Technical Library | 2019-05-21 17:31:39.0
In the field of electronics manufacturing, the end use of the product will always dictate the processes, procedures, and methods, not only for building the product, but also for testing, cleaning, and protecting the assembly in order to assure the level of quality required for proper operation. The need to protect an electronic assembly from its end use environment may stem from anyone of a number of hazardous (or potentially hazardous) conditions. Choosing the type of protective material is dependent upon matching that material’s characteristics with the conditions to be overcome. Naturally, the use of a protective (conformal) coating will require some method of verification to ensure the desired level and type of protection is achieved.
Technical Library | 2020-05-08 18:22:31.0
A customer contacted the Helpline to perform analysis on a lead-free assembly which exhibited intermittent functionality. The lead-free assembly exhibiting intermittent functionality when pressure was applied to the ball grid array (BGA) packages. Industrial adaptation of a Restriction of Hazardous Substances (RoHS) compliant solder standard has created a new host of failure modes observed in lead-free assemblies. Pad cratering occurs when fractures propagate along the epoxy resin layer on the underside of the BGA connecting pads. While originating from process, design, and end use conditions, it is the combination of a rigid lead-free solder with inflexible printed circuit board (PCB) laminates that has advanced the prevalence of this condition. Pad cratering is simply the result of mechanical stress exceeding material limitations.
Technical Library | 2019-06-11 09:36:13.0
An experiment was recently performed ACI Technologies for a customer that was interested in comparing the wetting of lead-free solders with varying temperature profiles and atmospheric conditions. In order to deliver an objective measurement of solder wetting (in addition to subjective inspection analysis), a simple wetting indicator pattern was added to the solder stencil in an area on the test vehicle that had exposed and unused copper.
Technical Library | 2023-09-23 22:31:52.0
Dry boxes can be implemented at various points within the Mfg. environment; for med-long term inventory, or for short term handling on the production floor, and in some cases (with certain conditions) as a process replacement for baking. Bare boards, raw components and partially assembled PCB's can benefit from ultra-low humidity storage.
Technical Library | 2013-09-25 20:57:24.0
Conformal coating is an enabling process that allows for the ruggedizing of electronic devices and modules. As the process increases the durability of electronics that are subjected to various end-use environmental conditions, it adds value to the product. While it does add value, consumers and manufacturers expect the electronics to work when subjected to dirt, humidity, moisture, corrosive materials, and various other contaminants. This expectation results in a drive to minimize the cost of the process. The lowest cost of ownership for a conformal coating process occurs by utilizing automated selective conformal coating equipment.
Technical Library | 2013-11-14 10:43:40.0
Understanding accuracy and repeatability is an important step to analyze fluid dispensing system performance. They can also be prone to misinterpretation when reviewing a product specification. A dispensing motion system can be made to perform better or worse under different operating conditions. This article will explain accuracy and repeatability, and how they can be applied to different specifications. It will also discuss key considerations when interpreting accuracy and repeatability for decision making.
Technical Library | 2019-06-21 10:39:15.0
Recently, an ACI Technologies (ACI) customer called to discuss failures that they had observed with some through-hole capacitor parts. The components were experiencing failures following vibration and accelerated stress testing. Upon receipt of the samples, ACI performed three levels of inspection and Energy Dispersive Spectroscopy (EDS) testing to investigate the root cause of the failures. These analyses enabled ACI to verify the elements comprising the solder joints and make the following recommendations in order to prevent future occurrences. The first inspection was to investigate the capacitor leads using optical microscopy, and no anomalies were found that could indicate bad parts from the vendor or improper handling prior to assembly. However, vertical fill in the barrel of the plated through-holes was too close to the IPC-A-610 minimum specification of 75% to determine a pass/fail condition, and therefore required further investigation.
Technical Library | 2019-07-11 11:07:08.0
Affordability is not exactly the primary word which comes to mind when discussing the use of design of experiments (DOE) principles, but is generally accepted as a necessary part of the engineering activities required in the development of a product or process. However, a number of studies have indicated that the cost savings derived from a well deliberated experimental design can be substantial in the initial stages where the conditions or parameters of a process are determined. Some studies have shown a greater than 50% cost savings compared to the more conventional means of trial and error approaches to process development. At ACI Technologies (ACI), we have found the use of DOE techniques fundamental in eliminating extraneous costs otherwise spent on unnecessary testing.
Technical Library | 2020-11-09 16:59:53.0
A customer contacted ACI Technologies regarding a high failure rate of their assemblies. They provided assemblies to be X-rayed and inspected for the purpose of identifying any process related issues such as (but not limited to) solder and assembly workmanship and evidence of damage due to moisture related problems during reflow (a.k.a. "popcorning"). Moisture damage usually appears as physical damage to the component. The first indication of moisture damage would be externally observable changes to the package in the form of bulging or fractures to the outer surface of the component, an example of which is shown in Figure 1. Internally observable indicators of moisture damage typically include fractures to the die inside the package and lifted or fractured wire bonds. These conditions would be apparent during transmissive X-ray inspection. Another symptom of moisture related damage would be inconsistent solder joint sizes that result from package deformation during the liquidus phase of the reflow process. None of these indicators of moisture related damage were present on the customer samples.
Technical Library | 2007-02-01 09:27:47.0
The purpose of the testing was to compare the resistance and check for open circuit conditions of reworked BGA test samples made with and without StencilQuik™ after 500 thermal shock cycles. StencilQuick™ is a product of Best Inc. In this series of tests, the resistance of daisy chain resistance patterns running between the BGA and test board after exposure to thermal shock was measured.
