Short run packaging: Intermittent offset or digital

The shrink in print volumes and move of multiple jobs to digital has been a driving change with number of commercial printers moving into packaging field. With labels and packaging still sustaining reasonable growth, this market seems to hold future though crowding is likely to occur sooner than later. With the general field of packaging, short runs or just in time packaging solutions seem to hold a niche market area with considerable promise. The challenge only is to address the market with right technology. Here Ranesh Bajaj, director, Creed Engineers tries to place his point of view in order to define the parameters to conduct a comparable study for better selection between these two technologies.

Project: A typical short run job (Labels or Cartons);
Print-run: 5,000

VINSAK L400 Digital Color Label PressLet us take a size of such product to be 200 mm X 250 mm. Though for a label, this seems to be a little large in size, for cartons in most applications, this is a standard size and for the purpose of comparison this will be an ideal size.

A typical web width of digital label or carton press will be 330 mm and hence for the intermittent offset we will stay with this web width itself. Based on this web width, such a job as above would be in linear meters 1,250 linear meters of substrate.

Most digital presses (with the exception of the latest generation UV inkjet presses) work at a speed of 10 to 12 meters per minute when running in the 6 or 7 colour mode. Based on a set up time of say a max of 10 minutes per job, and a running time of 125 minutes for 5,000 pieces (of size 200 x 250 mm), a total process time of 135 minutes per job is achieved. Assuming eight hours of running and 25 days in a month, the machine will be able to deliver 3.5 Jobs per day or 90 Jobs per month.

An intermittent offset press on the other hand works at an optimum press speed of 40 m/min (max mechanical speed being 70 m/min). Also the set up time on such a press for a 7 colour job with automatic inking and automatic register would be 40 minutes and a running time of 31 minutes (considering the same size with volume of 5,000 pieces), a total process time of 71 minutes is achieved. Keeping the eight hours per day running and 25 days in a month, the offset machine would be able to deliver 7 Jobs per day or 175 jobs per month.

To find out your process times for typical jobs, log on to www.vinsak.com/jrtc.xlsx and download your own job run time calculator.

A typical digital press today costs say USD 900 K and a typical intermittent offset press costs USD 600 K, the per hour cost of the digital press continues to be 1.5 times that of the offset. On top of the same the running cost of a digital press continues to be at least four times higher than an offset press after catering to set up waste, origination costs and click charges or cost of consumable.

A deeper detailed study into this market would further reveal that for runs length of upto 300 linear meters on the digital press, the cost of digital is lower than or equal to offset and for higher than that offset continues to be cheaper. It is therefore essential for printers to do an in-depth study of the run lengths of the jobs that are available in the market and then decide on the technology that suits them best.

As markets mature and technologies evolve, these comparisons will continue to change, but in the current highly competitive market scenario, it is essential for the printers to make the right choice to survive and thrive.