From SCDigest's On-Target E-Magazine

- April 4, 2012 -

Logistics News: Holste on Sortation Systems in Distribution

When Sortation Systems Go Wrong, Usually Due to Insufficient Upfront Planning, Holste Says, Though Outright Disasters Very Rare Today

SCDigest Editorial Staff

SCDigest editor Dan Gilmore sat down to discuss issues related to sortation systems in distribution with our Materials Handling Editor Cliff Holste, an engineer with more than 30 years in the business, with much of it devoted to sortation systems and projects, in which he is still actively involved.

In fact, he was involved in the development of the first commercially available sortation system.

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Below, he shares his insight.

Gilmore: What are some of the first things a company that decides they need a sortation needs to consider?

Holste: I think there are a number of issues that need to be considered at the outset. For example:

• Is manual sorting (utilizing a re-circulating conveyor loop) a possibility, or does capacity/operational requirements dedicate automatic sortation?

 

• If automation is required, are the cartons conveyable and do they contain an individual bar code?

 

• Do you have the internal resources to develop the plans and specifications, and handle the purchasing and project management phase of the project or will you need to obtain outside assistance?

 

• When you include the cost of the various sub-systems that are required to feed and takeaway product to and from an automatic sorter, even the most basic entry level system will require an investment approaching $750,000 to a million dollars or more. It can go up into the multiple millions from there. Therefore, a project budget must be established and justified early on.

 

• Determine system capacity requirements - what will the sorter handle and at what rate.

 

• Develop a system concept, which should include a general arrangement layout and operations plan.

 

• Develop a comprehensive changeover plan that includes operational changes, facility modifications, and re-training of management and staff.

Gilmore: When you've seen companies not get their sorting projects right, what are main reasons things that went wrong?

Holste: In situations where system performance is poor, it is generally due to insufficient overall system planning in the concepting and budgeting phase, which can then lead to overlooking important functions and requirements. For instance, in an automated sorting system accurate and timely replenishment of active inventory is critical to maintaining sorting system performance and customer service levels. If you don't get that right, which is outside of the sortation system itself, sorter system performance will suffer or even be considered a failure.

Another example of poor planning might be in failing to appropriately design in after-sort handling and shipping capacity, which can then lead to excessive system backups and shutdowns.

Gilmore: Some companies worry that a sortation system won't be flexible enough to meet future needs, as conditions change. What are the keys to designing a system that has enough flexibility?

Holste: There are several types of sorters available covering a wide range of incremental capacities. Before selecting a sorter, determine what your current capacity requirements are then add for growth. The sorter may run initially at a speed well below its maximum design speed and then be increased as throughput demand increases.

A typical sorter, operating single shift with normal preventative maintenance, will last 10 to 15 years, and even then it can be refurbished and/or reused in a new location.

Be sure that the system layout allows for expansion to the picking system (by increasing the picking locations and/or number of pick modules) and the shipping system (by adding more sort locations). However, special attention needs to be given to the location of the sorter induction area as this is often the most complex part of the system and its location should be considered permanent.

Understand how changes in products, SKU mix, order profiles, and customer demands for value added services will affect the future system operations. Have a plan or strategy worked out for dealing with them before finalizing the system layout.

Also note that in recent years, conveyor manufacturers have made a number of improvements in their designs to increase system flexibility over time - this is a very good thing.

[See our Material Handling Tech Note: Advances in Conveyor Technology Increases System Flexibility]

(Distribution/Materials Handling Story Continues Below )