Strengthening your supply chain one link at a time. 

Distribution Center Oddities or Normal Best Practice? You Decide?

I have visited hundreds of distribution centers over my 32+ year career and have seen a lot of things.  Sometimes, I find myself saying ’Nobody Does That’, but over the years I have learned to keep an open mind.  Instead of mumbling to myself, I will ask the operations manager, ‘Why Do You Do That?’ and often get one of these responses – “I wasn’t here when that was installed”, “It works for us”, “We’ve always done it that way”, and/or they provide a valid (and good) reason.

Then, inevitably, I start seeing the ‘Nobody Does That!” process in multiple warehouses.  Let me share some of these findings and you can decide if ‘Nobody Should Do That!”.  Some of these have been best practices for years, others might be new to you, and some could be worth considering in your operation.

Pallet Flow as Push Back

The concept of using pallet flow rails to enable a push back system is something that I have seen a lot over the years.  The value of push back is allowing you to stock and pull pallets in multi-deep lanes from the same aisle, increasing storage density.  And it is cheaper to use the pallet flow vs. push back, so why not always use pallet flow vs. push back rack?  The first constraint is the pallet weight and depth of the system.  If dealing with a 5+ deep pallet system, it is likely the pallet flow design isn’t feasible given the extreme weight to push back on the pallet flow rails.  The other consideration is even if you are using a two (2) or three (3) deep pallet system, you should utilize a braking system to stop the pallets.  But I have seen many with this design with no braking system, and use of just taller pallet stops – scary!

Wooden Pallet Supports

The use of wood (2” x 4”) as pallet supports, cut to fit within a pallet rack position (~42”) versus using typical metal bars.  I have seen this in retail and industrial distribution centers, and in multiple states.  Prior to seeing this in multiple facilities, I thought it was only for those with reduced budgets.  Is this a bad idea?  Is it better than not having supports?

In one location, the wood supports were not secured to the beam, and in that situation, it was a bad idea.  In the other facilities, the wood supports were secured to the beams and appeared very steady/strong.  An obvious consideration is wood can catch on fire and is more likely to break.

Picking Cases From 2-Deep Back-to-Back Rack Rows

This process is to use a 2-deep pallet rack position on the floor or push back rack in a back-to-back double-deep rack configuration for picking full cases.  The double-deep storage (reserve) above can be push-back (or pallet flow), or double deep rack.  But, given you have a double deep rack row behind, you can’t use 2-deep pallet flow rack on the floor for picking cases (you could use 4 deep pallet flow, but that’s not the point of this item).  Operators want the dense storage and are comfortable with using the 2-deep positions on the floor for picking cases.  Is this crazy?  Don’t you only do this when using 2-deep pallet flow to pick cases?

It seems that if you have a high-volume item that is going to deplete 2 pallets in a few days, you can replenish the 2 pallets and keep going.  For me, the idea of leaving the back-pallet pick position empty for more than a day is bothersome.  It is true, that the 2^nd pallet in a pallet flow design may also sit empty until that front pallet gets near empty.  But with pallet flow, you can replenish the 2^nd pallet from behind easily.  In a push back design, you must wait until the front pallet is gone before replenishing the pallets.  Alternatively, you can bring the 2^nd pallet when the remaining pallet has just a few cases, remove the partial pallet, top off with cases, stock a full 2^nd pallet, and replace the partial pallet with topped off cases.  Doesn’t that sound painful!

Also, if using 2-deep floor positions within the rack, I have seen people climbing through the first position to reach the back position (because they don’t want to pull the pallet forward).   While you can use the same process as above with pushback to replenish with two pallets.

The alternative is to separate the back-to-back double deep rack rows to add a replenishment aisle and use pallet flow rack (and/or carton flow rack). But this takes more space and lowers the storage density.  So, I have learned to be ‘okay’ with using push back on the first level for case picking, if the storage density of the warehouse is a priority.

Other mentions… This blog is getting too long!

• Pick from bins vs. vendor box – to bin or not too bin is the question. Bins result in increased picker efficiency and more units in the pick face, so it can be worth the added replenishment labor.
• Carton flow rack set-up to flow away from takeaway conveyor – come on, nobody should do this.
• Pick & replenishment traveling on same conveyor – lower investment, but increased risk of congestion on the conveyor system and within pick zones (even if the goal is to replenish on separate shift).
• Pallet jacks vs. pallet riders for order picking – there are people pulling pallets with manual jacks along 200+ foot-long pick paths. But, the added investment in electric pallet jacks, or pallet riders is worth the increased picker productivity and reduced injuries.
• Pallet rack tunnels – forever a great use of vertical space above storage cross-aisles. And, the added value is to provide required egress and shorter travel.  But, some are placing tunnels at the end of aisles – hum.  This does provide a walk-way and can be used for workstations/printers.  However, it feels like a safety concern with people walking directly in front of the end of rack aisles.
• Pick onto 1 or 2+ pallets – many operators have found a way to pick to multiple pallets (using pallet riders) for single orders and to batch multiple orders in the pick path. Make it happen if you want to lower labor costs.
• Carton flow rack with one SKU per level – typically an eight-foot wide and deep carton flow bay is designed with 20+ faster moving SKUs to leverage the investment and provide a dense pick area. So, designing the system with only one SKU per level (3 to 4 total SKUs per bay) in order to reduce the frequency of replenishment limits the intended value.
• Pallet positions with mixed SKUs – a sign of needing more space!

Keep an eye out for odd / unique solutions if touring in other facilities.  You might find something that works well for your operation!   And, if you are doing something that seems unique / different, but it is working for you, keep it going!
 
—Norm Saenz, St. Onge Company
 
 

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