As we all know, the continuous progress of electronic equipment and circuit technology, the peak of engineering art in the design, development and manufacture of printed mzunguko bodi (PCB) imeshuhudiwa na watu ulimwenguni kote. Our planet is full of highly intelligent machines, automated robots and scientific marvels, and of course, there are plenty of PCBS in every corner of the planet, no matter what country or city it is. Walakini, PCBS hizi hutofautiana katika utendaji, ugumu, gharama ya utengenezaji, ubora na uaminifu. Nakala hii inazingatia vidokezo viwili vya mwisho, ubora na uaminifu wa PCBS.

Ndio, wateja wanaowezekana daima wanataka umeme wa hali ya juu, lakini hii ni ghali sana na inaweza kuhusisha michakato tata ya utengenezaji. Katika mchakato tata wa utengenezaji wa PCB, mkutano na upimaji, kuna mchakato muhimu sana unaoitwa “mipako ya kufanana” ya PCB. Mipako hii ya kawaida ni muhimu sana katika PCBS kwa suala la ubora na uaminifu.

What is conformal coating and its importance:

Conforming coating, an ultra-thin protective coating of polymer film, can be used in conjunction with assemblies mounted on assembly surfaces to protect assembly leads, solder joints, exposed wiring, and other metal points on the PCB surface from corrosion, dust, or chemicals due to various operating or environmental conditions.

Mipako inayofanana inaweza kuwa nyembamba kama microns 25 na “inafanana” na sura na mpangilio wa sehemu ya bodi ya mzunguko. Kama ilivyoelezwa hapo juu, sababu ya kutumia mipako sawa juu (juu na chini) ya PCB ni kulinda PCB kutoka kwa hali mbaya ya mazingira, na hivyo kuongeza maisha ya huduma ya PCB na vifaa vinavyohusiana vya elektroniki.

Kama joto kali linalopatikana katika viwandani, kiwanda, na umeme wa nguvu nyingi, PCBS hizi zilizo na mipako sawa zinaweza kuhimili joto kali. Vivyo hivyo, vifaa vya elektroniki vilivyowekwa kwenye maeneo / maeneo karibu na bahari au bahari vinaweza kuathiriwa na unyevu mwingi, kama vile urambazaji vifaa vya majini vya elektroniki vinaweza kuwa chini ya kutu / mmomonyoko ambao unaweza kusababisha oxidation ya chuma. Similarly, in microbiology laboratories and the medical industry, sensitive electronic equipment can be exposed to toxic chemicals, acidic and alkaline solvents that can accidentally spill onto a PCB, but the PCB’s “conformation coating” will protect the PCB and components from fatal injury.

Jinsi ya kutumia mipako sawa?

In fact, the method of applying “conformal paint” in the right way is so important that careful consideration must be given to how conformal paint is applied. It is as important to choose suitable conformal coating materials.

Sababu kuu zinazoamua matumizi sahihi ya mipako sawa ni:

1- unene wa rangi

2- The level of coverage achieved

3- The degree of adhesion of paint to wood panels and their components.

There are five methods for applying conformal coatings:

1- Rangi kwa mkono na brashi

2- mipako ya erosoli

3- Atomizing spray gun coating

4- Automatic dip coating

5- Automatic selection of coating

Njia ya kuponya ya kawaida / kukausha:

Conformal coatings themselves can be classified according to the drying and curing methods used after conformal coatings are completed. These methods are:

1- Heat/heat curing: Conformal coating is dried at high temperature. Drying rate is much faster than normal room temperature drying/curing.

2- Uponyaji wa hali ya hewa: Mipako sawa ya PCB imekaushwa kwa joto la kawaida, unyevu kwenye anga hupunguza mchakato wa kuponya au kukausha.

3- ULTRAVIOLET (UV) curing: Here PCB with conformal coating is exposed to UV radiation. The uv energy determines the curing speed of PCB conformal coating

4- Uponyaji wa oksidi: Kwa njia hii, watengenezaji wa PCB wanakabiliwa na mazingira ya hewa ya wazi na kiasi kikubwa cha oksijeni ya anga, ambayo itasaidia katika kukausha / kuponya conformers inayotokana na kutengenezea.

5- Catalytic curing: This is the process of curing conformal coating in which two materials are fused together, one of which is conformal coating. Mara tu mipako ikiwa imechanganywa na vifaa vingine vya kichocheo, mchakato wa kuponya hauwezi kusimamishwa hadi ukamilike.

Classification of conformal coatings:

There are five main conformal coatings used: acrylic resin, epoxy resin, silicone, polyurethane (PU) and polyparaxylene coating.

L resin ya akriliki (AAR):

Acrylics are ideal for (low-cost and high-volume) common electronics because AAR is inexpensive and can be easily applied to PCB surfaces by brush, dip, and manual or automatic spraying, reducing turnaround time and producing cost-effective products.

Faida:

1 – gharama nafuu

2- Easy for manual or automatic robot applications

3- Easy to rework

4- Excellent moisture protection

5- Good surface elasticity, can withstand static voltage discharge, and does not react with the atmosphere, therefore helps cure through solvent evaporation

Hasara:

1- Due to the use of atmospheric curing/drying methods for this material, proper ventilation systems need to be ensured

2- Matengenezo ya chini ya mnato

3- Upinzani mdogo wa kuvaa na upinzani wa kemikali

L Epoxy conformal coating (ER) :

Mipako ya kawaida kulingana na resini za epoxy inaweza kukamilika kwa brashi ya mkono, dawa au mipako ya kuzamisha. Kunyunyizia dawa kunapendekezwa kwa idadi kubwa na kwa idadi ndogo au mfano wa PCBS.

Faida:

1- High moisture resistance and good dielectric resistance

2- Excellent chemical resistance, abrasion resistance, moisture resistance and high temperatures up to 150 O C

Hasara:

1-epoxy conformal paint is very hard and rigid and can damage PCB and its components if attempted peeling or removal. Ondoa mipako kwa kutumia kutengenezea hatari

2- Utendaji duni wa joto

3- Kuponya kupunguka

4- Ni ngumu kufanya upya

Mipako ya kufanana ya Silicone (OSR):

The softest of the above two types of conformal coatings is silicone resin (OSR) conformal coatings. They are widely used in LED lamp PCBS without reducing light intensity or color change. Ideal for PCB installation at high humidity and exposure to air. Suitable for PCB with high operating temperature and high power

Faida:

1- Upinzani mzuri wa kemikali, upinzani wa unyevu, dawa ya chumvi na joto la juu hadi 200 OC

2- Good flexibility makes it resistant to vibration stress on PCB from external environment.

3- Inafaa kwa matumizi ya nje ya PCB na unyevu mwingi

Mbaya:

1- Sio kuvaa sugu kwa sababu ya mali ya mpira

2- Inaweza kufanywa upya, lakini sio rahisi, inayohitaji vimumunyisho maalum, nyakati ndefu za kuloweka na kuchochea kama brashi au umwagaji wa ultrasonic

3- Low mechanical strength, weak adhesion to PCB substrate

L Polyurethane (PU) mipako sawa:

Inafaa kwa matumizi ya PCB katika magari, viwanda, vifaa vya mawasiliano na mawasiliano ya simu. Katika anga, haswa, mvuke za mafuta hugongana kila wakati na mwili kuu wa vifaa vya elektroniki na hivyo kupenya ndani ya mambo ya ndani na kuathiri bodi ya PCB

Faida:

1- High resistance to moisture, chemicals (acid and alkali) and wear

Hasara:

1- Baada ya mchakato mrefu wa kuponya kamili, huwa na manjano kwa joto kali kwa sababu ya yaliyomo kwenye VOC

2- Kama silicon, si rahisi kuondoa kabisa

L polyparaxylene conformal coating:

This type of coating is suitable for avionics, microelectronics, sensors, high-frequency circuits, and densely populated PCB-based components. It is applied by means of vapor deposition.

Faida:

1- Excellent dielectric strength

2- High resistance to moisture, solvents, extreme temperatures and acid corrosion

3- Can be applied evenly with very thin paint.

Hasara:

1- Disassembly/rework is very difficult

2- Gharama kubwa ndio shida kubwa.