Gravure vs Flexo
There are many misconceptions about the relative costs of rotogravure vs. flexography. For instance:
Rotogravure many years ago obtained a reputation for being a high cost process from the publication industry. The process was first used in publication and the nature of that business was usually a one-shot run. Therefore, rotogravure printing with its higher first-time cost had to be justified over a longer run, hence the adage:
"Rotogravure is a process for long runs"
Unlike publication printing, packaging normally consists of multiple production runs. (A very small volume of packaging work today is a one-run situation).
This is a very significant point, when comparing pre-press costs. In the case of flexo, there are pre-press costs associated with each run, as the following examples will show. In the case of rotogravure there is a pre-press cost for the first run, and then no cost associated with each successive re-run. The length of each run is relatively immaterial in the comparison, but the fact that after a relatively few successive re-runs rotogravure pre-press actually becomes lower in cost than flexo when considering this amortized over the life of the job.
Another factor concerning rotogravure, because of it's digital nature and the fact that almost all roto cylinders today are made using the electro-mechanical system, where a diamond stylus produces each cell; the scale of cost increase from very basic line work, or text, up to fine process tone work; is minimal. The cost of a roto engraving is essentially based on size and area, more so than difficulty.
This is not so true with flexo, where there is a much broader range of difficulty and hence costs involved, going from basic print, to high quality process work. The scale in plate cost alone can range five-times considering a rubber plate up to a high-end photo polymer.
Finally, another basic difference in flexo vs. roto printing is that rotogravure is a process that inherently can print both solids and process tones within the same image carrier. Flexo, Litho and Letterpress, because of their different ink delivery systems employed, cannot usually do this without severe compromise in quality.
For instance, if it is needed to print three colors, red, yellow, and blue in process and also the same colors in solid within the copy; rotogravure could easily do this in (3) stations. The latter processes would probably require six stations!
The following study uses data obtained from several trade houses that specialize in roto and flexo plate making as well as information obtained from printers that do their own flexo pre-press. It attempts to illustrate by practical example the cost differences that can be anticipated when considering a narrow-web press situation doing high-end tone printing.sidering this amortized over the life of the job.
Gravure vs Flexo - Results
A (6) color job, 4/c plus white and metallic, using 16" x 18" format, buying gravure bases for the job and making new flexo plates and back-ups for each run.
|Second Run||$2,174.00||$1,486.00||$ 0.00||$ 0.00|
|Third Run||$2,174.00||$1,486.00||$ 0.00||$ 0.00|
|Fourth Run||$2,174.00||$1,486.00||$ 0.00||$ 0.00|
Same as Example A except (9) colors flexo, 4/c process, 3/c line, plus white and metallic. (6) color gravure, 4/c process and line combined, plus white and metallic.
|Second Run||$3,261.00||$2,230.00||$ 0.00||$ 0.00|
|Third Run||$3,261.00||$2,230.00||$ 0.00||$ 0.00|
|Fourth Run||$3,261.00||$2,230.00||$ 0.00||$ 0.00|
Gravure vs Flexo - Conclusion
"In evaluating the data, it is obvious that the first time costs of rotogravure are more costly than the cost of flexo.
What is sometimes less obvious, is the real cost of the two processes, when compared over the life of the job. In evaluating the two examples, it's evident that in "Example A" the cost of flexo vs. rotogravure is equal after two production runs. In the case of "Example B", the break-even point is reached after just the first production run. So, when looking at the real cost, there is quite a potential savings in pre-press cost for rotogravure, when products are re-run multiple times throughout the year.
In evaluating the costs of various printing process for the packaging industry, it's important to evaluate the costs based upon the repeat runs that are common for many packaging products and not just the initial cost associated with the pre-press.
Aside from the pre-press costs, printers should also consider some of the other advantages of rotogravure:
- Easily attainable and repeatable process printing.
- Availability of printing the brightest metallic and fluorescent inks.
- Ease of handling lightweight films at high speeds with tight register control.
- The ability to create reverse printed laminated labels in-line.
- The high efficiencies associated with low cost gravure inks and high running speeds.
- Color consistency throughout the press run."
W. R. Chesnut Engineering, Inc.