Ogi tauletako prototipoen zirkuituetatik hasi eta gureak diseinatzeraino inprimatutako zirkuitu taula (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. PCBen diseinua ingeniaritza elektrikoaren (EE) prozesu batean egiten da. EE-k gailuek nola funtzionatzen duten “garuna” sortzen du. 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). Produktuen neurriak ingeniaritza elektronikoaren diseinurako prozesuan definitzen dira. You can watch a video about it here. 2. PCB geruzak – Zenbat eta geruza gehiago, orduan eta konplexuagoa da PCBaren FABRIKAZIOA. (Oharra: geruza bakarreko PCBa ere PCB konplexua izan daiteke, baina hemen PCBak egitearen konplexutasunaz ari gara. PCBak zenbat eta geruza gehiago izan, orduan eta garestiagoa da fabrikatzea.)

Layer 2 is usually used for simple toy products

Iot lotutako produktuek normalean 4 geruza dituzte

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.

PCB fabrikatzaileei eman behar diezun informazioa:

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

Materialak (FR-2 (kotoizko paper fenolikoa), FR-3 (kotoizko papera eta epoxi), FR-4 (beira-zuntza eta epoxi … eta abar)

Lodiera (0.5 mm, 1.0 mm … eta abar)

Color (red, black, green… eta abar)

Gainazalen tratamendua (ENIG (nikel kimikoa / urrezko murgiltzea), DIG (urrezko murgiltze zuzena), OSP (kontserbagarri organiko soldagarriak, etab.)

Copper weight (1 oz (35 microns), 2 oz (70 microns), 0.5 oz (18 microns)… eta abar)

Gerber fitxategia

PCB design process:

Zirkuituaren diseinua

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. Quadcept gustatzen zaigu fabrikaziorako PCBS diseinatzeko optimizatuta dagoelako (adibidez, Tresna faktura zuzenean esporta dezakezu materiala (BoM)) eta hodeian oinarrituta dago, beraz, edozein lekutan erraz erabil daiteke. (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

Maiztasun gailua

KiCad

Cadence allegro

mat

Ordenagailuz lagundutako diseinua

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. Eredu fitxategiak eskema marrazten lagunduko dizu. 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. (Oharra: diseinu prozesuaren xehetasunak aukeratutako software tresnaren araberakoak izango dira).

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. Gainera, fabrikatzaileak dokumentua probako puntuetan zehar gailua probatu dezake.

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. Eskemak ez bezala, PCBaren diseinuak benetako osagaiak PCBko kokapen zehatzetara esleitzen ditu eta osagai bakoitza PCB geruzen artean konektatzen duten pistak erakusten ditu. 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. Horrela, traza eroalea laburra izan dezakezu eta zarata eta interferentziak murriztu ditzakezu.

Erabiltzaile interfazea (UI) ere kontuan hartu behar da PCB bat diseinatzerakoan. Erabiltzaileen esperientzia onena lortzeko, hala nola audio-harguneak, konektoreak, led-ak eta abar bezalako osagaiak egokitu behar dira.

Once the layout is designed, a Gerber file is generated. Zure PCBA fabrikatzaileak fitxategi hau erabiliko du. There are many companies that offer these services, and from HWTrek’s expert library we recommend Kingbrother, NexPCB, and HQPCB.

Sample Gerber files

Osagaiak PCBan jartzea oso garrantzitsua da. 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. Hori izango da oinarria PCBari osagaiak gehitzeko eta PCBA (zirkuitu inprimatuko plaka multzoa) fabrikatzeko oinarriak eraikitzeko.

Unassembled PCBS

PCBA (Assembly)

Materiala prestatzea

Zure EE diseinuko une honetan, osagaiak hautatu beharko zenituzke. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Arreta behar duten gaiak:

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.

Eskariaren gutxieneko kantitatea: egiaztatu osagaiaren gutxieneko eskaeraren kantitatea. Gutxienekoa baino gutxiago erosten baduzu, ziurtatu hautatutako osagaiak stockean daudela. For small batches (up to 50), you can order online from DigiKey or Mouser. Kopuru gehiago lortzeko, eskatu zure fabrikatzaileari aholkularitza.

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 (azalera muntatzeko teknologia) masa ekoizpenean gehien erabiltzen den metodoa da. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Gogoan gauzak:

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 soldadura

Reflow soldering is the process of making components “stick” to the PCB. The PCBA heats the circuit board through a reflow furnace or an infrared lamp until the solder melts, thereby permanently attaching the component to the circuit board.

Hemen zatirik zailena ez da osagaiak berotu edo kaltetzea, pakete bakoitzaren ezaugarri termikoak desberdinak baitira. PCBA fabrikatzaile fidagarri bat arduratuko da prozesu honetaz, eta egin behar duzun guztia osagaien zehaztapenak ematea da.

Errefluxu prozesua.

Other welding methods:

Wave soldering is mainly used for manually added components by the through-hole method. Kasu honetan, zure PCBA erreflusiozko soldadura labetik pasatuko da lehenik, eta gero beste osagai batzuk eskuz gehituko ditu olatuen soldadura makinatik igaro ondoren.

Burdin soldadura egoera zehatzetarako erabil daiteke, baina ez masa ekoizpenerako.

Probak eta kalitatearen ikuskapena

Urrats honetan, PCBA laginak probatzen dira kalitatea bermatzeko. Ohiko akatsak hauek dira: deskonektatutako osagaietan zirkuitu laburrak, gaizki lerrokatutako osagaiak eta konektatu behar ez diren zirkuituaren zatiak. Probarik ohikoenak:

IKT (lineako probak). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. IKT makinak proba puntu hauek erabiliko ditu zirkuitu irekiko / laburreko probak egiteko eta egiaztatuko du osagai pasiboen balioak (erresistentziak, induktoreak, kondentsadoreak) zehaztapenaren barruan dauden.

AOI (ikuskapen optiko automatikoa). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Proba hau egiteko, hardware-sortzaileak zehaztapenak eta tolerantziak eman beharko dizkio fabrikatzaileari parametroak ezartzeko.

X izpiak. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Ikusi X izpien proba bideo honetan.