Improving Flat Mail Preparation at USPS - CiteSeerX

Improving Flat Mail Preparation at USPS John S. Usher and G. Don Taylor Department of Industrial Engineering University of Louisville Louisville, KY 40292 USA Abstract This paper presents the results of an effort aimed at identifying significant research issues related to the handling and preparation of flat mail by the United States Postal Service (USPS). We present a summary of the work including a brief problem statement, a review of existing literature, and the results of fact-finding visits to a number of printers, mailers, and postal processing and distribution centers (P&DCs). In particular we focus on research issues related to procedural changes, potential enhancements to the existing AFSM 100 sortation system, and physical handling methods & equipment.

1. Introduction The AFSM 100, (see Figures 1 & 2) has been designed as an answer to high-speed sortation needs for flat mail. The machine sorts magazines, catalogs, circulars, some newspapers, and oversized envelopes (flats) at more than twice the speed and at less operating cost than existing USPS flat sorters. It utilizes automated feeders, bar code and optical character recognition (OCR) capabilities, and on-line video coding for non-OCR flats. Designed and built by Rapistan Systems and Northrop Grumman's Electronic Sensors and Systems Sector, it is replacing the current FSM 881 and FSM 1000 systems. The system has throughput in excess of 15,000 pieces per hour and now processes approximately 35% of all flat mail. Nearly 600 of these systems will be in operation by May 2002.

Figure 1 – AFSM 100 Input Stations

Figure 2 – AFSM 100 Output Bins

2. Problem Statement The introduction of the AFSM 100 into P&DCs has vastly improved sortation speed, but corresponding improvements to flat mail preparation, presentation, and internal material handling lags behind. Part of the problem is that the USPS, in an effort to provide its customers with maximum flexibility, permits a wide variety of flat mail products (like magazines, brochures and catalogs) to be considered as “machinable flats”. Other problems with flat mail preparation stem from the variety of sources of flat mail for a typical P&DC, (see Figure 3). Because of huge variation in the ways that flat mail such as are produced, incoming flats arrive in a wide variety of forms including: stretch wrapped pallets stacked with banded bundles, loose flats in postal trays, large bags of loose flats, and many other specialized containers. USPS workers must move the unit loads to various areas in the plant to pre-sort bundles and trays. Bundles must be unpackaged, which involves manually cutting plastic-wrap, bands, and strings using simple hand tools. Most of the packaging materials are difficult and tedious to remove and care is needed to

prevent product damage. Once the material is removed it must be disposed of which requires additional floor space and processing time. Once unpackaged, flats must be “faced” with bar code up, and with bindings all in one direction, into an “ergo-cart” (see Figure 4). Each ergo-cart holds approximately 3,000 pieces of mail, and takes about 30-40 minutes for one worker to load. Ergo-carts are then moved to the input stations of the AFSM 100. There, operators manually load handful-size stacks of flats from the ergo-cart onto the induction conveyor at one of three stations on each AFSM 100. USPS standards indicate that three workers are needed to prep mail to maintain pace with the average rate of 15,000 pieces/hour on a 1st class sort, and 13,000 pieces/hour during a 2nd class sort on the AFSM 100.

Printers

Mailers

Consolidators

Other USPS Facilities

USPS Facilities (P&DC, BMC, and Sectional)

Figure 3 – Sources of Incoming Flat Mail

Figure 4 – Ergo Cart Used for Flat Mail While the sortation speed and throughput of the machine is extremely high, the preparation and supporting material handling functions are virtually all manual and labor intensive. For the USPS to obtain full value of the sortation automation, these supporting activities must be improved. The USPS Corporate Flats Strategy [1], prepared by Operations Planning and Processing at the USPS, contains a wide array of information about USPS plans to improve overall processing of flats, but provides no specific recommendations regarding material handling system design changes to reduce preparation costs. An intensive review of the engineering literature reveals no studies directly related to preparation of flat mail. Numerous papers have been published on other areas of mail handling and automation such as bar code readers, scanning, and OCR (See for example, Patel et al. [2], Itamoto et al. [3], Iwakawa et al. [4], or Holden [5]. For robotic applications, see Garibotto [6]. For ergonomics related issues of mail

handling, see Derksen et al. [7] and Stalhammar et al. [8]. For literature related to a variety of mail sortation and handling systems, see Maloney [9] and Glaskin [10].

3. General Findings The project team visited a number of postal facilities, printers, mailers and consolidators in VA, KY, IN, OH, IL, and WI. In every facility studied, workers and management provided numerous comments about problems involving flats preparation, including: • Difficulty in meeting standards. • High variety of packaging types which requires excessive handling time. • Difficulty in opening plastic wrapped bundles with the tools provided. • Excessive handling required for bundles that are banded and then wrapped. • Excessive waste produced which increases overall area cleanup time. • Static electricity caused by individually wrapped magazines. • Bundles already low-level sorted (5-digit) being sent for processing with 3-digit sorted mail. • Improperly trained bundle sorting operators. • Insufficient quantity of ergo-carts. • Tedious manual lifting tasks. • Lack of resources to meet overall demand for mail preparation.

4. Handling and Presentation Options In this section, we enumerate and discuss three broad sets of ideas for improving the handling and preparation of flat mail: procedural issues, AFSM 100 changes, and changes in physical handling methods. Each idea listed serves as an opportunity for further engineering research. Particular emphasis needs to be placed on the economic justification of these research ideas. 4.1 Procedural Changes Increased Use of Banding - Postal workers have indicated that they prefer banding to plastic or shrink-wrap that is more difficult to remove, creates more waste, and is more likely to create damage to the mail. However, plastic wrap is preferred by printers and mailers because it protects their product from environmental elements, provides security from tampering and prevents loose inserts from falling out during handling. Loading of Managed Mail Into Ergo-Carts - Some sites double-handle flat mail by taking managed mail (from other P&DCs) out of flats trays for re-loading in ergo-carts. The AFSM 100 is well equipped for working right out of the trays in at least two alternative orientations. Given that this mail is already faced, it is likely more efficient to work managed mail directly from the trays. Mixing Mail with Different Sort Depth Levels - Some sites prepare mail sorted to various depths within a single ergo-cart. For example, 3-digit, 5-digit and carrier route sorted mail is often disbanded and loaded on a single ergocart for concurrent processing through an AFSM 100 at a high level sort. In this case, if running a 3-digit scheme, why give a discounted rate for finer sortations? In effect, this means that the USPS is paying a mailer to do a partial sortation that is not used. Handle Local Mail in Trays - Mailers that are producing bundles for local delivery should be encouraged to provide flat mail unbundled in trays. It is counter-productive to bundle mail for local delivery into 3-digit or 5-digit bundles if it must be immediately disbanded for immediate local delivery. Utilize larger 3-digit bundles - Currently, mailers produce relatively small 3-digit bundles that use a disproportionate amount of fixed labor time. The recommendation is to increase 3-digit bundle sizes, where possible, and that of providing rates to help shape customer behavior in terms of providing larger 3-digit bundles. Review Flats Rate Structures - Because mail preparation is growing in significance, new rates should be developed to better characterize preparation costs. This focus may lead to rates that encourage larger groupings in pre-sort categories. Review Definitions for Machinable Flats - The USPS currently maintains a policy that provides a great deal of flexibility to the customer in terms of defining the characteristics of machinable flats in terms of both size and address position and orientation. It would be an effective exercise to more fully examine the costs and benefits associated with the development of tighter requirements on item size, address position, location and orientation. Eliminate Sacks - No existing material handling container is more universally disliked than sacks. While they allow for dense shipping, they are bulky, hard to open and hard to manage. The recommendation is to eliminate, to the extent possible, sacks from mail streams serviced by the AFSM 100.

Consider Increases in AFSM 100 Capacity - Current corporate standards demand a high utilization for AFSM 100 machines, (typical utilizations are ~20 hours per day). A reasonable question to ask is whether the target utilization levels have been established based on direct labor savings at the sortation equipment itself or whether they have been 'optimized' relative to total cost considerations including the preparation task as well. Consider Changes to the “MechJust” Justification System - Thoroughly review the justification systems in place at the USPS to ensure that they meet current needs for justification of automation. Ergonomics Issues - The labor intensive task of flat mail preparation has the potential to increase USPS costs in terms of lost hours due to injury or disability associated with lifting or repetitive motion. The recommendation here is to more thoroughly review all manual lifting tasks to prevent such injuries. Improve Training - A common complaint among flats preparation workers is that non-machinable mail is often sent to the AFSM 100 from the Small Parcel & Bundle Sorter (SPBS) and from elsewhere. This may indicate that persons in the mail stream prior to the AFSM 100 require additional training regarding which mail is machinable. Review Work Standards Associated With the AFSM 100 - Undertake an examination of the obstacles preventing expected performance and tackle the problems in rank order of perceived contribution to substandard performance. Improve Communications and Cooperation With Customers/Suppliers - Effectively communicating with mailers and printers and even with customers is an effective way of problem solving. Part of this communication process is formal (consider, for example, the messages sent to mailers via rate structures) and part of it is informal. All avenues of communication are valuable. Organizations such as the Mailer's Technical Advisory Committee (MTAC) are especially useful to the USPS. Avoid overcompensation in ergo-carts and bundles - A common observation is that mail is often overcompensated to account for differences in thickness of the binding. For example, a bundle might be built with 10 mail pieces with the thick side one way, followed by 10 more with the thick side facing the other way, etc. Compensation requires the AFSM 100 induction personnel to feed mail to the machine in very small volumes or to take the time to decompensate the mail prior to loading. Training is required to reduce over-compensation. 4.2 AFSM 100 Enhancements Consider Modifying the AFSM 100 to Increase Output Bin Locations - The standard AFSM 100 configuration has 120 output bin locations. If the number of output locations were increased, the machine could increase the depth of sortation permitted. This, in turn, would make the use of larger bundles more cost effective because additional zip code locations could be banded together for a common sort which leads to reduced mail preparation time. Consider Modifying the AFSM 100 to Read Both Sides of the Mail - The ability to read both sides of flat mail would help decrease mail prep time because it would no longer be necessary to 'face' the mail. Consider Modifying the AFSM 100 by Increasing the Number of Input Stations - The current process for loading the AFSM 100 involves the use of preparation personnel and machine feeding personnel because of limited input space availability at the machine. If feeding personnel take the time to prepare the mail for the sortation process, the machine is under utilized because of the preparation needs. If additional input stations were available, it would be possible to shift some preparation personnel to the machine itself. In this way, the double handling of mail by two different people could be avoided. There would be no need to load ergo-carts or flats trays with faced mail because the facing and mail orientation tasks could be completed at the machine during input. The disadvantages are the costs associated with the machine modification and perhaps more importantly, the additional floor space needs for additional input locations. Consider Modifying or Enhancing the AFSM 100 to Print Addresses - Even though the printing and sorting task is generally done in separate facilities (i.e., a printer/ mailer and the USPS), this still is a form of double handling. If the AFSM 100, or a machine attached to the front of the AFSM 100, had the capability to print addresses on a flat mail piece, additional double handling could be reduced. In this scenario, the mailer/printer would send nonaddressed mail pieces in bulk on pallets, logs, or some other form of dense, efficient packaging to the USPS along with an electronic listing of addresses. These dense packages of product could then be loaded onto the AFSM 100 using something similar to the mechanical assist equipment currently under development by the USPS in Merrifield, VA. The AFSM 100 would then print an address on the mail piece and send it to an appropriate output bin for delivery according to any sort depth desired by the USPS. Consider Modifying or the AFSM 100 to Automatically Label & Sweep Trays - Even though this is not related directly to the mail preparation task, it could lead to improvements in the total efficiency of the machine by eliminating the need for output side personnel. A side benefit might be that such automation would help to support the use of the AFSM 100 in a two-pass Delivery point Sequence (DPS) scheme in the future.

4.3 Changes to Physical Handling Methods and Equipment Ergo-Cart Inserts - The ergo-cart has been very well received within USPS facilities as a convenient and labor saving device. It has not been designed, however, for use outside the USPS or within transportation equipment. It is simply too large and cumbersome for inter-facility movement and does not lend itself to dense packing during transit. The proposal is to make use of an ergo-cart 'insert' that is effectively a flats tray designed to fit in the ergocart. Dimensionally, it would fit within one of the four spring-loaded, vertical slots on either side of the cart. The idea would be for printers/ mailers to load the 'inserts' directly in their own facility with faced mail. Just as in current practices, the mail would necessarily be compensated (but not necessarily banded) within the insert to account for the thickness of binding on the edges of the mail. The inserts, which are also hopefully sized to be pallet compatible, could then provide a means of providing mail security while maintaining the ability to densely pack the mail for efficient transit. Upon arrival in USPS sortation facilities, the inserts could be loaded directly into ergocarts for immediate shipment to the AFSM 100. In this way, the double handling of the mail during the preparation process could be avoided. Pallet-Sized Ergo-Cart Insert - In this case, the insert would likely be in the form of a large insert that would be removed from the ergo-cart for transport to/from the mailer or printer and loaded on the ergo-cart within postal sortation facilities. In effect, this option makes use of a removable rigid component that fully utilizes 1/2 of the ergo-cart. Closure would be similar to that presented in the previous section, perhaps a pallet-sized, corrugated slipsheet with banding. Several layers of this insert could be palletized for transport. The primary advantage of this option over the single-column insert discussed previously would be a slight reduction in handling brought about by the fact that no additional inserts would be utilized within the four ergo-cart columns. This reduced handling would likely further enhance the ultimate readability and machinability of flat mail due to reduced tearing, jamming, and mis-sorts. A disadvantage would be the empty container storage requirements at customer sites. Logs of Flat Mail Greater Than 24 Inches in Length - Currently, long bundles called “logs” are used by printers within and between their own facilities, but are not frequently used to ship products to the USPS. Advantages would be gained in terms of a larger unit load size and less handling. However, additional compensation may be required and log 'twisting' is introduced with larger logs as well. Logs are even heavier than large bundles and wooden endblocks are much more likely to be required than sortable cardboard for mail protection purposes. This option needs additional study. Extended Buffers to Attach to AFSM 100 Input Stations - The current practice of building compensated columns of mail for AFSM 100 input is inefficient. At the induction point, postal personnel must re-handle faced mail, decompensate it, and transfer it to the machine input buffer. The use of an extended input buffer would eliminate this double handling, eliminate the need for de-compensating, and would remove the transfer requirement. The basic idea would be to use a flexible (or rigid) conveyor system attached in some manner to the end of existing induction buffers. Preparation personnel could then build horizontal, faced, de-compensated 'logs' on the conveyor for transfer in large quantities to the machine input buffer. Once placed on the conveyor, the mail would be ready for immediate induction to the machine. An additional holding fixture may or may not be required. Automatic Bundle Opener - Currently, postal employees utilize cutting tools to open bundles manually. The process is very slow and is often a limiting process associated with the loading of ergo-carts. An automated opener could easily keep up with a human mail preparation worker. In spite of the difficulty associated with design, an automated bundle opener may be useful in the field Consider Increasing the Use of Flats Trays Throughout the System - This option is presented with a disclaimer that it may not be feasible, but it is a popular option with postal mail processing employees. The basic idea is to make increased use of flats trays instead of using bundles, whenever possible. The advantage of this is that postal employees feel that the flats tray is a convenient size for lifting and handling, the AFSM 100 input station is compatible with the tray, and the existing flats tray is compatible with automation already in place in many facilities. Customers have other concerns associated with the use of the flats tray in the field, including empty storage space and shipping considerations Ergo-Pallet Fixture at AFSM 100 Induction Sites - The ergo-cart is universally praised within postal facilities. However, it is too large, heavy and cumbersome to be accepted for use at customer sites. Mailers like to use pallets because they can be densely packed in transit. The problem with pallets is that postal employees working in AFMS 100 induction areas find them less acceptable than the ergo-cart. Effective application of pallet lifting devices may help alleviate this problem and in turn reduce the double handling of mail as pallets could be moved directly to AFSM 100 for induction. Development of a Mechanical Assist Device - several variations on a mechanical assist device have been proposed. The idea is to develop a device capable of assisting a human operator by grasping a larger stack of loose flats for transfer of mail to the AFSM 100 induction site. It must be capable of working with pallets or ergo-carts. Initial

prototypes have been relatively unpopular, as they have been found to be too slow and cumbersome with an endeffector capacity that is too small. Research is needed here to build a better device.

5. Conclusions This paper provides a comprehensive listing of ideas related to procedural change opportunities, equipment modifications, and handling improvements within the general area of flat mail preparation. Each of these represents a potential topic for further detailed engineering research. It is important to note that such research should also consider how postal rates would likely need to be adjusted to make the strategies attractive enough to the USPS customer base to entice them to participate in solutions. It is the hope of the authors that one or more of the ideas presented herein will lead to improvements at the USPS or at least add credibility to an established idea. In the end, the authors and the USPS have the same goal of making flats automation as effective as letter automation, thus passing on value to postal flat mail customers.

References 1.

United States Postal Service (2001), Corporate Flats Strategy, Operations Planning and Processing Group, USPS, July 2001.

2.

Patel, M. Shreesha, V., Hecht, K., Cox, J., and Schultz, (1995), “CCD-Based POSTNET Bar Code Reader”, Proceedings of SPIE, International Society for Optical Engineering, Philadelphia, 164 -169.

3.

Itamoto, Y., Watanabe, K., Egami, K., Uematsu, S., (1991), “Development of a Flat Sorter”, NEC Research and Development, 32(3), 410-420.

4.

Iwakawa, M., Shingu, S., Kato, H., Mutoh, H., Kakisima, T., and Watanabe, M., (1999), “Development of Wide Area Scanner for OCR Flat Sorter”, NEC Research and Development, 40(23), 171-175.

5.

Holden, C., (1997), “Artificial Intelligence Goes Postal”, Science, 275, p 1073.

6.

Garibotto, G.B., (1999), “Computer Vision and Robotics in Postal Automation”, Human Systems Management, 18(3), p 265-273.

7.

Derksen, J.C., Van Riel, M.P., Van Wingerden, J.P., (1994), “A Comparison of Working Postures of Parcel Sorters Using Three Different Working Methods”, Ergonomics, 37, 299-309.

8.

Stalhammar, H.R., Louhevaara, V. and Troup, J.D.G., (1996), “Rating of Acceptable Loads in Manual Sorting of Postal Parcels”, Ergonomics, 39, 1214-1220.

9.

Maloney, D., (1999), “Smart Sorting Drive New Business”, Modern Materials Handling, 54(13), 74-76.

10. Glaskin, M.(1998), “First Pass the Post”, Engineering, 239(4), 20-21.