SmartTurn Inventory and Warehouse Management Best Practices Series
If your operation is one of the tens of thousands of warehouses in the United States still using paper, Microsoft Excel, or processes first developed in the late 70s/early 80s, we’re here to help. To give you tools, information, guidance, tips, proven methodologies, we offer you the forthcoming "Best Practice Series for Inventory and Warehouse Management."
If your operation is one of the tens of thousands of warehouses in the United States still using paper, Microsoft Excel, or processes first developed in the late 70s/early 80s, we’re here to help. To give you tools, information, guidance, tips, proven methodologies, we offer you the forthcoming "Best Practice Series for Inventory and Warehouse Management."
Best Practices for Picking in Warehouses and Distribution Centers
Posted 10-23-2008 at 02:27 PM by Kevin Collins
Best Practices for Picking in Warehouses and Distribution Centers
In our recent Best Practices for Putaway chapter, we discussed how to efficiently move items from receipt to storage. Gazing at the inventory now stored throughout your warehouse, what are you going to do when an order comes in? With some industry estimates suggesting that order picking represents more than 60% of warehouse operating costs, few warehouse management decisions have as much effect on your profitability.
The modern warehouse and inventory business is much affected by the sense of immediacy and instant gratification that characterizes the age of the modern consumer. Your customers probably have a much greater expectation of short order cycle time and prompt delivery than ever before. Whereas same-day shipping was very rare decades ago, customers now expect much shorter cycle times, in addition to high degrees of accuracy. To deliver on these expectations, you need to evaluate how picking integrates into the receiving and shipping processes that bookend it and try to optimize the overall process.
Efficient picking begins with efficient putaway. By doing an efficient job in choosing where and how to position inventory items on shelves racks or in bins, you set yourself up for successful picking.
(If you haven't read the Best Practice chapter on putaway yet, read it first so that that you'll have more contextual understanding of the information that follows below).
OK, now that you understand what you should be doing as far as putaway, let's look at some of the factors that will affect your decision on which picking method to implement in your operation.
Some warehouses can use a single picking method. To truly optimize most operations, however, management may well have to use a combination of picking methods. Additionally, your picking method should evolve as products and the types of orders you receive grow in their diversity and volume.
Defining Your Key Picking Objectives
As you design your picking operation, think in terms of three key objectives; increasing productivity, increasing accuracy and reducing picking cycle time. Here are definitions for each:
A few words on product availability. Firstly, you need to regularly review your slotting processes to ensure that they aren't harming your picking. This is particularly important if your operation uses fixed picking locations.
Three Primary Picking Systems
Which picking system should you use? There is no golden rule other than pick the system (or hybrid system) which meets your needs.
Although we'll discuss them at length in the following chapter, there are are five common picking methods: basic picking, batch picking, multi-order picking, zone picking and wave picking. (In the next chapter, as we drill down into each picking method, we'll discuss the pros and cons of each, as well as the individual technologies and equipment you'll need to implement them).
Technologies in Picking Operations
To give you an idea why we need a complete separate chapter to explore best practices in picking methods and the myriad technologies to implement them, here are just a few of the choices:
Regardless of the picking system you select and the method and technology needed to implement it, you need to have some process of verifying outbound shipments. You need some checking method to catch mistakes before they reveal themselves when the customer opens the package. Did you get everything right? Pickers will make mistakes. It is unavoidable. What you should aim for is catching these errors before the goods leave your warehouse. Ideally, your quality assurance or quality control system will catch them while the picker is in front of the picking slot. If your system requires some kind of data entry (ID bar code or UPC code scanning, for example), you'll reduce shipping errors dramatically.
You need to understand the present and project into the future. Similar to many of the other best practices we've already explored in previous chapters, you need to analyze existing data to select and implement the best picking systems and methods. Some of the metrics to analyze include: total picks and orders, quantity and picks per order, and picks per SKU. Projecting future growth is really, really important, especially when you are considering installing automated systems. They can be very expensive--and generally have capacity limitations, In contrast, if you use manual picking methods, you can usually just hire more people when business expands. If your automated system is maxed out and business volume jumps, you have a problem.
If you take nothing else away from this chapter, understand that your picking system must minimize walk time and product handling. Each unnecessary footstep taken by a picker reduces optimal efficiency, as do multiple touches of items. The simplest and easiest way to avoid these situations is to locate product by pick frequency. The center of your picking world should be those items that comprise the majority of your orders. By analyzing your data, you may learn that a small percentage of items comprise half or more of your orders. Stock the fastest moving SKUs as close to the pick point as possible and at easily accessible heights. Consider picking from both sides of the aisle, using small pick facings as well as using batch picking, which is picking multiple smaller orders in one trip. Put slow movers further away from the action.
Picking optimization isn't a point in time; it is a constant process that requires investment (figuratively and literally) from everyone in your organization. While the technology part is critical–picking systems range from simple racks and shelving, to very complex systems that may incorporate multiple pick methods, and multi-million dollar investments in equipment–so is the human capital.
Make sure that your top and middle management are invested in the success. Don't just give lip service and then point accusative fingers when picking productivity and accuracy rates are lower than projected. On-going training and picking system review are mandatory as is some kind of rewards system for high achievers.
Kevin Collins,
Director, Product Management
SmartTurn, Inc.
177 Fremont St.
San Francisco, CA 94105
USA
Sales: 1-888-667-4758
Tel: 1-415-685-4200
Fax: 1-415-685-4201
About SmartTurn
SmartTurn™ Inventory and Warehouse Management System is the first true on-demand warehouse management system to provide enterprise class functionality at a fraction of the cost of traditional license and install software. Designed for quick implementation, ease-of-use, real-time inventory accuracy and warehouse performance, the SmartTurn system provides visibility on every item across single or multiple warehouses. Founded on the premise that software should be smart, simple and safe, SmartTurn’s customers span the value chain of most industries to include manufacturers, wholesalers as well as 3PLs. SmartTurn is privately held and backed by leading investors, NEA and Emergence Capital Partners. Website www.smartturn.com
About the Author
Mr. Kevin Collins joins SmartTurn having been in the warehousing and distribution business for over 15 years, where he fulfilled leadership roles for a military distribution company, a third party logistics service provider, a heating, ventilation and air conditioning company, a retail service warehouse and a general merchandise/wholesale grocery warehouse where he also partook in two acquisitions. Mr. Collins has spent his entire career learning the art of warehousing and logistics, and has been in every conceivable role within a warehouse. During his career span, Mr. Collins has also had the privilege of working directly with application developers learning about software from inventory and procurement to transportation and warehouse management systems. Mr. Collins brings to SmartTurn an invaluable background and information about processes, software and logistics, and the intricate balances between them.
In our recent Best Practices for Putaway chapter, we discussed how to efficiently move items from receipt to storage. Gazing at the inventory now stored throughout your warehouse, what are you going to do when an order comes in? With some industry estimates suggesting that order picking represents more than 60% of warehouse operating costs, few warehouse management decisions have as much effect on your profitability.
In this chapter, we'll look at Best Practices for Order Picking. We'll look at various strategies, planning issues, and options you can investigate when planning your own picking design. (We'll also touch on technology options but only briefly. In the next chapter, we'll dive down in much greater detail into picking methods and their relationship to diverse picking technologies that range from cheap and expensive, to decades-proven and cutting edge).TIP: The average warehouse or distribution center will have many more shipments than receipts so if you have to choose, concentrate on picking optimization over receiving optimization.
The modern warehouse and inventory business is much affected by the sense of immediacy and instant gratification that characterizes the age of the modern consumer. Your customers probably have a much greater expectation of short order cycle time and prompt delivery than ever before. Whereas same-day shipping was very rare decades ago, customers now expect much shorter cycle times, in addition to high degrees of accuracy. To deliver on these expectations, you need to evaluate how picking integrates into the receiving and shipping processes that bookend it and try to optimize the overall process.
Picking Strategies: Success begins with Putaway
Efficient picking begins with efficient putaway. By doing an efficient job in choosing where and how to position inventory items on shelves racks or in bins, you set yourself up for successful picking.
(If you haven't read the Best Practice chapter on putaway yet, read it first so that that you'll have more contextual understanding of the information that follows below).
OK, now that you understand what you should be doing as far as putaway, let's look at some of the factors that will affect your decision on which picking method to implement in your operation.
- What product or types of products/items are you shipping?
- Are you picking pieces, cases or pallets?
- How many transactions do you expect to pick per day?
- How many orders and how many picks comprise a typical order?
- How often are individual SKUs included in an order?
Some warehouses can use a single picking method. To truly optimize most operations, however, management may well have to use a combination of picking methods. Additionally, your picking method should evolve as products and the types of orders you receive grow in their diversity and volume.
Defining Your Key Picking Objectives
As you design your picking operation, think in terms of three key objectives; increasing productivity, increasing accuracy and reducing picking cycle time. Here are definitions for each:
ProductivityProduct Availability and Location are Critical
This is the answer to “how many?” Productivity within a piece pick warehouse is generally defined as the number of items you can pick per hour. Warehouses using case picking and pallet picking will typically measure cases per hour, and pallets per hour, respectively.
Accuracy
This is the answer to “Did you get it right?” How many picks does your team do correctly? What is the percentage of shipments that go out correctly? Many of the decisions you made far upstream–long before the moment when the picker is starting to fill an actual order–will affect your accuracy rate. You need to think of of how your labeling design (readability) and label production (legibility and robustness to harsh environments), as well as packaging, warehouse layout, storage design, environmental lighting, and the actual pick method(s) you choose work together because they can all influence (positively or negatively) the picking accuracy.
Cycle TimeThis is the answer to “How long did it take?” This is simply the amount of time it takes to move an order from the moment of entering it into your system, to delivering it to the shipping dock.
A few words on product availability. Firstly, you need to regularly review your slotting processes to ensure that they aren't harming your picking. This is particularly important if your operation uses fixed picking locations.
Another point to remember is that shelves and bins need to be filled. Make sure that whatever replenishment system you use keeps bins full. In an ideal world, this means that your Warehouse Management System (WMS) will only create pick lists containing in-stock items. If bins are empty, your pickers will have to stop their picking to restock through “emergency replenishments.” Not surprisingly, your pick rates will plummet. You really don't want pickers wasting their time as they correct or respond to errors in your inventory system.
Three Primary Picking Systems
Which picking system should you use? There is no golden rule other than pick the system (or hybrid system) which meets your needs.
Piece PickingPicking Methods
In piece picking, you pick individual items and put them into shipping containers (usually cartons or boxes). You often find this method in warehouses that inventory lots and lots of SKUs. When you have large quantities of items to pick (think in terms of thousands or tens of thousands of SKUs), this is typically what you will use. Your classic mail order house or parts distributor stores its inventory in fixed locations on static shelving or racks. Pickers fill one order at a time. It is a basic system that works well in warehouses that fulfill a smaller number of orders per day. As volume grows, however, the system can begin to fall apart due to excessive picker travel time and aisle congestion.
Case Picking
Case picking works for operations that aren't filling orders with open box picks. A warehouse using case picking usually has fewer product SKUs from which it fills its orders as well as higher picks per SKU. You'll see a lot of pallet jacks or pump trucks in these operations as well as motorized pallet trucks to retrieve cases stored in racks.
Pallet Picking
If you're shipping pallets out, then you're using some form of pallet picking. You've also got a lot of choices as far as storage configurations and equipment and the lift trucks/towmotors your pickers will use to retrieve pallet loads.
Although we'll discuss them at length in the following chapter, there are are five common picking methods: basic picking, batch picking, multi-order picking, zone picking and wave picking. (In the next chapter, as we drill down into each picking method, we'll discuss the pros and cons of each, as well as the individual technologies and equipment you'll need to implement them).
Technologies in Picking Operations
To give you an idea why we need a complete separate chapter to explore best practices in picking methods and the myriad technologies to implement them, here are just a few of the choices:
Automatic picking machinesQuality Control: verifying your orders
The use of fully automated picking machines is generally restricted to operations combining high volume with high accuracy requirements.
Automatic storage and retrieval systems
An expensive, high retrieval system of rows of racking used in both putaway and picking.
Automated conveyor and sortation systems
Automated conveyor systems and sortation systems are generally suitable for large-scale piece pick operation.
Carton flow rack
Similar to static shelving, except that the shelves are angled downwards, enabling gravity feed to the pick face.
Carousels
You've probably seen the horizontal carousel version of this used in your local dry cleaners. A system of hanging racks that hold storage bins. There is also a vertical carousel version found used in laboratories and specialty manufacturing operations, but rarely used in regular order picking operations.
Pick-to-light
Pick-to light systems consist of lights and LED displays for each pick location, using software to light the next pick task and display the quantity to pick.
Static shelving
Most commonly found in piece pick operations, this is best suited for low-volume small parts operations.
Voice and speech recognition
Many industry experts anoint this as the biggest technological innovation since the 1970s. While increasingly popular for inventory and receiving, it has tremendous picking application. Voice directed picking can have a huge impact on increasing productivity and accuracy.
Regardless of the picking system you select and the method and technology needed to implement it, you need to have some process of verifying outbound shipments. You need some checking method to catch mistakes before they reveal themselves when the customer opens the package. Did you get everything right? Pickers will make mistakes. It is unavoidable. What you should aim for is catching these errors before the goods leave your warehouse. Ideally, your quality assurance or quality control system will catch them while the picker is in front of the picking slot. If your system requires some kind of data entry (ID bar code or UPC code scanning, for example), you'll reduce shipping errors dramatically.
Planning Your Own Picking System
You need to understand the present and project into the future. Similar to many of the other best practices we've already explored in previous chapters, you need to analyze existing data to select and implement the best picking systems and methods. Some of the metrics to analyze include: total picks and orders, quantity and picks per order, and picks per SKU. Projecting future growth is really, really important, especially when you are considering installing automated systems. They can be very expensive--and generally have capacity limitations, In contrast, if you use manual picking methods, you can usually just hire more people when business expands. If your automated system is maxed out and business volume jumps, you have a problem.
If you take nothing else away from this chapter, understand that your picking system must minimize walk time and product handling. Each unnecessary footstep taken by a picker reduces optimal efficiency, as do multiple touches of items. The simplest and easiest way to avoid these situations is to locate product by pick frequency. The center of your picking world should be those items that comprise the majority of your orders. By analyzing your data, you may learn that a small percentage of items comprise half or more of your orders. Stock the fastest moving SKUs as close to the pick point as possible and at easily accessible heights. Consider picking from both sides of the aisle, using small pick facings as well as using batch picking, which is picking multiple smaller orders in one trip. Put slow movers further away from the action.
Summary
Picking optimization isn't a point in time; it is a constant process that requires investment (figuratively and literally) from everyone in your organization. While the technology part is critical–picking systems range from simple racks and shelving, to very complex systems that may incorporate multiple pick methods, and multi-million dollar investments in equipment–so is the human capital.
Make sure that your top and middle management are invested in the success. Don't just give lip service and then point accusative fingers when picking productivity and accuracy rates are lower than projected. On-going training and picking system review are mandatory as is some kind of rewards system for high achievers.
Remember that picking has an important effect on customer happiness so reward those who are productive, dependable, and accurate. By identifying and rewarding the high performers, you'll have a short (or long list if you have hired and trained well) of those employees best able to deliver when you really must. A similar focus on performance and accountability applies to operational efficiency. Establish order picking metrics that matter to you, such as inventory accuracy. Publish the results and trending data regularly so everyone is aware of how well the group is doing. Similarly, you need feedback to improve; It is essential to continual process improvement. Create a process of regularly soliciting feedback from your pickers to improve future performance.
Kevin Collins,
Director, Product Management
SmartTurn, Inc.
177 Fremont St.
San Francisco, CA 94105
USA
Sales: 1-888-667-4758
Tel: 1-415-685-4200
Fax: 1-415-685-4201
About SmartTurn
SmartTurn™ Inventory and Warehouse Management System is the first true on-demand warehouse management system to provide enterprise class functionality at a fraction of the cost of traditional license and install software. Designed for quick implementation, ease-of-use, real-time inventory accuracy and warehouse performance, the SmartTurn system provides visibility on every item across single or multiple warehouses. Founded on the premise that software should be smart, simple and safe, SmartTurn’s customers span the value chain of most industries to include manufacturers, wholesalers as well as 3PLs. SmartTurn is privately held and backed by leading investors, NEA and Emergence Capital Partners. Website www.smartturn.com
About the Author
Mr. Kevin Collins joins SmartTurn having been in the warehousing and distribution business for over 15 years, where he fulfilled leadership roles for a military distribution company, a third party logistics service provider, a heating, ventilation and air conditioning company, a retail service warehouse and a general merchandise/wholesale grocery warehouse where he also partook in two acquisitions. Mr. Collins has spent his entire career learning the art of warehousing and logistics, and has been in every conceivable role within a warehouse. During his career span, Mr. Collins has also had the privilege of working directly with application developers learning about software from inventory and procurement to transportation and warehouse management systems. Mr. Collins brings to SmartTurn an invaluable background and information about processes, software and logistics, and the intricate balances between them.
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