One of the enduring myths of the print/mail finishing industry centers is the belief that higher cycling speeds are the best way to boost the performance and productivity of inserting systems. But in-depth studies of scores of print/mail finishing centers across virtually every industry show that uptime or consistent performance is far more important in determining superior levels of throughput than raw speed alone.
In fact, the most impressive productivity gains are often achieved when managers carefully analyze and coordinate all of the key factors of production, including the various applications to be processed and then create material specifications and equipment operating procedures linked specifically to those applications. The result of this careful pre-planning is a level of operating performance that approaches zero defect quality and enables managers of print/mail finishing centers to fully capitalize on the faster speeds available from today's high-speed, high-integrity inserting systems.
Understanding productivity
In the print/mail finishing industry, productivity is typically measured as the total cost per good mailpiece, using a model that might include general costs such as space, capital and overhead and which also includes the costs of operators, materials, maintenance and rejected mailpieces.
Too often today, managers aren't fully aware of the huge negative impact that rejected mailpieces can have on costs and productivity, especially as inserting systems are operated at even higher cycling speeds. The problem? The cost of correcting the increasing number of errors that usually comes at higher operating speeds may diminish or even entirely outweigh the benefits of producing a higher number of mailpieces per hour. As a result, managers may never attain the productivity improvements or cost savings promised by the higher cycling speeds. Here's why.
A goal of higher speeds
Managers who use the traditional cost/productivity model for guidance when they seek to improve performance, typically concentrate on the key factors of equipment, production processes, operators and materials.
If everything else remains unchanged, they find that increasing the cycling speed of the inserting systems is often the best way to increase productivity. And in a perfect world, achieving faster cycling speeds with no stoppages or jams, the lowest possible cost for materials and no mailpieces of unacceptable quality will yield impressive gains in productivity.
But the world is not perfect. And attempting to impose these "ideal" conditions in the real world of high-speed print/mail finishing will create some frustrations.
The impact of stoppage on throughput
The real key to improving the productivity of inserting systems rests with the need to avoid or delay the onset of diminishing returns. Why? Because the fault rate or stoppage rate for an inserting system usually rises exponentially as cycling speeds increase, see Figure 1.
So to maximize productivity, managers need to keep extending the flat portion of the curve, i.e., avoid stoppages because the impact of every additional incremental fault is far greater in the higher fault region, which then negatively impacts throughput at an exponential rate.
But the impact on the cost per mailpiece is even more dramatic because the cost of manually regenerating the mailpiece can be 10 to 100 times the cost of preparing the initial mailpiece.
So why can increasing cycling speeds, without regard to the quality or integrity of the mailpiece or the efficiency or effectiveness of the processing operation, be hugely counter-productive? Because if the work process is flawed and the flaws increase at higher speeds, then speeding up the process will result in a greater percentage of flaws that need correcting.
Once managers understand how the cost of correcting errors can negatively impact the average cost per mailpiece, their focus then shifts from just increasing cycling speeds to avoiding the errors altogether. And that shift enables managers to consider an array of options to help boost performance and assure high-speed, high-quality processing.
The impact of collations on throughput
Mailing applications with higher page counts can also negatively impact the throughput of inserting systems by causing what is known as "input-constraint." This problem is not just a function of the average number of collations per hour but also of the distribution of collation size and the relative sequence in which the different size collations follow each other. The following guidelines will help improve throughput:
Any machine-induced delay is a missed opportunity to maximize productivity. The goal is to keep every chassis space full of material on every cycle. Even one minute of delay time per-hour over an eight-hour shift on a machine cycling at 12,000 mailpieces per hour is a lost opportunity to process 1,600 pieces of finished mail.
Specify materials carefully
The ability of inserting equipment to "tolerate" materials that are out-of-spec diminishes as the cycling speeds increase. To help assure peak performance, managers should pay particular attention to these four factors:
1. End clearance Assuring adequate end clearance can help managers compensate for unplanned variability in collation thickness, envelope design and envelope quality, all of which can interact with each other to impact insertion quality at high speeds.
2. Enclosure length The length of an enclosure is important, especially at higher speeds. Why? Because if · the enclosures '"skew" when placed on the chassis, a minimum length is needed to help "straighten out" the enclosure orientation and avoid a jam. Enclosures are less likely to skew at slower speeds plus material flow problems are easier to correct.
3. Collation thickness The thickness of a collation, along with the variability in thickness, can significantly reduce throughput and consistency of operation, especially at high speeds.
4. Envelope design Inserting systems have preferred envelope designs as well as designs that should be avoided. Key design issues include: size variability, total glue area, catch points, curl and paperweight. Managers can also specify alternate envelope feeders to handle non-standard envelope designs and construction.
The impact of cycle speed on costs
As the illustrations in Figures 2 and 3 show, cycle speed is only one of several factors that determines the cost per mailpiece. In fact, Figure 2 shows how the cost per mailpiece drops only marginally with increasing cycle speed for different rates of damaged mail. However, Figure 3 shows how higher cycling speeds tend to magnify the negative effects of other variables, causing the cost per mailpiece to increase and throughput to drop dramatically. The cost of damage and the stoppage rates are significant and exponential.
The lesson to learn? Managers and equipment suppliers should work together and focus on stoppage and damage rates as the principal factors for improving the cost effectiveness of inserting system operations. At low speeds, the cost per mailpiece is influenced by cycle speed and stoppage. But at high speeds, the cost per mailpiece is influenced more by the stoppage rate because a high stoppage rate both reduces throughput and escalates the cost of regenerating an increasing number of replacement mailpieces.
Different considerations for different sites
No two print/mail-finishing sites are identical. And that's a key reason why print/mail finishing managers should employ a sensitivity analysis using a cost model to determine the best sequence for addressing the multiple issues that are involved in minimizing costs.
For example, using the values from the models such as those included here, managers can answer questions like:
Key factors influencing throughput
While numerous issues can influence throughput at any print/mail finishing site, five factors are predominant and often account for more than 90% of throughput performance.
Application and system design Print/mail finishing managers and equipment suppliers should thoroughly review all existing and potential applications prior to specifying any equipment requirements. The review should include all the factors associated with the application such as coding symbology, input form, enclosure and envelope characteristics, fold requirements and collation specifications.
It may also be useful to conduct qualification runs on similarly configured equipment to make sure all intended applications can be processed smoothly. If alternatives are recommended such as code and material design or envelope vendors, the equipment supplier should quantify how the recommendations will impact throughput and cost per mailpiece.
Material quality and specifications Many organizations try to reduce costs and boost the return on marketing expenditures by purchasing materials that are inferior or uneven in quality. But poor quality in either materials or the printing of barcodes can result in increased stoppages, particularly at higher speeds, and the anticipated savings may never materialize.
Skills of operators and service personnel All system settings become far more critical at higher operating speeds. Equipment operators must be thoroughly trained in setups, adjustments and troubleshooting if peak levels of productivity are to be achieved. Operators should also employ a systemic rather than an intuitive or shotgun approach when troubleshooting stoppages.
Work cell design Operator fatigue can often result in sloppy work performance. In fact, equipment operators have been known to "dial down" high-speed inserting systems and operate the equipment at less than optimal speeds simply because they are unable to keep up. A good work cell design along with a thorough analysis of workflow and workload can help assure that high levels of throughput are achieved and maintained.
System maintenance Preventative maintenance is essential to the continued optimum performance of any high-speed inserting system. Managers must assure that the focus and procedures, during in between PM, are maintained for maximum performance.
Making a successful switch from fast to faster requires extra effort. But the extra effort can pay a huge dividend by assuring that faster also means more productive as processes become more precise, operators become well trained and procedures for selecting and handling materials are improved.
Ajay Ghia is the vice president of Marketing and Product Development at Pitney Bowes Document Factory Solutions. For more information on production of inserting systems in the print/mail industry, you can visit the company's Web site at www.pb.com.
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