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High-mix EMS in the Current Economy
December 31, 1969 |Estimated reading time: 7 minutes
This article examines how pick-and-place equipment will impact the CM business in a high-mix manufacturing environment and will point out what is necessary to be successful in a tough economy. The keys to success will be high uptime, quick changeover, equipment ease of use, flexibility offered by the equipment, and cost of ownership (COO).
By Geron Ryden, Juki Corporation
Contract manufacturers (CMs) will readily tell you that operating in the competitive high-mix SMT manufacturing market is tough enough in a strong economic environment, but can be downright brutal in an economic downturn. Welcome to 2009. To be successful, a CM needs to exceed customer expectations consistently by setting a standard that is difficult to match. Delivering superior quality products on time has come to be a given – failing to do this can lead to dire consequences for CMs. Where CMs can differentiate themselves is in the level of service that they provide to a customer. In an economy with so many variables and uncertainties, customers will lean more on the experience, technical proficiency, and overall expertise of their suppliers and partner more closely with them to make intelligent decisions. The CM that can outperform their competition in these areas will be a stronger company going forward.
While there will be many challenges for CMs this year, let us make three assumptions about 2009. First, customers will have difficulties with their forecasting and will require smaller inventories. Second, customers will delay order placement, requiring an even quicker turn on product. Third, in an effort to procure more business, CMs will work to expand their customer base and will encounter new technology challenges.
Uptime
The first key to success in a high-mix manufacturing environment is to have pick-and-place equipment that provides the highest uptime. Uptime has a few different connotations for the CM. First, it necessitates equipment that is dependable, reliable, and repeatable, operating flawlessly each day. In other words, equipment maintains near-constant operation and doesn’t break. It allows the CM the luxury of concentrating on the manufacturing process and product quality. Second, it means equipment that is running at a high level of efficiency with little operator intervention. Third, uptime means engineering redundancy into the equipment so that it continues to produce assemblies even in the event of failure. For example, if nozzle shafts are controlled by independent Z and theta motors, in the event that one of the motors fails, the entire head is not disrupted. Production can continue without the one nozzle while a service call is placed for repair. Finally, uptime means minimal maintenance. Only 15 to 30 minutes a month should be spent on equipment maintenance, with an annual maintenance routine typically occupying a couple of hours. This requires simple, robust equipment design.
Smaller, modular equipment offers additional advantages when it comes to high uptime.
Figure 1. A pick-and-place gantry in motion.
In a line with modular equipment, the chance of failure is spread across multiple machines. In the event that one machine fails, product can be passed through this machine to continue production on the next machine in the line.
High uptime also is a result of being able to quickly and efficiently change jobs on a manufacturing line. It is not uncommon to run up to a dozen jobs in a single shift, making changeover exceptionally important. There are many factors contributing to quick and efficient changeover. The first is line optimization software. Equipment vendors should provide robust optimization software that is functional and easy to use. It should include a library for easy upload and download of edited part descriptions and programs. Look for software that can automate a daily production run, eliminating the need for operator intervention to begin a new job. Line optimization software also should be able to cluster programs so that boards with minor variations can be run without having to change feeder setups. Line optimization software also can upload operational data from a day’s run of jobs and provide feeder setup of the allotted jobs to be run that day.
Look for pick-and-place equipment that supplies universal and robust trolleys. Trolleys can be loaded off-line while the production is being run on another job. When it is time to switch jobs, trolleys can be substituted easily. Your pick-and-place equipment should be able to read fiducial marks on the trolleys quickly to ensure accurate picking of the parts.
In the event that pick tracking is needed, look for equipment that supports automatic teach picking that checks feeder pick position and automatically makes necessary corrections for optimal picking of the parts.
Another feature that is critically important for high uptime is auto BGA teach. In the past, BGAs with asymmetrical ball patterns have taken a considerable amount of time and effort to program into placement equipment. With auto BGA teach, the machine has the intelligence to quickly program BGAs with asymmetrical ball patterns. This reduces the waste of valuable programming time.
Pick-and-Place System Criteria
The auto BGA teach function is one example of another important factor concerning high uptime: ease of use. Operator-friendly pick-and-place equipment will affect line uptime significantly. Look for equipment that offers the necessary features to get the machine up and running as efficiently as possible. For high-mix environments, it may be necessary to create programs right at the machine level. For more complex boards, operators may need to run through placement tracking on the machine to verify placement validation and accuracy. During production, equipment should offer clear and safe access to replenish depleted feeders. Some systems also allow for a duplicate set up of feeders for nonstop use of the equipment.
For multi-circuit boards, have a bad-mark reader using a downward-looking camera. This will detect a range of marks on various substrates, including flex circuits. This reader should support many board materials and have adjustable brightness and directional lighting to improve fiducial detection. The placement machine also should support a height measurement system. Laser height measurement quickly and accurately assesses the components’ pick height without contact. It can improve pick teaching of both standard and unique parts.
Easy-to-read graphical user touch panel interfaces (GUIs) with built-in component libraries make upload and download of new and adjusted parts easier.
Training also plays a big role in being able to properly and efficiently use line equipment. Make sure adequate training is provided during installation. Some vendors will assist the customer in running production during the installation period. Some vendors offer regularly scheduled training classes at their training facilities.
Figure 2. Checking the PCB prior to placement.
Machine flexibility plays a large role in the success of manufacturing in a high-mix SMT market. Pick-and-place machines that offer high flexibility will enable the CM to aggressively quote tough jobs and will help CMs seek out new business. Modular machines are the most flexible machines in the market and it is possible to place a wide variety of SMT components with one machine. Additional machines could be added at a later date if throughput times need to be improved.
Cutting-edge technology and machine uniformity are both key. Are you placing 01005s? Or large 74 × 74 mm or 50 × 150 mm odd forms? Or both? Multi-view camera systems offer blue, green, and red LED illumination for maximum flexibility; components can be individually profiled. A general vision placement will allow odd-shaped parts to be placed using manual methods designated by the user. As previously mentioned, auto teach BGA functions eliminate manually inputting asymmetrical BGAs and allow CMs to quote complex boards.
When placing a variety of parts, CMs need a wide variety of nozzles for placement. Pick speed and placement speed are important when working with unique parts. Auto fluxer within the pick-and-place machines are decisive factors in the flip chip market.
With board quality varying widely from lot to lot and screen printer misalignment cropping up, some pick-and-place vendors offer software allowing the user to specify certain parts to be placed on the paste instead of the pads. Alignment problems can be corrected during the reflow process.
The final piece of success in the high-mix manufacturing environment is cost management. It is essential to look for pick-and-place equipment that offers the lowest cost of ownership to the CM. The first piece of the cost puzzle is the initial investment in equipment. But as we have seen, there are many other associated costs with the equipment. One big cost is downtime, the time in which the equipment is not producing product. There are myriad reasons for downtime, with only some of the possibilities explained here.
Another factor in equipment cost is equipment migration. This deals with how easy it is to migrate accessories forward or backward among the same vendor’s equipment. Questions to ask include whether feeders and trolleys are forward/backward compatible, and if older machines fit in line with new machines. Also examine how difficult this will be to put in place.
Another piece of the cost of ownership puzzle is parts warranty and service support. Understand your parts warranty, find vendors that have parts in stock for immediate delivery, and investigate a vendor’s in-field lifetime.
Conclusion
The global situation in 2009 will present CMs operating in the high-mix SMT manufacturing market with many challenges. Keep in mind that where there are challenges, there also lies opportunity. In the pursuit of opportunity, seek out pick-and-place vendors that share your vision; that offer the latest in cutting-edge technology; and that value quality, flexibility, and cost rewards. SMT
Geron Ryden may be contacted at Juki, 507 Airport Blvd., Morrisville, NC 27560; 919-460-0111 x130; gryden@jas-smt.com; www.jas-smt.com.