2005 Articles
A Game of Microns
What is accuracy, and how can it be measured precisely? These tough questions, posed by Hugh Read of Speedline Technologies this month, are not rhetorical. And while Read writes in the context of dispensing, the implications are wide-ranging, covering almost every facet of our equipment sets.
In what I believe in time will become standard practice, Speedline uses an independent third party to verify test results. That company, CeTaq Americas, reviews the testing methodology and machine performance of solder paste printing, dispensing and placement. In a nutshell, the firm performs machine capability analysis. But what it is also evangelizing is a fundamental shift in thinking about how we define machine capability.
If you drill down, the company explains that its main objective is to reduce offsets and spread of a measured characteristic. As CeTaq says on its Website (cetaq.com):
It is important for customers and manufacturers to agree on unified standards, such as for acceptance testing of equipment. This means that it would not make sense to test equipment at ±100 µm ±6 Sigma which has been developed and constructed for the specification ±100 µm ± 4 Sigma without changing the specification concerning 6 Sigma to meet the [aforementioned] demands. To reach a valid examination, the specification should be changed to ± 150 µm ± 6 Sigma (this corresponds to ± 100 µm ± 4 Sigma).
Moreover, the company claims that 80% of failures are systematic and can be adjusted out of the machine using their methods.
A brief background. The parent company, CeTaq GmbH, was founded nearly 10 years ago, outside of Dresden, Germany. (The U.S. subsidiary was launched in 2004 and is led by general manager Mike Sivigny, a Six Sigma Black Belt.) Several major equipment OEMs have latched on to its vision, including Universal Instruments and Speedline.
The firm performs consulting work and has also designed its own measuring tool, the CMController5, for machine capability validation. The tool itself is remarkable, say those who have used it, and is starting to gain traction among equipment suppliers and assemblers. Mike Zurn, process engineering technical manager at Phoenix International, says the EMS provider turned to CeTaq to help implement process control and SPC in its production lines. “We said, ‘Let’s go after equipment, and identify the key characteristics that we want to monitor.’ ”
What Phoenix’s engineers found was that while they could use the calibration plates as supplied with most placement equipment, doing so means using the machine to check itself. “The tables move on the chipshooters,” according to Zurn. “We have some linear bearings that were showing wear over time.” After applying CeTaq’s system, Zurn says, “You can see the linear [glass] plate bring that right back” into calibration.
Traditional measurements meant creating novel programs, manipulating and moving test boards from room to room, and basically shutting down production for extended periods of time. The effort took time and was rife with variables. And the finer the pitch of components, the more crucial repeatability becomes.
The genius of the CMController5 is its mobility and ease of use. It is 2 x 2 x 4', and can be wheeled to the equipment being measured. Inside, a camera works with a glass plate and global fiducials, all in a single frame of view. That eliminates moving the gantry to look for fiducials, which could throw off the Gage R&R. The machine’s software frees users from all the associated tests that required a Ph.D. in statistics to perform. The camera looks at every point and validation takes about 15 minutes. The reading shows how off a machine is, in microns. The system accuracy is 2 µm and its existing optics can handle down to 0201 parts, CeTaq says.
“CeTaq took a very complex thing, requiring statisticians, Six-Sigma experts and so on, and made it that simple,” says an engineer at one major EMS firm who asked not to be named, noting that for high-mix lines, the ability to shift machine programs around is a huge advantage. “Without a gage to keep the machines constant, programs continually have to be tweaked when they shift from line to line. But if the machine-to-machine repeatability is highly consistent, then users can load the program on any line and [start production] without tweaking.” The EMS company’s ROI? Two months.
As finer pitch components take hold, more accurate equipment – and the means to validate those readings – will be thrust into the spotlight like never before. As electronics manufacturing becomes a game of microns, CeTaq is in great position to take advantage.
The holiday season is upon us. I’d like to borrow a little space on this page to recall a few ups and downs of 2005. There’s the people that bring you this magazine each month – especially Susan Jones, Robin Norvell, Kamden Robb and Javier Longoria – whom I thank for their dedication, hard work and most important, friendship. There’s my wife, who with humor and grace endures my work and travel schedule and general grumpiness around press time. There’s Ron Daniels, a friend and colleague who died this year, whose memory I recall often and with a profound mixture of sadness and joy. And I am eternally thankful for the joy that my new son, Calvin (born Oct. 9), and my “oldest,” Tommy (now 2 1�2), bring me each and every day. We at Circuits Assembly wish you the best this season.
