As an essential part of electronic products, papan sirkuit cetak (PCB) plays a key role in realizing the function of electronic products, which leads to the increasingly prominent importance of PCB design, because the performance of PCB design directly determines the function and cost of electronic products. Good PCB design can keep electronic products from many problems, thus ensuring that products can be smoothly manufactured and meet all the needs of practical applications.

Of all the elements that contribute to PCB design, manufacturing Design (DFM) is absolutely essential because it links PCB design with PCB manufacturing in order to find problems early and solve them in time throughout the life cycle of electronic products. One myth is that the complexity of PCB design will increase as manufacturability of electronics is considered at the PCB design stage. In the design life cycle of electronic products, DFM can not only make electronic products participate in automatic production smoothly, and save labor costs in the manufacturing process, but also effectively shorten the manufacturing time to ensure the timely completion of the final electronic products.

PCB manufacturability

Kanthi nggabungake pabrike karo desain PCB, desain pabrikan minangka faktor utama sing ngasilake manufaktur sing efisien, kualitas tinggi lan biaya murah. The research of PCB manufacturability covers a wide range, usually divided into PCB manufacturing and PCB assembly.

LPCB production

For PCB manufacturing, the following aspects should be considered: PCB size, PCB shape, process edge and Mark point. Yen aspek kasebut durung dipikirake ing tahap desain PCB, mesin laminating chip otomatis bisa uga ora bisa nampa papan PCB prefabrikasi kajaba langkah-langkah pangolahan tambahan ditindakake. Supaya luwih parah, sawetara piring ora bisa digawe kanthi otomatis kanthi nggunakake las manual. As a result, the manufacturing cycle will be longer and labor costs will increase.

1. PCB size

Saben installer chip duwe ukuran PCB sing dikarepake, sing beda-beda miturut paramèter saben installer. Contone, installer chip nampa ukuran PCB maksimum 500mm * 450mm lan ukuran PCB minimal 30mm * 30mm. Iki ora ateges kita ora bisa ngatasi komponen papan PCB sing luwih cilik tinimbang 30mm nganti 30mm, lan bisa ngandelake papan jigsaw yen dibutuhake ukuran sing luwih cilik. Yen sampeyan mung bisa ngandelake instalasi manual lan biaya tenaga kerja mundhak lan siklus produksi ora bisa dikendhaleni, mesin SMT chip ora bakal nampa papan PCB sing gedhe banget utawa cilik banget. Therefore, in the PCB design stage, the PCB size requirements set by automatic installation and manufacturing must be fully considered, and it must be controlled within the effective range.

The following figure illustrates the PCB board design document completed by Huaqiu DFM software. As a 5×2 board, each square unit is a single piece, measuring 50mm by 20mm. The connection between each unit is achieved by V-cut/V-scoring technology. In this image, the entire square is shown with a final size of 100mm by 100mm. Miturut sarat ing ndhuwur, bisa disimpulake manawa ukuran dewan ana ing kisaran sing bisa ditampa.

2. PCB shape

In addition to PCB size, all chip SMT machines have requirements for PCB shape. A normal PCB should be rectangular in shape with a length to width ratio of 4:3 or 5:4 (best). If the PCB is irregularly shaped, additional measures must be taken prior to SMT assembly, resulting in increased costs. Kanggo nyegah kedadeyan kasebut, PCB kudu dirancang kanthi bentuk umum sajrone fase desain PCB kanggo memenuhi persyaratan SMT. However, this is difficult to do in practice. Nalika bentuk sawetara produk elektronik mesthine ora teratur, bolongan cap kudu digunakake kanggo menehi PCB pungkasan wujud normal. Yen dirakit, baffle tambahan sing berlebihan bisa dicopot saka PCB kanggo memenuhi syarat instalasi lan ruang kanthi otomatis.

The picture below shows the PCB with irregular shape, and the processing edge is added by Huaqiu DFM software. The whole circuit board size is 80mm * 52mm, and the square area is the size of the actual PCB. The size of the upper right corner area is 40mm by 20mm, which is the auxiliary craft edge produced by the bridge of the stamp hole.

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3. Sisih proses

To meet the requirements of automatic manufacturing, process edges must be placed on the PCB to secure the PCB.

In PCB design stage, 5mm wide process edge should be set aside in advance, without leaving any components and wiring. The technical guide is usually placed on the short side of the PCB, but the short side can be selected when the aspect ratio exceeds 80%. Sawise dirakit, ujung proses bisa dicopot minangka peran produksi tambahan.

4. Mark point

For PCBS with components installed, Mark points should be added as a common reference point to ensure that component locations are accurately determined for each assembly device. Therefore, Mark points are SMT manufacturing benchmarks required for automated manufacturing.

Components require 2 Mark points and PCBS require 3 Mark points. These marks should be placed on the edges of the PCB board and cover all SMT components. Jarak tengah antarane titik Mark lan pinggiran piring paling ora kudu 5mm. For PCBS with double-sided SMT components, Mark points should be placed on both sides. If the components are too close together to place Mark points on the board, they can be placed on the edge of the process.

LPCB assembly

PCB assembly, or PCBA for short, is actually the process of welding components onto bare boards. Kanggo nyukupi kebutuhan manufaktur otomatis, perakitan PCB duwe sawetara persyaratan kanggo paket perakitan lan tata letak perakitan.

1. Kemasan komponen

During PCBA design, if component packages do not meet appropriate standards and components are too close together, automatic installation will not occur.

Kanggo entuk kemasan komponen sing paling apik, piranti lunak desain EDA profesional kudu digunakake kanggo tundhuk karo standar kemasan komponen internasional. During PCB design, the aerial view area must not overlap with other areas, and the automatic IC SMT machine will be able to accurately identify and mount the surface.

2. Component layout

Tata letak komponen minangka tugas penting ing desain PCB amarga prestasine ana gegayutan langsung karo kerumitan tampilan PCB lan proses manufaktur.

Sajrone tata letak komponen, permukaan majelis komponen SMD lan THD kudu ditemtokake. Ing kene, kita nyetel sisih ngarep PCB minangka komponen A sisih lan mburi minangka sisih komponen B. The assembly layout should consider the assembly form, including single layer single package assembly, double layer single package assembly, single layer mixed package assembly, Side A mixed package and side B single package assembly and side A THD and side B SMD assembly. Déwan sing beda-beda mbutuhake proses lan teknik manufaktur sing beda. Therefore, in terms of component layout, the best component layout should be selected to make manufacturing simple and easy, so as to improve the manufacturing efficiency of the whole process.

In addition, consideration must be given to the orientation of component layout, spacing between components, heat dissipation, and component height.

In general, component orientation should be consistent. Components are laid out in accordance with the principle of minimum tracking distance, based on which components with polarity markers should have uniform polarity directions, and components without polarity markers should be neatly aligned along the X or Y axis. Dhuwur komponen kudu nganti 4mm, lan arah transmisi ing antarane komponen lan PCB kudu 90 °.

To improve the welding speed of components and facilitate subsequent inspection, the spacing between components should be consistent. Components in the same network should be close to each other and a safe distance should be left between different networks according to the voltage drop. Silkscreen and pad must not overlap, otherwise components will not be installed.

Due to the actual operating temperature of the PCB and the thermal characteristics of the electrical components, heat dissipation should be considered. Tata letak komponen kudu fokus ing disipasi panas. Yen perlu, gunakake kipas angin utawa wastafel. Appropriate radiators should be selected for the power components and heat sensitive components should be placed away from heat. The high component should be placed after the low component.

More details should be focused on PCB DFM, and experience should be accumulated in practice. For example, high-speed signal PCB design requirements have special impedance requirements and should be discussed with the board manufacturer prior to actual manufacture to determine impedance and layering information. Kanggo nyiapake produksi ing papan PCB ukuran cilik kanthi kabel padhet, jembaré kabel minimal lan kapasitas pabrik diameter liwat-bolongan kudu dibahas karo pabrikan PCB supaya produksi PCBS kasebut bisa lancar.