Challenge the cost advantage of flexographic printing

In recent years, people seem to be keen to talk about the many advantages of flexographic printing, thinking that flexographic printing is the most effective printing method for packaging printing. Various magazines, study classes, and international industry exhibitions are also strongly promoting flexographic printing. It seems that compared with gravure printing, flexographic printing is inherently low in equipment cost, requires fewer operators, and has a short job replacement cycle. Such advantages, so it can meet the customer's short delivery time requirements.

But is this really the case? Is flexographic printing really as good as people say? GAA publishes an article by Jim Fishwick of ValmetRotomec SPA that compares and analyzes the costs of flexo printing and gravure printing in packaging printing, including various cost components and benefits, and concludes. The following is a translation of the article and hopes to help the printing business leaders who are engaged in and preparing to invest in the packaging and printing industry make the right decisions.

The true cost of flexographic printing

There is no doubt that in the field of flexible packaging printing, flexographic printing has made significant progress in quality and speed. However, from an objective point of view, compared with gravure printing, these are probably worth discussing. If only flexographic printing provides the latest technology at the lowest price, it is certainly not practical, and it is not. real. The fact is that the quality of the flexographic printing can only be the same as the gravure printing quality (in this case the cost of the flexographic printing will be higher). Therefore, it is necessary to unlock the "cost advantage" of flexographic printing. In the following analysis we will take a fair look at the advantages and disadvantages of the two processes.

Process Cost Analysis

In any form of packaging printing cost structure, except for the cost of the packaging material, it mainly consists of the cost of the machine, the cost of the job copying, and the cost of the printing plate.

1. Machine hour cost

Whether it is flexographic or gravure printing, machine-hour costs include many similar components, such as energy, plant, standby time, machine management expenses, and the like. Here we assume that these costs are "neutral", that is, these cost factors are not much different in flexographic and gravure printing. Other factors that make up the machine's hourly cost are the depreciation expense based on the machine cost and the employee's labor cost, among which the machine depreciation cost is the one with the greatest impact among all the cost factors.

There is often a common misconception or prejudice in real life that flexible printing equipment is cheaper than gravure printing equipment. However, the price analysis data from a company that produces both machines simultaneously (this company also produces soft and concave combination printing equipment) shows that gravure printing equipment is actually cheaper than flexographic printing equipment for high-end configurations at the standard configuration level. Nearly 30%. For modern flexo, gravure printing equipment, the staff costs are usually the same, with two operators per machine.

From the above analysis, it can be seen that the machine-hour cost of flexographic printing is actually higher than that of gravure printing (mainly the equipment cost of flexographic printing is high, and the labor costs of the two are not significantly different). Next we can also see that even if we assume that the machine's hourly cost is the same, we will still get surprising conclusions.

2. Job copy costs

Job copy costs include the cost of imposition and proofing (flex print and dot gain compensation costs). For flexo printing and gravure printing, the job copy costs are basically the same (approximately 220 euros/color). In many cases, an eight-color flexo printing job can be completed by a seven-color gravure printing, mainly because gravure printing can print high-quality color printing. Here, we still omit this advantage of gravure printing and assume that the two processes are the same for the same job.
After we made the above two assumptions, we would come to the conclusion that the cost per color is determined by the difference in the cost of the flexo and gravure cylinders. However, before we discuss printing costs in depth, let's take a look at the performance of the two printing presses and the difference in ink usage.

(1) Printing machine performance Each printing company will have its unique production process and structure, so all costs are controversial, but we can still affirm the following points:
1 Any flexographic printing press, even if it is fully automated and equipped with a robot, requires much more time and effort than the "sleeve type" gravure printing press for a 10-color flexographic printing press. In fact, the change time usually takes 2.3 to 3 hours, while the 10-color gravure printer only takes 1.5 hours.
The structure of the 2-rotary rotogravure printing press is very simple, mainly consisting of a plate cylinder, an ink tank, a doctor blade and an impression cylinder.

The structural simplicity of the gravure press provides a higher level of repeatability and reduces the time required for plate change, so even short runs can be completed more quickly. Today, connection processing is essentially an essential function of the press. In flexographic printing, there will be more factors that need to be controlled, so its speed can only be reduced. For the time being, regardless of the print quality problem of flexographic printing, assuming a machine hour cost of 500 euros, the extra two hours would add a cost of 125 euros/color to an eight-colored job.
(2) Ink dosage and its difference

Here we do not consider the cost of ink production, only consider the cost of the quantity. Due to the higher density of the flexographic printing ink, the amount of ink required per printing unit is higher than that of gravure printing. If gravure printing uses conventional heavy duty inks, its ink volume situation is essentially the same as flexographic printing. However, the newly developed "light" gravure printing ink significantly reduces the amount of ink required. At the same time, the structural design of the inking system has also been improved. Some gravure printing machines can use 7 liters of ink to complete the entire ink delivery cycle, while flexographic printing requires 15 to 20 liters, so the management costs of gravure printing inks are also reduced ( Especially when doing short-lived work).

3. Printing plate cost

(1) Cost and reuse of flexographic printing plate

Some European printing companies' analysis shows that the production cost per copy of flexographic printing is approximately 220 euros/color, and the cost per color plate is approximately 380 euros/color (plus the cost of platemaking: 160 euros/color). Some people may want to say that the reuse factor of flexo printing is, we cannot ignore the factor of reusing flexo printing. However, cleaning and stripping flexo plates is a labor intensive and time-consuming task, and used, restocked plates can become deformed, hardened, and brittle, so their service life is limited. Practical experience shows that the reusability of flexographic printing plates is approximately 50%, so the cost of reprintable plates in flexographic printing can be reduced to 80 euros/color.

(2) Thin-walled flexographic printing plate sleeve

For short runs that require repeated printing, flexo printing can use reusable thin-walled flexo printing sleeves, which cost about €140/color.

(3) Installation cost of flexographic printing plate

The flexographic printing plate is highly technical, and an experienced proficient person may take about 20 minutes to prepare the platen and install the plate, which takes nearly 2 hours and 10 minutes for an eight-color job. Correspondingly, an eight-color gravure printing machine using a sleeve type drum takes only 1 hour and 30 minutes. Another point to consider is that the installation of flexographic printing requires the use of tape (about 13 euros/color) and an anilox roller with a fine number of screens (more than 4500 euros/root), and each flexographic printing press tends to have Equipped with several anilox rollers for each unit, this also greatly increases the cost of flexographic printing.

(4) The cost of a gravure plate cylinder

The cost per gravure plate cylinder (in Europe) is about 630 euros/color, and the corresponding cost in the flexo printing described above is 380 euros/color, so the difference is about 250 euros/color. However, the gravure roll can withstand 5 million impressions (approximately 4 million square meters of printed material can be printed). Experience shows that the general short-lived version needs to be changed after eight times. As a result, the difference in remastering costs is only €51 per color.

in conclusion

Table 1 summarizes the cost-per-color difference between the flexographic and gravure printing processes (without considering the machine-hour cost, in fact, the cost of the flexographic printing is higher). Table 2 shows the cost comparison of an eight-color active print 6 times.

A slight analysis of Table 2 shows that for the first print, the cumulative cost per color for flexographic printing was 518 euros/color, for gravure printing was 630 euros/color, the difference between the two was 112 euros/color, and flexographic printing dominated. However, it can be seen next that when the second printing, the two differences become 51 Euro/color, and the gravure printing is dominant, and in the sixth printing, the difference has been increased to 718 Euro/color. It is 6,000 euros per job, of course, still dominated by gravure printing. As a result, the more frequently the job is printed, the more economical the gravure printing process will be and therefore it will be a better choice. ※