A new approach to work-in-progress tracking
Traditionally, enterprises have been using manual, spreadsheet-based methods to track their work-in-progress inventory.
The efficiency of such an approach, however, is rather questionable. Technicians spend a significant part of the shift filling out transaction forms instead of actually working on a product. The forms are batched at the end of the shift, which lefts production planning and inventory specialists work with the data that is always a day behind.
The good news is that with modern technologies, it becomes possible to track work-in-progress inventory remotely and in real time.
Technology-driven WIP tracking
The new approach to work-in-progress tracking leverages RFID and IIoT technologies. RFID serves as a means for collecting data about the location of each WIP item, while IIoT is used to store, process, and analyze the data from RFID systems.
RFID systems typically comprise three core components:
RFID tags serve as object identifiers. Each tag has a unique ID, which is correlated with the information about a WIP item a tag is attached to, e.g., a part or a sub-assembly. Considering that WIP items undergo a series of manufacturing operations, for WIP tracking, it is preferable to use passive RFID tags - they are small, flexible and, compared to active RFID tags, have a considerably lower price.
RFID antennas transmit the radio signal from an RFID reader to supply the energy for RFID tags and relay the signal carrying tag data back to the reader.
An RFID reader receives radio signals from the tags, extracts tags’ IDs and, along with the ID of the reader and the time of the reading, passes them to the cloud for storing and processing.
The essence of IIoT boils down to turning raw data fetched from RFID tags into informative insights about the status of each work-in-progress item at each stage of the production process.
How do RFID and IIoT work together?
Each WIP item is uniquely identified with an RFID tag. The ID of each tag is correlated with the data about a corresponding WIP item and saved to a data warehouse. To enable WIP tracking, across the manufacturing facility, RFID readers are used to scan the tags.
As WIP items pass from station to station, RFID readers scan the tags and provide information on the location of each WIP item. The RFID data is relayed to the cloud software, where it is analyzed to provide the insights about the locations, movements, and statuses of WIP items, the operation each WIP item undergoes, the time it took to carry out an operation, the total number of items on the shop floor, etc. The insights are then visualized and presented to the solution users via web or mobile user apps.
WIP tracking solutions can be additionally integrated with corporate systems. For instance, integration with ERP allows getting access to electronic work orders. Once a work order is created and the required materials are available, the WIP tracking solution matches the work order to the operational route and monitors the work order execution by tracking the status of WIP items belonging to the order.
The benefits of technology-driven WIP tracking
A robust WIP tracking solution streamlines the effectiveness of the manufacturing processes from several perspectives by providing:
With the data about the location and movements of each WIP item, inventory specialists are aware of the current levels of the work-in-progress inventory and can better estimate the amount of materials required for the next production cycle down to each SKU. It allows them to replenish resources on time and avoid stocking up on excessive materials.
The possibility to track, maintain and increase schedule adherence
RFID provides at-a-glance data about whether an order is advancing through the shop floor according to the schedule. If a block of some kind is identified and a batch is on hold, the WIP tracking solution automatically updates the status of all the WIPs of the batch and notifies a shop floor manager.
Increased process productivity
Work-in-process tracking frees the employees from filling in work order papers and lets them concentrate on the manufacturing process. Moreover, due to the optimization of the inventory, the machines do not idle waiting for the next batch of materials, which leads to better employee efficiency, optimized machine utilization, and higher productivity of the manufacturing process.
Who’ll benefit from automated WIP tracking?
While any manufacturing facility can benefit from improved inventory management and more consistent shop floor scheduling, WIP tracking systems are of the greatest relevance for the following types of manufacturing enterprises:
Enterprises dealing with multiple products within a single assembly line.
Enterprises producing complex and/or customized products in multiple plants at multiple locations.
Enterprises dealing with outsourced manufacturing operations.
Points to consider
Rolling out a WIP tracking solution, manufacturing enterprises have to keep in mind several limitations:
WIP items undergo a series of manufacturing operations, hence the tags should be placed in such a way that they do not interfere with and are not damaged during the production process.
The price of tags is from 5 cents to $10 per item, while the price of readers spans from $5,000 to $20,000 per item (installation and configuration included), therefore the solution’s optimization potential for a given enterprise should be proven and expected savings should be high enough for the WIP tracking solution to pay off.
RFID systems emit radio signals, which can interfere with the existing technology and equipment, therefore enterprises should choose the right RFID frequency to bring the possibility of interference down to a minimum.
With a considerate approach to the solution implementation, these limitations can be defeated. To ensure that the solution brings maximum value, it is worth turning to IoT consultants, who will make sure that the solution meets the needs of a specific enterprise, select an appropriate technology stack, and provide for optimal system configurations.
To sum it up
Work-in-progress can account for 25-30% of an enterprise’ annual inventory carrying costs, and the WIP part of inventory is usually the most difficult to manage.
Technology-driven WIP tracking solutions help change WIP tracking for the better. Leveraging RFID and IIoT, they drive significant process and business benefits, the most significant of which include optimized inventory tracking, improved shop floor management and enhanced schedule adherence.
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