RFID improves precision and efficiency in automobile production

 

The automobile manufacturing market favors rapid customer responsiveness in a competitive environment. Production leaders have started exploring ways to identify, catalog and deliver materials using radio frequency identification (RFID) to enable faster assembly of customized products.

What are the challenges of automobile production?

Manufacturers in the automotive industry launch new models frequently, which has shortened both product lifecycles and the timeline of upgrades. Producers rely on mixed-mode assembly production lines to provide the high level of personalization and customization consumers crave. These mixed-mode assembly production lines require a dynamic staging process, with a variety of suppliers delivering a high volume of diverse materials on short notice. Manufacturers face cross-cutting challenges in their supply chains, logistics and production management.

Mixed-mode assembly for vehicle manufacturers is very manual and reactive to changes in the queue. Material delivery is driven by a predetermined daily material plan and by pulling material consumption from assembly sites. As buffer stock arrives to replenish stock to sufficient levels, workshop internal stock will request additional material based on manually reported needs; workers on the assembly floor will then identify each vehicle, determine required materials and deliver necessary supplies to their respective stations by hand. Many steps depend on workers’ input and effort, potential risks include high labor costs, operational inefficiency, lack of agility and human error.

In an effort to mitigate assembly line risks, manufacturers employ lean production methods, including just-in-time (JIT) practices, manufacturing resource planning (MRP II) practices, waste reduction, process standardization, and an emphasis on defect-free production. Industry efforts tend to focus on process improvements that decrease variability and reaction times. Auto manufacturers are researching applications of low-cost technology upgrades that can adjust to material delivery needs.

What is RFID?

Radio frequency identification (RFID) uses wireless sensors to passively tag objects with digital information such as production codes, bill of material (BOM) lists and other key identifiers. This information can be scanned into a larger network when the RFID tag is within proximity to an RFID reader which enables tracking of products, tools, people and workflows. RFID tags have become low cost and low power through extensive industry research and development efforts – some RFID sensors don’t even require a battery to supply power.

For more background on RFID products and research, see Control Engineering’s article on RFID capabilities, “What is radio frequency identification? What can RFID products do?”

How can RFID improve automobile production?

An RFID-based mixed-mode assembly buffer material delivery method is capable of providing the proactive insight vehicle manufacturers seek. Installing RFID tags on each vehicle, RFID tags on each material transfer container, and RFID sensors on each assembly workstation would automate the identification of models, cataloging of required supplies, and delivery of necessary materials.

On average, mixed-mode assembly lines simultaneously produce 20-30 vehicle models. Many auto manufacturers currently use barcodes to streamline model identification. However, barcodes still require manual scanning as a vehicle enters and exits each assembly station. RFID sensors at each workstation can automatically identify each model and its location in the assembly line.

Based on data from the Automotive News Data Center, each vehicle model, on average, requires roughly 1,200 materials; some models require up to 2,300 material types. Production buffer material racks store various – but limited – quantities of these materials, which are replenished from larger internal stock rooms. Determining which vehicles need what materials at each workstation can be challenging.

Along with model information, RFID tags can hold a bill of materials for a specific vehicle configuration and will automatically queue requests for upcoming material delivery needs. The facility inventory list will automatically update to reflect this new material consumption. By automatically updating both material consumption and material delivery in real time, error in material demand is virtually eliminated.

RFID enables material delivery

As materials need to transition from storage facilities to the assembly line, there is a delay between submitting requests and receiving material. A key benefit of RFID systems is their ability to optimize material delivery based on lead time. Lead time of delivery between storerooms and workstations is the sum of material preparation time, online time and safety time. Material preparation time includes gathering, packaging and loading supplies. Online time includes transport and unloading time. Safety time is a buffer reserved for emergencies and unexpected situations. Material is pulled from storerooms when the buffer inventory balance is less than the demand within one lead time. Some items are too large or heavy to be stored on workstation buffer racks, so these must be delivered before they are needed. In buffered and JIT deliveries, material transit containers are tracked through their RFID tags to confirm on-time delivery of necessary supplies to the correct location.

What other technology could maximize RFID benefits?

Software can integrate RFID capabilities with existing production management tools. Software will provide a user interface to monitor the production status of a mixed-model automobile assembly plant, monitor buffer material consumption, and coordinate buffer material demand and delivery. Sophisticated software can optimize parameters to:

• Increase fidelity of lead time calculations
• Meet safety constraints (like maximum weight) of material transit containers
• Optimize (un)loading order of material transit containers
• Eliminate redundant input between RFID sensors by manipulating data acquisition/fetch cycles
• Initialize material requests with RFID sensors recording vehicles before they reach assembly workstations.

What are potential weaknesses of RFID?

While RFID systems offer many advantages in automotive assembly, there are some weaknesses in RFID technology (See related table).

• RFID systems may be more expensive than alternatives (such as barcode stickers or manual identification). Lifecycle cost of RFID systems may balance out against efficiency improvement and error reduction.
• RFID data is broadcasted over radio frequencies, which could be intercepted by outside parties, creating a cybersecurity concern. Encryption protocols are available, like the NIST Advanced Encryption Standard (AES).
• Environments that are dense with metallic objects, like factories, may be susceptible to signal interference. RFID sensor integrity can be improved by using software to correlate multiple signals in an area from additional sensors.

Current research has prototyped standalone RFID-based material delivery methods and accompanying software for mixed-model automobile assembly. Additional research and development to integrate RFID systems with existing enterprise systems would be required before RFID applications become widely accepted.

Caitlyn Caggia is a content writer and Daniel Browning is business development coordinator at PDF Supply. Edited by Mark T. Hoske, content manager, Control Engineering, CFE Media and Technology, mhoske@cfemedia.com.

MORE ANSWERS 

Keywords: RFID, automotive, automation, material delivery, assembly, production

RFID can address some automotive production challenges.

Other automation technologies can make RFID more effective.

RFID weaknesses can be addressed (see table).

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How could RFID applications automate other industries?

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Who is Caitlyn Caggia? Caitlyn Caggia is a content writer at PDF Supply. She is an experienced systems integrator and solutions architect, and she holds an MS in Electrical and Computer Engineering from Georgia Tech.

Who is Daniel Browning? Daniel Browning is the business development coordinator at PDF Supply, a global supplier of automation products. He enjoys writing about automation, AI, and new technology.

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