Raws li qhov tseem ceeb ntawm cov khoom siv hluav taws xob, luam tawm hauv Circuit Court board (PCB) ua lub luag haujlwm tseem ceeb hauv kev ua tiav kev ua haujlwm ntawm cov khoom siv hluav taws xob, uas ua rau muaj txiaj ntsig tseem ceeb ntawm PCB tsim, vim tias kev ua tau zoo ntawm PCB tsim ncaj qha txiav txim siab ua haujlwm thiab tus nqi ntawm cov khoom siv hluav taws xob. Kev tsim PCB zoo tuaj yeem khaws cov khoom siv hluav taws xob los ntawm ntau qhov teeb meem, yog li ua kom ntseeg tau tias cov khoom lag luam tuaj yeem ua haujlwm tau zoo thiab ua tau raws li txhua qhov kev xav tau ntawm cov ntawv thov.

Ntawm txhua lub ntsiab lus uas pab txhawb rau PCB tsim, Kev Tsim Khoom Tsim (DFM) yog qhov tseem ceeb tshaj vim tias nws txuas PCB tsim nrog PCB kev tsim khoom txhawm rau nrhiav teeb meem thaum ntxov thiab daws lawv hauv lub sijhawm thoob plaws lub neej ntawm cov khoom siv hluav taws xob. 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 kev tsim khoom

Los ntawm kev sib txuas kev tsim khoom nrog PCB tsim, kev tsim khoom tsim yog qhov tseem ceeb ua rau kev tsim khoom tau zoo, ua tau zoo thiab raug nqi tsawg. 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. Yog tias cov xwm txheej no tsis ua tiav rau hauv tus lej ntawm PCB tsim theem, cov tshuab siv lub tshuab laminating tsis zoo tuaj yeem tsis tuaj yeem lees txais PCB cov phiajcim ua ntej tshwj tsis yog kev ntsuas ua tiav ntxiv. Txhawm rau ua teeb meem hnyav dua, qee cov phaj tsis tuaj yeem ua tiav siv phau ntawv vuam. As a result, the manufacturing cycle will be longer and labor costs will increase.

1. PCB size

Txhua lub tshuab teeb tsa nws muaj nws tus kheej xav tau PCB loj, uas txawv raws li qhov ntsuas ntawm txhua tus neeg teeb tsa. Piv txwv li, tus txhim kho nti lees txais qhov siab tshaj plaws PCB loj ntawm 500mm * 450mm thiab qhov tsawg kawg PCB loj ntawm 30mm * 30mm. Qhov no tsis txhais tau tias peb tsis tuaj yeem ua haujlwm PCB pawg thawj coj loj dua 30mm los ntawm 30mm, thiab tuaj yeem tso siab rau cov laug cam thaum xav tau me me. Thaum koj tsuas tuaj yeem tso siab rau kev teeb tsa phau ntawv thiab cov nqi ua haujlwm tau nce thiab cov khoom tsim tawm tsis raug tswj, nti tshuab SMT yuav tsis lees txais PCB cov laug cam uas loj dhau lossis me me. 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.

Daim duab hauv qab no qhia txog PCB daim ntawv tsim qauv ua tiav los ntawm Huaqiu DFM software. Raws li 5 × 2 lub rooj tsavxwm, txhua lub xwmfab yog ib daim, ntsuas 50mm txog 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. Raws li cov kev xav tau saum toj no, nws tuaj yeem txiav txim siab tias qhov loj ntawm lub rooj tsavxwm yog nyob hauv qhov kev lees paub.

2. PCB shape

In addition to PCB size, all chip SMT machines have requirements for PCB shape. Ib qho PCB ib txwm yuav tsum yog lub duab plaub nrog qhov ntev rau qhov dav sib piv ntawm 4: 3 lossis 5: 4 (zoo tshaj). If the PCB is irregularly shaped, additional measures must be taken prior to SMT assembly, resulting in increased costs. Txhawm rau tiv thaiv qhov no los ntawm qhov tshwm sim, PCB yuav tsum tau tsim nyob rau hauv ib qho zoo ib yam thaum lub sijhawm PCB tsim theem kom tau raws li SMT cov tseev kom muaj. Txawm li cas los xij, qhov no nyuaj ua hauv kev xyaum. Thaum cov duab ntawm qee yam khoom siv hluav taws xob yuav tsum tsis xwm yeem, lub thwj cim yuav tsum raug siv los muab PCB zaum kawg kom zoo li qub. Thaum sib sau ua ke, cov khoom sib txuas uas tsis tuaj yeem tuaj yeem tshem tawm ntawm PCB kom tau raws li kev teeb tsa tsis siv neeg thiab qhov chaw xav tau.

Daim duab hauv qab no qhia txog PCB nrog cov duab tsis xwm yeem, thiab cov txheej txheem ua tiav tau ntxiv los ntawm 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. Txheej txheem sab

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

Hauv PCB tsim theem, 5mm txheej txheem txheej txheem dav yuav tsum tau muab tso tseg ua ntej, yam tsis tau tawm ib qho khoom siv thiab txuas xov. Cov txheej txheem qhia feem ntau muab tso rau sab luv ntawm PCB, tab sis sab luv tuaj yeem xaiv thaum qhov piv piv ntau dua 80%. Tom qab sib dhos, txheej txheem ntug tuaj yeem raug tshem tawm raws li lub luag haujlwm tsim khoom pabcuam.

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. Yog li ntawd, Cov ntsiab lus cim yog SMT cov qauv tsim qauv xav tau rau kev tsim khoom lag luam.

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. Qhov nruab nrab nruab nrab ntawm Mark point thiab phaj ntug yuav tsum yog yam tsawg 5mm. Rau PCBS nrog ob tog SMT Cheebtsam, Kos cov ntsiab lus yuav tsum tau muab tso rau ob sab. 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 los ua ke, lossis PCBA kom luv, yog qhov txheej txheem ntawm cov khoom siv vuam mus rau cov laug cam. Txhawm rau ua kom tau raws li qhov xav tau ntawm kev tsim khoom tsis siv neeg, PCB sib dhos muaj qee qhov xav tau rau pob khoom sib dhos thiab teeb tsa sib dhos.

1. Ntim cov khoom

Thaum lub PCBA tsim, yog tias cov khoom ntim tsis ua tau raws li cov qauv tsim nyog thiab cov khoom siv sib ze dhau, kev teeb tsa tsis siv neeg yuav tsis tshwm sim.

Txhawm rau kom tau txais kev ntim khoom ntim zoo tshaj plaws, kev tshaj lij EDA tsim software yuav tsum tau siv los ua raws li cov txheej txheem ntim khoom ntim thoob ntiaj teb. 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

Cov txheej txheem txheej txheem yog ib txoj haujlwm tseem ceeb hauv PCB tsim vim tias nws qhov kev ua tau zoo cuam tshuam ncaj qha rau qhov nyuaj ntawm PCB cov tsos thiab tsim cov txheej txheem.

Thaum lub sijhawm teeb tsa kev teeb tsa, kev sib dhos ntawm SMD thiab THD cov khoom yuav tsum raug txiav txim siab. Ntawm no, peb teeb lub hauv ntej ntawm PCB raws li kev tivthaiv A sab thiab sab nraub qaum raws li tivthaiv B sab. 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. Kev sib dhos sib txawv xav tau cov txheej txheem tsim khoom thiab txheej txheem sib txawv. 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.

Feem ntau, kev taw qhia cov khoom siv yuav tsum zoo ib yam. 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. Qhov siab ntawm kev tivthaiv yuav tsum yog txog 4 hli, thiab kev xa mus ntawm cov khoom thiab PCB yuav tsum yog 90 °.

Txhawm rau txhim kho vuam nrawm ntawm cov khoom thiab pab txhawb kev tshuaj xyuas tom ntej, qhov sib nrug ntawm cov khoom siv yuav tsum zoo ib yam. 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 thiab ncoo yuav tsum tsis txhob sib tshooj, txwv tsis pub cov khoom yuav tsis raug teeb tsa.

Due to the actual operating temperature of the PCB and the thermal characteristics of the electrical components, heat dissipation should be considered. Cov txheej txheem ntawm cov khoom siv yuav tsum tsom mus rau cov cua sov ua kom sov. Yog tias tsim nyog, siv lub kiv cua lossis lub dab cua sov. Cov tshuab hluav taws xob tsim nyog yuav tsum tau xaiv rau cov khoom siv hluav taws xob thiab cov khoom siv cua sov yuav tsum tau muab tso kom deb ntawm cov cua sov. Cov khoom tiv thaiv siab yuav tsum tau muab tso tom qab cov khoom siv qis.

Cov ntsiab lus ntxiv yuav tsum tau tsom mus rau PCB DFM, thiab kev paub yuav tsum tau suav nrog hauv kev xyaum. Piv txwv li, kev teeb tsa high-speed PCB tsim kom muaj qhov tshwj xeeb kev xav tau tshwj xeeb thiab yuav tsum tau tham nrog pawg thawj coj ua ntej kev tsim khoom tiag los txiav txim siab qhov cuam tshuam thiab cov ntaub ntawv txheej. Txhawm rau npaj rau kev tsim khoom ntawm cov laug cam PCB me me nrog cov kab sib txuas, qhov tsawg kawg ntawm txoj kab dav dav thiab hla qhov taub qhov peev xwm tsim khoom yuav tsum tau tham nrog PCB chaw tsim khoom kom ntseeg tau kev ua tau zoo ntawm cov PCBS no.