Selecting PCB core thickness becomes an issue when a papan sirkuit dicitak Pabrikan (PCB) nampi cutatan anu nyungkeun desain multilayer sareng sarat matéri henteu lengkep atanapi henteu nyatakeun pisan. Kadang-kadang ieu kajantenan kusabab gabungan bahan inti PCB anu dianggo henteu penting pikeun kinerja; If the overall thickness requirement is met, the end user may not care about the thickness or type of each layer.

But at other times, performance is more important and the thickness needs to be tightly controlled for optimal performance. If the PCB designer clearly communicates all requirements in the documentation, then the manufacturer will know what the requirements are and will set the materials accordingly.

Isu désainer PCB kedah diperhatoskeun

Éta ngabantosan désainer ngartos bahan anu aya sareng anu biasa dianggo, ngarah tiasa nganggo aturan desain anu cocog pikeun ngawangun PCBS gancang sareng leres. Naon ieu mangrupikeun pedaran ringkes jinis bahan pabrik resep dianggo, sareng naon anu kedah diperyogikeun ku aranjeunna pikeun muterkeun gancang tanpa nyangsang proyek anjeun.

Ngartos biaya laminasi PCB sareng inventarisasi

Penting pikeun ngarti yén bahan laminasi PCB dijual sareng dianggo dina “sistem” sareng bahan inti na prepreg dipikagaduh ku pabrikan kanggo panggunaan langsung biasana tina sistem anu sami. In other words, the constituent elements are all parts of a particular product, but with some variations, such as thickness, copper weight and prepreg style. Salaku tambahan kana kawawuhan sareng kaulangan, aya alesan sanés pikeun nyayogikeun sajumlah terbatas jinis lamina.

Prepreg and inner core systems are formulated to work together, but may not work correctly when used in combination with other products. For example, the Isola 370HR core material will not be used in the same stack as the Nelco 4000-13 prepreg. It’s possible they’ll work together in some situations, but more likely they won’t. Sistem hibrid nyandak anjeun kana daérah anu teu acan diparkir, dimana paripolah bahan (dipikaterang nalika dianggo salaku sistem homogen) moal tiasa diémutan deui. Careless or unwitting mixing and matching of material types can lead to serious failures, so no manufacturer will mix and match unless the type is proven to be suitable for “mixed” stacking.

Alesan sanés pikeun nyimpen inventaris bahan sempit nyaéta biaya sertifikasi UL anu tinggi, janten umum di industri PCB pikeun ngawatesan jumlah sertifikasi kana pilihan bahan anu kawilang leutik. Manufacturers will often agree to make products on laminate without standard stock, but be aware that they cannot provide UL certification through QC documentation. Ieu mangrupikeun pilihan anu saé pikeun desain non-UL upami diungkabkeun sareng disatujuan sateuacana sareng pabrikna kenal sareng persyaratan pamrosésan sistem laminating anu dimaksud. For UL work, it is best to find out the manufacturer inventory of your choice and design boards to match it.

Ipc-4101d and foil construction

Now that these facts are out in the open, there are two other things to know before jumping into design. First, it is best to specify laminates according to industry specification IPC-4101D and not to name specific products that not everyone can stock.

Secondly, it is easiest to construct multiple layers using the “foil” construction method. Foil construction means that the top and bottom layers (outer) are made from a single piece of copper foil and laminated to the remaining layers with prepreg. Sanaos sigana intuitif ngawangun PCB 8 lapisan kalayan opat inti dua sisi, langkung saé nganggo foil sacara éksternal heula, teras tilu inti pikeun L2-L3, L4-L5, sareng L6-L7. Kalayan kecap séjén, ngarencanakeun mendesain tumpukan multi-lapisan sahingga jumlah intina sapertos kieu: (jumlah total lapisan dikurangan 2) dibagi ku 2. Salajengna, gunana pikeun terang hal ngeunaan pasipatan inti. Sorangan.

Inti kasebut disayogikeun dina PIECE anu lengkep diubaran tina FR4 kalayan tambaga dilapis dina dua sisi. Cores ngagaduhan seueur ketebalan, sareng ukuran anu langkung umum dianggo biasana disimpen dina saham anu langkung ageung. Ieu mangrupikeun ketebalan anu kedah diémutan, utamina nalika anjeun kedah mesen produk perputaran gancang supados henteu nyéépkeun waktos kalungguhan pesenan ngantosan bahan anu henteu standar sumping ti distributor.

Common iron core and copper thickness

Inti anu paling sering dianggo pikeun ngawangun 0.062 “multilayer kandel nyaéta 0.005”, 0.008 “, 0.014”, 0.021, 0.028 “, sareng 0.039”. Inventory of 0.047 “is also common, as it is sometimes used to build 2-layer boards. Inti anu sanés anu bakal teras disimpen nyaéta 0.059 in., Sabab éta dipaké pikeun ngahasilkeun papan 2-lapis anu 0.062 in. Kandel, tapi ngan ukur tiasa dianggo pikeun papan gandakan anu langkung kandel, sapertos 0.093 in. Pikeun posisi ieu, urang ngawatesan ruang lingkup kana desain inti kalayan kandel nominal akhir 0.062 inci.

Copper thicknesses range from half an ounce to three to four ounces, depending on the particular manufacturer’s product mix, but most stocks can be in two ounces or less. Inget ieu sareng émut yén ampir sadaya saham bakal nganggo beurat tambaga anu sami dina kadua sisi inti. Coba hindarkeun sarat desain PCB anu meryogikeun tambaga anu béda-béda dina unggal sisina, sabab sering ieu peryogi mésér khusus sareng tiasa meryogikeun biaya buru-buru (gawena buru-buru), sakapeung henteu minuhan urutan minimum distributor.

For example, if you want to use 1oz of copper on an airplane and plan to use H oz of signal, consider making the airplane in H oz or increasing the signal to 1oz to make the core use both sides like copper with weight. Tangtosna, anjeun ngan ukur tiasa ngalakukeun ieu upami anjeun masih tiasa nyumponan sarat listrik desain sareng gaduh cukup wilayah XY pikeun nampung aturan desain tilas / desain ruang pikeun minuhan minimum 1oz dina lapisan sinyal. If you can meet these conditions, it is best to use it like a copper weight. Otherwise, you may need to consider a few extra days of lead time.

Assuming that you have selected the appropriate core thickness and available copper weight, various combinations of prepreg sheets are used to establish the remaining dielectric locations until the total thickness required is met. For designs that do not require impedance control, you can leave the prepreg option to the manufacturer. They will use their preferred “standard” version. On the other hand, if you do have impedance requirements, state these requirements in the documentation so that the manufacturer can adjust the amount of prepreg between cores to meet the specified values.

Kadali imppedansi

Naha kendali impedansi diperyogikeun atanapi henteu, henteu disarankeun anjeun nyobian ngadokuméntasikeun jinis sareng kandel prepreg pikeun tiap lokasi kecuali anjeun ahli dina prakték ieu.Often, such detailed stacks eventually need to be adjusted, so they can cause delays. Sabalikna, diagram tumpukan anjeun tiasa nunjukkeun ketebalan inti tina pasangan lapisan jero sareng nunjukkeun “posisi prepreg diperyogikeun dumasarkeun impedansi sareng sarat ketebalan umum”. This allows manufacturers to create ideal laminations to match your design.

Propilna

Tumpukan inti anu idéal dumasar kana stok anu aya penting pisan pikeun nyingkahan penundaan anu teu perlu nalika mesen giliran gancang sareng garis waktos anu ketat. Kaseueuran pabrik PCB nganggo struktur multilayer anu sami dumasar kana kernel anu sami sareng pesaingna. Kacuali PCB salira dikustomisasi, moal aya sihir atanapi pangwangunan rahasia. Therefore, it is worth familiarizing yourself with the preferred material for a particular layer and making every effort to design a PCB to match it. Bakal aya pengecualian pikeun kabutuhan desain khusus, tapi sacara umum, bahan baku mangrupikeun pilihan anu pangsaéna.