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 printplaat (PCB) is tsjûge troch minsken oer de heule wrâld. 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. Dizze PCBS ferskille lykwols yn funksjonaliteit, kompleksiteit, produksjekosten, kwaliteit en betrouberens. Dit artikel rjochtet him op ‘e lêste twa punten, de kwaliteit en betrouberens fan PCBS.

Ja, potensjele klanten wolle altyd elektroanika fan hege kwaliteit, mar dit is heul djoer en kin komplekse produksjeprosessen omfetsje. Yn it komplekse proses fan PCB -fabrikaazje, assemblage en testen, is d’r in heul wichtich proses neamd “conformal coating” fan PCB. Dizze konformale coating is heul wichtich yn PCBS yn termen fan kwaliteit en betrouberens.

Wat is konformale coating en it belang dêrfan:

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.

De konformale coating kin sa dun wêze as 25 mikron en “foldocht” oan ‘e foarm en komponintopmaak fan it circuit board. Lykas hjirboppe neamd, is de reden foar it oanbringen fan in konformale coating op it oerflak (boppe en ûnder) fan in PCB om it PCB te beskermjen tsjin adversive eksterne omjouwingsomstannichheden, en dêrmei de libbensdoer fan ‘e PCB en byhearrende elektroanyske apparatuer te ferheegjen.

Lykas hege temperatueren fûn yn yndustriële, fabryk en elektroanika mei hege macht, kinne dizze PCBS mei konforme coatings ekstreme temperatueren ferneare. Op deselde manier kin elektroanyske apparatuer ynstalleare yn gebieten/gebieten tichtby de see of oseaan wurde beynfloede troch hege fochtigens, lykas navigaasje elektroanyske marine -apparatuer kin ûnderwurpen wêze oan korrosysje/eroazje dy’t kin liede ta metaaloksidaasje. 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.

Hoe konformale coating oan te bringen?

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.

De haadfaktoren dy’t de juste tapassing fan konformale coatings bepale binne:

1- Dikte fan ferve

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- Skilderje mei de hân mei in kwast

2- Aerosolcoating

3- Atomizing spray gun coating

4- Automatic dip coating

5- Automatic selection of coating

Konformale coatinghurd-/droechmetoade:

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- Curing fan kondensaasje: De konformale coating fan PCB wurdt droech by ambient temperatuer, focht yn ‘e sfear fertrage it genêze as droechproses.

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- Oksidaasje genêze: Yn dizze metoade wurde PCB-konformers bleatsteld oan in iepen loftomjouwing mei grutte hoemannichten atmosfearyske soerstof, wat sil helpe by it droegjen/genêzen fan oplosmiddel-basearre konformers

5- Catalytic curing: This is the process of curing conformal coating in which two materials are fused together, one of which is conformal coating. As de coating ienris is fuseare mei oare katalysatormaterialen, kin it genêzingsproses net wurde stoppe oant it foltôge is.

Classification of conformal coatings:

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

L Acrylhars (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.

foardielen:

1 – lege kosten

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

neidielen:

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

2- Underhâld mei lege viskositeit

3- Leech wearbestindichheid en gemysk ferset

L Epoxy conformal coating (ER) :

Konformale coatings basearre op epoksyharsen kinne wurde foltôge mei hânborstel, spray as dipcoating. Spuiten wurdt oanrikkemandearre foar gruttere folumes en foar lytsere folume as prototype PCBS.

foardielen:

1- High moisture resistance and good dielectric resistance

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

neidielen:

1-epoxy conformal paint is very hard and rigid and can damage PCB and its components if attempted peeling or removal. Ferwiderje de coating mei in gefaarlik oplosmiddel

2- Min prestaasjes fan lege temperatuer

3- Hege genêzende krimp

4- Se binne dreech om opnij te dwaan

L Silicone hars (OSR) konformale coating:

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

foardielen:

1- Goede gemyske ferset, fochtbestindigens, sâlt spray en hege temperatueren oant 200 OC

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

3- Geskikt foar PCB bûtenapplikaasjes mei hege fochtigens

De minne:

1- Net wearbestindich fanwege rubbereigenskippen

2- Kin wurde ferwurke, mar net maklik, fereasket spesjale solvents, lange sochtiden en roerjen lykas in boarstel as ultrasone bad

3- Low mechanical strength, weak adhesion to PCB substrate

L Polyurethane (PU) konforme coating:

Geskikt foar PCB -tapassingen yn auto’s, yndustry, ynstrumintaasje en telekommunikaasje. Yn ‘e loftfeart, yn’ t bysûnder, brânstofdampen konstant botsje mei it haadmateriaal fan elektroanyske apparatuer en dringen sa yn ‘t ynterieur en beynfloedzje it PCB -boerd

foardielen:

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

neidielen:

1- Nei in lange tiid fan folslein genêzingsproses hat it de neiging om giel te wurden by hege temperatueren fanwegen syn hege VOC-ynhâld

2- Lykas silisium is it net maklik folslein te ferwiderjen

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.

foardielen:

1- Excellent dielectric strength

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

3- Can be applied evenly with very thin paint.

neidielen:

1- Disassembly/rework is very difficult

2- Hege kosten is it grutste nadeel.