Technical Library | 2019-09-19 00:28:48.0
The symbiotic relationship between solder masks and selective finishes is not new. The soldermask application is one of the key considerations to ensure a successful application of a selective finish. The selective finish is the final chemical step of the PCB manufacturing process, this is when the panels are at their most valuable and are unfortunately not re-workable. Imperfections are not tolerated, even if they are wholly cosmetic. Quality issues often manifest themselves in the form of a 'ping pong' conversation between the fabricators, the soldermask suppliers and the selective finish suppliers. Without tangible evidence these discussions are difficult to resolve and the selective finish process is usually regarded as responsible. This paper will focus on the chemical characteristics and use them to predict or identify potential issues before they occur rather than specifically name 'critical' soldermasks. It is also the intention of this paper to address the potential of a soldermask to react to common yield hiking practices like UV bumping and oven curing. It is hoped that this awareness will help fabricators to ensure maximum yields by asking the right questions. 'Critical’ soldermasks impact all selective finishes. In this paper, practical experience using immersion tin will be used to highlight the relationship between 'critical' soldermasks and some of the issues seen in the field. The paper will include a novel approach to identify re-deposited volatiles after the reflow.
Technical Library | 2019-11-12 02:09:22.0
Thermal shock test chamber can be used for testing the chemical change or physical damage on composite materials caused by the thermal expansion and contraction of the sample in the shortest time,which is subjected to extremely and continuous high and low temperature environment.so how to check the temperature recovery time of this chamber? Normally we take following steps to inspect the temepratuire recovering time: 1.Install the temperature sensor at the specified position, and adjust the temperature controller of hot zone and cold zone to the required nominal temperature respectively. 2.The temperature increases and reduces respectively,30min after temperature in two zones reach stable status,record temperature value of the measuring point,pls set the temperature value of two zones to be required nominal temperature. 3.The temperature shock test chamber automatically places the inspected load into theh ot zone,select the corresponding retention time according to regulated standard. 4.Set the transfer time,then the inspection load is transferred from hot zone to cold zone, and the temperature of the measuring point is observed and recorded, and then the reverse conversion of the load from cold zone to hot zone is carried out according to the same method, and the temperature of the measuring point is observed and recorded. www.climatechambers.com
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 | 2023-05-02 19:03:34.0
The demand for 0201 components in consumer products will increase sharply over the next few years due to the need for miniaturization. It is predicted that over 20 billion 0201 components will be used in more than one billion cell phones worldwide by the year 2003. Therefore, research and development on 0201 assembly is becoming a very hot topic. The first step to achieve a successful assembly process is to obtain a good PCB design for 0201 packages. This paper presents the data and criteria of PCB design for 0201 packages, including the pad design for 0201 components, and the minimum pad spacing or component clearance between 0201 components or between 0201 and other components. A systematic study on pad design and pad spacing was undertaken, using two test vehicles and three Design of Experiments (DOEs). In the first DOE, 2 out of 18 types of 0201 pad designs were selected based on process yield. The second DOE was focused on pad spacing, including 10mil, 8mil, 6mil and 4mil. The third experiment was final optimization, using two types of optimized pad designs with 10mil, 8mil and 6mil pad spacing. Through the above experiments, the design guideline for PCB layout for 0201 packages and the assembly process capability are identified.
Technical Library | 2019-11-13 02:09:44.0
Dry oven is a must instrument almost for every laboratory in different industries,with nearly 20 years efforts and innovation,Climatest now masters core technique of dry oven manufacturing,no matter on temperature uniformity or temperature stability.Behind the quality is 15 years of consistent persistence,strong belief in excellence; from design to R & D to production, from promotion to sales to installation; every step should reach excellence,What you see, you use our products, you choose, you feel that we do our best,this is our faith. Dry Ovens are used to dry or temper electronic components,material tests,torrefaction, wax-melting ,high temperature aging ,preheating and sterilization in industrial and mining enterprises, laboratories and scientific research institutes. .Exterior chamber is made by reinforced steel with painting; working chamber made by anti-corrosion stainless steel SUS#304 .Intelligent PID control, LED controller with over-temperature alarm,timing range within 0~9999min .Hot air circulation system composed of Germany imported low-noisy air blower and optimal air duct which ensure uniform temperature distribution .Double layers of glass door, large transparent window to observe specimen .Forced air convection Climatest manufactures desktop and floor-standing models with RT+10°C-200°C,250°C,300°C,350°C,400°C temperature range,and customized as per special requirement,if you wanna know more details about our dry oven,please visit our product page:https://climatechambers.com/industrial-dry-oven/200-degree-c-hot-air-oven.html
Technical Library | 2020-08-27 01:22:45.0
Initially adopted internal specifications for acceptance of printed circuit boards (PCBs) used for wire bonding was that there were no nodules or scratches allowed on the wirebond pads when inspected under 20X magnification. The nodules and scratches were not defined by measurable dimensions and were considered to be unacceptable if there was any sign of a visual blemish on wire-bondable features. Analysis of the yield at a PCB manufacturer monitored monthly for over two years indicated that the target yield could not be achieved, and the main reasons for yield loss were due to nodules and scratches on the wirebonding pads. The PCB manufacturer attempted to eliminate nodules and scratches. First, a light-scrubbing step was added after electroless copper plating to remove any co-deposited fine particles that acted as a seed for nodules at the time of copper plating. Then, the electrolytic copper plating tank was emptied, fully cleaned, and filtered to eliminate the possibility of co-deposited particles in the electroplating process. Both actions greatly reduced the density of the nodules but did not fully eliminate them. Even though there was only one nodule on any wire-bonding pad, the board was still considered a reject. To reduce scratches on wirebonding pads, the PCB manufacturer utilized foam trays after routing the boards so that they did not make direct contact with other boards. This action significantly reduced the scratches on wire-bonding pads, even though some isolated scratches still appeared from time to time, which caused the boards to be rejected. Even with these significant improvements, the target yield remained unachievable. Another approach was then taken to consider if wire bonding could be successfully performed over nodules and scratches and if there was a dimensional threshold where wire bonding could be successful. A gold ball bonding process called either stand-off-stitch bonding (SSB) or ball-stitch-on-ball bonding (BSOB) was used to determine the effects of nodules and scratches on wire bonds. The dimension of nodules, including height, and the size of scratches, including width, were measured before wire bonding. Wire bonding was then performed directly on various sizes of nodules and scratches on the bonding pad, and the evaluation of wire bonds was conducted using wire pull tests before and after reliability testing. Based on the results of the wire-bonding evaluation, the internal specification for nodules and scratches for wirebondable PCBs was modified to allow nodules and scratches with a certain height and a width limitation compared to initially adopted internal specifications of no nodules and no scratches. Such an approach resulted in improved yield at the PCB manufacturer.
Technical Library | 2019-10-24 06:29:59.0
Making your novel electronic item design ready for mass fabrication and printed circuit board assembly consists of a lot of steps as well as risks. I will provide a few recommendations about how to neglect pricey errors and how to reduce the time to promote your novel item designs. You can hire printed circuit board assembly services for this. As soon as you have accomplished your product as well as printed circuit board design, you wish to get started developing prototypes prior to you commit to big fabrication volume. A lot of design software packages, for instance, PCB layout design software, as well as an industrial design software program, possess simulation potentials incorporated. Carrying out a simulation facilitates curtailing numerous design mistakes prior to the first prototype is developed. In case you are developing an intrusive item, you might desire to think about a modular design wherein all of the chief functionalities are situated in individual modules. All through your testing, you could then swap modules that don’t cater to the design limits. Spinning individual modules would be swifter and more cost-effective in comparison to spinning a complete design. Counting on the design intricacy, you can mull over manually mounting printed circuit board elements to bank dollars. Nonetheless, for medium to big intricacy this procedure likely to be very time taking, typically in case you wish to create numerous prototypes. Hence it makes sense thinking about a contract manufacturer for the assembly. Whilst running miniature quantity fabrication runs, the fabrication setup expenditure will usually control the by and large prototype constructs expenditure. Whilst seeking a subcontractor, it is finest to choose a vendor that focuses on prototype builds to reduce the cost. Prototype printed circuit board fabricators characteristically join the circuit boards of a number of clients which efficiently shares the setup expenditure in the midst of some customers. The disadvantage is that you would characteristically only be able to want among numerous standard printed circuit board material thicknesses as well as sizes. Apart from choosing a supplier with low setup expenditure, choosing a firm that would moreover be capable to manage your whole fabrication runs curtails mistakes because switching fabricators have the chance of errors owing to a specific supplier interpreting fabrication design data in a different way. This manner your design is already translated into the particular machine data that implies little or no setup expenditure for your final fabrication. A few PCB manufacturers also provide printed circuit board design services that are awesome plus if you do not possess experience with the design. Moreover, these vendors would be capable to help you in case there are issues with your design folders and be capable to detect issues prior to the fabrication.
