weathering:Less stable minerals break down to become silica sand


Anhydrous sodium carbonateTexture: soft Color: grayish & whiteAppearance: lump / powder in nature


Naturally:Erosion of igneous rock form sodium depositsTransport by waters as runoffs & collect in basinsWhen sodium comes in contact with CO2, precipitates out sodium carbonate


Includes hydrated lime Ca (OH)2 & quicklime CaOOnly quicklime can use to make glass


MANUFACTURE


Cullet Recycled glass (from plant and post consumer) used at levels as high as 80% when available. It is needed and added to enhance the melting rate and it significantly reduces energy required for glass production.



Glass Container Recycling100% recyclableCan be recycled again and again with no loss in quality or purity In 2005, 25.3% of glass container recycledGood for the environment recycling glass reduces consumption of raw materials, extends the life of plant equipment, and saves energy Lighter weightMore than 40% lighter than 20 years ago.



Benefits of Using Quality CulletOver a ton of natural resources are saved for every ton of glass recycled. Energy costs drop about 2-3% for every 10% cullet used in the manufacturing process.

For every six tons of recycled container glass used, one ton of carbon dioxide, a greenhouse gas, is reduced.

Glass has an unlimited life, it can be recycled over and over again. *CSP TRG AIDS - AUG 2008Lesser sodium oxide stronger the glassAluminium oxide increases the hardness & durability.Use of Na2SO4 & Arsenic reduces blisters


CSP TRG AIDS - AUG 2008*Three standard furnace colours are Flint, Amber and EmeraldBlue coloured bottle make product look white OPAL: MINUTE CRYSTALS OF FLUORINE COMPOUNDS ARE ADDED (CALCIUM FLUORIDE)

METALS USED TO IMPART COLOR TO GLASS Cadmium Sulfide YellowGold Chloride RedCobalt OxideBlue-VioletManganese Dioxide PurpleNickel Oxide VioletSulfurYellow-AmberChromic Oxide Emerald GreenUranium OxideFluorescent Yellow, Green Iron OxideGreens and Browns Selenium Oxide RedsCarbon Oxides Amber Brown Antimony Oxides WhiteCopper CompoundsBlue, Green, Red Tin Compounds WhiteLead Compounds YellowManganese Dioxide A "decoloring" agent Sodium Nitrate A "decoloring" agent


CSP TRG AIDS - AUG 2008*Colour agents added in melt or forehearthGlass has no distinct melting or solidifying temperatureDecolorizers are added to remove the colour by mineral impuritiesCullet + SAND + OTHER RM MELTED in furnace (15000C) (100 to 500 MT)GLASS MELTING


CSP TRG AIDS - AUG 2008*Orifice 12 mm to 50mm Furnace draw-off orifice and gob shearsGob is one individual mass of molten glass which makes one container Molten glass flows depending on the bottle size.Mechanical shears snip off "gobs" of molten glass. Each makes one container. Falling gob is caught by spout and directed to blank molds. Mass-production is made up of several individual sections, each is an independent unit holding a set of bottle-making molds.Large bottles consists of a blank mold and a blow mold. Higher production using double or triple gobs on one machine. two or three blank molds and similar blow molds. Gobs ---to form blank moldGOB FORMATION


*CSP TRG AIDS - AUG 2008GLASS MOULDINGBLOWING (Bottle or Jar) TWO STAGE MOULDING BLANK MOULD blank mold forms neck and initial shapeparison mould where gob falls and neck is formedhas number of sectionsfinish section cavity section (made in two halves to allow parison removal) a guide or funnel for inserting gob a seal for gob opening once gob is settled in mold blowing tubes through the gob and neck openings

BLOW MOULD - blow mold produce the final shapeTWO TYPES OF PROCESSES


*CSP TRG AIDS - AUG 2008GLASS MOULDINGTWO TYPES OF PROCESSESBLOW & BLOWPRESS & BLOW

*CSP TRG AIDS - AUG 2008BLOW & BLOWBlow-and-blow process--- for narrow-necked bottlesThe two processes differ according to the parison producing.Blow-and-blow process: 1. Gob dropped into the blank mold through a funnel-shaped guide (985C) 2. parison bottomer replaced guide ;air blown into settle mold to force the finish section. At this point the bottle finish is complete. 3. Solid bottom plate replaced parison bottomer ; air is forced to expand the glass upward and form the parison. 4. Parison removed from the blank mold, rotated to a right-side-up orientation for placement into the blow mold. 5. Air forces the glass to conform to the shape of the blow mold. The bottle is cooled to stand without becoming distorted and is then placed on conveyors to the annealing oven.


*CSP TRG AIDS - AUG 2008BLOW & BLOW


Press and blow forms the parison by mechanical action Gob delivery and settle-blow steps are similar to blow-and-blow forming. Parison is pressed into shape with a metal plunger rather than blown into shape The final blowing step is identical to the blow-and-blow process.Used for smaller necked containers. Better control of glass distributionpress-and-blow process--- for wide-mouthed jars*CSP TRG AIDS - AUG 2008PRESS & BLOW


Bottle ManufactureDifference of the two processesBlow-and-blow used for narrow-necked bottles. Press-and-blow used to make wide-mouthed jars and for increasingly smaller necked containers. Better control of glass distribution.

Typical production rates range from 60 to 300 bottles per minute, depending on the number of sections in a machine, the number of gobs being extruded, and the size of the container.

The blown bottle is removed from the blow mold with takeout tongs and placed on a deadplate to air cool for a few moments before transfer to a conveyor that transports it to the annealing oven. *CSP TRG AIDS - AUG 2008


DIFFERENCE IN PROCESSESDifference of the two processesBlow-and-blow used for narrow-necked bottles. Press-and-blow used to make wide-mouthed jars and for increasingly smaller necked containers. Better control of glass distribution.

Typical production rates range from 60 to 300 bottles per minute, depending on the number of sections in a machine, the number of gobs being extruded, and the size of the container.

The blown bottle is removed from the blow mold with takeout tongs and placed on a deadplate to air cool for a few moments before transfer to a conveyor that transports it to the annealing oven. *CSP TRG AIDS - AUG 2008

ANNEALINGANNEALINGto reduce internal stresses; in annealing oven- Walls are comparatively thick and cooling will not be even.- The inner and outer skins of a glass become rigid - The still-contracting inner portion build up internal stresses - Uneven cooling develop substantial stresses in the glass.- Bottle passes through an lehr after removal from the blow mold. - LEHR is a belt passing through the controlled temperature oven at a rate of about 200mm to 300mm per minute. Glass temp is raised to 5650 C and then gradually cooled to room temperature with all internal stresses reduced to safe levels in about an hour as they exit

Improperly annealed bottles are fragile and high breakage Hot-filling also produce unacceptable breakage levels.



SURFACE COATINGSSURFACE COATINGSPurpose--- to reduce the coefficient of frictionReasons---The inner and outer surfaces have different characteristics The outer surface comes in contact with the mold and takes the grain of the mold surface Both surfaces are PRISTINE, MONOLITHIC, STERILE, CHEMICALLY INERT. Pristine glass has high COF, surface scratchinhg and brusing can occur when surface rub. Surface scratching has lower breakage resistanceMethods--- hot-end coating ; cold-end coatings The hot-end coating applied at the entrance to the annealing lehr to strength the glass surface Cold-end coatings depending on the filling process and end use. Typical cold-end coatings---oleic acid, monostearates, waxes, silicones, polyethylenesThe label adhesive as one cold-end coating. *CSP TRG AIDS - AUG 2008


INSPECTION & PACKAGINGINSPECTION AND PACKINGUse mechanical and electronic means. 1) Squeeze testers subject the container walls to a compressive force ( between two rollers) 2) Plug gauges check height, perpendicularity, inside and outside finish diameters. 3) Optical devices inspect for stones, blisters, checks, bird swings, and other blemishes and irregularities by rotating the container past a bank of photocells (Figure 6.4). Faulty containers crushing into cullet. Transported in reusable corrugated shippers; Shipped on palletsAutomatic equipment used to clear tiers off the pallet and feed into the filling machine. *CSP TRG AIDS - AUG 2008


DECORATIONFrosting Etching by Hydrofluric Acid (HF) / sand blasting expensive

PrintingScreen Printing inks are fired. APPLIED CERAMIC LABEL

Ceramic Frosting spray with ceramic paint ( ground glass + oil mixture) fire oil evaporates and ground glass fuses on surface.

DESIGN FEATURES

BOTTLE PARTS Smooth round shapes---easily formedSuitable on filling lines Labeled at relatively high speeds Accurately positioned in spot-labeler Greater strength-to-weight ratios Better material utilization*CSP TRG AIDS - AUG 2008Finish is that part which receives the closure


BOTTLE DEFECTSFlat shapes inherent problems.

bird swing and spike defects.

Spikes --- glass projections inside the bottle

Bird swing--- glass thread joining the two walls

Careful design to avoid stress points. angular shapes---difficult to form*CSP TRG AIDS - AUG 2008


FINISH & CLOSURESFINISH AND CLOSURESFinishes are broadly classified according to diameter ,sealing method, and special features. Continuous-thread (CT), lug, crown, threaded-crown, and roll- on are common finish designs. Closures are based on the cost, utility, and decoration thread profile has a curved or partially semicircular profile COLOURINGFlint Clear & Transpareent Green Chrome oxide for emerald green upto 5%Brown Iron and sulphur for amberBlue Cobalt oxide for BlueOpal Opaque white*CSP TRG AIDS - AUG 2008


NECK & SHOULDER AREASNeck and Shoulder AreasThe impact on filling, air displacement, and dispensing. Fill level in long narrow necks Headspace for thermal expansion and facilitate filling. Manufacturing defect ---choke neck Ridge on the sealing surface---overpress

Upper shoulder --- below the neck.

Shoulder and neck blending ---important design and production. lower shoulder--- the integration point between the upper shoulder and the body. Contact area*CSP TRG AIDS - AUG 2008


SIDESSidesThe most generalized areas of the bottle.

Labeling styles and preventing scuffing must be considered. Bottles designed with label panels to prevent scuffing. The panel may have prominent base and shoulder ridges.

In angular bottles, rounded corners are preferable for wraparound or three-side labeling. Spot labeling is normally a one- or two-sided application.Labeling of non-round shapes is slower than for round shapes. *CSP TRG AIDS - AUG 2008


HEEL & BASEHeel and BaseHigh-abuse area--- start high from the base curving into the base to a suitable base diameter.Body-to-base curve should combine 3 radii. The largest blends body to heel, the smallest blends heel to base. Diameter as large as possible as a good design. Center of the base ensure a flat, stable bottom .Stippled or knurled on the circular bearing surface to protect the scratches not to weaken the body during handling and usage. Ketchup bottles and other sauce bottles require: heel and base be heavier and contoured when expelling the contents. Wide-mouthed jar bases have designed-in stacking features. Container base fits into recessed cap. Indented container base fits over cap. Heel tap --- excess glass distributed to the heel.*CSP TRG AIDS - AUG 2008


STABILITY & MACHINABILITYStability and Machinabilitybottle's stability the center of gravity ; the base surface area problem in manufacturing ---tall and narrow bottles handling and labeling in packaging line --- high center Short round oval bodies --- efficient for machine handling and labeling problems. baby food ; cold cream jars. As much as possible, bottles should be designed to be all-around trouble free to manufacture, fill, close, and ship. Some designs are inherently weaker or more prone to cause trouble in their filling and the distribution cycle than others. *CSP TRG AIDS - AUG 2008


VIALS & AMPOULESVials and ampoulesVials and ampoules--- mainly for pharmaceuticals and sera Preformed tubing stock Sealed glass containers Constriction--- easy fracture stress concentration coated with a ceramic paint Standard sizes ---1, 2, 5, 10, and 20 ml. Serum vials a rubber septum ; an aluminum neck ring. a needle cannula to withdraw serum can be accessed several times. standard sizes--- 1, 2, 3, 5, 10, and 20 ml. Tumblers --- wide-mouthed containers Carboys ---bulk containment for acids or chemicals. *CSP TRG AIDS - AUG 2008


BONATED BEVERAGESCarbonated Beverages The pressure factors: gas dissolved in the product. Beverage producers express this as the number of volumes of gas dissolved in a unit volume of the product. For example, if a 48 oz. volume of carbon dioxide at standard conditions is dissolved in 12 oz. of beverage, then the beverage is said to yield 4 gas volumes. Carbonated beverage and beer bottles internal gas pressure : soft drink 0.34 millipascal (50 psi), beer 0.83 millipascal (120 psi). capped wellThe loss of bottle strength Bottle designs ---round in cross section gently curving radii to maximize strength. *CSP TRG AIDS - AUG 2008


TYPES & PROPERTIES

Benefits of Glass PackagingInertRegalEnsures freshness and tasteNontoxicFDA-approved 2.5 g/cc


Glass Types and General Propertiesinorganic substance fused at high temperatures and cooled quickly principle component ---silica (quartz),Ingredients of components makes different formulations. Mineral compounds used to achieve improved properties: decolorizeration, Clarity, Colouring Other glass types used for special packaging purposes. lead compounds, boron compounds, borosilicate glasses*CSP TRG AIDS - AUG 2008

Glass Types and General PropertiesAdvantages as a packaging material:inert perfect food container. impermeabilityclarityregal image rigidity stable at high temperatures Disadvantages : fragility high weighthigh energy costs *CSP TRG AIDS - AUG 2008

CSP TRG AIDS - AUG 2008*Although INERT Sodium and other ions can leach out on ceratin solution.

USP Type-I Borosilicate Flint (clear), Amber (brown) glass vials,

USP Type-II De Alkalized Soda Lime Glass(type3) that has been treated in the lehr with sulphur to reduce alkali solubility. The treatment produces a disccoloured appearance.

USP Type-III conventional soda glassTYPES OF GLASS

CSP TRG AIDS - AUG 2008*TYPE 1ADDITION OF 6% BORON REDUCES LEACHING ACTION Least reactive glass available for containers. It can be used for all applications and is most commonlyused to packaged water for injection, UN-buffered products, chemicals, sensitive lab samples, and samples requiring sterilization. All lab glass apparatus is generally Type I borosilicate glass. Type I glass is used to package products which are alkaline or will become alkaline prior to their expiration date USP TYPE I BOROSILICATE (neutral) GLASS

CSP TRG AIDS - AUG 2008*USP TYPE II DE ALKALIZED SODA LIME GLASSHas higher levels of sodium hydroxide and calcium oxide.It is less resistant to leaching than Type I but more resistant than Type III.GOOD ALKALI RESISTANCEIt can be used for products that remain below pH 7 for their shelf life

CSP TRG AIDS - AUG 2008*USP TYPE III SODA LIME GLASSAcceptable in packaging some dry powders which are subsequently dissolved to make solutions or buffers. It is also suitable for packaging liquid formulations that prove to be insensitive to alkali. Type III glass should not be used for products that are to be autoclaved, but can be used in dry heat sterilization

CSP TRG AIDS - AUG 2008*USP TYPE NP SODA LIME GLASSIs a general purpose glass and is used for non-parenteral applications where chemical durability and heat shock are not factors. These containers are frequently used for capsules, tablets and topical products.

PERFORMANCE& TESTING

CSP TRG AIDS - AUG 2008*It is important that containers comply withspecification and general industry guidelines in order to withstand the normal stresses andmechanical abuse right through until the end user has finished using it.PERFORMANCE& TESTING


CSP TRG AIDS - AUG 2008*VERTICAL LOADForces of this nature might be produced during capping or throughstacking products on top of each other. To help ensure glass containershave adequate vertical load strength, we test to BS EN ISO 8113-2004using a Universal Testing Machine.


CSP TRG AIDS - AUG 2008*IMPACT TESTINGTo help ensure glass containers have an adequate impact resistance,we can test to standard manufacturing codes of practice using anindustry standard Pendulum Impact Tester.


CSP TRG AIDS - AUG 2008*THERMAL SHOCKHot-fill or heat-treated glassware can be tested for thermal shock resistance to ensure theproduct is fit for the intended purpose. Testing can be carried out to ASTM C149 and BS EN ISO 7459 either as pass/fail test typically at 42OC downshock or progressive testing to complete sample failure.EFFECT OF SUDDEN TEMPERATURE CHANGEEFFECT IS MINIMAL IF BOTH SIDES ARE HEATED OR COOLED SIMULTANEOUSLYEFFECTI IS PROMINENT WHEN ONE SURFACE IS HOT AND THE OTHER SURFACE IS CHILLED


CSP TRG AIDS - AUG 2008*COATING PERFORMANCEAssessment of surface protection can be carried out by use of sliptables and hot end coating technology. The longevity of thecoating performance can be assessed using line simulator, whereby bottle to bottle abrasion damage which maybe expected to occur on a filling line can be replicated and thesubsequent damage of the container tested. This is of particularuse for returnable glassware.


CSP TRG AIDS - AUG 2008*INTERNAL PRESSURE RESISTANCECarbonated beverage bottles need to be able to withstand without failure thepressure produced by their contents over long periods.


CSP TRG AIDS - AUG 2008*RESIDUAL STRAINMeasurement of annealing stresses/residual strain to ASTM C148;


CSP TRG AIDS - AUG 2008*ON-LINE INSPECTION OF GLASS BOTTLES

Bottle Spacer. This machine is pre-set to create a space between the bottles on the conveyer to avoid bottle to bottle contract.

Squeeze Tester. Each bottle is passed between discs that exert a force to the body of the container. Any obvious weakness or crack in the bottle will cause it to fail completely with the resulting cullet being collected by a return conveyor running underneath.

Bore Gauger. The internal and external diameter at the neck finish entrance to the bottle and the bottle height are measured. Bottles outside specification are automatically rejected by means of a pusher positioned downstream from the gauger.


CSP TRG AIDS - AUG 2008*Check Detector. Focuses a beam of light onto areas of the container where defects are known to occur from previous visual examinations, any crack will reflect the light to a detector, which will trigger a mechanism to reject the bottle.

Wall Thickness Detector. This test uses dielectric properties of the glass, the wall thickness can be determined by means of a sensitive head which traverses the body section of the container. A trace of the wall thickness is then obtained and bottles falling below a specified minimum will be automatically rejected.

Hydraulic Pressure Tester. A test carried out on bottles which will be filled with carbonated beverages and gauges the internal pressure of every bottle before it is packed.


CSP TRG AIDS - AUG 2008*Visual Check. Bottles are passed in front of a viewing screen as a final inspection.

Glass failure is usually as a result of thermal shock or impact stresses. Each glass container has a maximum thermal expansion threshold and a maximum vertical load stress, which it can withstand without cracking. These values should be known before it is used for a particular application.

The shape of the container will influence its strength, smooth edges result in the formation of a stronger container than one with rectangular or sharp edges


CSP TRG AIDS - AUG 2008*There are 6 broad classifications of glass defects

Checks Seams Non-glass inclusions Dirt, dope, adhering particles or oil parks Freaks and malformations, and Marks


CSP TRG AIDS - AUG 2008*Defects are classified as Critical, those that are hazardous to the user and those that make the container completely unusable.

Major, those that materially reduce the usability of the container or its contents

Minor, those that do not affect the usability of the container, but detract from its appearance or acceptability to the customer.


CSP TRG AIDS - AUG 2008*Critical Defects in Glass Bottles or ContainersStuck Plug. A piece of glass, usually very sharp, projecting inwards just inside the neck bore Overpress. Is a defect where a small ridge of glass has been formed on the sealing surface of the finish Split. An open crack starting at the top of the finish and extending downward. Check. A small, shallow surface crack, usually at the bore of the container Freaks. Odd shapes and conditions that render the container completely unusable. Bent or cocked necks are a common defect of this type. Poor Distribution. Thin shoulder, slug neck, choke neck, heavy bottom are terms used to describe the uneven distribution of glass. Soft Blister. A thin blister, usually found on or near the sealing surface. It can however show up anywhere on the glass container.


CSP TRG AIDS - AUG 2008*Choked Bore. Here excess of glass has been distributed to the inside of the finish or opening Cracks. Partial fractures, usually found in the heel area. Pinhole. Any opening causing leakage. It occurs most often in bottles with pointed corners. Filament. A hair-like string inside the bottle. Spike. Spikes are glass projections inside the bottle. Bird Swing. Is a glass thread joining the two walls of the container


CSP TRG AIDS - AUG 2008*Some Major Defects Commonly Found in Glass ContainersChipped Finish. Pieces broken out of the top edge in the manufacturing process. Stone. Small inclusion of any non-glass material Rocker Bottom. A sunken centre portion on in base of the container Flanged Bottom. A rim of glass around the bottom at the parting line


CSP TRG AIDS - AUG 2008*Some Minor Defects Commonly Found in Glass ContainersSuncker Shoulder. Not fully blown, or sagged after blowing Tear. Similar to a check, but opened up. A tear will not break when tapped, a check will. Washboard. A wavy condition of horizontal lines in the body of the bottle. Hard Blister. A deeply embedded blister that is not easily broken. Dirt. Scaly or granular nonglass material. Heel Tap. A manufacturing defect where excess glass has been distributed into the heel Mark. A brush mark is composed of fine vertical laps, e.g. oil marks from moulds. Wavy bottle. A wavy surface on the inside of the bottle. Seeds. Small bubbles in the glass Neck ring seam. A bulge at the parting line between the neck and the body.


TOLERANCE

CSP TRG AIDS - AUG 2008*Tolerances as per GLASS PACKAGING INSTITUTE CAPACITY1% for large bottles and upto 15% for small bottlesWEIGHTgenerally 5%HEIGHT0.5 to 0.8% overall HEIGHTDIAMETER1.5% for 200mm & 3% for 25mm TOLERANCE


CSP TRG AIDS - AUG 2008*The following are examples of some permitted tolerances: Vertical load control valuesTOLERANCE

Glass bottleVertical loadRefillable6000NNon-refillable4000N

CSP TRG AIDS - AUG 2008*CAPACITY

Nominal Capacity (ml) up to and includingTolerances (ml) Nominal capacity (ml) up to and includingTolerances (ml) 1002.74505.71253.05006.01503.36006.51753.57007.12003.88007.62504.29008.03004.610008.43505.0125012.54005.3150015.0


CSP TRG AIDS - AUG 2008*BODY AND HEIGHT DIMENSIONS

Body/Diameter Height TolerancesTolerancesD (mm) up to and includingTD (mm) H (mm) up to and includingTH (mm)

25.00.8250.736.50.9500.850.01.1750.962.51.21001.075.01.41251.187.51.51501.2100.01.71751.3112.51.82001.4125.02.02251.5137.52.12501.6150.02.32751.73001.8


CSP TRG AIDS - AUG 2008*VERTICALITY CONTROL VALUES FOR VERTICALITY

Height H (mm) up to and includingTv (mm) 1202.21502.71753.12003.42253.92504.2


CSP TRG AIDS - AUG 2008*MINIMUM GLASS THICKNESS VALUES

Body overall Diameter (mm)Minimum glass thickness (mm)Non-refillable bottlesRefillable bottlesSurface protected non-refillable bottlesUp to 601.11.50.8>61 to 711.41.80.9>71 to 811.51.91.0>81 to 961.72.01.1>96 to 1101.82.21.3


CSP TRG AIDS - AUG 2008*THINK


glass manufacture

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