PRINTING TECHNOLOGY
GRAVURE PRINTING & PRODUCTION PROCESS & MATERIALS
Gravure Printing
There is a wide variety of modern printing techniques, which can be categorised according to the type of plate:
Printing Type
Application
Gravure Printing
Printing flexible packaging, plastic films and paper films.
Flexographic Printing
Printing self-adhesive, corrugated boxes and flexible packaging.
Offset Printing
Printing books, cartons and labels.
Digital Printing
Pprinting books, labels and flexible packaging.
Screen Printing
Printing textiles.
In flexible packaging printing , gravure printing occupies an important position in the industry by virtue of its high printing quality, high register accuracy and high printing efficiency.
Advantages
High Printing Quality
》Rich image layers
The metal printing plate of gravure printing adopts a recessed aperture structure. After filling the recesses, the ink will be transferred to the substrate by the impression cylinder, which can precisely control the ink amount, thus presenting rich colour layers and delicate image details.
》Vivid and full colors
Gravure printing uses solvent-based ink, which has high color saturation and produces vivid and bright printing effects, and can well reproduce the colors of the design.
》Thick printing ink layer
Gravure printing has a thicker ink layer than other printing methods, which can present better three-dimensionality and texture.
High Register Accuracy
》Stability of mechanical structure
Gravure printing adopts an integral metal cylinder as the printing plate (copper plate or chrome-plated steel plate), compared with the flat plate of offset printing or the flexible resin plate of flexographic printing, the metal cylinder is not easy to be deformed in high-speed operation, which avoids overprinting deviation due to the expansion, contraction and displacement of the plate. In addition, the gravure printing machine adopts high-precision gear transmission between the impression cylinder and the metal cylinder, with minimal mechanical clearance to ensure that the graphic position of each colour group is strictly synchronized.
》Plate Characteristics Advantage
Gravure's graphics are formed into uniform apertures through engraving or etching. With controllable depth and shape of the apertures and stable ink transfer, register errors caused by fluctuations in ink layer thickness can be effectively reduced.Besides, compared with offset printing, which requires the control of ink and water balance, gravure printing transfers ink directly through embossing without the need for fountain solution, which avoids register problems caused by imbalance of ink and water.
More Advantages
》High Printing Efficiency
Gravure printing adopts rotary printing method. The printing speed is fast enough to achieve continuous printing, suitable for mass production.
》Good anti-counterfeiting performance
Gravure printing can be combined with a variety of anti-counterfeiting technologies to improve the anti-counterfeiting performance of products.
Here's how gravure printing machine works:
Production Process of Composite Flexible Packaging
Composite flexible packaging usually requires two or more film materials with different properties. After completing the gravure printing, the printed layer and other functional layers will be combined together through the lamination process to form a new high-performance flexible packaging material with multiple functions. It combines the advantages of each layer of material, overcoming the limitations of a single material, to meet the needs of different products in transportation, storage, sales and other aspects of packaging performance.
1. Preparation for Printing
Design draft production: According to the customer's needs, design the packaging pattern, text and other content, and determine the colour, font, size and other details.
Metal cylinder making: The design is output to film and then the graphic information is transferred to the metal cylinder by means of electronic engraving or laser engraving.
Ink blending: According to the colour requirements of the design, blend spot-colour inks or use CMYK four-colour inks.Up to 14 colors can be printed.
Metal cylinder loading: Mounting the finished metal cylinder on the printing press.
Inking: Pouring the prepared ink into the ink tank and transferring it evenly to the metal cylinder through the ink rollers.
Squeegee: Using a squeegee to remove ink from the blank portion of the metal cylinder surface, leaving only the ink in the pits.
Imprinting: The transfer of ink from the pits to the substrate (plastic film) by imprinting it on the metal cylinder.
Drying: Drying and curing the ink on the surface of the printed film using hot air or ultraviolet light.
3. Production of Packaging Film
Laminating: Laminated the printed film with other materials (e.g. aluminum foil, Polyamide, etc.) to improve the barrier, strength and other properties of the package.
Curing：Put the already laminated film into the curing room. The temperature of the curing room is generally 40℃ to 60℃, and the curing time varies from 24 to 72 hours according to the number of layers to be laminated. The final product is packaging bag film.
Slitting: Slitting the packaging bag film into the required size and shape.
Bag-making: The slit material is made into various shapes of bags, such as three-side sealed bags, stand-up pouches, zip bags, etc.
Inspection: Conduct quality inspection of finished products to ensure that the printing quality and size specifications meet the requirements.
Packing: Pack the qualified finished products and label them.
Warehousing: Store in the warehouse and prepare to ship.
Diversified Customization
Gravure printing has a far superior surface finishing capability than other technologies (e.g. flexo printing, offset printing).
It is particularly suited to the refinement processing of high value-added products.
Valve
Tear Notch
Suction Nozzle
Spot UV
Silver Gold Hot Stamping
Resealable Zip Lock
Punch Holes
Plastic Handle
Metallic Color Print
Matte Finish
Holographic
Clear-Window
Available Material
The core of the performance of composite flexible packaging bags lies in the design of material combinations. The commonly used materials can be divided into three layers of the core structure :
-Printing layer (appearance and protection)
-Intermediate layer (functional barrier)
-Heat sealing layer (sealing and contact with the contents)
Through the scientific stacking to form a composite structure to meet the needs of different products.
Material for Outside (Printing and Protection)
Characteristic
PET
(Polyethylene Terephthalate)
High gloss, high temperature resistance, high stretch resistant, good printability, suitable for high definition printing (e.g. cosmetics, snack bags).
BOPP
(Bi-oriented Polypropylene)
Low cost and high transparency, suitable for labeling and light packaging (e.g. candy, cookies).
Available in matte/pearl finish to enhance texture.
PA
(Polyamide/Nylon)
High temperature resistance, high strength, good flexibility, good barrier properties, puncture resistance.
Freeze resistant (-40℃ without brittleness), commonly used for frozen foods.
Material for Middle (Functional Barrier)
Characteristic
AL
(Aluminum)
Completely blocks oxygen and light, UV resistance, fragrance wrapping,
extending shelf life by more than 3 times (e.g. milk powder, medicine).
High temperature resistant, available in high temperature cooking.
Disadvantages: Non-bendable, high cost.
PA
(Polyamide/Nylon)
High temperature resistance, high strength, good flexibility, good barrier properties, puncture resistance.
Freeze resistant (-40℃ without brittleness), commonly used for frozen foods.
VMPET/VMCPP
(Aluminum Plated Film)
Retains 80% of aluminum foil barrier, bendable and 30% lower cost.
EVOH
(Ethylene Vinyl Alcohol Copolymer)
Ultra-high oxygen barrier (<0.1 cc/m²/day), suitable for nitrogen-filled preservation (e.g. ham, cheese).
Disadvantages: High cost.
Material for Inside (Heat Sealing)
Characteristic
CPP
(Cast Polypropylene)
High temperature resistance (above 121°C), high heat seal strength, suitable for steaming packaging (e.g. instant rice).
PE
(Polyethylene)
LDPE (soft) and HDPE (rigid), good heat sealing and moisture resistance, strong tear resistance and toughness, low cost.
Disadvantages: Low temperature resistance (below 100°C).
Packaging Application
Material Structure Suggested
Ordinary food packaging
BOPP/CPP, BOPP/PE, PET/PE
For packaging which need good barrier and moisture proof
PET/AL/PE, BOPP/AL/PE, PET/VMPET/PE, PET/VMPET/CPP, PET/VMPET/PE, BOPP/VMCPP
For vacuum,frozen food packaging
PA/PE, BOPP/PE
For liquid packaging
PET/AL/PA/PE, PET/PA/PE, PET/PET/PE, PET/AL/PE
For high temperature resist packaging
PET/PA/RCPP, PET/AL/PA/RCPP, PET/AL/PET/RCPP
Address：
No.30,Shengye Road,Jinping District,Shantou, Guangdong,China.
Contact us
Address：
No.30,Shengye Road,Jinping District,Shantou, Guangdong,China.
Call Us：
Tel：+86-754-82533008
Tel：+86-13501400992
Email Us：
SALES@HQPACK.COM
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