Mini-Flute Packaging

T E C H N I C A L B U L L E T I N

B,E,F and N Flute

Outer Beauty/Inner Strength Mini-Flute is not short for a small flutist in an orchestra; it refers to the family of cor-rugate that uses small flutes (low profile), and a high number of flutes per inch (flute pitch) to produce a smooth surface. When a printed top-sheet is applied to single face, the result is a corrugated box with the look and feel of a folding carton. Typical mini-flute (micro-flute) profiles include B, E, F and N flutes.

Why mini-flute?

In the modern retail environment, the carton is the silent salesman attracting attention to your product. The addition of high-end graphics has converted the conventional brown-box into the primary product pack-age. The traditional secondary or tertiary role of corrugated is now that of a messen-ger of quality inside. Mini-flute minimizes the washboard look of wider flute profiles and gives the appearance of a paperboard-folding carton.

Did You Know?History of corrugated in the America

• 1690:ThefirstpapermillinNorthAmerica built near Philadelphia.

• 1767:EnglandimposedtheStampAct, which included a tax on all paper made in the colonies. Many consider this fuel for the American Revolution.

• 1856:Corrugatedwaspatentedfor sweatband material in hats.

• 1871:Unlinedcorrugatedfirstappears as packaging material for glass. Albert L. Jones patents “A” flute to wrap glass chimneys for kerosene lamps.

• 1895:“Cellularboardboxes”,latercalled corrugated boxes, are produced by sandwiching fluted medium between two liners. Wells Fargo begins using boxes for small freight shipments.

• 1919:Railroadclassificationcodifiedinto Rule41,whichspecifiesminimumcaliper and Mullen (burst strength).

• 1968:NationalMotorFreightClassification (NMFC)Item222providestruck-shipping rules and specifications for corrugated packaging.

• 1991:TheEdgeCrushTestisaddedto NMFCandRule41asanalternativeto burst strength.

• 1990’sto2005:Mini-flutetakesoff,as customers demand high-quality printing andfinishingoncorrugatedcartons.Club stores and large retailers require the “box to sell the product” and become the silent salesman of the retail aisle.

Have you seen this on a corrugated box and wondered what it meant?

Deconstructing mini-flute:

The structure of mini-flute is the same as con-ventional corrugated, except the flute height is lower and the external liner (top sheet) is printed. Additionally, the top sheet is usually printedona10or12pt.stock,whichpro-vides a smooth external surface and excellent printability. This also dramatically reduces or eliminates any score fracturing that can occur when you laminate a label onto a corrugated sheet. There are top sheet alternatives includ-ingfoillaminatedpaperboard,CCNBandvariety other substrates.

Onmosttopsheets,DISCcanapplyunique coatings, stamp or emboss to enhance the graphic features and wow the consumer. You can also add cello-phane or rigid window materials to allow easy product viewing without comprising product protection. Pre-printed top sheet liners can be printed using offset sheet fed or flexo web presses. In most instanc-es, offset is more cost effective because of the lower plate costs, which also provides flexibility for copy and image changes. Flexo is typically meant for large volume runs due to the high up-front plate and die costs.

These circles are calledCer-

tificates of Box Manufacture or“BoxCerts”.A throwback to federal regulation of

the trucking industry, the

government specified minimum packaging required for freight to be accepted for truck and/or rail transport. The regulations dictate that all shipping cartons bear a manu-facturer’scertificationofcompliancetotrans-port regulation and a guarantee that you are getting what you paid for.

Each number is a specification threshold for thebox’sperformancestandards.

A. BurstingStrength(MullenTest)simply measures the strength of the liners (the two outside walls of the corrugate). The test is a measure of the pressure required to burst through or rupture a piece of board.Forexample,200poundsof pressure is required to rupture a piece of 200-poundtestcorrugated.B. TheMinimumCombinationWeightisthe totalweightoftheliners.Example:a200 lb.testcartonhastwo42lb.linerssothe totalis84.C. Sizelimitisarecommendationofthe maximum outside dimension (MOD) to hold a certain weight. Formula:Length+Width+Depth=MODD. Gross Weight Limit is the maximum weight that a carton and its contents should weight in pounds.

Nextwe’lllookatthemiddleormedium, which is the fluted portion of the corrugat-ed. The inspiration behind creating flutes came from the architectural structures of arches and columns. When sandwiched between two liners the arches are ca-pable of supporting a significant amount of weight and when placed on end the column effect provides excellent stacking strength. The term flute is named after the vertical grooves in an architectural col-umn.

Kraft (brown paper stock) is traditionally used to create the medium in weights from18to40lbs.Thefluteconfigurationis formed by applying steam for moisture to the sheet as it comes off the role. The paper is pressed through two gear-like rollers called corrugating rolls.

The next step is applying the liner (inside ply) to the flutes. An adhesive, in the form of starch, is applied to the tips of the flut-ed medium and the linerboard is married to the flute forming “single face” corru-gated.Uponexitingadryer,theexposededge of the flutes receives an application of a cold glue adhesive and the face liner or top sheet is applied. In many applica-tions, the top sheet is pre-printed with high-quality graphics. The pre-print can be done on a web and applied directly from a roll or sheet-fed, which is Disc Graph-ics’specialty.Thefinishedroleisslitintosheets and stacked in preparation for die cutting, folding, gluing and conversion into a folding carton or other construc-tions.

Above is the other common BoxCertifi-cate, which includes EdgeCrushTest(ECT).

This alterna-tive classifica-

tion focuses on the edgewise compression or stacking strength of the cartonratherthanburstresistance.Sim-plystatedECTmeasurestheamountofforce, in terms of pounds, necessary to crush the edge of a corrugated box.

Resources:Perkins,S.andSchnell,P.(2000).TheCorrugatedContainersManufacturingProcess.TappiPress:Danvers,MA.

FibreBoxAssociation(1999).FibreBoxHandbook.FibreBoxAssociation:Roll-ing Meadows, Il.

FluteHeightSpecification:Belowarethemostcommonmini-fluteconfigurations:

N-flute is one of the smallest flute configurations, which minimizes the look of corrugated without comprising the strength you expect.

Which liner/medium configurations to use?

The look and cost of the final carton will be impacted by your choice of liner and medium:

• Typicalconfigurationforaprintedmini- flute carton is a kraft inside liner and medium, combined with a printed top sheet.

• Whiteliner/kraftmedium.Thewhite liner is normally a #3 grade referred to as “mottled white”, “Oyster white” or “Sno-Top”.Thisconfigurationisusedin beverage boxes, pizza and food boxes. This offers modest printability, but presents a more upscale look than Kraft.

• Triplewhite:bleachedwhitelinerand medium.Usedincosmetics, pharmaceuticals and presents a premium look.

RetailReady,ShelfReady,DisplayReadyand PDQs (Pretty Darn Quick) packaging

The term Retail Ready packaging (RRP) generally describes packaging that fits withinthemeaningofthe“fiveeasies”:• EasytoOpen

• EasytoIdentify

• EasytoStock

• EasytoShop

• EasytoDispose

B

47 Flutes Per Ft. / 155 Per Meter

.097

Droll Yankees

Droll Yankee Bird Feeder

Specifications:B-FluteCarton

TopSheet:12pt.SBS,4-ColorProcessKraft Medium and Liner

Isopure

Isopure 6pk Promo Box w/ Insert

Specifications:E-FluteCarton

TopSheet:12pt.SBS,4-ColorProcess+PMS

Kraft Medium and Liner

Hypertherm

Plasma Torch Box

Specifications:B-FluteCarton

TopSheet:12pt.SBS,4-ColorProcessKraft Medium and Liner

K’NEX

K’nex-Motorized Madness

Specifications:E-FluteCarton

TopSheet:10pt.silver-Mylarfoil,Hexachrome6-ColorProcess+PMS

DISC Products and Services

• Printed paperboard packaging (print, die cut, fold/glue, foil stamping, embossing, UV

coating in-house)

• Print technologies include offset sheet-fed lithography, narrow web flexography, digital

and silk screen

• Printed substrates include all varieties of paperboard comprising SBS, CCNB, SUS;

specialty stocks such as foil laminated board; paper; plastic and synthetic materials

• Mini-flute corrugated for “high-end” graphics (B, E, F and N flute) in house

• Rigid boxes and similar specialty packaging

• DVD, CD paper inserts, wraps, booklets

• Stickers and labels

• Commercial printers and posters

• Vacuum formed packaging

• Displays

• Lenticular printing

• Windowing (both rigid window and cellophane)

• Specialty packages for a variety of products and markets

• P.A.S.S. program (Packaging Authentication Security Solutions)

• Full service in-house creative team for structural and graphic design

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