In PCB design, there are many places that need to consider the safety distance. Here, it is classified into two categories for the time being: one is electrical-related safety clearance, and the other is non-electrical-related safety clearance.

1. Umbali wa usalama unaohusiana na umeme
1. Nafasi kati ya waya

Kuhusu uwezo wa kuchakata wa watengenezaji wakuu wa PCB, nafasi ya chini kati ya nyaya haipaswi kuwa chini ya 4mil. Umbali wa chini wa mstari pia ni umbali kutoka mstari hadi mstari na mstari hadi pedi. Kwa mtazamo wa uzalishaji, kadri inavyokuwa bora zaidi ikiwezekana, ndivyo kawaida zaidi ni 10mil.

2. Kipenyo cha pedi na upana wa pedi

Kwa kadiri uwezo wa usindikaji wa watengenezaji wa kawaida wa PCB unavyohusika, ikiwa shimo la pedi limetobolewa kimitambo, kiwango cha chini haipaswi kuwa chini ya 0.2mm, na ikiwa uchimbaji wa laser unatumiwa, kiwango cha chini haipaswi kuwa chini ya 4mil. Uvumilivu wa aperture ni tofauti kidogo kulingana na sahani, kwa ujumla inaweza kudhibitiwa ndani ya 0.05mm, na upana wa pedi wa chini haupaswi kuwa chini ya 0.2mm.

3. Umbali kati ya pedi na pedi

As far as the processing capabilities of mainstream PCB manufacturers are concerned, the distance between pads and pads should not be less than 0.2mm.

4. Umbali kati ya ngozi ya shaba na makali ya ubao

Umbali kati ya ngozi ya shaba iliyoshtakiwa na makali ya bodi ya PCB ni vyema si chini ya 0.3mm. Weka sheria za nafasi kwenye ukurasa wa muhtasari wa Bodi-Kanuni.

If it is a large area of ​​copper, it usually needs to be retracted from the edge of the board, generally set to 20mil. In the PCB design and manufacturing industry, under normal circumstances, due to the mechanical considerations of the finished circuit board, or to avoid curling or electrical short-circuiting due to the exposed copper skin on the edge of the board, engineers often spread copper on a large area The block is shrunk by 20 mils relative to the edge of the board, instead of spreading the copper to the edge of the board. There are many ways to deal with this kind of copper shrinkage, such as drawing a keepout layer on the edge of the board, and then setting the distance between the copper paving and the keepout. Here is a simple method to set different safety distances for copper paving objects. For example, the safety distance of the whole board is set to 10mil, and the copper paving is set to 20mil, and the effect of 20mil shrinkage of the board edge can be achieved. The dead copper that may appear in the device is removed.

2. Kibali cha usalama kisicho na umeme
1. Upana wa tabia, urefu na nafasi

Filamu ya maandishi haiwezi kubadilishwa wakati wa kuchakata, lakini upana wa mstari wa herufi wa D-CODE chini ya 0.22mm (8.66mil) umeongezwa hadi 0.22mm, yaani, upana wa mstari wa herufi L=0.22mm (8.66mil), na herufi nzima Width=W1.0mm, urefu wa herufi nzima H=1.2mm, na nafasi kati ya herufi D=0.2mm. Wakati maandishi ni madogo kuliko kiwango kilicho hapo juu, uchakataji na uchapishaji utatiwa ukungu.

2. Nafasi kati ya kupitia shimo na kupitia shimo (makali ya shimo hadi ukingo wa shimo)

Umbali kati ya vias (VIA) na vias (makali ya shimo hadi ukingo wa shimo) ni vyema zaidi kuliko 8mil.

3. Umbali kutoka skrini ya hariri hadi pedi

Skrini ya hariri hairuhusiwi kufunika pedi. Kwa sababu ikiwa skrini ya hariri imefunikwa na pedi, skrini ya hariri haitapigwa wakati wa kupiga, ambayo itaathiri uwekaji wa sehemu. Kwa ujumla, kiwanda cha bodi kinahitaji nafasi ya 8mil ili kuhifadhiwa. Ikiwa eneo la PCB ni pungufu, kiwango cha 4mil hakikubaliki. Ikiwa skrini ya hariri itafunika pedi kwa bahati mbaya wakati wa kubuni, kiwanda cha ubao kitaondoa moja kwa moja sehemu ya skrini ya hariri iliyoachwa kwenye pedi wakati wa utengenezaji ili kuhakikisha kuwa pedi hiyo imefungwa.

Bila shaka, hali maalum zinachambuliwa kwa undani wakati wa kubuni. Wakati mwingine skrini ya hariri iko karibu na pedi kwa makusudi, kwa sababu wakati pedi mbili ziko karibu sana, skrini ya kati ya hariri inaweza kuzuia kwa ufanisi uunganisho wa solder kutoka kwa mzunguko mfupi wakati wa soldering. Hali hii ni jambo lingine.

4. Urefu wa 3D na nafasi ya usawa kwenye muundo wa mitambo

Wakati wa kuweka vifaa kwenye PCB, fikiria ikiwa kutakuwa na migogoro na miundo mingine ya mitambo katika mwelekeo wa usawa na urefu wa nafasi. Kwa hiyo, wakati wa kubuni, ni muhimu kuzingatia kikamilifu kubadilika kati ya vipengele, bidhaa ya PCB na shell ya bidhaa, na muundo wa nafasi, na kuhifadhi umbali salama kwa kila kitu kinacholengwa ili kuhakikisha kuwa hakuna mgongano katika nafasi.