RFID Supply Chain
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In a companies supply chain, RFID solutions are often used for applications like Asset Tracking, Inventory Control, and Work in Process.

• Supply Chain
• Inventory Tracking
• Work-In-Process (WIP)

Supply Chain

Tracking your assets within a facility is a perfect use for RFID technology.  It is a diverse application that can have different meanings to different organizations.  Some companies view asset tracking as the physical means to count the non-sellable assets within offices, factories, or labs.  Others organizations utilize asset tracking when reconciling assets that are moving from facility to facility – either expecting them to return or move from one balance sheet to another.

RFID asset tracking is non-vertical in nature.  Many different industries such as healthcare, manufacturing, insurance, banking, government and even law offices are using RFID technology in a slightly different environment.

Applying RFID to asset tracking can be a difficult endeavor. There are 3 primary RFID technologies to choose from depending on the assets being tracked.  The tag types are: 

• passive tags (no battery),
  
• active tags (battery),
  
• UWB tags (GPS-like features).  

The tag system choice greatly depends on how you can trigger a read, when the read is important, and exact location resolution required for the application. Of course, system complexity and cost rise depending on the type of tag chosen for your application.

When deciding on which type of RFID tag is right for your application, users must assess the type of assets, location of reads, and necessity to be able to pinpoint a location for that asset.  Below is a description of each of the RFID tag options available, and an outline of what type of applications they are typically best suited for.

Passive tags. The most important feature used in passive RFID asset tracking is the idea of “last seen”. Passive tags have the ability to be viewed by a reader and antenna to determine when it was last seen.  This provides the user with a general area where the unit is located. However, it does not pin down an exact location for the item the user is attempting to locate. However, utilizing passive tag technology for asset tracking is the most economical option for an RFID system.  Passive tags are the lowest cost tag available and the RFID reader can be spread out to cover more space within your facility.  Typically, passive tags are used for tool cribs, hospital equipment tracking, and kanban systems.

Active tags.  The use of active tags in asset tracking is typically tied to more “theft worthy” devices that could breach a security system.  An organization may want to track a laptop computer with sensitive information. Or an IT department will use active RFID tags to monitor the movement of the laptops but also confirm if it is authorized to enter or leave certain rooms or buildings.  The most important aspect of active tags is their ability to have a microswitch to alarm if the tags are removed – ensuring that the system knows of the breach.

UWB (Ultra Wide Band) RFID tags.  This type of RFID tag is used when pinpoint accuracy is needed to determine the exact location of an item – usually within 10 feet.  These tags can determine current travel direction so the user can be alerted if a item is moving south within a building.  This is accomplished through the use of triangulation which determines the range of the item from a reader as well as their location in relation to other tags.  Typically, UWB tags are used in tracking people and highly valuable assets like vehicles, high end electronics, and weapon systems.

Inventory Tracking

RFID technology is used in many if not all the functions of inventory control.  RFID proliferation is driven by the premise of accurate identification of people or objects with no or little user involvement.  Inventory processes rely on counting and location descriptors to determine what is the exact quantity and location of the goods. The use of RFID technology for inventory control applications is a natural fit.

Inventory tracking with RFID takes some thought to gain the return on the investment.  In some cases, ROI is absolutely transparent to the user and at other times we need to change the process and the users involved.  As incorrect shipments and miscounts go down inventory accuracy goes up enabling companies to have greater efficiencies in inventory.

There are some prime inventory processes that use RFID:

• Inventory Receiving – items that are RFID tagged items can be reconciled and counted against a purchase order immediately and discrepancies are noted.
• Inventory Putaway/Moves – taking products from one warehouse slot to another without barcode scanning locations or pallet tags.
• Inventory Picking – Fork readers can read and validate pallet level picks.
• Ship Confirmations – Using RFID readers at a standalone station or wrap station, users can verify the goods and accurately count the items.
• Shipping Validation – Compare goods being shipped against a master sales order and create a manifest on the fly for the shipper.
• Physical Inventory / Cycle Counting – Using handheld RFID readers, users can read and count cartons and pallets.

All of these processes are normal functions in a warehouse that rely on accuracy and improve visibility and customer service.  Many of them are being performed through a warehouse management system (WMS) using barcode scanning.  In many cases barcode and RFID technology work together side by side.

Work-In-Process (WIP)

RFID works very well within the manufacturing setting of most companies as its very nature speeds up the tracking process with very little human intervention. This leads to improved line speeds and more product per hour with less errors on the line.  Manufacturing engineers are always looking for ways to signal the line. They need to alert the manufacturing cell as to what needs to be made and confirm that the needed parts are on site and available. In this instance, RFID technology begins to show its ability to ensure supply chain efficiencies over any other technology.

Most WIP applications are started by the desire of the engineering group to ensure that the product to be made is done correctly.  This task has traditionally been done through the use of barcode technology.  However, this usually takes a human to stop and scan a work order, bill of materials or other paperwork to identify the product, serial number, or job number. 

As the product moves from cell to cell the users are “prompted” to scan the barcode to start the work and stop the work. 

This, in theory, should get the information tracked within a data system – but has one major drawback – a human must stop and scan every time thus increasing the chance of human error.

Eliminating the need to scan is one of the primary reasons organizations utilize RFID technology.  Tagging the source document or traveling fixture with an RFID tag that identifies the product serial number, order number, or job number is the first step.  A standard practice is to setup RFID readers in each of the cells to read the tag as it comes into the zone.  The date and time is stamped to the read and a start process can be signaled when the unit hits the zone and stop process sent when the unit leaves the zone.

Furthermore, we can use RFID to read and verify the cell inventory once the unit gets to the cell.  This instant inventory can alert managers to a low or no inventory situation, which can eliminate a line stoppage. 

For some manufacturers there is a customer service aspect of RFID that becomes very valuable.  If a product is custom made for an order, giving the exact line position to customer service allows them to give an accurate ship estimate, setting the proper expectations for delivery.