Payvandlash niqobi, shuningdek, lehim blokirovkasi niqobi sifatida ham tanilgan, polimerning yupqa qatlami PCB kartasi Lehim birikmalarining ko’priklar hosil bo’lishining oldini olish uchun. Payvandlash niqobi, shuningdek, oksidlanishni oldini oladi va PCB kartasidagi mis izlariga qo’llaniladi.

What is PCB solder resistance type? The PCB welding mask acts as a protective coating on the copper trace line to prevent rust and prevent solder from forming Bridges that lead to short circuits. PCB payvandlash niqoblarining 4 ta asosiy turi mavjud – epoksi suyuqlik, suyuq fotografli, quruq plyonkali, yuqori va pastki niqoblar.

Payvandlash niqoblarining to’rt turi

Payvandlash niqoblari ishlab chiqarish va materialga qarab farq qiladi. Qanday va qanday payvandlash niqobini qo’llash dasturga bog’liq.

Yuqori va pastki yon qopqoq

Yuqori va pastki payvandlash niqobi Elektron muhandislar ko’pincha yashil lehim to’siq qatlamidagi teshiklarni aniqlash uchun foydalanadilar. Qatlamga epoksi qatron yoki kino texnologiyasi yordamida oldindan qo’shiladi. Keyin komponent pimlari niqob bilan qayd qilingan teshik yordamida taxtaga payvandlanadi.

The conductive trace pattern on the top of the circuit board is called the top trace. Yuqori yon niqobga o’xshab, pastki niqob elektron plataning teskari tomonida ishlatiladi.

Epoksi suyuq lehim niqobi

Epoxy resins are the cheapest alternative to welding masks. Epoxy is a polymer that is screen printed on a PCB. Ekranni bosib chiqarish – bu siyohni blokirovka qilish modelini qo’llab -quvvatlash uchun mato to’ridan foydalanadigan bosib chiqarish jarayoni. The grid allows identification of open areas for ink transfer. In the final step of the process, heat curing is used.

Suyuq optik tasvirli lehim niqobi

Suyuq fotokonduktiv niqoblar, LPI deb ham ataladi, aslida ikki xil suyuqlikning aralashmasidir. Liquid components are mixed prior to application to ensure a longer shelf life. It is also one of the more economical of the four different PCB solder resistance types.

LPI ekranni bosib chiqarish, ekranni bo’yash yoki purkash uchun ishlatilishi mumkin. The mask is a mixture of different solvents and polymers. Natijada, maqsadli hudud yuzasiga yopishgan yupqa qoplamalar olinishi mumkin. Bu niqoblar niqoblarni lehimlash uchun mo’ljallangan, lekin PCB bugungi kunda keng tarqalgan qoplamali qoplamalarni talab qilmaydi.

Eski epoksi siyohlardan farqli o’laroq, LPI ultrabinafsha nurlarga sezgir. Panelni niqob bilan yopish kerak. Qisqa “davolanish davri” dan so’ng, taxta fotolitografiya yoki ultrabinafsha lazer yordamida ultrabinafsha nurlar ta’siriga tushadi.

Before applying the mask, the panel should be cleaned and free of oxidization. Bu maxsus kimyoviy eritmalar yordamida amalga oshiriladi. Bu, shuningdek, alumina eritmasi yordamida yoki panellarni osilgan pomza bilan tozalash orqali ham amalga oshirilishi mumkin.

One of the most common ways to expose panel surfaces to UV is by using contact printers and film tools. The top and bottom sheets of the film are printed with an emulsion to block the area to be welded. Use the tools on the printer to fix the production panel and film in place. The panels were then simultaneously exposed to an ULTRAVIOLET light source.

Boshqa texnikada to’g’ridan -to’g’ri tasvirlarni yaratish uchun lazer ishlatiladi. But in this technique, no film or tools are needed because the laser is controlled using a reference mark on the panel’s copper template.

LPI niqoblarini turli xil ranglarda, jumladan, yashil (mat yoki yarim porloq), oq, ko’k, qizil, sariq, qora va boshqalarda topish mumkin. LED sanoati va elektron sanoatidagi lazer ilovalari ishlab chiqaruvchilar va dizaynerlarni kuchli oq va qora materiallarni ishlab chiqarishga undaydi.

Quruq plyonkali fotosuratlarni tasvirlovchi lehim niqobi

A dry film photoimagable welding mask is used, and vacuum lamination is used. Keyin quruq plyonka ochiladi va rivojlanadi. After the film is developed, openings are positioned to produce patterns. Shundan so’ng, element lehim yostig’iga payvandlanadi. Keyin mis elektrokimyoviy jarayon yordamida elektron plataga laminatlanadi.

Mis teshikda va iz maydonida qatlamlangan. Oxir -oqibat qalay mis davrlarini himoya qilish uchun ishlatilgan. In the final step, the membrane is removed and the etching mark is exposed. Usul issiqlik bilan ishlov berish usulini ham qo’llaydi.

Dry film welding masks are commonly used for high-density patch boards. Natijada, u teshikka tushmaydi. These are some of the positives of using a dry film welding mask.

Qaysi payvandlash niqobini ishlatishni tanlash turli omillarga bog’liq – shu jumladan, tenglikni fizik o’lchamlari, oxirgi qo’llaniladigan dastur, teshiklar, ishlatiladigan komponentlar, o’tkazgichlar, sirt tuzilishi va boshqalar.

PCB -ning zamonaviy dizaynlarining aksariyati fotosuratga o’xshash lehimga chidamli plyonkalarni olishlari mumkin. Therefore, it is either LPI or dry film resistance film. The surface layout of the board will help you determine your final choice. If the surface topography is not uniform, the LPI mask is preferred. If a dry film is used on uneven terrain, gas may be trapped in the space formed between the film and the surface. Therefore, LPI is more suitable here.

Biroq, LPIdan foydalanishning kamchiliklari bor. Its comprehensiveness is not uniform. You can also get different finishes on the mask layer, each with its own application. For example, in cases where solder reflow is used, the matte finish will reduce solder balls.

Build solder masks into your design

Niqobni qo’llash optimal darajada bo’lishini ta’minlash uchun sizning dizayningizda lehimga chidamli plyonka yaratish zarur. When designing a circuit board, the welding mask should have its own layer in the Gerber file. In general, it is recommended to use a 2mm border around the function in case the mask is not fully centered. Ko’priklar hosil bo’lmasligi uchun tagliklar o’rtasida kamida 8 mm bo’sh joy qoldirishingiz kerak.

Thickness of welding mask

Thickness Welding mask will depend on the thickness of the copper trace on the board. Umuman olganda, iz chiziqlarini niqoblash uchun 0.5 mm payvandlash niqobiga afzallik beriladi. If you are using liquid masks, you must have different thicknesses for different features. Bo’sh laminatlangan joylarning qalinligi 0.8-1.2 mm bo’lishi mumkin, tizzalar kabi murakkab xususiyatlarga ega bo’lgan joylar ingichka cho’zilgan (taxminan 0.3 mm) bo’ladi.

xulosa

Xulosa qilib aytganda, payvandlash niqobining dizayni dasturning ishlashiga jiddiy ta’sir ko’rsatadi. Qisqa tutashuvga olib kelishi mumkin bo’lgan zang va payvandlash ko’priklarining oldini olishda muhim rol o’ynaydi. Shuning uchun, sizning qaroringiz ushbu maqolada keltirilgan turli omillarni hisobga olishi kerak. Umid qilamanki, ushbu maqola PCB qarshilik plyonkasining turini yaxshiroq tushunishga yordam beradi. Agar sizda biron bir savol bo’lsa yoki biz bilan bog’lanishingiz kerak bo’lsa, biz sizga yordam berishdan doim xursandmiz.