Issue link: https://iconnect007.uberflip.com/i/582861
October 2015 • The PCB Magazine 73 job to test on either machine. Today it still re- mains that the most expedient way to test a PCB is using a well manufactured fixture on a grid test machine. However, there are increased costs with fixtures. There is the actual fixture cost, maintenance of the fixture itself and also the storage. Poor yield and excessive rework are two of the other main attributes that increase cycle time in ET. Although these are causes on the diagram they are not specifics that can be solved in ET. As briefly stated earlier, load balancing is a large contributor to cycle time. We see this listed in Figure 2 under Method. Both flying probes with automation and grid test machines can be used. However, with flying probes there can be an indirect or direct method to the test. Using the indirect method does provide a faster test but some customer/industry standards do not allow this on some product. Direct method testing, albeit favored by some customers, is a slower test. These variables can cause a wide range in cycle time for specific product. Drawing some conclusions for the above exercise, we can see that manufacturing and TesTing Todd BREAKING THE BOTTLENECK: ELECTRICAL TEST CyCLE TIME REDUCTION methodology are the two largest "bones" that have the highest impact on cycle time in ET. While in manufacturing, ET cannot influence the yield and rework attributes but the other two, scheduling and requirement, it can. This goes along with the attribute in methodology. The solution here is…communication! Com - munication of requirements, expected vol- ume, layout, and requirements for TDR/HiPot all come in to play when going through ET. Knowing well in advance can influence wheth- er grid test fixturing should be used or flying probe. Also, should manual HiPot testing be used or a multi-channel fixture? Here alone, significant time can be saved if this is known in advance. Many times a first time build is only a few panels with no visibility for the fu- ture. Generally, flying probe is used. It is now tooled and forgotten. Two months down the road volume is manufactured and arrives with only flying probe tooled as the solution. Cycle time skyrockets as the test solution is no longer correct. Scanner/flying probe combinations can also significantly reduce cycle time on flying probe Figure 2: Populated Fishbone diagram.