Article

Haste Makes Waste? Maybe Not Any Longer

In the same way that our cars take longer to stop when we go faster, today’s high-speed conversion lines have the potential to create a lot more waste than their predecessors when something goes wrong. In any plant producing folding cartons, especially those using just-in-time (JIT) methods, such unnecessary waste can cost much more than the dollar value of the lost materials. Consider short deliveries, unhappy customers or lost orders?

So does this mean that carton makers should stick with slow-running equipment? Of course not. The way to control production waste is to train, maintain, improve and upgrade.

Clearly, the more highly trained a plant’s operators are, the less likely they are to create waste. However, the value of training extends beyond a machine’s operators to those who have an indirect bearing on the operation. Designers, estimators, assistants, and operators of upstream equipment need to understand the downstream effects of their decisions on productivity and waste.

When it comes to maintenance, a program that stresses corrective and preventive maintenance doesn’t just help productivity, but also can reduce the amount of waste caused by equipment failure. A failing component may affect performance or quality and contribute to waste for some time prior to failure.

Among the most expensive materials the carton maker handles are foils and holograms. Where a job calls for multiple foils, it is vital that the press can advance each shaft independently. Otherwise usage of all foil is determined by longest impression. Even better are the powerful computer based products, such as the OACS system available on Bobst’s Foilmaster® presses, which calculate optimum foil advance based on the foil pattern on the sheet and provide minimum foil consumption.

Additionally, register systems which ensure the precision of hologram application or shim-line detection units for pre-printed holographic patterned foil, can help ensure that every sheet foiled is a saleable sheet, or at least that it passes to the diecutter.

The latest generation of diecutters offers powerful dynamic register systems that give precise cut-to-print positioning using printed marks or the sheet edge as a reference. Such systems are useful for tight register jobs in particular where there is embossing or critical print designs.

Inline stripping and/or blank separation also can have a major effect on waste reduction, both at the diecutter and downstream. Hand stripping and separation tends to deform the printed and diecut blank to some extent and, therefore, makes it more likely to fail on the gluer line. Inline stripping and blanking is not only favorable for the folding line, but saves a tremendous amount of time over the manual alternative.

Without adequate provision for controlling quality, the potential for producing waste cartons on a modern high speed gluer line is huge — given that it could be processing as many as 50 blanks a second. A perennial problem is marking or scuffing of the print, but in most cases, this can be cured by maintaining a minimal height of cartons in the feeder. This reduces the downward pressure on each blank as the belts pick it up and so reduces the friction that causes marking.

In today’s quality conscious markets, the use of a pre-feeder ensures that only the minimum necessary number of blanks are maintained in the feeder at any one time.

Many carton makers will be familiar with modern quality assurance systems which can be configured to detect glue line or overhead glue inaccuracies, bad codes, mis-register or window errors. A good system will, if properly set, identify the non-conforming carton and then stop the machine to allow the operator to investigate the cause.

Our own Bobst folder-gluer technical specialists have observed a reduction in gluing waste of as much as 80 percent in carton plants where methodical setting has been combined with the use of a good quality assurance system.

Effective waste reduction requires a thorough study of every aspect of the production process from inventory through to waste reclamation and recycling. Minimizing production waste is a key part of this process, especially at a time when carton makers are under continued downward price pressure.  Few can afford not to look at it seriously.