By Sean Smyth, Print and Packaging Analyst
Across the world there are some 2,200-2,500 high-speed single-pass webfed inkjet press lines in operation. The equipment manufacturers have succeeded in providing very high reliability systems, with print quality steadily improving which allows the technology to be used in catalogues, magazines, marketing collateral and general commercial printing. The economics makes inkjet attractive for short to medium runs, with the inherent flexibility and variable content capability valued by print companies and their customers.
The press suppliers now offer systems that deliver the equivalent of good litho print on offset papers, although some grades benefit from priming to optimise the quality. New presses sales were interrupted in 2020 as COVID-19 disrupted the business cycles of every print operation. The cancellation of drupa meant delays in announcements and new machine launches, and the remaining installations were interrupted as restrictions prevented installation teams travelling and many print providers were unwilling to allow visitors into their plants. This meant many companies were unable to upgrade their machinery as planned. Instead they focussed on survival and then their future growth strategies, in light of the fast-changing market conditions.
COVID-19 has changed many buying patterns, forcing print suppliers to revise their production strategies in light of the market uncertainty as lockdowns and restrictions continue. Buyers are finding it difficult to make forecasts, so they demand faster response as their customer markets and requirements rapidly change. Run lengths are falling as companies act to reduce resources tied up in inventory and make changes in design to more potential consumers. Digital printing is well suited to meet these demands, inkjet providing economic advantages over cut-sheet electrophotography provided the print quality is satisfactory.
Webfed inkjet, linked with finishing systems offers a proven solution in direct competition with offset litho as well as toner printing. Anything the operator can do to boost the speed and efficiency of the production is advantageous to make it more competitive. As demand increases companies will offer overtime and may look to add additional shifts to satisfy their customers when they cannot invest in a new press. An alternative is to increase the capacity of the existing press.
There are lots of proven techniques to improve productivity, following lean manufacturing methods to minimise downtime and wastage and optimise the overall operating efficiency of the equipment. These are holistic approaches from enquiry to delivery, using workflow automation to minimise touchpoints in prepress, materials handling, printing and finishing.
A useful tool is value activity, or value stream mapping. This identifies every activity carried out over the course of a shift or a day for a machine, or a personnel member. Then determine if the activity is directly adding value to customers – if the activity does add value then continue to do it (preferably better), if the activity is not valuable then stop doing it if that is possible.
For inkjet web printing there will be press start-up routine, then make-ready and printing, with further job change overs and a close down at the end of the day (or week if running a 24 hour shift pattern). There may be necessary cleaning and maintenance routines carried out while jobs are running to make sure the quality is fine, perhaps a calibration test of a new paper substrate is needed and maybe some proofing. All these activities contribute positively to customer requirements. There are other non-productive events. The press may be delayed if there are issues with job files, but ideally the prepress workflow will ensure jobs are ready and queued in a way to reduce paper changes and keep the press printing. If there is no work the press won’t run of course, but another cause of downtime is reel changes. Depending on the reel diameter and caliper of paper there may be between six and twenty kilometres of paper on a reel. At a print speed of 150m per minute it will take between just under 40 minutes to 2 hours and 10 minutes to print the reel when a new one is needed. The time to change a reel can vary hugely, from an optimal 5 minutes to over twenty if the operator is doing other tasks. At a nominal 10 minute changeover, with a roll taking an hour to print, this non-productive time in an eight hour shift amounts to 68.5 minutes, 14.3% of the available time. Often the printed reel will be changed at the same time elongating the downtime, but this is a much faster process. In the worst case it can be almost a third of the time may be lost, in the best case (running slowly) between 5-10% of time may be lost for reel changes. If there are substrate changes between jobs there will be additional downtime, with part reels increasing the frequency of reel changes.
The print operation will often carry out printhead cleaning during the reel change to make the most of the lost time, but this may reduce the urgency of maintaining production. The economics of print production do not change for digital production, print companies only make money when they print saleable copies. This does not happen during non-productive time. Provided there is enough work eliminating lost time for reel changes is an easy way of saving a lot of non-productive time, increasing capacity without adding additional shifts or overtime. If a press has an hourly rate of €200, adding automatic reel changing can easily release €55,000-100,000 of additional machine time for a single shift operation annually, higher for multi-shift patterns. There will also be paper savings, increasingly important in printshops where flexibility means regular paper changes. So, installing an automatic reel splicer provides a short payback period as well as providing sustainability advantages, and the equipment can be switched onto any new press in the future.
Increasing market pressures in 2021 in commercial printing makes every player do more with less. Inkjet is now a more attractive option for sheet and web offset printers who need to offer greater agility to help their customers, while controlling cost and reducing their environmental footprint. Experienced inkjet printers are increasing their output by moving into commercial print where there are more substrates used, often for short runs. Even with ideal workflows to batch jobs there may be regular reel changes needed, so reducing the wasted time is proving to be valuable for all print providers. Investing in automatic reel changing equipment may be an easy win.
The digital print process is highly digitized and automated. However, one costly and time-consuming factor disturbs this efficient chain: the need to change paper reels manually.
For printers who would like to optimize their workflow, shorten their delivery times, reduce labor costs and use their web inkjet press to the max, Contiweb non-stop winding equipment is the solution!
As the demand for digital printing and the need to diversify print offerings intensifies, the need for quality printed products and higher productivity grows.
When Rotomail installed a new premium-performance inkjet printer in 2016, Contiweb’s modular CD Unwinder and CR Rewinder systems opened the door to increased efficiency, speed and time-savings.