While it is possible to sabotage any order picking system, the
following 8 points should get you as close as humanly possible to
perfect order picking.
Automatically verify everything
Design your order picking system to double-verify every step of the
picking process. People will make mistakes – that is human nature.
But double (or even triple) checking will catch the mistakes –
preferably while the picker is still in front of the pick slot,
where correction will cost you almost nothing. A system that
requires scanning of slot ID bar code labels and product UPC codes,
along with a blind entry of the quantity picked, will guarantee the
right pick is made.
Touch items once
Touch each piece of product exactly ONCE. The pick process should
allow enough verified accuracy that further repacking, QC checking,
or shipping checking, is NOT required. A pick unit should go into
the outbound truck touched only by the original picker’s hands.
Minimize selector walking by:
Picking from both sides of the aisle, using small pick facings.
Placing slow-moving items on side aisles which are entered only
Picking many smaller orders in one trip (batch picking.)
100% product availability
Design your replenishment system to insure a selector never has to
face an empty pick slot waiting for replenishment, and that orders
never need to be segregated, awaiting missing items before shipping.
Ideally, pick lists should contain only items KNOWN to actually be
in stock at the pick slot. It is unproductive to have pickers waste
precious time correcting inventory system shortcomings.
Use ABC item analysis
If 10% of your items can completely satisfy 50% of your orders
(typically true), then I call these "A" items You can set up a short
pick line comprised of only these "A" items, and immediately half of
your orders require walking through only 10% of the pick area. Then,
find another 20% of your items that will satisfy an additional 30%
of orders, and slot them as branches off the short pick line.
Almost 80% of your orders will now require travel passing in front
of only 15-20% of your total pick slots!
Stop pick and pass line picking
"Pass-along" picking (passing totes along a conveyor line from
picker to picker), slows all orders to the speed of the slowest
picker, or, to the capacity of the busiest pick station. Pick rates
of the better pickers can often be increased by 30% to 200%, just by
switching from conveyor picking to individual cart picks.
Invest in training and quality circles
No matter how well designed your picking system WAS, changing
customer requirements will undermine its original excellence. Your
pickers and supervisors are your first line of defense against
"creeping obsolescence." An investment in productivity and accuracy
improvement (Total Quality), and management supported quality
circles that meet regularly to identify problems and propose
solutions, will pay big dividends in continuous improvement of even
an already excellent system.
Walk your talk
In my experience, the least costly, most effective way to improve
your distribution system is through direct, continuous and
enthusiastic top and middle management support, of the workers’
striving for the highest level of picking accuracy and efficiency.
Workers sense immediately, if management is only giving "lip
service" to their commitment to excellence. Caring is contagious.