Shadowing Practice: What is SMT (Surface Mount Technology)? PCB Assembly (Part 3) - Learn English Speaking with Video

Ders oluşturuluyor...
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Welcome to this video.
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This is part 3 of using surface mount technology to assemble PCBs.
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Electrical testing process.
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This is the last section of the process as you can see here.
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So So physical testing of printed circuit boards can also be carried out within the SMT production line.
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This is known as inline testing.
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However, it is more common for physical testing to be carried out offline in a separate area or test station.
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This is known as in-circuit testing.
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Although the generic term in-circuit testing or ICT is widely used within the electronics manufacturing industry,
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there are actually several different types of tester that are available.
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The type of tester required is dependent upon the manufacturing test process used, the volume and the boards that are used.
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Let's have a look at the different types of in-circuit tester.
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Let's start with the flying probe tester.
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In view of the issues of developing and manufacturing complete bed of nail access fixtures,
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they are costly and difficult to change if any component positions or tracks are moved.
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Another approach is to use a roving or flying probe.
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This has a simple fixture to hold the board
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and contact is made via a few probes that can move around the board and make contact as required.
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These are moved under software control so any board updates can be accommodated with changes to the software program.
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Another reason to use flying probes is the shrinking component size and denser chip scale packaging technologies.
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Manufacturing Defect Analyzer or MDA.
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The tester makes contact to the board under test using a bed of nails fixture
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and this means that a different fixture is generally required for each board.
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It needs to make contact with specific points on the board where often there may be test point
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or a land area for the probe.
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This form of tester offers a basic in circuit test of resistance, continuity and insulation.
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As the name implies it is just used for detecting the manufacturing defects like short circuits across tracks and open circuit connections.
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Automated X-ray inspection.
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AXI as is known is a technology based on the same principles as automated optical inspection or AOI.
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It uses x-rays as its source instead of visible light to automatically inspect features which are typically hidden from view.
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Automated x-ray inspection equipment can not only check the solder joints under components,
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but also reveal any defects in solder joints that may not be visible with ordinary optical inspection equipment.
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First off, sample inspection.
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The inspection microscope is generally used in FAI or first article inspection,
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which is required to ensure that the first product produced is 100% correct.
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In the SME industry, there is a need to ensure
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that the first off from any SMT assembly line is perfect before running the rest of the batch.
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Functional testing.
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At the end of the line, there needs to be a functional test to establish if the PCB actually functions and conforms to specification.
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The key features of the functional test are Identify errors in all functional aspects of the PCB
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Identify failure thresholds in the PCB when both upper and lower voltages are applied Simulate the operating environment for the PCB
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Verify speed, frequency, oscillations and other onboard timing elements Verify all input and output features conform to specification
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and establish all communication features are operational.
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Burn-in testing.
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Burn-in is a technique used as part of the quality insurance
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procedures where assembled printed circuit boards are operated under both normal and accelerated environmental conditions prior to shipment.
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Theoretically, any weak components would fail during the burn-in time allowing those parts to be replaced.
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Replacing the weak components would prevent premature failure, infant mortality failure, or other latent defects.
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On the right-hand side here, we can see a typical burn-in bathtub graph.
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We can see that the decreasing failure rate shows the early infant mortality failures.
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The constant failure rate covers the constant or random failures, whereas the increasing failure rate shows the wearout failures.
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This graph is failure rate over time
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Don't forget to check out our other videos in this PCB series
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You can contact us if you need any help with your projects at all in China And don't forget to like, share and subscribe to our channel
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And you see this little bell symbol If you hit that you'll get a notification each time we upload new content
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So thanks for listening, my name is Paul Adams from SofEast and I shall see you in the next video

Bu dersin kelimeleri ve konuşma notları

Bu C1 seviyesindeki konuşma dersi “What is SMT (Surface Mount Technology)? PCB Assembly” videosuna dayanıyor. En çok tekrarlanan kelimeler: failure, board, circuit, testing, inspection. Bu videoda gölgeleme çalışması için 56 cümle ve 769 kelime var. Konuşma bölümü 5:51 sürüyor. Konuşmacı dakikada yaklaşık 131 kelimelik dengeli bir hızla konuşuyor; gölgeleme için rahat bir tempo. Kelimelerin yalnızca %77’i İngilizcede en sık kullanılan 3.000 kelime arasında, bu yüzden kelime dağarcığı zorlayıcı.

Bu videodaki önemli kelimeler

Videodaki en ileri düzey 15 kelime, telaffuzu ve anlamıyla:

KelimeTelaffuzAnlam
probe isim/pɹoʊb/sonda
defect isim/ˈdiːfɛkt/eksik, kusur
solder isim/ˈsɒl.də(ɹ)/lehim
conform fiil/kənˈfɔɹm/uymak
specification isimşartname
mortality isim/mɔɹˈtælɪti/ölümlülük
infant isim/ˈɪn.fənt/bebek
graph isim/ɡɹæf/grafik
bathtub isim/ˈbæθtʌb/küvet
latent sıfat/ˈleɪ.tənt/saklı
oscillation isim/ˌɒ.sɪˈleɪ.ʃən/salınım
microscope isim/ˈmaɪ.kɹəˌskoʊp/mikroskop
accelerate fiil/ɪkˈsɛl.əˌɹeɪt/hızlandırmak
offline sıfat/ɔfˈlaɪn/çevrimdışı
shipment isim/ˈʃɪpmənt/parti

Duyacağınız deyimsel fiiller

KelimeAnlam
check out fiilgözden geçirmek

Dikkat edilecek telaffuzlar

Konuşmacı don't, you'll gibi kısaltılmış biçimleri 3 kez kullanıyor. Bunları duyduğunuz gibi kısa söyleyin.

  • “th” sesleri: bathtub /ˈbæθtʌb/, threshold /ˈθɹɛʃ(h)oʊld/
  • “sh” ve “zh” sesleri: oscillation /ˌɒ.sɪˈleɪ.ʃən/, insulation /ˌɪnsəˈleɪʃən/, shipment /ˈʃɪpmənt/, notification /ˌnoʊtɪfɪˈkeɪʃn̩/, threshold /ˈθɹɛʃ(h)oʊld/
  • Uzun kelimeler — vurguyu doğru yere koyun: mortality /mɔɹˈtælɪti/, oscillation /ˌɒ.sɪˈleɪ.ʃən/, accelerate /ɪkˈsɛl.əˌɹeɪt/, insulation /ˌɪnsəˈleɪʃən/, continuity /ˌkɑn.tɪˈn(j)u.ə.ti/

Bu videoyla nasıl çalışılır

  1. Videonun tamamını konuşmadan bir kez dinleyin ve bilmediğiniz kelimeleri not edin.
  2. Normal hızda cümle cümle tekrar edin; ritminiz konuşmacıyla aynı olana kadar her cümleyi yineleyin.
  3. Kendinizi kaydedin ve orijinaliyle karşılaştırın; probe, defect, solder gibi kelimelere özellikle dikkat edin.

Gölgeleme Tekniği Nedir?

Gölgeleme, başlangıçta profesyonel tercüman eğitimi için geliştirilen ve çok dilli Dr. Alexander Arguelles tarafından popüler hale getirilen, bilim destekli bir dil öğrenme tekniğidir. Yöntem basit ama güçlüdür: ana dili İngilizce olan bir sesi dinler ve hemen yüksek sesle tekrar edersiniz — konuşmacıyı 1-2 saniye gecikmeyle takip eden bir gölge gibi. Pasif dinleme veya dilbilgisi alıştırmalarının aksine, gölgeleme beyninizi ve ağız kaslarınızı gerçek konuşma kalıplarını eşzamanlı olarak işlemeye ve yeniden üretmeye zorlar. Araştırmalar, telaffuz doğruluğu, tonlama, ritim, bağlı konuşma, dinleme anlama ve konuşma akıcılığını önemli ölçüde geliştirdiğini göstermektedir — bu da onu IELTS Konuşma hazırlığı ve gerçek dünya İngilizce iletişimi için en etkili yöntemlerden biri yapar.

Shadowing tekniği: adım adım eksiksiz rehberi okuyun →