Technical Library | 2022-05-02 21:35:53.0
Testing of electronic assemblies involves three elements: the device under test, test equipment, and fixturing to make the connections between them. The challenge for a test engineer building a sophisticated test system is that instrumentation may need to measure thousands of test points through the mechanical interconnect.
Technical Library | 2021-05-20 13:55:14.0
Quality Control is essential in production processes. In the PCB Assembly process there are several Quality Control steps or options. The most popular tests are the electrical (In-Circuit or ICT) and the function (functional or FCT/FVT) test. ICT test fixtures are standardized and there are several major test platforms available which are industry standards. For FCT applications there are many more variations possible due to the vast number of testers and interface approaches unique to each customer; also due to an endless list of applications which fall under the category of Functional Test (RF, High Current, LED test, Leak test etc.) Test Probes are a very important part in ICT as well as in FCT applications. If the wrong test probe (type, spring force, tip style etc.) is used, the test fixture will not work as intended. In addition the test probe must be installed correctly in order to work properly. This presentation will show general information and some guidelines for a proper Test Fixture design to assure the most efficient production.
Technical Library | 2019-08-15 13:31:52.0
Cracks in ceramic chip capacitors can be introduced at any process step during surface mount assembly. Thermal shock has become a "pat" answer for all of these cracks, but about 75 to 80% originate from other sources. These sources include pick and place machine centering jaws, vacuum pick up bit, board depanelization, unwarping boards after soldering, test fixtures, connector insulation, final assembly, as well as defective components. Each source has a unique signature in the type of crack that it develops so that each can be identified as the source of error.
Technical Library | 2014-09-25 18:16:47.0
For the past few years there has been a shift in the Lighting Industry that has carried over to the surface mount technology assembly line. What is this shift you may ask? Well it is the LED revolution. This revolution or change in lighting has some very promising results already in practice and many more companies looking to implement the LED technology into their product portfolio's. With a number of companies looking to expand their portfolio to include LED fixtures there has been an increase in the number of companies that have started their own SMT lines, as well as a significant number of contract manufacturers to meet this new industries demands (...)This presentation will discuss some issues in the pick and place process for LEDs and presents a method to troubleshoot and resolve these issues.
Technical Library | 2016-06-23 13:24:56.0
Proper assembly of components is critical in the manufacturing industry as it affects functionality and reliability. In a heat sink assembly, a detailed manual process is often utilized. However, an automated fixture is used whenever applicable.This paper will illustrate the use of strain gauge testing and Finite Element Analysis (FEA) as a simulation tool to evaluate and optimize the heat sink assembly process by manual and automated methods. Several PCBAs in the production line were subjected to the manual and automated assembly process. Strain gauge testing was performed and FEA models were built and run. Results were compared with the goal of improving the FEA model. The updated FEA model will be used in simulating different conditions in assembly. Proposed improvement solutions to some issues can also be verified through FEA.
Technical Library | 2019-08-14 22:20:55.0
Cleanliness is a product of design, including component density, standoff height and the cleaning equipment’s ability to deliver the cleaning agent to the source of residue. The presence of manufacturing process soil, such as flux residue, incompletely activated flux, incompletely cured solder masks, debris from handling and processing fixtures, and incomplete removal of cleaning fluids can hinder the functional lifetime of the product. Contaminates trapped under a component are more problematic to failure. Advanced test methods are needed to obtain "objective evidence" for removing flux residues under leadless components.Cleaning process performance is a function of cleaning capacity and defined cleanliness. Cleaning performance can be influenced by the PCB design, cleaning material, cleaning machine, reflow conditions and a wide range of process parameters.This research project is designed to study visual flux residues trapped under the bottom termination of leadless components. This paper will research a non-destructive visual method that can be used to study the cleanability of solder pastes, cleaning material effectiveness for the soil, cleaning machine effectiveness and process parameters needed to render a clean part.
Technical Library | 2020-05-07 03:46:27.0
The selective soldering process has evolved to become a standard production process within the electronics assembly industry, and now accommodates a wide variety of through-hole component formats in numerous applications. Most through-hole components can be easily soldered with the selective soldering process without difficulty, however some types of challenging components require additional attention to ensure optimum quality control is maintained. Several high thermal mass components can place demands on the selective soldering process, while the use of specialized solder fixtures and/or pallets often places an additional thermal demand on the preheating process. Fine-pitch through-hole components and connectors place a different set of demands on the selective soldering process and typically require special attention to lead projection and traverse speed to minimize bridging between adjacent pins. Dual in-line memory module (DIMM) connectors, compact peripheral component interface (cPCI) connectors, coax connectors and other high thermal mass components as well as fine-pitch microconnectors,can present challenges when soldered into backplanes or multilayer printed circuit board assemblies. Adding to this challenge, compact peripheral component interface connectors can present additional solderability issues due to their beryllium copper termination pins.
Technical Library | 2022-08-08 15:06:06.0
Selective soldering has evolved to become a standard production process within the electronics assembly industry, and now accommodates a wide variety of through-hole component formats in numerous applications. Most through-hole components can be easily soldered with the selective soldering process without difficulty however some types of challenging components require additional attention to ensure that optimum quality is maintained. Several high thermal mass components can place demands on the selective soldering process, while the use of specialized solder fixtures, or solder pallets, often places additional thermal demand on the preheating process. Fine-pitch through-hole components and connectors place a different set of demands on the selective soldering process and typically require special attention to lead projection and traverse speed to minimize bridging between adjacent pins. Dual in-line memory module (DIMM) connectors, compact peripheral component interface (cPCI) connectors, coax connectors and other high thermal mass components as well as fine-pitch microconnectors, can present challenges when soldered into backplanes or multilayer printed circuit board assemblies. Adding to this challenge, compact peripheral component interface connectors can present additional solderability issues because of their beryllium copper base metal pins. Key Terms: Selective soldering, drop-jet fluxing, sustained preheating, flux migration, adjacent clearance, lead-to-hole aspect ratio, lead projection, thermal reliefs, gold embrittlement, solderability testing.
Technical Library | 2018-10-18 15:41:45.0
One specific market space of interest to emerging printed electronics is In Mold Label (IML) technology. IML is used in many consumer products and white good applications. When combined with electronics, the In Mold Electronics (IME) adds compelling new product functionality. Many of these products have multi-dimensional features and therefore require thermoforming processes in order to prepare the labels before they are in-molded. While thermoforming is not a novel technique for IML, the addition of printed electronic functional traces is not well documented. There is little or no published work on printed circuit performance and design interactions in the thermoforming process that could inform improved IME product designs. A general full factorial Design of Experiments (DOE) was used to analyze the electrical performance of the conductive silver ink trace/polycarbonate substrate system. Variables of interest include trace width, height of draw, and radii of both top and bottom curvatures in the draw area. Thermoforming tooling inserts were fabricated for eight treatment combinations of these variables. Each sample has one control and two formed strips. Electrical measurements were taken of the printed traces on the polymer sheets pre- and post- forming with a custom fixture to evaluate the effect on resistance. The design parameters found to be significant were draw height and bottom radius, with increased draw and smaller bottom curvature radii both contributing to the circuits’ resistance degradation. Over the ranges evaluated, the top curvature radii had no effect on circuit resistance. Interactions were present, demonstrating that circuit and thermoforming design parameters need to be studied as a system. While significant insight impacting product development was captured further work will be executed to evaluate different ink and substrate material sets, process variables, and their role in IME.
