Manufacturing of Corrugated Boxes
You have brought a new Television set and threw the box in a corner,then you have kept all your old junk and placed it on the loft,lifting it wondering what is that box about.
when you shift to a new place,you lift up these boxes,unwary of their origin or their make,you just lift them and transport.
These boxes are called as 'corrugated boxes' which are made from 'kraft paper'
UNDERSTANDING PAPER
• What is paper?
Fabric of cellulose fibers irregularly interlocked together, Prepared from pulps of various coniferous trees
• Types-
cultural paper (fine paper used for writing, printing, news prints.) and
industrial paper (coarse paper used for packaging operations)
• Varieties of paper-kraft, duplex,white, poly coated, hessin coated, laminated, glass line paper, wax paper, vegetable parchment paper, tissue paper, etc
Kraft paper-
• German word, meaning “strength”, generally used as raw material for Corrugated Board manufacturing
• Strength of the paper is determined by the fiber characteristics based on the mechanical refining treatment done on the fibre
• Prepared from sulphate process and machine glazed
• Good tensile stress, steatch and tearing resistance.
• Colors- generally brown, varies from light yellow to khaki color, golden and pink shades
Figure : Kraft paper
MANUFACTURING PROCESS
RAW MATERIALS: Kraft paper, glue (adhesive), stitching wire, printing/ print ink, threads for bundling
PROCESS
Corrugation
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Sheet/liner cutting
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Pasting (single wall/ double wall/triple wall)
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Pressing
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Creasing and sleeting
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Slotting
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Stitching/ glueing
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Drying
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Bundling
CORRUGATION
• Corrugators- heart of corrugated board manufacture
• Automatic type (3 ply/5ply board without separate pasting machine)
• Semi automatic type-the medium (fluting paper) is conditioned with heat and steam and passed between two fluted metal rolls to form corrugation
• Adhesive is applied to the tips of flute and conditioned liner (top/packing paper) is brought into contact with flute tips to form adhesive bonds, results in 2 ply liner
Figure :The corrugator machine
SHEET/LINER CUTTING
• 2 ply liner is cut to required size
PASTING
• A top paper (printed/plain) cut to the 2 ply liner size is pasted with the help of pasting machine, by passing the adhesive 2 ply liner between 2 rollers/pasting machine
• This results in 3 ply or double walled
• Similar process is used for 5 / 7 / 9 ply etc as the case may be.
Figure:The pasting machine
PRESSING
• Pasted sheets lot by lot are kept under the press for smooth evenness and uniform application of glue to the whole area of the sheet
• This is called ‘board’
Figure: The pressing machine
CREASING AND SLEETING
• The board is trimmed using a slitter and scored to define the flaps and depths of the box
• This process involves crushing the flutes in a narrow groove in the machine direction so that the box can be folded along these lines later when assembled
Figure: The creasing machine
SLOTTING
• Body scores and slots are made
• Slots permits the side flap to fold over the end flaps, the flaps forming
the top and bottom of the box
Figure:The slotting machine
STITCHING / GLUEING
• Done with the help of galvanized wire/ rust proof wire / metal staples
• Taping with paper/ cloth type or self glueing with glueing machine
Figure: The stiching machine
DRYING
• Mechanical drying or sun drying
BUNDLING
• It is also known as strapping where the boxes are bundled together
• Palleting for shipment-manually/mechanically
APPLICATION OF CORRUGATED BOARD
• Generally used as packaging material
• Primary packaging materials for home appliances and electronic goods
• Secondary or cushioning packaging for fragile products like bulbs, glass ware, etc and for agricultural and horticultural products
• Tertiary packaging materials for transportation of food products