The 12 Principles of High Performance Warehousing #4: Match materials handling equipment with storage systems

Match your materials handling equipment with your storage systems, inventory and order profiles to drive efficiency and safety

Part 4 of a series on the 12 Principles of High Performance Warehousing.  The eBook can be downloaded for free by joining the High Performance Warehouse Network on the Logistics Help website.

For each storage system there will be a variety of materials handling equipment options to facilitate storage and picking.  As with the storage system each type or variant of materials handling equipment will also suit a particular variation in inventory and order profile.  This section will cover the most commonly used variations in equipment and their applications.  The eBook version of this post also includes a pictures and examples for each equipment type not included in this blogpost.

The right materials handling equipment is essential for productivity and safety
Do you have the right equipment for your warehouse?

Trolleys

• Trolleys for shelving and pedestrian picking.  Trolleys are very widely used for picking from shelving and multi-level shelving modules.  Conventional two tub trolleys are great for picking large orders of small items.  If your order profile swings the opposite way with a high volume of small orders from a large SKU range with only a few unit picks per order (a typical profile of an online direct to consumer business) then your most efficient picking method may be a multi-order picking where multiple orders are picked in one pass through the warehouse.  This requires a special configuration that lets you pick into multiple tubs (or cartons or bags) on the trolley to maintain separation between different orders.

A multi-order pick trolley with put to light technology;
very fancy but there are simpler ways to achieve the same result

• Motorised trolleys: These come in all shapes and sizes from the pallet jack or ride on order picking trolley with a motor, to the mid-level order pick vehicle like the Crown WAVE.  They are more expensive than their manual counterparts but have significant productivity and health and safety benefits.
• The pallet jack is still a very useful tool for the warehouse.   It provides pallet moving and basic case pick to pallet functionality.  It is very cheap and suits relatively low order volume use.  Past a certain order volume or size of order, manual handling and speed will become an issue and a motorised pallet mover will improve efficiency and reduce manual handling risk.
• Motorised pallet jacks are useful where the loads being moved are heavy or they are in constant use for order picking.  While they are mostly designed for pedestrian use some have fold down platforms for ride on use.  Some designs also have a lift mechanism which will lift the pallet higher to reduce back strain when transferring heavy cartons or equipment onto the pallet.  When they have a fixed ride on platform and higher performance motors and batteries the motorised pallet jack is commonly referred to as a stock picker. 

Ladders

• Do not use ladders for order picking in your warehouse.  They are slow and unsafe.  Instead use a WAVE type motorised man up order picker or similar unit.  Whilst the cost of these units may be 100X the cost of a ladder, the savings in productivity and reduced risk of injury makes them a bargain.  I cringe every time I walk into a work place and see ladders being used for stock picking.  Ladders belong in the maintenance shed not the warehouse.

Forklifts

• Walkie stacker forklifts are so called because they are operated by a pedestrian rather than being a ride on unit.  They come in a wide variety of sizes and can even be fitted to suit double deep pallet racking.  They are perfect for smaller warehouses with limited space and low movement volume.  They can operate in narrow aisles of just over 2m which allows high storage density to maximise orderly pallet storage in a limited space.
• Stock picker / mid-level stock picker.  These units are designed for fast case picking from pallet racking at floor level, although some units (mid-level stock picker) are made with lifts to allow picking from the second and third level.  They can carry up to three pallets on extended tines.  This type of machine is the mainstay of the FMCG wholesale and large retail distribution centre.  Crown equipment recently introduced a remote controlled unit that allows the operator to move the unit whilst walking along side.  This enhances productivity because the operator does not have to step in and out of the vehicle to advance it to the next location within an aisle.
• Counterbalanced forklifts are best suited to truck and container loading/unloading and moving stock and materials around in larger open areas outside and open staging areas in warehouses.  They have generally been replaced by reach trucks for accessing pallet racking, which operate in narrower aisles and have much higher mast heights.
• Reach trucks are designed for accessing pallet racking in aisle widths as narrow as 2.8m (pallet to pallet) and rack heights up to ~12m.  There are two types; moving mast and fixed mast with pantograph type reach mechanisms.  Pantograph mechanisms are generally faster and more capable but both are widely used.  Extended pantographs or extendable tines (for moving mast units) are available for accessing double deep racking.  The reach truck is the workhorse of the bulky goods warehouse and is good for mixed case picking and pallet movements, replenishing pick faces from bulk reserve storage at higher levels in pallet racking.
• Man up stock pickers are used for case picking from pallet racking above ground level. They can operate in the same racking as a reach truck or very narrow aisles like a turret truck.  They cannot remove pallets from the racks.  They are great for case picking a long tail of slower moving SKUs where there are too many items to fit into ground level pick faces.
• Turret trucks are designed for very narrow aisle pallet racking with heights up to 17m and aisle widths of only 1.8m between pallet faces.  High racking and narrow aisles provides for high density storage and is great for when large volumes of stock must be carried either due to a very large SKU range or when the lead times are long and high volumes of stock must be carried. Turret trucks are cheaper and more flexible than a crane systems, but cranes can go even higher.  Turret trucks  are suitable for bulk movements of full pallets as well as case picking a long tail of slow moving bulky SKUs.  Although they can move freely in and out of aisles they are not suitable for use in conventional pallet racking due to the lack of a guidance system.

A Crown turret truck, used to access very narrow aisle racking which provides high density storage

Specialist forklifts.  

There are a few specialist types of forklifts that are worth mentioning for completeness.

• Aisle-master:  a special type of counterbalanced forklift that pivots the mast to allow it to operate in very narrow 2m wide aisles.  In this sense they are like a turret truck but are not man up or as high masted.  They are also slower to operate.  They are not common but have their place if you need the storage density of very narrow aisle and your pallet movement volume is not too high.  They can be combined with a stock picker to provide case picking out of the very narrow aisle racks.
• Manitou:  The Manitou is really a piece of  construction/mining/agriculture equipment more than a warehousing tool, but it is a forklift and invaluable for its designed purpose.
• Container forklift:  The container forklift is used for moving containers at Ports and other container handling facilities.  Large and specialised they are an essential part of the supply chain.

Forklift Attachments

A forklift is also platform for all sorts of specialist attachments to lift and manipulate almost any type of load you can imagine.  Here are a few of the more common attachments.

• Drum handler: used to grab and move 200litre drums.  These attachments come in a variety of forms and also include attachments to safely pour from drums and to grab two or more drums at a time.
• Big box grabber:  used to move large flat sided things such as fridges and cable drums that are not stored on pallets.
• Slip sheet grabber:  If you want to save a bundle on your containerised freight then start using slip sheets.  Slip sheets allow palletised loads to be loaded into containers without the pallet and easily unloaded and palletised during container unloading.  This is much cheaper and faster and safer than hand loading/unloading containers.
• Crane jib:  Turns your forklift into a crane for moving heavy things that are not on a pallet and can be picked up with a hook.
• Safety cage:  Every warehouse with a forklift should have a safety cage.  They are invaluable for periodic maintenance tasks such as changing high bay light bulbs (if you haven’t yet converted to LED lighting) and much safer than a big ladder.

Other materials handling equipment

• Pallet stacker cranes:  These are usually sophisticated automatic storage and retrieval systems for very high density storage.  They can be combined with in rack shuttles for multi-deep storage for high volume bulk inventory.  Such installations are rare in Australia but more common in Europe where the limited availability of land and high price of real estate justifies the investment.  They can reach up to 50m in height.
• Tow tractors:  The tow tractor is designed to tow a variety of customised trailers configured for a particular application.  They are not really a warehousing machine although they could conceivably be used for order picking.  However they are widely used for a variety of logistics purposes to move materials and supplies in manufacturing, industrial sites, airports, hospitals and large institutions and other campus based facilities.  There are an almost infinite variety of these types of units for any conceivable application.

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