-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueTechnology Roadmaps
In this issue of PCB007 Magazine, we discuss technology roadmaps and what they mean for our businesses, providing context to the all-important question: What is my company’s technology roadmap?
Wet Process Control
In this issue, we examine wet processes and how to obtain a better degree of control that allows usable data to guide our decisions and produce consistently higher-quality products.
Don’t Just Survive, Thrive
If we are to be relevant and prosper during these next critical decades in electronics, we must do more than survive. As an industry, we can and must thrive. In this issue, our contributors explore these concepts meant to help you take your business to the next level.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - pcb007 Magazine
TECHNICAL PAPER: Novel Automatic Repair of Populated PCBs in a Cost-effective and Adaptive Way
February 21, 2024 | Essemtec, a NanoDimension DivisionEstimated reading time: 3 minutes
Introduction
Did you ever have to consider repairing an electronic product? Repairing populated boards is getting more and more popular due to several reasons, for example, placement of wrong components, refurbishment or function enhancement of existing products, counterfeit components, etc. The cost of the top five most counterfeited parts represents $169 billion worth of semiconductor revenue. Around 140,000 tons of electronic products are wasted every day globally with few repair options on the market, representing the fastest-growing category of waste in developed countries.
Changing an electrical component is a tedious job. Desoldering it from the board, removing the extra solder from the pads, applying fresh solder and flux to the component or pads, placing the new component, and finally soldering the component again are the typical processes involved. Regarding soldering, there are two ways to perform this process, the first is heating only the affected component locally, and the second is using low-temperature solder, which allows submitting the whole product to temperature. Two main disadvantages of the current repair process are the use of the valuable time of expert personnel and that only one component per product can be replaced at a time. Applying solder paste and placing the component is very problematic, especially on fine-pitch components—the risk of short circuits due to misplacements of packages or solder paste is high.
The proposed method in this work is focused on applying solder paste and placing the component. By using solder jetting instead of printing or dispensing, the time required to deposit solder paste can be significantly reduced. Special needles were designed to perform the jetting process without damaging the already populated components. Another advantage of using a fully programmable jetting system is that the required volume can be customized per pad; for example, pads for a TQFP package with 200 μm width pins and a large pad in the middle can easily be jetted, delivering the correct amount depending on the situation. Pick and place of the components is performed with the same instrument as well in a fully automatic way and the throughput is further improved. The possibility to replace several components on the same product is also given. There is no need for an expert operator once the equipment is programmed.
The repair process has been implemented with different alloys, including SnPb, SAC305, and SnBi. This work presents the results of products reworked using SnPb and SnBi. The results show that the XY positioning accuracy and dot repeatability exceed acceptable expectations for a 400 μm pitch. With this fully automatic jetting and pick-and-place method, the repair of a product can be made in a very accurate and agile way. This represents remarkable cost advantages for companies performing repairing activities.
Experimental Methodology
The experimental studies aim to test the positioning accuracy of the solder deposits as well as the dot repeatability. The throughput achieved with the proposed repair method was also measured. The positioning and dot accuracy was assessed against product needs, and the throughput was compared with the current customer experience. All the accuracy data was collected at Essemtec’s lab, and the throughput data was collected at the customer’s facilities.
Even though every soldered component type can be repaired with the proposed method, this work only analyzed two cases. The first one is a product with a TQFP (thin quad flat package) component requiring a type 6 paste with a Sn63Pb37 alloy. This TQFP has 128 terminals of 200 μm in width with a pitch of 400 μm and a contact area in the middle of 8.4 x 8.4 mm. The size of the TQFP is 14 x14 mm. The second case is a product with a BGA using a low temperature soldering type 6 paste with a Sn63Bi37 alloy. This BGA has a total of 1599 terminals with a diameter of 200 μm and a pitch of 400 μm, the size of the BGA is 18.5 x 27 mm.
A total of 20,000 dots were jetted to verify the stability of the jetting process. For every 1,000 dots jetted on production, 10 dots were jetted on a separate test plate where the dot’s diameter and X-Y accuracy was measured. A total of 200 data points were collected per experiment.
Positioning accuracy and precision together with the dot diameter were measured utilizing the ePlace software which is integrated into Essemtec machines. A normality test was performed on all data using the Anderson Darling method. A capability analysis was performed on every data set using the Minitab software version 19.
Continue reading this paper in the January 2024 issue of SMT007 Magazine.
Suggested Items
Circuit Technology Center Announces Expanded Tinning Services Capacity
09/16/2024 | Circuit Technology CenterCircuit Technology Center announces it has expanded its electronic component tinning services capacity. Four (4) Hentec-Odyssey 1325 robotic hot solder dip machines are in full operation to meet the increasing demand from the defense and high-reliability customer base that requires component tinning services for tin whisker mitigation, gold mitigation, and lead re-conditioning.
A Parametric Approach to the Environmental Impact of PCB Fabrication
09/09/2024 | Maarten Cauwe, imecSustainability for electronics is receiving more attention due to environmental concerns, regulatory obligations, and to ensure competitiveness in a growing market for sustainable products. To facilitate the discussion on the environmental impact of electronics, there is a strong need for data on energy use, carbon footprint, greenhouse gas (GHG) emissions, hazardous chemicals used during manufacturing, waste generation, etc.
Altium, Mouser Team Up to Advance Electronics Education and Careers Worldwide
09/05/2024 | AltiumAltium LLC, a global leader in software and solutions for the electronics industry, and Mouser Electronics, a global authorized distributor of semiconductors and electronic components, are excited to announce a strategic partnership aimed at advancing electronics education and careers worldwide.
Quiet Power: An Evolution in PCB Design Costs
09/04/2024 | Istvan Novak -- Column: Quiet PowerIn this column, I want to cover my experiences, particularly where costs are concerned, with printed circuit boards from the 1960s to the present day. I grew up in an apartment building in downtown Budapest, where I began doing hobby projects building circuits from our kitchen table. Now, I’m lecturing about the most recent advances in signal integrity at Oxford University. We’ve come a long way. Over the decades, new technologies allowed users to have more layers, lower-loss dielectrics, fine-pitch surface connections, blind and buried vias, and HDI and HDI+ board constructions that allow us to design higher-performing systems. I expect this trend to continue.
CELUS Goes Global with Simplified Electronics Design Process
08/29/2024 | BUSINESS WIRECELUS, announced the worldwide availability of its revolutionary AI assisted hardware design platform that empowers engineers with the ability to find the right components for their projects through smart algorithms and the use of machine learning and AI.