Alates prototüüpide vooluahelatest leivalaudadel kuni meie enda disainimiseni trükkplaat (PCBS), it was like getting off the training wheels. There’s a lot to learn about this process, so let’s get started. PCB design is carried out in an electrical engineering (EE) process. EE loob seadmete toimimise „aju”. 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). Toote mõõtmed määratakse elektroonilise projekteerimise käigus. Siit saate vaadata videot selle kohta. 2. PCB kihid – mida rohkem kihte, seda keerulisem PCB TOOTMINE. (Märkus. Isegi ühekihiline PCB võib olla keeruline PCB, kuid siin räägime PCB valmistamise keerukusest. Mida rohkem kihte PCB -l on, seda kallim on selle tootmine.)

Layer 2 is usually used for simple toy products

Iotiga seotud toodetel on tavaliselt 4 kihti

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.

Teave, mida peate PCB tootjatele esitama:

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

Materjalid (FR-2 (fenoolne puuvillapaber), FR-3 (puuvillapaber ja epoksü), FR-4 (klaaskiud ja epoksü… Etc.)

Thickness (0.5 mm, 1.0 mm… Etc.)

Color (red, black, green… Etc.)

Pinnatöötlus (ENIG (keemiline nikli/kulla keelekümblus), DIG (otsene kullast sukeldamine), OSP (orgaanilised jootetavad säilitusained jne)

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

Gerberi toimik

PCB design process:

Vooluringi kujundus

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

Sagedusseade

KiCad

Cadence allegro

matt

Arvutipõhine disain

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. Mudelifail aitab teil skeemi joonistada. 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. (Märkus: projekteerimisprotsessi üksikasjad sõltuvad valitud tarkvaratööriistast).

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. Te oleksite pidanud valima komponendid (või valite neid praegu) ja me kirjeldame seda protsessi EE projekteerimisprotsessi videos (vt videot).

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. Lisaks saab tootja seadet testida käesoleva dokumendi testpunktide kaudu.

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. Erinevalt skemaatilisest skeemist määrab trükkplaadi paigutus tegelikud komponendid trükkplaadi täpsetele asukohtadele ja näitab radu, mis ühendavad iga komponendi PCB kihtide vahel. 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. Sel viisil saate juhtiva jälje lühikeseks hoida ning vähendada müra ja häireid.

PCB projekteerimisel tuleb silmas pidada ka kasutajaliidest (UI). Selliseid komponente nagu helipistikud, pistikud, valgusdioodid jne tuleb parima kasutajakogemuse saavutamiseks reguleerida.

Once the layout is designed, a Gerber file is generated. Teie PCBA tootja kasutab seda faili. There are many companies that offer these services, and from HWTrek’s expert library we recommend Kingbrother, NexPCB, and HQPCB.

Sample Gerber files

Komponentide paigutamine trükkplaadile on väga oluline. 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. See on aluseks, et ehitada edasi vundament PCB -le komponentide lisamiseks ja PCBA (trükkplaadi koost) tootmiseks.

Unassembled PCBS

PCBA (Assembly)

Materjali ettevalmistamine

EE -disaini praegusel hetkel oleksite pidanud komponendid valima. You can ask the PCBA manufacturer to order the required components for you, or do it yourself if you choose a supplier. Tähelepanu vajavad küsimused:

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. Kui ostate miinimumist vähem, veenduge, et valitud komponendid oleksid laos. For small batches (up to 50), you can order online from DigiKey or Mouser. Suurema koguse saamiseks küsige nõu tootjalt.

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 (pinnale paigaldamise tehnoloogia) on masstootmises kõige laialdasemalt kasutatav meetod. It is done by fast, accurate SMT machines that save you time, money and avoid human error.

Asjad, mida meeles pidada:

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 jootmine

Reflow soldering is the process of making components “stick” to the PCB. PCBA soojendab trükkplaati läbi tagasivooluahju või infrapunalambi, kuni joodis sulab, kinnitades seeläbi komponendi püsivalt trükkplaadile.

The trickiest part here is not to overheat or damage the components, because the thermal characteristics of each package are different. Selle protsessi eest vastutab usaldusväärne PCBA tootja ja kõik, mida peate tegema, on esitada neile komponentide spetsifikatsioonid.

Reflux process.

Other welding methods:

Wave soldering is mainly used for manually added components by the through-hole method. In this case, your PCBA will first go through the reflow welding furnace, and then manually add other components after it will go through the wave soldering machine.

Raudkeevitust saab kasutada konkreetsetes olukordades, kuid mitte masstootmiseks.

Testimine ja kvaliteedikontroll

Selles etapis testitakse kvaliteedi tagamiseks PCBA proove. Tavalised vead on: lahtiühendatud komponentide lühised, valesti paigutatud komponendid ja vooluahela osad, mida ei tohiks ühendada. Kõige tavalisemad testid:

IKT (veebipõhine testimine). When designing a PCB, some test points are usually reserved for debugging, programming, and other purposes. IKT -masin kasutab neid katsepunkte avatud/lühise testimiseks ja kontrollib, kas passiivsete komponentide (takistid, induktiivpoolid, kondensaatorid) väärtused jäävad spetsifikatsioonide vahemikku.

AOI (automaatne optiline kontroll). Manufacturers use a “gold sample” (reference PCBA) to compare with other samples. Selle testi jaoks peab riistvara looja esitama tootjale parameetrite määramiseks spetsifikatsioonid ja tolerantsid.

Röntgen. The PCBA manufacturer will use X-rays to check the welding conditions of the BGA (ball Grid Array) components. Vaadake röntgenikatset sellest videost.