Achieving “QualFiciency” in a High-Mix EMS Environment
By Meng Gao, Quality/Process Engineer
At Javad EMS (JEMS), we believe in “QualFiciency”, the co-existence of excellent quality and while maximizing performance efficiency in a “smart” way tailored to our established material and manufacturing systems. In the past, Electronic Manufacturing Service (EMS) providers have been challenged with the dilemma of optimizing efficiencies throughout their production facilities while not at the expense of quality. The wave of the Industry 4.0 and the Smart Factory in recent years has changed in many aspects the way we can integrate the material systems, equipment, and manufacturing processes. Many EMS companies, especially high-mix factories, after attempting to embrace this Smart technology, found out the costly capital investments and the massive overhaul of their existing material handling systems, Manufacturing Execution Systems (MES), and manufacturing processes was not easily achievable.
Similar to other high-mix EMS companies, we run multiple products in varying volumes on our 5 Surface Mount (SM) lines every day. Implementing a complete ready-to-use smart factory system would have required a massive capital investment on our part with a move away from everything we have invested and implemented in over the past 10 years. We assemble boards and systems for customers in military, aerospace, and high-end industrial segments, so our quality is world class. Therefore, the challenge was bridging the benefits of the aspects of the new Smart factory and our established manufacturing technologies and processes.
Now, we can proudly state that we have overcome this challenge, as a high-mix and high-tech EMS provider, by reinventing our existing systems in the following four areas.
Automating Material Storage Systems to Improve Non-Value-Added Processes in Material Handling
With the advent of outsourced manufacturing came the rise of EMS companies. Relatively new to manufacturing, these companies in many instances implemented a patchwork of equipment and simple material system solutions. Over the years, the Surface Mount (SM) equipment made significant improvements in process capabilities yet focus on improving automated material solutions was clearly lacking. With the miniaturization of parts (01005’s) and the use of much more complex packages (micro BGA’s) it is not possible to replace machines with people placing parts but many feel, and still do to this day, that to more effectively manage your materials flow inside your 4 walls is just a matter of throwing more bodies at it.
EMS companies had to use their own material handling systems to manage material movements throughout the manufacturing process including kitting and Work-in-Progress (WIP) return. Material picklists in Excel spreadsheet or PDF format have been widely using for identifying WIP materials in a lot of EMS companies. They also have to use the machine manufacturer’s operating systems for the SM placement programs and feeder set-up.
By mapping out the manufacturing material flow chart, the non-value-added processes can be easily identified.
At JEMS, we consider SM assembly as a value-added process. Material handling processes including kitting, WIP referencing, and WIP return are unavoidable low-value-added processes. Feeder set-up is an improvable non-value-added process. It was also found to be the bottle-neck in our process. Our operators had to handle each part at least twice during the feeder set-up operation. The first handling step was to search the machine and feeder positions in the placement program for each part number. The second handling step was to physically set up the package (reel or tube) on the feeder and place it in the designated position. These two steps were caused by the gap between our existing material handling system and machine operation programs such as placement and feeder set-up program.
To help bridge the connection between our material handling systems and machine operation programs, we’ve purchased and deployed 10 automated Inovaxe SMT reel and tube storage systems. These products were introduced to the market five years ago. With the help from Inovaxe, we were able to modify their existing systems to accommodate our current WIP material handling processes allowing for more automated material storage systems within our defined framework. Inovaxe has been our material handling solutions partner since 2014 and been key to helping us take our ideas and turning them into a defined and functional shop floor process.
By using automated material storage and handling systems, we significantly reduced the feeder set-up time by over 50% with the new process eliminating one handling step of feeder set-up position searching. The handling efficiencies in both kitting and WIP return processes were also significantly improved.
Upgrading Material Handling Software to Enable Package Level Material Control and Traceability
Automated material handling systems are package (i.e. reels, tubes, and trays) based. The software will guide the operator to pull or return a package (reel or tube) from a unique storage location.
JEMS established Unique Identification (UID) numbering system in 2010 and had been using it for material tracking and identification. By using the new automated material storage system, we realized that with the benefit of UID we can leverage our material tracking capability at the package level throughout our entire material and manufacturing processes. After collaborated with Inovaxe on customizing the software, a real-time UID based WIP scanning system was deployed at JEMS in 2015, which was tailored to our WIP handling processes.
For many of our customers we are building in excess of over 50 different PCBA’s for them with many using some of the same raw components. When we build multiple jobs for a customer in a short period of time, how to efficiently and accurately reference large amount of common parts in WIP from job to job became a challenge to our production efficiency as in many cases one job is being taken from the line and the next one is scheduled immediately thereafter on any of our lines.
WIP referencing has been the biggest beneficiary since the UID system was integrated to our new automated material storage and handling systems. The WIP referencing time was reduced by 80% based on our observations. According to our studies, a job with 100 SMT part numbers, on average, 15 feeders would be referenced to the new machine positions for the next job in line without tearing down the feeders. More often than not this process can be time consuming as once the job has been completed on the SM line, operators need to locate the 15 referenced feeders from the 100 feeders used to complete the job. In addition, the referenced feeders need to be placed to new machine positions, based on the placement program for the next job. In the new system, the operator can simply access the “WIP Referencing” interface from their tablet for locating and re-assigning the feeders to the new job.
Package level traceability was also achieved by using the UID numbers throughout our entire manufacturing process from incoming receiving inspection to WIP return. A detailed report can be easily generated for any part number or UID including the user’s name who handled it during the entire manufacturing process with time stamps. Component manufacturing information was also tied to the UID number including manufacturing part number, purchase order number, and lot code number which could be used for investigating quality issues or potential recalls.
Utilizing the Material Handling System to Achieve Advanced Material Control and Manufacturing Goals
- FIFO (first in, first out) –
Many studies have revealed that component aging can cause poor solderability and product reliability issues. At JEMS, we integrated date code information into the UID numbering system for each package we received to ensure the packages with the oldest date codes always get consumed first. It also helped us on reducing partial reels in stock which improved the package quantity accuracies as well as our vertical carousel and smart feeder cart space utilization.
- Error Proofing (no wrong parts placed on boards) –
During feeder setup, operators are required to scan the UID number of the package on each feeder to a designated feeder position. Our system will simultaneously validate the scanned feeder positions with the feeder set-up list. An alert will pop up if the scan feeder position does not match with the programmed feeder position. We haven’t had any wrong part quality issue on any PCB we built, since 2015.
- Moisture-sensitive Device (MSD) Control Conform to IPC/JEDEC J-STD-033 –
MSD’s require special attention during the PCB assembly process. These devices absorb the moisture in factory ambient conditions when removed from their moisture barrier bag which might lead to component damage during the reflow process or unknown field failures. Using the system allows us for each package to define and track its specific real-time requirements. We established customized moisture control rules in our system, based on IPC/JEDEC J-STD-033 requirements. Any package with MSD floor life expired or below the threshold floor life percentage will be flagged in the system and not allowed to be used on any of our SM lines. On the other hand, MSD floor life percentage will be tracked for each UID number in WIP to ensure their MSD floor life will be correctly calculated during reset, pause or bake.
A significant contribution to the ability to intelligently monitor and track Moisture-sensitive Devices was an InoAuto Smart MSD Cart from Inovaxe which is compatible with our customized material handling software.
- Paperless Manufacturing –
When using paper as the primary means of communication or documentation in a manufacturing environment, your communication efficiency is relatively low and the chance of making mistakes in your process is relatively high. The paper can be as simple as a note for transferring information between processes or a form for documenting manufacturing records where human error can cause misinterpretations.
By using our customized material handling and manufacturing system, the risk of human error is very low. Can human error ever be 100% eliminated, simple answer is ‘no’ but our goal is to remove processes that have a higher probability to this occurring. Below are some of the paper usages that were eliminated at JEMS.
- Material pick list
- Feeder set-up list
- Feeder position validation form
- WIP reference parts list
Continuously improving the System by Using Customized Data Mining Tools
Once you have your customized smart system set up and running, you already have the data of material handling and WIP movements. From material management’s stand point, parts that have been frequently used should be stored in the automated smart storage systems to continuously reduce the low-value-added and non-value-added process time.
For example, we established a Kit Issuing Source Analysis report based on the recently closed work orders for better understanding of this issues related to material sources. Analysis can be driven down to customer level, assembly level, and job level for a selected time frame. This data can be used to streamline the current processes and improve the overall material management efficiencies.
Overall, Industry 4.0 and “Smart Factory” concepts we feel were initially focused on the High-volume manufacturing environment. JEMS being a high-mix low-to-medium volume manufacturing facility liked what we understood as to the benefits of the Smart factory and decided we would implement as much as possible these concepts into our day-to-day operations.
At JEMS, we found our own “smart” way to achieve our “QualFiciency” goals, as a high-mix EMS company. Our own customized material handling systems and manufacturing processes have laid a solid foundation for our future quality and efficiency improvement activities. This is an on-going process and never will end as each day we think of ways to improve upon what we do to exceed the expectations of our customers.
Javad EMS (JEMS) is a San Jose, CA-based EMS company founded to focus on low- to medium-volume, high-mix applications for customers needing prototype through volume production levels and wanting it from one source. Today, the company is a thriving, full-service contract electronics manufacturer providing leading-edge, high-quality products for its customers.
Contact:
Javad EMS Inc.
900 Rock Ave., San Jose, CA 95131
Tel: (408)770-1700
E-mail: ems@javad.com or info@javadems.com
Web: http://www.javad.com/jems/
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