WarehouseManagement Systems (WMS).
Theevolution of warehouse management systems (WMS) is very similar tothat of many other software solutions. Initially a system to controlmovement and storage of materials within a warehouse, the role of WMSis expanding to including light manufacturing, transportationmanagement, order management, and complete accounting systems. Touse the grandfather of operations-related software, MRP, as acomparison, material requirements planning (MRP) started as a systemfor planning raw material requirements in a manufacturingenvironment.
SoonMRP evolved into manufacturing resource planning (MRPII), which tookthe basic MRP system and added scheduling and capacity planninglogic. Eventually MRPII evolved into enterprise resource planning(ERP), incorporating all the MRPII functionality with full financialsand customer and vendor management functionality. Now, whether WMSevolving into a warehouse-focused ERP system is a good thing or notis up to debate. What is clear is that the expansion of the overlapin functionality between Warehouse Management Systems, EnterpriseResource Planning, Distribution Requirements Planning, TransportationManagement Systems, Supply Chain Planning, Advanced Planning andScheduling, and Manufacturing Execution Systems will only increasethe level of confusion among companies looking for software solutionsfor their operations.
Eventhough WMS continues to gain added functionality, the initial corefunctionality of a WMS has not really changed. The primary purposeof a WMS is to control the movement and storage of materials withinan operation and process the associated transactions. Directedpicking, directed replenishment, and directed put away are the key toWMS. The detailed setup and processing within a WMS can varysignificantly from one software vendor to another, however the basiclogic will use a combination of item, location, quantity, unit ofmeasure, and order information to determine where to stock, where topick, and in what sequence to perform these operations.
At a bare minimum, a WMS should: Have a flexible location system. Utilize user-defined parameters to direct warehouse tasks and use live documents to execute these tasks. Have some built-in level of integration with data collection devices. |
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DoYou Really Need WMS?
Notevery warehouse needs a WMS. Certainly any warehouse could benefitfrom some of the functionality but is the benefit great enough tojustify the initial and ongoing costs associated with WMS? WarehouseManagement Systems are big, complex, data intensive, applications.
Theytend to require a lot of initial setup, a lot of system resources torun, and a lot of ongoing data management to continue to run. That’sright, you need to "manage" your warehouse "management"system. Often times, large operations will end up creating a new ISdepartment with the sole responsibility of managing the WMS.
TheClaims:
WMSwill reduce inventory!
WMSwill reduce labor costs!
WMSwill increase storage capacity!
WMSwill increase customer service!
WMSwill increase !
TheReality:
Theimplementation of a WMS along with automated data collection willlikely give you increases in accuracy, reduction in labor costs(provided the labor required to maintain the system is less than thelabor saved on the warehouse floor), and a greater ability to servicethe customer by reducing cycle times. Expectations of inventoryreduction and increased storage capacity are less likely. Whileincreased accuracy and efficiencies in the receiving process mayreduce the level of required, the impact of this reduction willlikely be negligible in comparison to overall inventory levels. Thepredominant factors that control inventory levels are , lead times,and demand variability. It is unlikely that a WMS will have asignificant impact on any of these factors. And while a WMS certainlyprovides the tools for more
organizedstorage which may result in increased storage capacity, thisimprovement will be relative to just how sloppy your pre-WMSprocesses were.
Beyondlabor efficiencies, the determining factors in deciding to implementa WMS tend to be more often associated with the need to do somethingto service your customers that your current system does not support(or does not support well) such as first-in-first-out,
cross-docking,automated pick replenishment, wave picking, lot tracking, yardmanagement, automated data collection, automated material handlingequipment, etc.
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Setup
Thesetup requirements of WMS can be extensive. The characteristics ofeach item and location must be maintained either at the detail levelor by grouping similar items and locations into categories. Anexample of item characteristics at the detail level would includeexact dimensions and weight of each item in each unit of measure theitem is stocked (each, cases, pallets, etc) as well as informationsuch as whether it can be mixed with other items in a location,whether it is rack able, max stack height, max quantity per location,hazard classifications, finished goods or raw material, fast versusslow mover, etc. Although some operations will need to set up eachitem this way, most operations will benefit by creating groups ofsimilar products. For example, if you are a distributor of music CDsyou would create groups for single CDs, and double CDs, maintainingthe detailed dimension and weight information at the group level andonly needing to attach the group code to each item. You would likelyneed to maintain detailed information on special items such as boxedsets or CDs in special packaging.
Youwould also create groups for the different types of locations withinyour warehouse. An example would be to create three different groups(P1, P2, P3) for the three different sized forward picking locationsyou use for your CD picking. You then set up the quantity of singleCDs that will fit in a P1, P2, and P3 location, quantity of doubleCDs that fit in a P1, P2, P3 location etc. You would likely also besetting up case quantities, and pallet quantities of each CD groupand quantities of cases and pallets per each reserve storage locationgroup.
Ifthis sounds simple, it is…well… sort of. In reality mostoperations have a much more diverse product mix and will require muchmore system setup. And setting up the physical characteristics ofthe product and locations is only part of the picture. You have setup enough so that the system knows where a product can fit and howmany will fit in that location. You now need to set up theinformation needed to let the system decide exactly which location topick from, replenish from/to, and put away to, and in what sequencethese events should occur (remember WMS is all about “directed”movement). You do this by assigning specific logic to the variouscombinations of item/order/quantity/location information that willoccur.
BelowI have listed some of the logic used in determining actual locationsand sequences.
LocationSequence. This is the simplest logic; you simply define a flow through yourwarehouse and assign a sequence number to each location. In orderpicking this is used to sequence your picks to flow through thewarehouse, in put away the logic would look for the first location inthe sequence in which the product would fit.
ZoneLogic. By breaking down your storage locations into zones you can directpicking,
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putaway, or replenishment to or from specific areas of your warehouse. Since zone logic only designates an area, you will need to combinethis with some other type of logic to determine exact location withinthe zone.
FixedLocation. Logic uses predetermined fixed locations per item in picking, putaway, and replenishment. Fixed locations are most often used as theprimary picking location in piece pick and case-pick operations,however, they can also be used for secondary storage.
RandomLocation. Since computers cannot be truly random (nor would you want them tobe) the term random location is a little misleading. Randomlocations generally refer to areas where products are not stored indesignated fixed locations. Like zone logic, you will need someadditional logic to determine exact locations.
First-in-first-out(FIFO). Directs picking from the oldest inventory first.
Last-in-first-out(LIFO). Opposite of FIFO. I didn't think there were any real applicationsfor this logic until a visitor to my site sent an email describingtheir operation that distributes perishable goods domestically andoverseas. They use LIFO for their overseas customers (because oflonger in-transit times) and FIFO for their domestic customers.
Pick-to-clear. Logic directs picking to the locations with the smallest quantitieson hand. This logic is great for space utilization.
ReservedLocations. This is used when you want to predetermine specific locations to putaway to or pick from. An application for reserved locations would becross-docking, where you may specify certain quantities of an inboundshipment be moved to specific outbound staging locations or directlyto an awaiting outbound trailer.
MaximizeCube. Cube logic is found in most WMS systems however it is seldom used.
Cubelogic basically uses unit dimensions to calculate cube (cubic inchesper unit) and then compares this to the cube capacity of the locationto determine how much will fit. Now if the units are capable ofbeing stacked into the location in a manner that fills every cubicinch of space in the location, cube logic will work. Since thisrarely happens in the real world, cube logic tends to be impractical.
Consolidate. Looks to see if there is already a location with the same productstored in it with available capacity. May also create additionalmoves to consolidate like product stored in multiple locations.
LotSequence. Used for picking or replenishment, this will use the lot number orlot date to determine locations to pick from or replenish from.
It’svery common to combine multiple logic methods to determine the bestlocation. For example you may chose to use pick-to-clear logicwithin first-in-first-out logic when there are
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multiplelocations with the same receipt date. You also may change the logicbased upon current workload. During busy periods you may chose logicthat optimizes productivity while during slower periods you switch tologic that optimizes space utilization.
OtherFunctionality/Considerations
WavePicking/Batch Picking/Zone Picking. Supportfor various picking methods varies from one system to another. Inhigh-volume fulfillment operations, picking logic can be a criticalfactor in WMS selection. See my article on for more info on thesemethods.
TaskInterleaving. Task interleaving describes functionality that mixes dissimilartasks such as picking and put away to obtain maximum productivity. Used primarily in
full-pallet-loadoperations, task interleaving will direct a lift truck operator toput away a pallet on his/her way to the next pick. In largewarehouses this can greatly reduce travel time, not only increasingproductivity, but also reducing wear on the lift trucks and saving onenergy costs by reducing lift truck fuel consumption. Taskinterleaving is also used with cycle counting programs to coordinatea cycle count with a picking or put away task.
Integrationwith Automated Material Handling Equipment. Ifyou are planning on using automated material handling equipment suchas carousels, ASRS units, AGNS,
pick-to-lightsystems, or separation systems, you’ll want to consider this duringthe software selection process. Since these types of automation arevery expensive and are usually a core component of your warehouse,you may find that the equipment will drive the selection of the WMS. As with automated data collection, you should be working closely withthe equipment manufacturers during the software selection process.
AdvancedShipment Notifications (ASN). If your vendors are capable of sending advanced shipmentnotifications (preferably electronically) and attaching compliancelabels to the shipments you will want to make sure that the WMS canuse this to automate your receiving process. In addition, if you haverequirements to provide ASNs for customers, you will also want toverify this functionality.
YardManagement. Yard management describes the function of managing the contents(inventory) of trailers parked outside the warehouse, or the emptytrailers themselves. Yard management is generally associated withcross docking operations and may include the management of bothinbound and outbound trailers.
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LaborTracking/Capacity Planning. Some WMS systems provide functionality related to labor reportingand capacity planning. Anyone that has worked in manufacturingshould be familiar with this type of logic. Basically, you set upstandard labor hours and machine (usually lift trucks) hours per taskand set the available labor and machine hours per shift. The WMSsystem will use this info to determine capacity and load. Manufacturing has been using capacity planning for decades with mixedresults. The need to factor in efficiency and utilization todetermine rated capacity is an example of the shortcomings of thisprocess. Not that I’m necessarily against capacity planning inwarehousing, I just think most operations don’t really need it andcan avoid the disappointment of trying to make it work. I am,however, a big advocate of labor tracking for individual productivitymeasurement. Most WMS maintain enough data to create productivityreporting. Since productivity is measured differently from oneoperation to another you can assume you will have to do some minormodifications here (usually in the form of ).
Integrationwith existing accounting/ERP systems. Unless the WMS vendor has already created a specific interface withyour accounting/ERP system (such as those provided by an approvedbusiness partner) you can expect to spend some significantprogramming dollars here. While we are all hoping that integrationissues will be magically resolved someday by a standardizedinterface, we isn’t there yet. Ideally you’ll want an integratorthat has already integrated the WMS you chose with the businesssoftware you are using. Since this is not always possible you atleast want an integrator that is very familiar with one of thesystems.
WMS+ everything else = ? As I mentioned at the beginning of this article, a lot of othermodules are being added to WMS packages. These would include fullfinancials, light manufacturing, transportation management,purchasing, and sales order management. I don’t see this as aunilateral move of WMS from an add-on module to a core system, butrather an optional approach that has applications in specificindustries such as 3PLs. Using ERP systems as a point of reference,it is unlikely that this add-on functionality will match thefunctionality of best-of-breed applications available separately. Ifwarehousing/distribution is your core business function and you don’twant to have to deal with the integration issues of incorporatingseparate financials, order processing, etc. you may find these WMSbased business systems are a good fit.
ImplementationTips
Outsideof the standard “don’t underestimate”, “thoroughly test”,“train, train, train” implementation tips that apply to anybusiness software installation ,it’s important to
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emphasizethat WMS are very data dependent and restrictive by design. That is,you need to have all of the various data elements in place for thesystem to function properly. And, when they are in place, you mustoperate within the set parameters.
Whenimplementing a WMS, you are adding an additional layer of technologyonto your system. And with each layer of technology there isadditional overhead and additional sources of potential problems. Nowdon’t take this as a condemnation of Warehouse Management Systems. Coming from a warehousing background I definitely appreciate thefunctionality WMS have to offer, and, in many warehouses, thisfunctionality is essential to their ability to serve their customersand remain competitive. It’s just important to note that everysolution has its downsides and having a good understanding of thepotential implications will allow managers to make better decisionsrelated to the levels of technology that best suits their unique
environment.
仓库管理系统（WMS）
仓库管理系统（WMS）的演变与许多其他软件解决方案是非常相似的。最初的系统用来控制物料在仓库内的流动和贮存，仓库的作用正在延伸到包括轻型制造业，交通运输管理，订单管理，和完整的会计制度中。利用与先前的业务有关的软件，制造资源计划，作为一个比较，材料需求计划（MRP）开始作为一个规划要求，原材料的生产环境的系统。
物料需求计划很快演变成以MRP系统，补充调度和容量规划为基础的逻辑制造资源计划（MRPII系统）。最终MRPII系统演变成企业资源规划（ERP），吸收所有的MRPII系统的功能包括充分的财务与客户和供应商管理功能。现在，无论仓库管理系统演变成一个以仓库为中心的ERP系统是一件好事或不可达的辩论。清楚的是，在仓库管理系统，企业资源规划，布局规划要求，交通运输管理系统，供应链计划，高级计划与排程，以及制造执行系统之间扩大重叠功能性只会增加那些寻找软件解决方案业务的公司混乱水平。
尽管仓库继续获得额外的功能，最初的仓库管理系统的核心功能还没有真正改变。其主要目的是控制管理系统在工艺操作相关联的交易中的流动和材料储存。定向采摘，定向补充，定向收集是仓库的关键。从一个软件供应商到另一个在一个管理系统中详细的安装和处理可以有一个很大的差别，但是其基本逻辑将使用相结合的项目，地点，数量，度量单位，并以收集信息以确定在哪里储存，在哪里挑选，以及以何种顺序执行这些操作。
一最低限度，一个仓库管理系统应采取下列措施
有一个灵活的定位系统。
利用用户定义的参数，指导仓库任务和使用Live文件来执行这些任务。
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| 有一些内置的一体化和数据收集设备结合体。 |
您是否真的需要仓库管理系统？
并非每一个仓库需要一个仓库管理系统。当然，任何仓库可受益于其中一些功能，但这些受益是否足以证明管理系统最初的和正在进行的相关费用是正确的？仓库管理系统是大的，复杂的，数据密集型的应用。他们往往需要大量的初始安装，很多系统资源的运行，很多正在进行的数据管理为继续运行。没错，你需要“管理”你的仓库“管理”制度。一般情况下，大规模的行动最终将建立一个新的IS部门用来唯一负责管理仓库管理系统。
二声明
1)仓库管理系统将减少库存！
2)仓库管理系统将减少劳动力成本!
3)仓库管理系统将增加存储容量！
4)仓库管理系统将提高客户服务！
5)仓库管理系统将增加！
三现实
实施一个仓库管理系统用来自动的数据收集将可能使你的准确性增加，减少劳动力成本（提供需要维持系统的劳动力少于物品保存在仓库楼需要的劳动力）和更好地来服务客户以降低周期。预期库存减少和增加存储容量的可能性较小。虽然在接收过程中增加了准确性和效率可能降低库存安全水平，但这种降低产生的影响与整体库存水平相比可以忽略不计。控制库存水平最主要的因素是多种尺寸，交货时间和需求的变化，仓库管理系统将对任何因素有重大影响是不可能。而且同时仓库管理系统确实的为更多的有组织的存储提供工具，因为这种存储可能会导致更多的存储容量，相对于这种改善您之前的仓库管理系统是多么草率啊。除了劳动效率，决定实施仓库管理系统的决定因素，往往与一些能满足您的客户的需求有更多关联，比如您目前的系统不支持（或不太支持）像先进先出，交叉对接，自动挑选补充，波采摘，多种跟踪，停车场管理，自动数据采集，自动材料处理设备等。
四设置
仓库管理系统的设置需求是广泛的，每个项目和地点都必须保持在详细或分组类似项目和地点分类。一个例子，项目详细程度的特点将包括确切尺寸和重量，每个项目在每个单位的项目储备（项目，案件，托盘等），以及信息，如是否可以与其他物品混在一个位置，无论是的最高层次，最大堆叠高度，最高量的位置，危险性分类，半成品或原材料，快与慢动，等。尽管一些行动将需要用这种方式设立每个项目，但大多数业务将有利于创造群体的类似产品。例如，如果你是一个音乐CD分销商，您将创建集团单一CD和双张
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CD，保持详细的尺寸和重量的资料在组一级，只需要对每个项目附上组代码。您可能会需要对特殊物品保持详细的资料，如盒装套或CD的特别包装。您也可以为地域的不同类型在您的仓库里创造群组。一个例子是，为您用于CD采摘的三种不同大小前瞻性采摘地点建立3个不同群体（小一，二，三）。然后，您可以建立单一的光盘数量，将适合P1，P2和P3的位置，多种双张CD适合在小一，二，小三的位置等。您可能还设立案件的数量，每个CD组光盘数量,货箱的数量和光盘的每个后备存储位置组。
如果这听起来很简单，但在现实中很多业务有更多元化的产品组合，将需要更多的系统设置。而且建立产品的物理特性和产品的位置只是蓝图的部分。你设定的使系统知道产品可以适合哪里并且多少产品将满足这个地方已经足够了。您现在需要建立必要的信息，以让系统决定从哪些位置选择，补充，并采集，并在这些事件应该出现这些序列中（记得仓库管理就是“指示”流动）。你分配具体逻辑的的做法使各种组合项目/订单/数量/位置信息将出现。
下面我列出一些用于确定实际位置和序列的逻辑
1)位置顺序。这是最简单的逻辑;您只需确定流经你的仓库和为每一个地点分配序列编号。为了挑选这是把您选择的在流经的仓库排序，在采集逻辑将寻求在第一位置的顺序适合的产品。
2)区逻辑。由于把你的储存地点分到区，您可以直接采摘，收集，或补充或特定地区的仓库。自区逻辑唯一指定的一个地区，则需要再加上一些其他类型的逻辑，以确定确切位置在禁区内。
3)固定的位置。逻辑使用预先确定的固定地点，每一项目中分拣，采集，和补充。固定地点是一块采摘挑选和个案选择的行动最常用的首要位置，但是，它们也可用于二级存储。
4)随机地点。由于电脑不能真正随机（也不想要他们）的任期随机位置有点误导。随机地点一般指的是产品不会储存在指定的固定地点的地方。如Zone逻辑，您将需要一些额外的逻辑，以确定确切位置。
5)先入先出（FIFO的）。首先指示挑选最古老的库存。
6)最后，先出（LIFO）。我不认为这种逻辑有任何实际应用，直到我的网站访问者发送一封电子邮件，说明自己在国内和海外销售易腐货物的行动。他们为海外客户使用LIFO（因为长期在途中）和为国内客户使用FIFO。
7)挑选到清楚。用最少的人手挑选逻辑指示的地点。这种逻辑是巨大的空间利用率。
8)预留位置。这个是在预约具体地点采集时使用。从申请预留位置将交叉对接，在那里 你可以指定一定数量的入境货物转移到具体的举办地点外，或直接到等待出境拖车。
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9)最大限度地立方。立方体逻辑中是在WMS系统发现最多的，尽管它很少使用。立方体逻辑基本上使用单位面积计算立方体（立方英寸每单位）。然后比较这个位置的立方体能力，以确定有多少适合。现在，如果这些单位能堆叠成的位置，以填补每立方英寸的空间中的位置，立方体逻辑将工作。由于这很少发生在现实世界，立方体的逻辑往往是不切实际的。
10)巩固。查询看是否有一个以现有性质存放相同产品的位置。还可以创造更多的行动， 以巩固同类产品存放在多个位置。
11)很多序列。用于采摘或补充，这将使用大量批号或日期，以确定位置，以选择或补充。这是非常常见的逻辑结合多种方法，以确定最佳的位置。例如您可以选择使用挑选到清晰的逻辑内先入先出逻辑当有多个地点以同样的收据的日期。您也可能会根据目前的工作量改变的逻辑。在繁忙时段内您可以选择的逻辑，优化生产力，同时在速度较慢时期您切换到逻辑，优化空间利用率。
五其他功能/思考
1)波拾取/批次拣货/区拣货。支持各种不同选择方法从一个系统到另一个。在高销量的完成作业，可采摘逻辑中的一个关键因素韦氏选择。见我的文章的欲知有关这些方法。
2)任务交织。工作交织介绍混合不同的功能，任务，如挑选和采集获得最大的生产力。主要用于全货负荷运作，任务交织将指示叉车经营者抛弃托盘上他/她的方式在未来选秀权。在大型仓库这可以大大减少旅行时间，不仅提高生产力，而且还减少磨损叉车和节约的能源成本，减少燃料消耗叉车。工作交织也使用周期计算程序，以协调的循环计数与采摘或采集任务。
3)集成自动材料处理设备。如果你计划使用自动材料处理设备，如传送带，ASRS单位，AGVS，挑选到照明系统，或分拣系统，您需要考虑在软件选择过程考虑它们。由于这些类型的自动化是非常昂贵，通常是一个核心组成仓库的部分，您可能会发现，这些设备将驱动WMS的选择作用，你应该与设备制造商在软件选择过程密切合作。
4)先进的装运通知（ASN）。如果您的供应商有能力向先进装运通知（最好以电子方式），并附加遵守标签的出货量您会希望以确保仓库可以使用这个自动化您接受过程。此外，如果您需要向客户提供ASNS，你也将要验证此功能。循环计数。大多数仓库将有一些循环计数功能。修改循环计数系统是常见的，以满足特定的业务需求。
5)堆场管理。堆场管理描述了管理职能的内容（库存）的拖车停在仓库，或空拖车本身。 堆场管理通常与交叉对接，并可能包括管理入站和出站拖车。
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6)劳动跟踪/容量规划。 有的WMS系统提供的功能有关的劳动报告和容量规划。任何人都一直在制造业应该熟悉这种类型的逻辑。基本上，您设定标准工时和机器（通常叉车）小时以上的任务，并设置可劳动和机时数的转变。该仓库系统将利用这一信息，以确定能力和负载。制造能力已使用了几十年规划的结果好坏参半。需要因素的效率和利用率，以确定额定容量就是一个例子中存在的缺点这一进程。不是说我一定对规划的仓储能力，我想大多数业务并不真的需要它，并能够避免的失望试图使它发挥作用。然而，我一个大倡导的个别劳动生产率的跟踪测量。大多数仓库保持足够的数据来创建生产力报告。由于生产力是衡量从一个不同的行动，另一个你可以假设你将不得不做一些小的改动这里（通常的形式是自定义的报告）。
7)整合现有的会计/ERP 系统。除非仓库管理系统供应商已经建立了一个特定的接口与您的会计/ERP系统（如所提供的经批准的商业合作伙伴）您可以预期花费一些重大编程美元这里。虽然我们大家都希望这种融合的问题将得到解决，有一天奇迹般地由一个标准的接口，但是我们还没有。理想您需要一个积分，已经集成了仓库管理系统您选择与商业软件您使用。systems.由于这并非总是可能你至少需要一个积分，这是非常熟悉的系统。
8)仓库+一切=？正如我前面提到在本文开头，还有很多其他模块被添加到仓库管理系统软件包。这将包括全面的财务，轻型制造业，交通运输管理，采购和销售订单管理。我不认为这是一个单方面行动的仓库管理系统由一个附加模块，核心系统，而是一个可选的办法，已应用在具体行业，如3PLs。用ERP系统作为一个参照点，这是不太可能，这个附加的功能，将匹配的功能，最佳的应用软件可单独购买。如果仓储/分销的核心业务职能和你不想必须处理一体化问题纳入单独的财务，订单处理，等您可能会发现这些仓库管理系统基础的业务系统是一个良好的生长。
六执行小贴士
标准以外的“不低估”，“彻底的测试”，“火车，火车，火车”执行情况提示，适用于任何商业软件的安装,尤其要强调的是,WMS的设计非常依赖数据和限制性。也就是说，您需要使系统正常运行的所有适合的不同的数据元素。此外，当他们已到位，您必须在规定的参数操作。
当执行一个仓库管理系统，你是给您的系统额外增加了技术。并且相互层技术有额外的开销和其他的潜在问题来源。现在不考虑这是一个谴责仓库管理系统。对于一个仓库背景我肯定赞赏WMS所提供的功能，并且，在许多仓库，这个功能是为客户服务，保持竞争力必不可少的能力。这里必须指出，每个解决方案都有其缺点，能良好的理解可能产生的影响将让管理者做出与最适合其独特的环境的技术水平相关的更好的决策。
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