Slowing Down the Flow in Carton Flow

Impact Plate used to slow down a 48" tote full of metal stamping at the Toyotetsu plant.

How to decrease speed of cartons to reduce damage and breakage and increase safety and productivity.

In a fast paced world where speed is everything, sometimes it may make sense to slow down the flow in carton flow.

When replenishing, heavy cartons shooting down the empty lanes can gather some serious speed. The fast moving cartons might slam into another carton and damage either the master pack or the contents of one (or both) cartons. If the lane is completely empty, it may shoot straight over the built in stop and fall out of the rack. This will most certainly damage the carton and its contents but could also be a safety concern for order pickers who might be in the vicinity. There are a few accessories to prevent this; impact plates, slowdown strips.  Another option to consider would be as simple as lowering the "pitch" of the tracks.


Impact Plates

The intended use for our impact plates is to prevent damage to both the cartons and the tracks in abusive loading situations. Span-Track's aluminum rollers can be dented by rigid cartons that impact the rollers at sharp angles.  By snapping a steel plate over the first 12" of rollers or wheel, we've created a heavy duty plate that spreads out the impact force and protects the rollers and cartons. Another benefit is that it prevents the rollers underneath from turning. This is great on the charge end (loading end) if you're double or triple stacking products as you can stack on the plate and gently push them off and onto the rollers.

UNEX Impact Plate on Spantrack Lane

On the discharge (pick) end, snapping one of these in place would act as a brake. The rollers cannot spin and the friction of the galvanized steel surface slows the boxes down to a complete stop. Impact plates can also be used further up the track (underneath the second carton from the front) to relieve line pressure in each or full case pick applications. Line Pressure is the result of a full lane of cartons pushing on the first carton. As the carton is emptied in an each pick operation, the carton can collapse under the weight of the cartons behind it. Installing the impact plate under the carton in the second position alleviates that pressure, but requires the picker to pull the new carton forward.



Slow down strips are simply narrow versions of impact plates that can be installed wherever flow needs to be slowed down. These, being smaller, have less friction and allow the user to tweak the amount of braking they need for a specific carton or application. The most typical application for the slowdown strip would be in the knuckle transition (pictured below). Carton flow lanes being loaded onto empty knuckles can sometimes miss the stop entirely!


Slow Down Strip on Spantrack Knuckle



Low Profile Spantrack Install

SpanTrack installation instructions recommend an initial setup of 1 inch of rise per 1 foot of depth. A typical install would be 8" elevation over 96" deep rack setup. However, if your carton are heavier, less pitch may be necessary. This can be accomplished rather easily. First, empty the bay of cartons and remove the tracks. The hangers can stay installed. Next, lower the rear beam or raise the front beam one increment (most racks allow for 2" or 3" adjustment). You may find that the cartons will still flow at the reduced pitch, albeit slower. This alone may be enough to reduce line pressure or prevent boxes from overshooting the front stop.  Check out the video for more help.


In summary, there's numerous options for slowing down the flow of SKUs in your order picking operation. Impact plates and slowdown strips are an easy way to add some mechanical friction to the system. Reducing the pitch or slope is technique you can use to lower the speed of cartons for free!


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Posted by: UNEX