Companies considering a new material handling system are often simultaneously evaluating warehouse management systems (WMS) or have already implemented a WMS. When considering an automated material handling solution such as the Kiva Mobile Robotic Fulfillment System, companies often ask how the systems will work together.
Kiva Systems provides a new approach to automated order fulfillment using a fleet of mobile robotic drive units, moveable shelves, work stations and sophisticated control software for pick, pack, and ship operations. To pick orders, operators stand at stations around the perimeter of the building while inventory is stored on mobile shelving racks, called pods. These pods are arranged in a grid pattern in the interior of the building; when an operator requires an item for an order, a mobile robot brings the pod containing that item to the worker’s station. The worker picks the items they need out of the pods and places them into the orders they are working on. Once the items have been picked, the mobile robots return each of the pods they are carrying to a storage location on the grid floor (which is frequently a different location than the one it picked the pod up from). Each worker is usually supported by 5-10 mobile robots so they are kept continuously busy filling orders. The Kiva system is useful for both split-case and full-case picking, and for fast as well as slow moving stock, across a wide range of product categories and industry verticals. All the inventory in the Kiva System is mobile so every worker has access to all products to fill complete orders at anytime.
Kiva is a total fulfillment solution that incorporates hardware and software elements to perform replenishment, picking, and shipping sortation. During implementation, the Kiva software is integrated with the client’s enterprise systems, and typically the primary interface point is a warehouse management system.
The simple way to think about the interaction between a WMS and a Kiva system is to think of Kiva as the forward pick and order sortation zone contained within the facility-wide sphere of WMS control.
Inventory from storage locations defined in the WMS is replenished into the Kiva zone. Orders are passed from the WMS to the Kiva system for processing. All of the operations within the Kiva zone are handled by the Kiva hardware and software system, and completed orders emerge from the Kiva zone/system. Those orders are passed back to the WMS to manage the shipping or other downstream transactions. This is an over-simplification of what actually happens, but it is a good starting point to describe the relationship between the two systems.
A warehouse management system is used to control the overall flow of materials through the warehouse (or distribution center). While different WMS systems offer different capabilities, the most common modules include the following process areas:
• Receiving
• Replenishment
• Slotting / Location Management
• Picking
• Packing
• Quality Control
• Shipping
• Labor Management
At its core, a WMS is designed to track inventory as it is processed into, stored, moved around and transferred out of a facility, while providing a systematic way to conduct distribution processes.
The Kiva material handling system (MHS) is the software component of the Kiva solution that tracks and directs all processing within the Kiva system. It integrates directly to the WMS and exchanges various types of information with it, much like a warehouse control system. The MHS is not designed to replace a WMS, though there is some overlap in functionality. Instead, the MHS manages all the Kiva gear (robots, pods, stations and wireless infrastructure) along with the inventory SKUs, orders, and work in the Kiva zone. The MHS reports operational status and transactions back to the WMS.
Both the WMS and MHS track the inventory stored in the Kiva zone, but the level of location granularity is different. To the WMS, inventory in the Kiva zone is typically all contained in the logical location ‘Kiva_Zone’ which may be physically quite large. On the other hand, the Kiva MHS track of the exact location of all inventory within the Kiva zone down to the bin location on individual pods. Additionally, the pods are constantly changing positions so the Kiva system also tracks the individual pod locations within the Kiva zone in real time. Strategies for the amount of inventory to hold in the forward Kiva zone vary by customer, but a common approach is to keep 3 to 7 days of stock for fast moving items and just a few cases for slow movers. Products that tend to ship in full pallet quantities are not usually held in the Kiva zone. They are stored and picked from traditional racking and merged with orders coming out of the Kiva zone at shipping.
While a WMS is the most common enterprise touch-point for the Kiva MHS, some clients do not utilize WMS packages. In these cases the MHS is interfaced with ERP systems, order management systems, or some form of legacy inventory and order processing system. Kiva provides an agent-based integration layer as part of the standard MHS software package that transfers the necessary message sets to and from WMS and other enterprise systems.
For a company that already uses a WMS or is considering both a WMS and a Kiva system, the following illustrate, how the functionality of a WMS is affected by the presence of a Kiva system.
The Kiva MHS does not handle receiving functions. When products are first brought into the building, they are typically reconciled against purchase orders and inspected – this function remains unchanged in the WMS when a Kiva system is implemented..
The movement of product from a reserve warehouse storage location to the Kiva forward picking zone can be handled by either the WMS or MHS, depending on the solution design. In a distribution center where reserve product is stored in pallet racks and cases are brought forward manually to fill a Kiva forward picking zone, it is typical for the WMS to “push” inventory to Kiva. However, since the Kiva system keeps track of all inventory held in the Kiva zone and all orders that are pending against that inventory, Kiva can also issue a “pull” request to the WMS to transfer inventory from the reserve area to the Kiva zone. In a system where reserve inventory is stored on Kiva CaseFetch pods within the Kiva zone and moved to a Kiva ItemFetch system for picking, Kiva manages the movement automatically.
In a Kiva system there are no permanent locations and thus no “slotting” of the pick zone in the traditional sense. Unlike traditional automation approaches where the capacity of forward pick locations is constrained by rack size and a static layout, the Kiva system implements a flexible, mobile storage paradigm. A Kiva design includes Kiva storage pods to hold all fastand slow-moving items in whatever quantities are necessary. And, all items are available to any operator at any time. To do this, Kiva actively manages the constantly changing locations of all products within the Kiva zone.
When products are replenished into pods, the system selects the best pods to hold the merchandise based on a sophisticated strategy that encompasses pod type, merchandise characteristics, available pod space, pod proximity to replenishment & picking stations, like-item consolidation, expiration dates, lot integrity, companion items, product/ SKU movement and other factors. During the replenishment process Kiva station software controls a laser pointer that directs an operator to the best bin for each item. In deciding the optimal bin for each item, the software considers a broad a set of product characteristics including weight, pick velocity and pick ergonomics. Additionally, the MHS can be configured at installation to accommodate operator directed put-away rather than system directed put-away for situations where large segments of the stored product and pod configurations are fairly homogeneous.
The Kiva system calculates the optimal storage location on the grid floor for each pod based on a complex algorithm that takes into account product pick volumes, SKU popularity, number of pods containing the same items, station locations, order history, current orders, etc. Finally, the decision about where to place each pod is revisited every time it is moved, so the storage aspect of the Kiva system is constantly adapting to optimize the processing for the entire operation. Traditional “slotting” is not required with a Kiva system because Kiva continuously and dynamically “re-slots” the entire Kiva zone in real-time without human intervention.
The Kiva system is a real-time order picking solution that does not require batching and waving of orders. Batching and waving is meant to improve the utilization of traditional warehouse automation equipment. However, these practices introduce operational complexity and increase cycle time. The kiva solution is built on flexible, parallel processes which make batching and waving unnecessary.
Orders are passed to the Kiva MHS directly from the WMS or order management system, and Kiva manages the order pool and pick operations to maximize throughput while meeting downstream shipping commitments. Generally, no order manipulation outside of the Kiva MHS is required. The Kiva MHS assigns multiple orders to each worker at her station, retrieves the products the worker requires, and directs the worker in the picking and packing process. Orders can be picked to totes, cartons, pallets or other containers. Pick & pack workflows are configurable in the Kiva system to provide scanning, special verifications, multi-picks, single picks, value-added activities and other work steps to meet the unique requirements of each client.
Order pickers typically work on several orders at once and pick orders to completion, rather than pick partial orders and pass containers to workers in other zones as is often the case with traditional automation methods. The Kiva approach results in extremely short cycle times. Packing activity such as labeling, documentation, tape and dunnage application, and other shipping preparation actions may be completed in pick stations or at separate pack stations depending on the most efficient design for the client’s order profiles. Value-added steps such as gift wrapping, personalization, promotions and other order specific tasks can also be done at pick, pack or specialized stations within the Kiva zone. The Kiva system manages all of these work flows and processes then passes the completed order notifications back to the WMS.
High quality, in terms of inventory and order accuracy, is a core benefit of the Kiva system. Quality is built into the standard system-guided processes encompassed by the Kiva solution. Laser pick-light indicators for picking and replenishment, put lights for directing item placement into orders, barcode scanning and easy-to-follow operator screens deliver industry-leading accuracy for both correct items and quantities throughout the system. As such, many Kiva clients have been able to eliminate quality control (QC) checks. Kiva recognizes how critical quality is to distribution operations and offers several levels of quality control functionality.
The QC of orders can happen within the Kiva zone or after the orders leave the control of the MHS, though there are substantial benefits to allowing the MHS to guide this process. Quality control strategies vary from enterprise to enterprise and the MHS includes a flexible set of rules for conducting QC within the Kiva zone. Examples of these include: random checks, checks based on merchandise and/or order profiles (e.g. check orders with high value items), checks based on picker profile (e.g. check all or every fifth order picked by a specific worker) and combinations of rules. Alternatively there are Kiva implementations where order QC is conducted downstream of the Kiva zone and all of the handling and rules governing this activity is under the purveyance of the WMS.
Kiva solutions achieve world-class accuracy levels for both orders and inventory, but some operator error is still possible. Maintaining bin accuracy and detailed inventory visibility are high priorities at each Kiva installation. Quality control of the Kiva system/zone for inventory integrity is accomplished via a number of features for cycle counting merchandise stored in the Kiva zone. There is a robust set of tools for identifying and adjusting inventory as necessary within Kiva and synchronizing with the WMS.
The Kiva MHS does not interact directly with transportation providers or handle other shipping transactions that require passing data outside the facility. The Kiva system does not create shipping manifests. These tasks are accomplished by the WMS (or other shipping system). The Kiva MHS will acknowledge when complete orders have moved out of the Kiva zone and into shipping so that the WMS can update the order status appropriately.
From an operational standpoint, the Kiva solution adds value to the shipping process by automatically delivering completed orders directly to the correct shipping docks in the most efficient sequence and timing to optimally load trucks, satisfy route plans and deliver efficiency outside of the warehouse. In this capacity the Kiva system performs the role of a shipping sortation system, but the shipment transactions themselves are handled by the WMS.
Most WMS packages include some type of labor management module which tracks and reports labor efficiency across the zones, activities and processes under the control of the WMS. Labor management data is core to the Kiva system. With Kiva, processes are standardized to a detailed task management level and each operator action and transaction is automatically captured for reporting and analysis. Reports can be generated for individual operators, teams, departments and custom groupings.
The Kiva system enables in-depth labor management for all functions encompassed by the Kiva zone without requiring additional data capture or equipment not included in the base solution.
Workers in the Kiva zone are always on task, and work independently of other pickers/packers/replenishers. Pickers select complete orders so worker productivity is not impacted by upstream and downstream processes. This allows management to fairly and reliably measure activity, provide incentives and target training for workers performing the bulk of the work in the distribution center.
The Kiva Mobile Fulfillment solution is a game-changing automation technology for distribution environments. Kiva systems are typically integrated with a WMS package. There is moderate overlap in functionality between Kiva and WMS applications, but the primary responsibility of the Kiva system is to act as the forward pick & pack zone within the overall set of distribution center processes and operations that are managed by the WMS.
The content & opinions in this article are the author’s and do not necessarily represent the views of RoboticsTomorrow
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