{"id":2649,"date":"2026-10-19T11:00:00","date_gmt":"2026-10-19T03:00:00","guid":{"rendered":"https:\/\/www.jingpengpcb.com\/?p=2649"},"modified":"2026-10-08T20:14:53","modified_gmt":"2026-10-08T12:14:53","slug":"manual-panelization-benefits","status":"publish","type":"post","link":"https:\/\/www.jingpengpcb.com\/en\/blog\/manual-panelization-benefits\/","title":{"rendered":"What Are the Benefits of Manual Panel Assembly Before SMT? Materials and Soldering Challenges for Yin-Yang Panels"},"content":{"rendered":"<style>\n.jp-tw{overflow-x:auto;margin:26px 0;-webkit-overflow-scrolling:touch;}\n.jp-tw table{border-collapse:collapse;width:100%;min-width:560px;font-size:15px;line-height:1.65;background:#fff;}\n.jp-tw th,.jp-tw td{border:1px solid #dde3ea;padding:11px 14px;text-align:left;vertical-align:top;}\n.jp-tw thead th{background:#eef2f7;color:#1b2733;font-weight:700;white-space:nowrap;border-bottom:2px solid #c9d3de;}\n.jp-tw tbody tr:nth-child(even){background:#fafbfc;}\n.jp-tw tbody tr:hover{background:#f1f5fa;}\n.jp-tw tbody td:first-child{font-weight:600;color:#1b2733;}\n@media(max-width:767px){.jp-tw table{font-size:14px;min-width:520px;}.jp-tw th,.jp-tw td{padding:9px 11px;}}\n<\/style>\n<h2>1. What Exactly Is a \u201cYin-Yang Board\u201d?<\/h2>\n<p>Yin-Yang panels (also known as double-sided panels) refer to<strong>Components are mounted on both sides of the same PCB<\/strong>assembly configuration. In contrast, there is single-sided mounting. This term has a more specific meaning in the context of SMT production lines\u2014it refers to<strong>The first side of the board has been soldered; after flipping it over, it will be assembled into a \u201cnew board\u201d to print the second side.<\/strong>This method is designed to improve the efficiency of solder paste printing and component placement.<\/p>\n<p>First, let\u2019s clarify a few concepts that are easily confused:<\/p>\n<ul>\n<li><strong>Double-Sided Mounting Board<\/strong>: The product design itself features components on both sides; this is a concept within the realm of design.<\/li>\n<li><strong>Yin-Yang Plywood Panels<\/strong>: Arranging the front and back sides of the same board on a single panel (so both sides are completed in a single pass through the oven) is a panel layout technique that eliminates the need for the flipping process.<\/li>\n<li><strong>The Yin-Yang Panels Discussed in This Article<\/strong>: A production line process in which solid boards with the first side already soldered are manually assembled into sets, then sent for printing and component placement on the second side.<\/li>\n<\/ul>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Plan<\/th>\n<th>Instructions<\/th>\n<th>Advantages<\/th>\n<th>Disadvantages<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Pass the circuit board through the reflow oven in two passes<\/td>\n<td>Print the first side, solder the components, and pass through the reflow oven \u2192 Flip the board \u2192 Repeat for the second side<\/td>\n<td>It's the simplest method\u2014no special tooling required.<\/td>\n<td>The printing machine and the pick-and-place machine have to be started and stopped twice, which reduces efficiency.<\/td>\n<\/tr>\n<tr>\n<td>Yin-Yang Panel Layout (Design Phase)<\/td>\n<td>When assembling panels, place half of them right-side up and half upside down.<\/td>\n<td>Both sides are finished in a single pass through the oven, for maximum efficiency<\/td>\n<td>The board must be symmetrical, with matched component placement on both sides; design is constrained.<\/td>\n<\/tr>\n<tr>\n<td>Manual Assembly (This Article's Approach)<\/td>\n<td>Boards that have had the first side soldered are manually assembled into sets before the second side is printed.<\/td>\n<td>Flexible, without relying on board geometry symmetry<\/td>\n<td>Increased labor and vehicle costs, reliance on operational consistency<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>In the field of electronics manufacturing, PCBs (Printed Circuit Boards) have always played a critical role. Among the various aspects of PCB manufacturing, \u201cyin-yang\u201d boards (also known as front-and-back panels) have long been a focus of attention. Manufacturing experts in Taiwan have been continuously innovating to overcome certain limitations and drawbacks associated with traditional PCB front-and-back panels. Their efforts have made this field smarter and more efficient. This article will introduce a compromise solution adopted by Taiwanese manufacturers to address some of the limitations of PCB front-and-back panels.<\/p>\n<h2>2. Limitations of Traditional PCB Positive and Negative Plates<\/h2>\n<p>Positive and negative PCBs are typically used in applications that require the simultaneous mounting of different types of components on a single circuit board. This can effectively reduce the size of the circuit board and improve space utilization. However, traditional manufacturing methods for positive and negative PCBs have some obvious limitations and challenges:<\/p>\n<h3>2.1 Waste of Materials<\/h3>\n<p>In traditional PCB positive-negative board production, a circuit board is typically cut into two parts and then reassembled. This process results in a certain amount of scrap, which increases costs and leads to a waste of resources.<\/p>\n<p>There are three main sources of waste:<strong>Edge of the panel-joining process<\/strong>(V-Cut or material removed from the edge during milling),<strong>Scrap frames after panel separation<\/strong>\u3001<strong>Scrap Generated During the Cutting and Reorganization Process<\/strong>. Based on a large sheet measuring 250 \u00d7 350 mm, the process margins typically consume 8\u201315% of the area, and the cost of this portion can only be allocated to each small panel.<\/p>\n<h3>2.2 Manufacturing Complexity<\/h3>\n<p>The manufacture of positive and negative PCBs typically involves complex processes, including multiple<a href=\"\/en\/smt-factory\/\">Reflow Soldering<\/a>Assembly and installation. This increases production time and labor costs.<\/p>\n<p>\"Multiple reflow cycles\" are the key challenge: When the second side passes through the reflow oven, the components on the first side must go through the entire temperature profile again. This means<strong>The components and solder paste used on the first side must be able to withstand two reflow cycles.<\/strong>, and when printing the second side, the components on the first side must not interfere with the printing machine's work surface (a carrier or support is required).<\/p>\n<h3>2.3 Welding Difficulty<\/h3>\n<p>Due to the wide variety of components on the positive and negative sides of a PCB, the reflow soldering process may be complicated by differences in temperature sensitivity among the various components, thereby increasing the difficulty of soldering.<\/p>\n<p>Three types of components are most prone to problems:<strong>High-capacity components<\/strong>(Large BGAs, shielding covers) Heat up slowly, making cold solder joints more likely;<strong>Thermal Sensor Element<\/strong>(Electrolytic capacitors, some connectors, and LEDs) are not resistant to repeated high temperatures;<strong>Fine-pitch components<\/strong>(01005, Fine-Pitch BGA) During the second reflow, bridging can easily occur due to solder paste collapse. To resolve this, place large components on the second side whenever possible, solder heat-sensitive components last, and adjust the temperature profile accordingly.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1598\" height=\"899\" class=\"alignnone size-large wp-image-8891\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques.jpg\" alt=\"10 Details and Tips for PCB Panelization\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques.jpg 1598w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques-768x432.jpg 768w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2024\/01\/10-pcb-panel-assembly-details-and-techniques-1536x864.jpg 1536w\" sizes=\"auto, (max-width: 1598px) 100vw, 1598px\" \/><\/p>\n<h2>3. Innovative Solutions from Taiwan<\/h2>\n<p>To overcome these limitations in the traditional manufacturing of positive and negative PCB layers, some Taiwanese manufacturers have adopted an innovative approach: the 4-in-1 PCB manufacturing method. This method primarily involves the following steps:<\/p>\n<h3>3.1 Pre-SMT Manufacturing<\/h3>\n<p>First, during the initial stages of SMT (Surface Mount Technology) manufacturing, the manufacturer prepares 100 PCB boards; this quantity can be adjusted as needed. The boards are then fed into a reflow soldering machine for soldering on the first side.<\/p>\n<h3>3.2 Manual Assembly<\/h3>\n<p>The next step is critical: The manufacturer retrieves the PCB that has already been soldered on one side and then manually assembles the new board, which is ready to have its first side printed. During this process, it is essential to ensure that the soldered components remain unaffected and maintain stability.<\/p>\n<p>Here\u2019s a technical detail: After the first side of the panel has been welded, when placing it in the carrier with the second side facing up,<strong>The components on the first side are suspended in the grooves of the carrier.<\/strong>. Therefore, the carrier must be designed with clearance (a recessed groove) based on the component height shown on the first page; otherwise, the components will be damaged by the pressure. This is the aspect most easily overlooked in carrier design.<\/p>\n<h3>3.3 Improving Solder Paste Printing Efficiency<\/h3>\n<p>Another advantage of this 4-in-1 manufacturing method is that it improves the efficiency of solder paste printing. During the reflow process for the first side, the manufacturer has already mounted some components onto the board. This means that while the first side is being printed, a new PCB can be prepared on the other side, thereby saving time and resources.<\/p>\n<p>The essence of improving efficiency is<strong>Reduced the number of start-ups, shutdowns, and changeovers for printing presses and pick-and-place machines<\/strong>. Originally, 100 PCBs required two rounds of component placement (totaling about 200 loading and unloading cycles); after consolidating them into a 4-in-1 layout, this was reduced to 25 sets \u00d7 2 cycles, cutting the number of loading and unloading cycles to one-fourth. For an SMT line where costs are billed by the second, this savings is significant.<\/p>\n<h3>3.4 Fabrication of Artificial Yin-Yang Panels<\/h3>\n<p>Although this method may involve some additional labor costs, the operators who originally worked on the solder paste printers can be reassigned to perform manual panel assembly, provided they can keep up with the production cycle. In addition, to ensure the accuracy of manual panelization, manufacturers need to create a dedicated carrier so that operators can easily place the PCBs into it without any positional misalignment.<\/p>\n<p>Key Design Considerations for Carriers (Carrier \/ Fixture):<\/p>\n<ul>\n<li><strong>Positioning Reference<\/strong>: Use the board edges or process holes for alignment; avoid using component outlines for alignment (since the components themselves have tolerances).<\/li>\n<li><strong>Yielding Lane<\/strong>: Mill a groove based on the height of the tallest component on the first side, adding a margin (typically 0.3\u20130.5 mm) to prevent damage from pressure.<\/li>\n<li><strong>Support Surface<\/strong>: The board must be supported flat during printing; if it is left unsupported, it will result in uneven solder paste thickness.<\/li>\n<li><strong>Materials<\/strong>: Typically made of synthetic stone or aluminum alloy, which must withstand reflux temperatures and resist deformation; aluminum alloy conducts heat quickly, which may affect the local temperature profile and requires evaluation.<\/li>\n<li><strong>Foolproof Design<\/strong>: Can only be inserted in one direction to prevent incorrect installation.<\/li>\n<\/ul>\n<h3>3.5 Solder Paste Printing<\/h3>\n<p>During solder paste printing, the manufacturer removes the boards from the carrier and uses tape to secure the manual stencils together. Each board has its own fiducial marks, which ensure precision during the pick-and-place process and maintain accuracy even if there is a slight misalignment in the panel.<\/p>\n<p>The fiducial mark is key to the success of this solution. Its purpose is to allow the placement machine to<strong>Calculate coordinates based on each panel's own reference points<\/strong>...rather than relying on the mechanical precision of panel assembly. Therefore, even if manual assembly results in deviations of several tens of micrometers, the placement of the components remains accurate.<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Accuracy Section<\/th>\n<th>Typical Accuracy<\/th>\n<th>Does it rely on the precision of manual assembly?<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Manually load into the vehicle<\/td>\n<td>\u00b1100\u2013200 \u03bcm<\/td>\n<td>Yes (using vehicle positioning)<\/td>\n<\/tr>\n<tr>\n<td>Solder Paste Printing Alignment<\/td>\n<td>\u00b125\u201350 \u03bcm<\/td>\n<td>No (using a steel mesh alignment system)<\/td>\n<\/tr>\n<tr>\n<td>SMT Placement Machine Fiducial Alignment<\/td>\n<td>\u00b125\u201350 \u03bcm<\/td>\n<td>No (each plate is calibrated independently)<\/td>\n<\/tr>\n<tr>\n<td>Final Placement Accuracy<\/td>\n<td>\u00b150 \u03bcm range<\/td>\n<td>Virtually unaffected by human activity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Common fiducial design rules: At least 2 fiducials per panel unit (arranged diagonally), plus 3 additional global fiducials for the entire board; fiducials should have a diameter of 1 mm, with a 1\u20132 mm clear zone around them free of solder mask and traces, and should be solid circles.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1500\" height=\"844\" class=\"alignnone size-large wp-image-8904\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/smt-solder-paste-printing-process-flow.jpg\" alt=\"SMT Solder Paste Printing Process Flow\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/smt-solder-paste-printing-process-flow.jpg 1500w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/smt-solder-paste-printing-process-flow-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/smt-solder-paste-printing-process-flow-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/smt-solder-paste-printing-process-flow-768x432.jpg 768w\" sizes=\"auto, (max-width: 1500px) 100vw, 1500px\" \/><\/p>\n<h2>4. Key Process Points for the Two-Pass Reflow Process<\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1100\" height=\"619\" class=\"alignnone size-large wp-image-8907\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/solder-paste-for-smt-processing.jpg\" alt=\"Solder Paste for SMT Assembly\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/solder-paste-for-smt-processing.jpg 1100w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/solder-paste-for-smt-processing-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/solder-paste-for-smt-processing-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/solder-paste-for-smt-processing-768x432.jpg 768w\" sizes=\"auto, (max-width: 1100px) 100vw, 1100px\" \/><\/p>\n<p>When the second side goes through the reflow oven, the solder joints on the first side are already in place, which raises four issues that must be addressed:<\/p>\n<ul>\n<li><strong>A component fell off the first panel<\/strong>: When the second side is facing up, the components on the first side face down and are held in place solely by the surface tension of the solder joints. Heavy components (such as large inductors or shielding covers) may fall off when the solder paste melts. The solution is to control the ratio of component weight to pad area and, if necessary, reinforce them with red adhesive.<\/li>\n<li><strong>Re-soldering<\/strong>: The solder joints on the first side will remelt during the second reflow cycle; if there is insufficient support or vibration, this may cause the solder joints to deform. The solution is to optimize the temperature profile for the second side by lowering the peak temperature or reducing the time spent above the liquidus.<\/li>\n<li><strong>Solder Paste Printing Thickness<\/strong>: When printing the second side, components protruding from the board surface and uneven support can cause uneven solder paste thickness. The solution is to use a carrier or support blocks with clearance grooves.<\/li>\n<li><strong>Oxidation and Flux Residue<\/strong>: Solder joints on the first side that have undergone one reflow cycle experience accelerated oxidation during the second high-temperature cycle. The solution is to shorten the interval between the two processes and control the furnace atmosphere.<\/li>\n<\/ul>\n<h2>5. Key Engineering Considerations for Panel Assembly and Panel Cutting<\/h2>\n<p>Regardless of which yin-yang panel solution is used, the panel layout design must adhere to the following principles:<\/p>\n<ul>\n<li><strong>Panel Dimensions<\/strong>: The maximum usable area adjacent to production line equipment (typically 250 \u00d7 330 mm or 400 \u00d7 330 mm); if it is too large, it is difficult to handle, and if it is too small, it wastes production capacity.<\/li>\n<li><strong>Process Edge<\/strong>: Generally, leave 5 mm for guide rail clamping and marker placement; if V-cut separation is used, the process margin can be smaller.<\/li>\n<li><strong>Connection Methods<\/strong>: V-Cut is suitable for regular rectangles and produces clean edges after panel separation; break-away tabs are suitable for irregular shapes and board edges with components; milled grooves are suitable for applications requiring high precision.<\/li>\n<li><strong>Component Spacing<\/strong>: Do not place components within 1 mm of either side of the panel-separation line to prevent damage from panel-separation stress.<\/li>\n<li><strong>Board Separation Methods<\/strong>: Use a panel-splitting machine for V-cuts; snap off the stamp holes by hand or with a jig; the milling grooves have already been cut by the router. For detailed panel assembly techniques, see<a href=\"\/en\/blog\/the-size-and-assembly-techniques-of-a-single-pcb\/\">How to Determine the Size of a Single PCB and Panelization Techniques<\/a>\u3002<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1600\" height=\"900\" class=\"alignnone size-large wp-image-8580\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt.jpg\" alt=\"SMT Basics and Characteristics\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt.jpg 1600w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt-768x432.jpg 768w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/basic-knowledge-and-characteristics-of-smt-1536x864.jpg 1536w\" sizes=\"auto, (max-width: 1600px) 100vw, 1600px\" \/><\/p>\n<h2>7. Production Line Implementation: Five-Step Verification<\/h2>\n<p>When implementing this solution on the production line, follow these five steps to verify it:<\/p>\n<ol>\n<li><strong>Build the first vehicle and test the evasion system<\/strong>: Verify that the tallest component on the first face does not interfere with the carrier.<\/li>\n<li><strong>Verify Print Thickness<\/strong>: Use SPI (solder paste inspection) to verify that the solder paste thickness is consistent across all boards after assembly.<\/li>\n<li><strong>Verifying Placement Accuracy<\/strong>: After placement, perform AOI and first-article inspection to verify that the offset is within specifications.<\/li>\n<li><strong>Debugging the Temperature Curve for the Second Surface<\/strong>: Focus on checking whether any components have come loose on the first side and whether the solder joints are deformed.<\/li>\n<li><strong>Small-batch trial production<\/strong>: Run the entire batch first, then perform a full switchover, while tracking the actual processing time saved.<\/li>\n<\/ol>\n<h2>8. Cost Analysis: When Is It Worth It?<\/h2>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Cost Items<\/th>\n<th>Traditional two-pass single-board reflow<\/th>\n<th>4-in-1 Manual Assembly<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Number of Loading and Unloading Cycles for a Solder Paste Printer<\/td>\n<td>200 times (100 sheets \u00d7 2)<\/td>\n<td>50 repetitions (25 sets \u00d7 2)<\/td>\n<\/tr>\n<tr>\n<td>Start-up, Shutdown, and Line Changeovers for SMT Machines<\/td>\n<td>\u591a<\/td>\n<td>Decrease by 75%<\/td>\n<\/tr>\n<tr>\n<td>Manual Assembly Hours<\/td>\n<td>\u65e0<\/td>\n<td>Add (may be performed by the printing operator)<\/td>\n<\/tr>\n<tr>\n<td>Vehicle Deployment<\/td>\n<td>None or Simple<\/td>\n<td>Requires a dedicated carrier (one-time investment)<\/td>\n<\/tr>\n<tr>\n<td>Supplies such as tape<\/td>\n<td>\u65e0<\/td>\n<td>A small amount<\/td>\n<\/tr>\n<tr>\n<td>Applicable Batch Size<\/td>\n<td>Small batches, flexible<\/td>\n<td>Medium to large quantities offer better value<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The dividing line is very clear:<strong>The larger the batch, the smaller the boards, and the higher the hourly cost of the production line\u2014the more cost-effective this solution becomes.<\/strong>. For small-batch prototyping (a few dozen pieces), there\u2019s no need to use a carrier; it\u2019s simpler to run the boards through the reflow oven in two batches. For batches of several hundred pieces or more, the machine time saved usually offsets the costs of the carrier and labor.<\/p>\n<h2>Conclusion<\/h2>\n<p>Positive and negative PCBs play a crucial role in electronics manufacturing, but traditional manufacturing methods have certain limitations. Through an innovative \u201c4-in-1\u201d manufacturing approach, Taiwanese manufacturers have overcome some of the limitations of traditional methods, improving efficiency and reducing costs while maintaining high quality and precision. This innovation demonstrates the exceptional capabilities of Taiwanese manufacturing experts in the electronics sector and provides a strong model for future PCB manufacturing.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" class=\"alignnone size-large wp-image-8480\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/screen-printed-pcba-assembly.jpg\" alt=\"Why Is Screen Printing Critical in PCBA Assembly?\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/screen-printed-pcba-assembly.jpg 1280w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/screen-printed-pcba-assembly-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/screen-printed-pcba-assembly-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/screen-printed-pcba-assembly-768x432.jpg 768w\" sizes=\"auto, (max-width: 1280px) 100vw, 1280px\" \/><\/p>\n<p>The four most common issues encountered during implementation and how to troubleshoot them:<\/p>\n<ul>\n<li><strong>Uneven Solder Paste Thickness<\/strong>: This is most likely caused by an uneven support surface for the vehicle or a groove that is too deep, causing the panel to hang in the air.<\/li>\n<li><strong>SMT Offset<\/strong>: Check whether the fiducial is contaminated, whether there is sufficient clearance around it, and whether the mark is covered by solder mask.<\/li>\n<li><strong>A component fell off the first panel<\/strong>: If a component is overweight or the peak temperature on the second side is too high, consider reinforcing it with red adhesive or adjusting the curve.<\/li>\n<li><strong>Adhesive residue from tape<\/strong>: Switch to high-temperature-resistant tape and check for warping after printing and before reflow.<\/li>\n<\/ul>\n<h2>Frequently Asked Questions<\/h2>\n<h3>1. What are positive and negative PCBs?<\/h3>\n<p>A PCB with different component types on each side is a printed circuit board on which one side is populated with one type of component and the other side with another type; it is typically used in applications that require different types of components to be mounted on a single circuit board.<\/p>\n<h3>2. Why are there limitations in the traditional manufacturing of positive and negative PCB layers?<\/h3>\n<p>Traditional methods of manufacturing positive and negative PCB layers are subject to limitations such as material waste, high manufacturing complexity, and difficult soldering, which result in higher costs.<\/p>\n<h3>3. What is the 4-in-1 PCB manufacturing method?<\/h3>\n<p>The 4-in-1 PCB manufacturing method is an innovative approach in which, during the early stages of SMT production, manufacturers prepare 100 PCB boards and then manually assemble them into 4-in-1 double-sided positive-negative boards to improve efficiency and reduce costs.<\/p>\n<h3>4. How can we ensure the accuracy of manual assembly?<\/h3>\n<p>To ensure the accuracy of manual assembly, manufacturers need to create a specialized carrier so that operators can easily place the PCBs into it without any positional deviation.<\/p>\n<h3>5. What are the advantages of the 4-in-1 PCB manufacturing method?<\/h3>\n<p>The 4-in-1 PCB manufacturing method reduces material waste, improves manufacturing efficiency, and lowers labor costs while maintaining high quality and precision, making it an innovative alternative to traditional positive-negative PCB manufacturing.<\/p>\n<h3>6. Why doesn't manual assembly affect surface-mount accuracy?<\/h3>\n<p>This is because the placement machine does not rely on the mechanical positioning of the panel but instead uses the fiducial marks on each board for visual alignment. Deviations in manual assembly can reach hundreds of micrometers, but after the placement machine reads the fiducial marks, it performs calculations based on the board\u2019s own coordinate system; the final accuracy is ultimately determined by the machine\u2019s own repeatability (generally within \u00b150 \u03bcm). This is also why every board must have fiducial marks.<\/p>\n<h3>7. When the second side is passed through the reflow oven, why don\u2019t the components on the first side fall off?<\/h3>\n<p>The components are primarily held in place by the surface tension of the molten solder. However, this \u201csupporting force\u201d has an upper limit; as a rule of thumb, the ratio of the component\u2019s weight to the pad area must not exceed a certain threshold (which varies depending on the component type). If this threshold is exceeded, red adhesive should be applied for reinforcement, or large components should be moved to the second side for soldering. Large shielding enclosures and large electrolytic capacitors are the two types most commonly requiring reinforcement.<\/p>\n<h3>8. Why is composite stone used for the vehicle instead of regular plastic?<\/h3>\n<p>Composite stones (such as Durostone-type materials) can withstand reflux temperatures exceeding 260 \u00b0C, exhibit minimal thermal deformation, do not absorb moisture, and have good mechanical strength. Ordinary plastics soften, deform, or even decompose at reflux temperatures. Aluminum alloys can also be used, but they conduct heat quickly, which alters the local temperature profile and requires recalibration of the furnace temperature.<\/p>\n<h3>9. Under what circumstances should this approach not be used?<\/h3>\n<p>There are three scenarios: First, the batch size is too small (a few dozen boards), making it impossible to spread the costs of the fixture and debugging evenly. Second, the first side of the board contains large components, posing a high risk of them falling off during a second reflow and making it impossible to reinforce them. Third, product models change frequently, requiring the fixture to be redesigned with each change; this offers less flexibility than reflow-soldering the boards in two separate passes.<\/p>\n<h3>10. How do you choose between a V-cut and a stamp hole when panelizing?<\/h3>\n<p>Regular rectangles, no components along the board edges, and a requirement for smooth edges after panelization \u2192 Use V-Cut, which offers the lowest cost and highest efficiency. Irregular-shaped boards, boards with components protruding from the edges, or cases with strict delamination stress requirements \u2192 Use stamp holes or milled grooves. With V-Cut, delamination stress is concentrated along the tangent line; stamp holes generate less stress but result in burrs on the edges that require sanding.<\/p>\n<p><strong>Additional Information<\/strong>\uff1a<a href=\"\/en\/blog\/smt-solder-paste-printing-process-flow\/\">SMT Solder Paste Printing Process Flow<\/a> \u00b7 <a href=\"\/en\/blog\/5g-pcb-copper-plating-process-problems-solutions\/\">Common Issues and Solutions for the 5G PCB Copper Plating Process<\/a> \u00b7 <a href=\"\/en\/pcba-capabilities\/\">PCBA Manufacturing Capabilities<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>1. \u300c\u9634\u9633\u677f\u300d\u5230\u5e95\u662f\u4ec0\u4e48 \u9634\u9633\u677f\uff08\u4e5f\u79f0\u6b63\u53cd\u9762\u677f\uff09\u6307\u540c\u4e00\u5757 PCB \u7684\u4e24\u9762\u90fd\u8d34\u88c5\u5143\u4ef6\u7684\u7ec4\u88c5\u5f62\u6001\u3002\u4e0e\u4e4b\u76f8\u5bf9\u7684\u662f\u5355 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"What Are the Benefits of Manual Panel Assembly Before SMT? Materials and Soldering Challenges for Yin-Yang Panels","description":"What are the benefits of manual panelization prior to SMT? This article explains the limitations of traditional \"yin-yang\" panels in terms of material waste, manufacturing complexity, and soldering difficulty, as well as proposed solutions. It provides ready-to-use parameters and key operational guidelines."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[409,26],"tags":[],"class_list":["post-2649","post","type-post","status-publish","format-standard","hentry","category-smt-assembly","category-blog"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2649","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/comments?post=2649"}],"version-history":[{"count":4,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2649\/revisions"}],"predecessor-version":[{"id":19895,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2649\/revisions\/19895"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=2649"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=2649"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=2649"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}