Flexographic Printing Technology In Asia - part 3

The following article is not exhaustive and only able to cover a small angle of the very complex comparison of flexo and gravure printing technology. I would be happy about feedback and further input from converting companies that are using rotogravure and/or flexo printing technology to print packaging. The article is intended to ignite conversations about advantages and disadvantages of flexographic printing in Asia as well as the opportunity to establish flexographic printing as a more widely used and complementary printing technology in Asia, next to the already established rotogravure printing technology.

During the last 20 years I have been promoting flexo printing technology in Asia and during all these years I have encountered many conversations with gravure printers regarding the main advantages and disadvantages of flexo printing compared to rotogravure printing.

Gravure printing is still the dominating printing technology for flexible packaging with a percentage of far more than 90% of the total flexible packaging printing market. This clear domination might change in the future. A strong change would require support from governments for environmental reasons and the important subject of sustainable packaging, requests from print buyers as well as flexonomics.

1.      Sustainable packaging

Under the leadership of the Chinese government, we see that more and more Asian governments are focusing on the aspect of environmentally friendly printing and sustainable packaging. This gives flexo printing a great opportunity to show the clear advantages of the flexographic technology in terms of sustainable printing.

What are the reasons for flexo printing being more environmentally friendly than the current gravure printing technology?

The ink commonly used in flexo printing is alcohol-based ink, which is creating a healthier work environment for the operators than the conditions caused by toluene and MEK, the solvents commonly used in gravure printing in Asia. Toluene and MEK in flexo ink would harm and dissolve the flexo printing plate, whereas the plate is resistant to softer flexo solvents like Ethanol and a low percentage of Ethyl acetate (EA). Moreover, the flexo printed packaging does not run the risk of traces of toluene and MEK, which is clearly a risk of a major part of today’s gravure printed packaging in Asia.

There are more and more requirements to use water-based ink for packaging printing. Water based ink has been used in flexo printing for more than 20 years. Over the years there has been a very positive technological development and a huge accumulation of knowledge and experience, which can be used in the day to day operation of printing companies, which are aiming for the use of water-based ink. The experience and development of water based flexo inks have been ground breaking in order to achieve good printing quality, bonding strength and suitability for even high-performance packaging applications.

Gravure cylinder imaging is using various processes (copper and chromium plating) that need to be handled with very high care from a point of view of environmental regulations, whereas the imaging of a flexo plate can apply a process, completely solvent free.

Usually the set-up waste is higher for a gravure machine than for a flexo machine. Flexo technology can lead to the use of less resources like film. Moreover, flexo printing uses less ink and solvents.

Gravure printing usually requires stable films like PET and BOPP with certain minimum thicknesses in order to achieve a good colour register. Unstable and thinner film creates the risk of stretching in the machine and can lead to a higher register tolerance. Most of the flexo printing machines, which are printing flexible packaging, are using a central impression (CI) cylinder and are called CI-flexo printing machines. The CI-cylinder supports and cools the film during the printing and drying process. This feature has the result that even very thin and flexible substrates can be printed with an excellent colour register.

This fact enables down gauging and the use of innovative films and hence, the consumption of less and more environmentally friendly plastic in our packaging. Moreover, less expensive films like low density polyethylene (LDPE) can be used for many packaging applications with a good printing quality.

This becomes a very important issue when we consider sustainable packaging with the use of mono-structure laminates, based on (barrier) PE films and PE mono-structures, which could replace more complex structures with PET and BOPP, which are not easily recyclable.

2.      Print buyers

Different from other parts of the world, in Asia, print buyers usually determine the choice of the printing process used to produce a certain type of packaging.

Many brand owners (print buyers) are focusing in their mission statements on sustainability and governments are requiring them to use sustainable solutions for packaging. Hence, we see pressure on the packaging printers to use more and more flexo printing. From some printing companies I have heard that in spite of the mission statements, brand owners are usually not willing to pay more for sustainable packaging printing. Hopefully this will change and brand owners should put a higher value (and price) on sustainable packaging.

Sustainable packaging (and flexo printing) can be used as well as a marketing tool to promote sustainable packaging. Brand owners can use this tool to signal to their customers that the product is packed in sustainable packaging, that it has a higher value and that it meets the expectation and requirement of the consumer to buy sustainable products.    

We see that there are various print buyers in Asia, which are actively asking for flexo printing. This is usually done for the above described reason as well as for one additional issue: Brand owners would like to print the same type of packaging worldwide with the same printing process to have a worldwide uniform look of a certain brand. Packaging in USA and Europe is commonly printed with flexographic printing technology; hence it makes sense that packaging of top selling products from USA and Europe (e.g. snack food) is printed as well in Asia with the same technology.

In spite of this positive trend, we see that many (especially local) print buyers still prefer gravure printing and use gravure friendly printing designs. In order to improve the situation for flexo printing, packaging designers should learn how to create a flexo friendly printing design in order to play out the flexo strengths.

Whenever a printing company asked me to help with the evaluation of an investment in flexo printing, I have always urged the printing company to include the print buyer in the investment decision and develop the flexo investment project together and be clear about the pros and cons of flexo printed packaging.

3.      Flexonomics

Besides the aspects, sustainability and brand owners, it is highly important to evaluate as well the economics of flexo printing and potential advantages and disadvantages in terms of margins and productivity.

Flexo printing requires a higher skill level of the operator, who are required to follow a very standardized process (especially for repeat jobs), e.g. in terms of using the correct anilox sleeve and double tape for a certain print design. In Asia it is still difficult to find operators with a profound flexo knowledge and experience. These are valid arguments against flexo printing, but the issues can be solved with training and turned around by creating an attractive high skill profession “flexo printer”. On the one hand the flexo printer might demand a higher salary for the higher skill set, which needs to be considered in the calculation of total cost of ownership. On the other hand, we need to account for the fact that a CI-flexo machine usually requires far less operators than a standard rotogravure machine.

Rotogravure printing is the common printing technology in Asia and prices of rotogravure cylinders and ink are very low. This is based on economies of scale as well as a strong competition between multinational and local manufacturers. As a result, in Asia rotogravure consumables usually are less expensive than flexo consumables.

Nevertheless, a cost calculation, which stops at higher prices for operators and consumables is surely not complete. Factors like time to market, faster turn around, start-up waste, change-over times, energy cost, labour cost of less operators, labour efficiency - based on a cleaner work environment -, process efficiency and productivity, ink and solvent consumption, substrates, explosion danger, Extended-Colour-Gamut-Printing (ECG) etc. need to be taken into account and a detailed cost-benefit-calculation needs to be established.

Flexographic technology allows for a shorter time to market and job turnaround than rotogravure technology, since the imaging of the flexo plate is by far faster than the imaging of a gravure cylinder. A full set of flexo plates can be imaged within a couple of hours.

A flexo press produces usually less waste, especially less start up waste. The web length in the machine will be shorter in flexo than in a typical gravure machine. Register adjustments are achieved more quickly with flexo than in gravure and the register is stable during the print job, even if the machine speeds up and down. This leads to the fact that a CI-flexo machine does not require an auto-register system.

A flexo machine can be run by one person and the job change over is usually very fast. With a modern CI-flexo press a new job can be up and running in less than 30 minutes.

A flexo machine is more compact and uses less energy, i.e. to run the machine and for the drying. In a CI-flexo machine there are only two drying units and less ink needs to be dried in flexo compared to rotogravure printing.

Flexo consumes less ink and less solvent, which leads to savings, even if the flexo ink is slightly more expensive (e.g. in Asia) than gravure ink.

In a flexo press the ink system of the machine is designed as a closed loop. This leads to less solvent evaporation during the printing process as well as a reduced risk of explosion. Moreover, it is very common to use water based flexo ink. Water based ink does not require an explosion proof machine, which reduces the machine investment and insurance premiums.

A CI-Flexo press can print very thin and stretchable substrates. Films like 12-micron LDPE can be printed with an excellent colour register, which makes flexo printing the dominant printing technology for breathable films used in various hygiene products.

Within the trend to sustainable packaging it is very common to down gauge substrates and use innovative, often more stretchable substrates, which cause challenges for a standard rotogravure machine. A CI-flexo printing machine can print such substrates at high speeds with excellent register accuracy. This opens up the opportunity to reduce cost by thinner and less expensive substrates and to improve the productivity of the machine in order to reduce the cost per printed unit.

Another advantage of flexo is the possibility – based on the very accurate colour register – to substitute pantone colours by extended colour gamut printing (ECG). ECG can be achieved with fixed palette colour systems like CMYK or CMYKOGV and leads to greater productivity and lower running cost of the printing press thanks to fewer wash-ups, less down time between jobs (ECG avoids the common colour matching process on the press). ECG can almost eliminate the need to print spot colours and the printer can bundle different printing jobs on the same printing plate. As brand owners are starting to understand the advantages of ECG, they might be open to accept slightly bigger tolerances in delta-e values for the printing of pantone colours with ECG.

Thank you very much for your time to read the article until the end. The article is intended to ignite conversations about advantages and disadvantages of flexographic printing in Asia as well as the opportunity to establish flexographic printing as a more widely used and complementary printing technology in Asia, next to the already established rotogravure printing technology.

There are surely valid arguments in favour of rotogravure printing as well as valid arguments for flexographic printing. I am convinced that it is very important for every flexible packaging printing company to evaluate flexo printing as a complementary printing process, at least for a small and potentially growing part of flexible packaging printing jobs.

Please let me know if I can provide further information and/or help you in the process towards flexographic printing. Thank you very much for your attention and consideration.

Joerg Kullwitz, Singapore, 04.09.2020