Soti nan sikwi pwototip sou planch pen pou desine pwòp nou yo an lèt detache sikwi tablo (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. Se konsepsyon PCB te pote soti nan yon pwosesis jeni elektrik (EE). EE kreye “sèvo a” nan ki jan aparèy travay. Without electronics, you’re left with little more than a pile of metal and plastic.

Things to know before starting PCB design: 1. PCB size – this depends on your product size (or case size). Dimansyon pwodwi yo defini pandan pwosesis konsepsyon jeni elektwonik la. You can watch a video about it here. 2. Kouch PCB – Kouch yo pi plis, pi konplèks la FABRICATION nan PCB. (Remak: Menm yon PCB yon sèl kouch kapab yon PCB konplèks, men isit la nou ap pale de konpleksite nan fè yon PCB. Plis kouch yon PCB genyen, li pi chè pou fabrike.)

Layer 2 is usually used for simple toy products

Iot pwodwi ki gen rapò anjeneral gen 4 kouch

Typically used for floors 6 to 8 of a smartphone or smartwatch.

3. Your PCB manufacturer’s requirements. Be sure to read the guidelines for rhythm, trace size, power isolation, and file naming before you start designing.

Enfòmasyon ou bezwen bay manifaktirè PCB yo:

Number of layers (e.g. 2, 4, 6, etc.)

Materyèl (FR-2 (papye koton fenolik), FR-3 (papye koton ak epoksidik), FR-4 (fib vè ak epoksidik … Etc.)

Epesè (0.5 mm, 1.0 mm … Etc.)

Color (red, black, green… Etc.)

Tretman andigman (ENIG (chimik nikèl / imèsyon lò), DIG (imèsyon dirèk lò), OSP (préservatifs òganik soudabl, elatriye)

Copper weight (1 oz (35 microns), 2 oz (70 microns), 0.5 oz (18 microns)… Etc.)

Dosye Gerber

PCB design process:

Konsepsyon Awondisman

For this step, you need to create the schematic. This is a document, like a blueprint, that describes how components relate to each other and work together. To create the schematic file, you will need a software tool. We like Quadcept because it is optimized for designing PCBS for manufacturing (for example, you can export a Bill of Material (BoM) directly from the tool) and is cloud-based, so it can be easily used anywhere. (They also offer a free community version of the tool for manufacturers and students.)

There are many other options you can choose from:

Altium

ExpressPCB

Aparèy frekans

KiCad

Cadence allegro

Manje

Computer aided design

DipTrace

After you install the selected tools, you need to obtain the component specifications for each selected component. They can often be found on the supplier’s website. Fichye modèl la ap ede ou trase schematic la. This component becomes available in the database when you upload the model to the software tool. Then, all you have to do is follow the data manual and connect the wire to each pin in the component. (Remak: detay yo nan pwosesis la konsepsyon pral depann de zouti nan lojisyèl chwazi).

Each schematic symbol needs to have an associated PCB space area to define the physical dimensions of the component and the location of the through holes on the brazing pad or PCB. You should have selected the components (or are now selecting them), and we describe this process in the EE Design Process video (see video).

Example diagram

A good schematic is really important, as it will be used as a reference document during debugging and is a good communication tool with other engineers. Anplis de sa, manifakti a ka teste aparèy la nan pwen tès yo sou dokiman sa a.

PCB layout + Gerber file

To design the PCB layout and create Gerber files, you can use the same software tools we mentioned in circuit design. Kontrèman ak yon schematic, yon Layout PCB asiyen eleman aktyèl yo nan kote egzak sou PCB la epi li montre tras yo ki konekte chak eleman ansanm ant kouch PCB yo. As mentioned at the beginning of this article, the more layers, the more complex the manufacturing required, and the higher the cost.

Divide the PCB into logical parts based on functions (e.g. power supply, audio output, etc.). Then, be sure to group the components of each section into the same area. Nan fason sa a, ou ka kenbe tras la konduktif kout epi redwi bri ak entèferans.

Koòdone itilizatè a (UI) bezwen tou kenbe nan tèt ou lè konsepsyon yon PCB. Eleman tankou jak odyo, konektè, poul, elatriye bezwen ajiste pou reyalize pi bon eksperyans itilizatè a.

Once the layout is designed, a Gerber file is generated. Manifakti PCBA ou a pral itilize dosye sa a. There are many companies that offer these services, and from HWTrek’s expert library we recommend Kingbrother, NexPCB, and HQPCB.

Sample Gerber files

Plasman eleman sou PCB la trè enpòtan. Some components can interfere with each other and cause unexpected behavior. For example, if you have both Bluetooth and Wi-Fi modules, they have the same 2.4ghz bandwidth and can interfere with each other if incorrectly placed.

PCB production

When you send the Gerber file to the PCB manufacturer, they can print the board. Sa a pral baz la plis bati fondasyon an pou ajoute eleman nan PCB la ak fabrikasyon PCBA a (enprime asanble tablo sikwi).

Unassembled PCBS

PCBA (Assembly)

Preparasyon materyèl

Nan pwen sa a nan konsepsyon EE ou, ou ta dwe chwazi eleman yo. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Matyè ki bezwen atansyon:

Lead time: As these components come from different suppliers, keep the lead time in mind. For some components, it can take up to 8-16 weeks.

Packaging: Order components from reels that are automatically picked up by SMT machines instead of packaging them individually.

Minimum order quantity: Check the minimum order quantity of the component. Si ou achte mwens pase minimòm lan, asire w ke eleman yo chwazi yo nan stock. For small batches (up to 50), you can order online from DigiKey or Mouser. Pou plis kantite, tanpri chèche konsèy nan men manifakti ou.

Loss: Order 10% more to cover loss (not for expensive components)

Install components on the PCB

There are two main ways to place components on a PCB surface:

Through-holes (through-holes) are manual methods of assembling assemblies with wires into holes on the surface of a PCB. It is also commonly known as DIP or dual in-line packaging process. (See SMT in progress in this video)

SMT (sifas mòn teknoloji) se metòd ki pi lajman itilize nan pwodiksyon an mas. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Bagay sa yo sonje:

Your component type number must not exceed the number of reels that the manufacturer’s SMT machine can support.

Optimize and consolidate your components so that only one SMT runs.

Check manufacturer supported footprint pad sizes. Otherwise, the SMT machine will not install components correctly.

Some larger components cannot be installed by machine and still require manual through-hole work. Therefore, both technologies can be used on the same board.

Any components you need to manually add via the through-hole method add to the manufacturing cost.

Reflow soudaj

Reflow soldering is the process of making components “stick” to the PCB. PCBA a chofe tablo sikwi a nan yon founo reflow oswa yon lanp enfrawouj jiskaske soude a fonn, kidonk pèmanan atache eleman nan tablo sikwi a.

The trickiest part here is not to overheat or damage the components, because the thermal characteristics of each package are different. Yon manifakti PCBA serye pral responsab pou pwosesis sa a, ak tout sa ou bezwen fè se bay yo ak espesifikasyon eleman.

Reflux pwosesis.

Other welding methods:

Wave soldering is mainly used for manually added components by the through-hole method. Nan ka sa a, PCBA ou a pral premye ale nan gwo founo dife a soude reflow, ak Lè sa a, manyèlman ajoute lòt konpozan apre li pral ale nan machin nan soude vag.

Iron soude ka itilize pou sitiyasyon espesifik, men se pa pou pwodiksyon an mas.

Tès ak enspeksyon kalite

Nan etap sa a, echantiyon PCBA yo teste asire bon jan kalite. Erè komen yo se: sikwi kout nan eleman dekonekte, konpozan dezenfekte ak pati nan kous la ki pa ta dwe konekte. Tès ki pi komen:

ICT (Tès sou entènèt). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. Machin ICT a pral sèvi ak pwen tès sa yo pou tès sikwi ouvè / kout epi tcheke valè eleman pasif yo (résistans, enduktè, kondansateur) nan limit spesifikasyon la.

AOI (Otomatik enspeksyon optik). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Pou tès sa a, kreyatè a pyès ki nan konpitè ap bezwen bay espesifikasyon ak tolerans nan manifakti a yo mete paramèt yo.

X ray. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Gade tès radyografi a nan videyo sa a.