In my previous blog, I discussed Goods-To-Person (GTP) picking
systems and how they can help solve the problem of Omni Channel Distribution
for DC Managers. I don’t mean to hint that they are right for every application
or that they are the only solution to fulfilling orders for multiple channels
of distribution. GTP, like all material handling technologies, is just one tool
in the integrator’s tool box of solutions.
Traceability
I’d like to finish up on GTP systems in this blog by
talking about the lowly tote. You know, plastic totes, or bins, or stackables.
They go by many names and come in a lot of shapes and sizes. How do totes and GTP
systems go together you ask? Very well, thank you. In fact they’re almost
indispensable to a smooth running order fulfillment operation and should always
be strongly considered. Most of the time when working with a client on the
storage/retrieval element of their fulfillment system, I bring up the use of
totes for storage and 99.9% of the time my client will roll their eyes and tell
me they don’t use totes, just the carton. I’m sure they are doing the math in
their head and trying to figure out how they can justify the expense to the
boss. But as strange as it may sound, the lowly tote in automation might mean
the difference between success and failure of the overall project.
I can think of several reasons why totes are your best
option for storage and picking:
Uniformity
When we deploy any type of Automated Storage Retrieval
System (ASRS), the load size is critical of course, but so is the integrity of the load. What I mean is
that automated systems are very precise and repeatable, therefore the load
being carried and stored is factored into the performance of the ASRS machine.
If my carton size is 18 x 14 x 12 when I design the system and your vendor
decides to change the carton size to 20 x 12 x 14 next year, we have a real
problem. Maybe it won’t fit into the storage opening or the device designed to
extract the load can’t handle that extra 2” of length. And cartons have flaps
that pop up and cartons bulge and sag from humidity. Tape fails and cartons
fall apart. Any idea what that does to a mini load or carousel or shuttle
system? What I see most often is a variety (I mean mishmash) of carton sizes in
distribution centers so the sizes range all over the place. This is very bad
for an automated system. They require uniformity of load size. They run to
their optimum level of performance with a uniform load. We reduce errors and
maintenance when the product is safely tucked inside a standard size tote. With
a tote we know what we’ve got every time. With cartons, every transaction is an
adventure.
Productivity
Studies have shown that picking items from a tote is
actually faster than picking from a corrugated carton. A picker knows what to
expect every time the machine delivers the tote and that eliminates their
hesitation because they don’t have to process a variety of carton arrangements.
They don’t ever have to deal with flaps in the way. They won’t ever have to
pull an empty carton out and throw it onto a trash conveyor. In fact I can
eliminate the cost of trash conveyors in the system by having a central
“detrash” station prior to replenishment. Dividers in totes can allow for pick
multiple items for the order from the same tote and the GTP software directs them
to the proper compartment within the tote. A QC check on the product can be
done during the replenishment function, one less task for the picker to
perform. All of these little
enhancements allow the picker to produce more picks per hour, and that reduces
the overall cost of the operation. Add a few more picks per hour by a full day
and multiply that by the number of people picking and we’ve generated quite a
nice cost reduction that continues every
day we use the system.
One of the jokes we like to tell in material handling is
that all conveyors work great, until someone puts a load on it. That mishmash
of carton sizes and construction plays havoc with conveyors, sorters, label
applicators and scales. Conveyor is mechanization, a machine if you will. And
machines love uniformity.
Eventually product has to be transported from the picking
area to some other point in the DC. That may be a consolidation station or pack
station or QC area. If I store in totes and pick to totes (or shipping cartons
on trays) I can reliably and safely convey the product wherever it needs to go
in the process. Most likely we can reduce the cost of a conveyance system if we
have that uniform load in a rigid wall tote. And studies show that the cost to
maintain a conveyor system is reduced if we eliminate the contamination from
dirt, dust and pieces of corrugate.
Traceability
Collecting data during the fulfillment process is becoming
more and more important, especially if the DC is delivering to multiple
channels of sales. The use of totes makes this far easier and reliable than
trying to keep track of various cartons in a system. Tote ID labels (license
tags) tend to be more uniform when on a tote—we know exactly where the label is
every time so scanning on the fly is faster and more reliable. RFID tags can be
imbedded in a captive tote system which will dramatically increase the data
collection capability of the fulfillment operation. We can manage inventory
more accurately inside the GTP storage system with the use of uniform totes and
this data can be uploaded to the Warehouse Management System (WMS) for reliable
inventory counts. Product picked into totes and transported to packing or QC
stations can be tracked more reliably as they move along a conveyor network or
on carts. I think the word we want to remember is reliable. The use of totes in a fulfillment center can help us
accumulate and use data more reliably than with cartons. As I said before, with
a tote we know what we’ve got every time. With cartons, every transaction is an
adventure. DC Managers like to avoid adventures.
I can think of more good reasons to use standardized
totes in a fulfillment center but I think this is enough for today. Next time
I’d like to start a conversation about voice directed systems so drop me a line
to let me know how you already use voice systems, or how you might use voice
direction in your facility. I’d love to hear from you.
Have a happy and safe holiday season and thank you for reading.
Michael




