Electronic Product Production and Manufacturing
From the 60s to 90s Electronic Manufacturing had many manual
operations. Even today and the future small volume production
and custom electronic manufacturing use these methods.
60s and Earlier Electronics had Valve Tubes and then the
transition to semiconductors. Later ICs made things much
smaller. Embedded Systems and SMD technology later shrunk
thinks to pocket size systems.
Inspection for Quality Control
It goes like this .... Technology and Size in
Volume of a Music Player with Radio in Housing or Cabinet.
It was first a Huge Wooden Cabinet that would be kept in the
Living Room with a Valve Radio, Turntable to play LP Records
and a Spool Player which was like a Large Tape Recorder.
The same thing now is a mp3 player and Radio that can be put
in your Shirt Pocket and you could move around town too, all
day long on a single charge.
How much Footprint and How much Volume the product. example a
Music System takes
Vacuum Tube based units - 50 Liters
Transistor based products - 10 Liters
DIP Chips or IC - 1000 CC or 1 Liter
Microcontroller Systems - 100 CC
SMT ASIC SoC Devices - 10 CC
First Inspect PCB for hairline shorts and cuts and also traces
of unwanted copper in the edges and repair them. Also Check if
all Drill holes & Slots are proper size and PCB is Fitting
in its Place properly, This is because Drilling and Filing
should not be done after assembly as it causes serious
in Axial and Radial Plastic Capacitors
Second populate all the resistors, Jumpers, Diodes and Ceramic
Capacitors these are tough components. Then Insert all
Transistors, LEDs, Displays, Electrolytic Capacitors and IC s
(Bases), Here care should be taken not to overheat any component
as it may damage them. Lastly Solder Connectors, Relays, Coils
and Transformers which may require a high wattage Iron, and
Precautions during Production
- Observe Polarity for Diodes, El-caps, Connectors, etc.
- Make sure of Pin 1 for IC s, Regulators, Transistors and
Mosfets before insertion.
- Avoid bases for ICs in production as these fail on use.
- Make use of Electrostatic protection for CMOS devices.
- When Cutting Leads use protective Goggles and do it in a
separate place as the cut leads fly all over the place.
- Use Iso Propyl Alcohol (IPA) as de-greasing agent on PCB.
- Water & Detergent wash is very good but only if coils,
Transformers, Relays are hermetically sealed- Impregnated.
Use a Lacquer-Varnish or RTV rubber coat on both sides of PCB
including on the components to prevent corrosion and also it
helps maintain accuracy-precision.
Lead is a kind of poison, use gloves or wash hands with soap
after work is over. Flux, IPA, Thinner Fumes can cause
respiratory health problems. Work in a ventilated area use
Exhaust Fans and Open Windows. Dispose of Metal, Plastic and
Chemical waste separately and well packed as these can
contaminate the environment and also cause Injury.
Published online around - Nov 1999
Some Pilot Production And testing points
when building electronic Projects
These are also important while prototyping and Bread-boarding.
These are things that i used to keep telling youngsters when
they are new in manufacturing. This was when i was running my
own firm making industrial equipment and instruments.
I used to even give this and some other pages around in printed
format, it was composed with word on windows 3.11. Then i
realized it has to instructed at every incident by example.
Reading does not help unless someone is passionate and
enthusiastic about learning.
- Use 1% MFR 100 ppm resistors for all analog
- Use plastic or-and multilayer capacitors as ceramics are
- Product should have minimum number of fasteners.
- Nuts, Bolts and screws locked with adhesive so that they
do not slip and the product falls apart.
- Potentiometers should move smoothly and not get twisted,
strained or locked due to cabinets.
- Use Strain relief for wires and strip the wire and solder
properly where required.
- Strip with a stripper do not use your teeth., Twist all
the strands Tin the tip of the wire.
- After Tweaking and setting presets or trimpot lock it with
paint or varnish.
- Big Components should have large pads and separate
mechanical fixing to PCB.
- Acrylic and plastic can get blurred or deformed with some
Do assembly of the card with a tested assembled 3D reference.
Even after all the care if the card does not work, then after
full assembly do visual inspection in this order First keep both
the cards one reference and the other manufactured under a
- Compare resistor color patterns one by
- Compare Electrolytic capacitors
physical appearance and POLARITY.
- Verify values of plastic and ceramic
- Cross-check Diode sizes and POLARITY.
Verify Zener values.
- Check IC and Regulator POLARITY and
Exact type number / brand
- Check Transistor, MOSFET, LED,
POLARITY. and verify display type No. and Polarity .
- Check for connector patterns and
polarity and switches etc.
- Reverse the card and Check for solder
bridges between close pins .
- Reverse card and Check for hairline
shorts and solder streaks due to bad PCB processing or
- Reverse card and check for hairline
cuts or pads lifted off card.
- Closely observe for dry solders on big
- L and TX a dry solder will cover the
pin and will be dull in shine.
- before calibration allow for product to
warm up for 15 mts.
If all the components were subject to incoming inspection and
testing. If still unit does not work remove power and do cold
check comparison with reference unit in DMM 200K R range, if
still problem persists continue with power on testing and solve
by DMM or scope tests.
Danger ! when DMM is in Ohms Mode, Even if one probe touches 230
V, DMM is Gone, so take extra care while doing this. test probe.
First written and printed offline in the Nineties. Word on
Windows 3.11 with Epson 24 Pin Dot Matrix Printer., updated
Tables and Charts
How to Test Verify the Testing Methods Itself
Testing and Evaluation tools must have dynamic decoys added into
the device under test DUT or the batch under test. In a Conveyor
system, identifiable (RFID) decoys must be artificially
introduced every 100 pieces. This will constantly counter check
the Testing system and in not a One time operation. The decoys
should be defective or have a fault, a little above threshold.
This is caught by the testing system. Even when the testing
system ages or goes out of calibration, this method can raise a
Even in software and text/data processing; this method ensures
database quality and software program integrity.
Work Culture and Discipline
Systematic and Meticulous work has its own Rewards. An Engineers
Notebook or a Hobby Experiments Log Book can go a long way in
making a Cauliflower out of every Cabbage. (The credits of the
Vegetable Analogy goes to Mark Twain)
Keep Work Place Clean
Clean Tables and shelves every day before closing office, Put
Cut leads and Solder shots in a separate cup to be accumulated
and disposed later as these are toxic. In this cup other
irritants like staple pins can be added and these can be clubbed
in a month and disposed off as one metallic bulk for recycling.
Never bring coffee or food to work area, Keep a waste paper
basket on your side.
Work carefully to avoid injury
When cutting leads hold the lead in the hand and cut or it will
fly all over the place. A piece like that may land on another
equipment and cause shorts or it may go right into your eyes and
cause blindness. Lead and Isopropyl alcohol and other Chemicals
may be dangerous for health if handled carelessly. Do not use
fingers, and teeth as tools it is bound to cause a injury to
repent a lifetime. Be extra careful with 230V AC and more so
with 440V 1 tr 2mA thru your heart and a weak streak of luck may
be the last experience you ever had. Do not press your Luck too
Protect Desk or table surface
If you are cutting something let it not leave marks on table,
even adhesive stains should not deface table, use a asbestos,
hylam fiberglass, hardboard surface which can be disposed once
in a way. Before working put two layers of news paper on the
table this prevents table from getting spoilt while soldering
and newspapers being hygroscopic (water absorbent) they provide
a natural antistatic surface to protect CMOS Ics and are
nonconductors for any Live PCB kept on the paper.
Use tools and equipment's in a gentle manner
When you use weller Iron use it as a heat transfer tool never
use it for prying or crimping leads or just pressing use pliers
or other tools for that.
Document what you do and vice versa
Have a register in which you can make records of what you did to
solve a problem or what you learnt while making an equipment
this information is valuable for the company to develop
production methods and also useful to your team to solve a
similar problem. Share abilities and skills with fellow
employees but don't share your company's technology and database
with any other company. When you leave a company use only the
abilities and skills in that broad area to evolve as a
professional. - Engineers Notebook.
Hobby and Do it Yourself
It is by Hobby and DIY - Do it Yourself, Education Starts even
without books. Then you need to read to enhance your abilities
to Design your own.
In order to compensate or enhance your education, you need
to work at a small shop as an apprentice even as a student,
not for the sake of project work alone. An Evening job at a
factory or a home mini workshop-lab is very essential for
obtaining the skills.
Published online around - Nov 1999
Solderman Talks - 1707 AD
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