Je! Ni PCB ya shimo-kwa nini na kwa nini ni muhimu printed mzunguko bodi? PCB inahitaji kupitia mashimo au visima ili kuunganisha safu zake. Understanding the standard through-hole sizes used by PCB manufacturers can help you design boards to meet common bit sizes.

Kawaida kupitia saizi ya shimo

Watengenezaji wa PCB wana seti yao ya saizi za kawaida za shimo kuchagua kutoka wakati wa kuchimba mashimo, lakini kawaida wanaweza kutumia saizi yoyote ya kawaida ya shimo. Kwa ujumla, wazalishaji wa PCB wanaweza kutengeneza kipenyo cha PCB kupitia mashimo kuwa ndogo kama 0.15 mm, ikilinganishwa na saizi ya kawaida ya 0.6 mm.

Mahitaji ya saizi ya PCB kupitia shimo

Hii ni utafiti wa kina wa mahitaji ya saizi.

PCB kupitia saizi ya shimo

Ukubwa wa PCB kupitia shimo inaweza kutofautiana kulingana na eneo lake, matumizi, na sababu zingine, ndiyo sababu kila mtengenezaji wa PCB hutoa ukubwa wa PCB kadhaa. Most manufacturers can make holes as small as 0.15 mm or larger holes of 1 mm or larger. Wakati wa kuzingatia saizi ya shimo linalohitajika, unahitaji pia kuzingatia pete au pedi ya shaba karibu na shimo, ambayo itaunda.

How do you calculate rings? The ideal ring is equal to the sum of the diameter of the copper pad minus the diameter of the drill hole divided by 2, which gives the rig the best chance of hitting the center of the pad for optimal connectivity.

Kawaida kupitia saizi ya shimo

Hakuna lazima kuwa na kiwango cha kawaida cha PCB kupitia shimo kwenye utengenezaji wa PCB, kwani kawaida ya PCB kupitia-shimo kawaida hutofautiana kutoka kwa mtengenezaji hadi kwa mtengenezaji wa PCB. Walakini, wazalishaji wengi wa PCB wanapendelea kutumia ukubwa wa kawaida, ambao wanaweza kutaja ukubwa wa kawaida wa PCB. Moja ya ukubwa wa kawaida ni 0.6 mm, lakini 0.2 mm na 0.3 mm pia hutumiwa kawaida.

Type of PCB through hole

Unaweza kutumia kila kiwango cha kawaida kupitia shimo kuunda aina anuwai ya PCB kupitia mashimo, kulingana na safu, ujenzi, muundo, na kusudi la PCB. Aina tatu za kawaida za PCB kupitia-shimo ni:

Imefunikwa kupitia shimo

Electrated kupitia-mashimo (PTH) ni kupitia-mashimo ambayo hupitia matabaka yote ya PCB kuunganisha tabaka za juu na za chini. Unapaswa kuona PTH kutoka mwisho mmoja wa PCB hadi nyingine. PTH inaweza kupakwa au kutofunikwa. Zisizopakwa kwa njia ya mashimo hazifanyi umeme, wakati zilizofunikwa kupitia mashimo zimepigwa kwa umeme, ambayo inamaanisha kuwa hufanya umeme katika matabaka yote ya PCB.

Shimo la kipofu

Blind holes connect the outer (top or bottom) layers of the PCB to one or more inner layers, but do not completely drill through the board. Precise drilling of blind holes can be challenging, so they are typically more expensive to manufacture than PTH.

iliyoingia

Embedded holes can also increase the cost of PCB because they are difficult to manufacture. The holes are located in the inner layer of the PCB to connect two or more inner layers. Huwezi kuona nyenzo zilizozikwa kwenye safu ya nje ya PCB.

Mambo ya kuzingatia

Kuna mambo machache ya kuzingatia wakati wa kuunda PCB. Kwanza, unapaswa kujua ni uwiano gani wa muundo katika PCB. The aspect ratio is the PCB thickness relative to the diameter of the through hole, which determines the reliability of the copper plating on the PCB. The higher the ratio, the more difficult it is to obtain reliable plating, which affects the type of hole and plating method you choose.

Mashimo yaliyopachikwa au vipofu yanaweza kutumikia PCB yako bora na uwiano wa 15: 1, wakati PTH inaweza kufanya kazi vizuri na uwiano wa chini wa 2: 1. Je! Unachaguaje unene wa shaba ya PCB? Usually, through holes in the outer layer (e.g., through holes) require a thicker layer of copper than the buried through holes inside. Voltage inayotumiwa na PCB pia huathiri unene wa shaba. High voltage applications typically require thicker PCB copper than low voltage applications.

By filling program

Sometimes PCB through-holes need to be filled, for example to reduce the risk of trapping air or increase electrical conductivity. Some common ways to fill through holes include:

Kupitia hema

Hema la kupitia-shimo huunda safu ya kizuizi cha solder juu ya PCB kupitia-shimo badala ya kujaza shimo na nyenzo. This can be a quick, easy and cost-effective option to cover the through-holes, but the tent-style through-holes may reopen over time.

Kwa kuzuia

Mchakato wa kuziba-shimo hujaza shimo na nyenzo zisizo za kusonga na kuifunga na kinyago. Through-hole clogging also covers the ring and does not produce a smooth, glossy surface.

Kwa kujaza

Kujaza kupitia shimo hutumia resin kuunda shimo lililojazwa kabisa. A through-hole fill is a common through-hole fill in which the manufacturer fills the through-hole with conductive material, coats the surface with copper, and then trims the surface. This process can route signals to other areas of the PCB.

PCB kupitia matumizi ya mipako ya shimo

Watengenezaji wanaweza kutumia mbinu kadhaa tofauti kutumia PCB kupitia upako wa shimo ili kuhakikisha ufanisi wake. One common method is to use a low viscosity ink that covers the inside of the through-hole to form a conductive layer. Then through the heat curing process to bond the ink.

Njia nyingine ni electroplating, ambayo PCB huenda kwenye umwagaji wa umeme. Katika mchakato huu, shaba inashughulikia kuta za kila PCB kupitia mashimo, na kusababisha unene wa nyenzo zinazoendesha. Njia hii huwa ndefu zaidi na ya gharama kubwa kuliko mchakato wa inking, lakini pia inaweza kuunda mipako na dhamana ya kuaminika zaidi.

Sequential drilling blind drilling and deep drilling

PCBS zilizo na mashimo vipofu zinaweza kutengenezwa kwa njia mbili. This can be done by laser drilling or by a method called continuous layer construction. Using the sequential construction method, pairs of layers can be drilled and electroplated before bonding is applied. Because they have holes at both ends, electroplating is easy to penetrate for chemical coatings. It also allows blind holes to be designed in such a way that they can pass through multiple layers.

Uwezo wa kuchanganya muunganiko unaofaa, kuchimba visima na mpangilio wa mchovyo inafanya uwezekano wa kuunda miundo mingi ya shimo kipofu. Yote inategemea ikiwa shimo kipofu linaweza kupita hata kwa tabaka kutoka kwa safu ya nje.

Simultaneous deep drilling or reverse drilling is the process of removing any unused copper drum residue from the through hole. Hii kawaida hufanyika wakati ishara zenye kasi kubwa hupotoshwa wanapopita kwenye mirija ya shaba kati ya tabaka za PCB. Ikiwa ukitumia safu ya ishara inasababisha upitiaji mrefu, kutakuwa na upotovu mwingi.

Uwiano wa kipengele cha PCB hufafanuliwa kama uwiano wa unene wa sahani na kipenyo cha kisima. Mashimo ya kipofu yanahitaji uwiano wa 1 hadi 1 au zaidi.

Wakati kuchimba visima kwa kina kunafanywa, kina cha shimo hufafanuliwa kwa kuweka jozi ya mashimo ambayo inabainisha tabaka za kuanzia na kumaliza kutoka upande wa bodi. Kipenyo kidogo cha kuchimba visima kirefu kinahesabiwa na fomula ifuatayo:

Ukubwa wa kuchimba nyuma = Shimo / ukubwa wa shimo la pedi + 2 x Sheria za kubuni Ukubwa wa kuchimba nyuma ni kubwa sana

PCB overinductance calculator

Uingizaji wa PCB kupitia-shimo hutegemea mambo kadhaa, pamoja na saizi ya shimo, saizi ya pete, uwiano wa hali, na usahihi wa kuchimba visima. Unaweza kupata mahesabu ya mkondoni kukusaidia kuhesabu PCB sahihi kulingana na saizi unayohitaji kutumia.