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 reliability problems.
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 Mechanical Reinforcements.
b. 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.
“Earth leakage currents arise mainly from the EMC filters built into electronic equipment with switched mode power supplies. Standards limit the leakage current from non-fixed equipment (i.e. equipment that plugs into a standard socket outlet) to less than 3.5 mA. When a lot of electronic equipment is in use, the total leakage current in the protective conductor can become significant.”
The PQ E-library is a collection of electronic technical reference documents covering introduction, costs, harmonics, resilience, voltage disturbances, earthing, energy efficiency and renewables/distributed generation
Copper Development Association
Computers cannot work without copper
Electricity in buildings
Copper Development Association Website for information on Copper and Copper Alloys
This is an educative and important guide for Electrical Equipment Safety. This can be also applied partially to Power Electronics and Home Energy Systems. Electronic Equipment also have to be maintained by Calibrating them and protecting them from environmental parameters like dust, grime, direct sunlight, moisture, humidity, sea wind (brine), corrosive fumes and chemicals. They should not be even placed near machines like a big lathe, sub-sonic or low frequency vibrations.
Electrical Safety is a Serious Issue Electrical Safety in the workplace is the most important job of an electrical worker. No matter how much training one has received or how much employers try to safeguard their workers, Electrical Safety is ultimately the responsibility of the electrical worker.
Earthing or Grounding is something Audio Enthusiasts make a lot of fuss about. The Articles here about Balanced Power, Symmetrical Power Systems and Earthing throw light on ways to counter Audio Noise.
AC Power has the 50/60 Hz noise, now more AC noise can be picked up by poorly designed systems when so many gadgets around. These articles are also relevant for the instrumentation engineer. Dissonance is encountered when you build sensitive strain gauge based measurements or while measuring and transmitting micro-volts from a remote sensor to the dashboard/control panel.
Product should not give even the lightest shock, Even metal parts on user side to be laminated.
High energy circuits never enters analog and digital circuit areas without Opto or other Isolation.
Gadgets, Furniture, Tools and Storage Units should not cause injury. Rounded Edges, Non Toxic.
Helmet, Goggles and Face/Respiratory Mask when working with power tools/ abrasion and large objects.
Crepe Bandage, Neoprene Ankle/Knee/Thigh Support when pushing or pulling or Physical Exertion.
Waist/Back Support Belts and Straps to reinforce back/spine while doing Heavy Lifting or Movement.
Waistband Thick Belt or Traditional Sash helps Posture and prevents slipped disc or spinal injury.
When using a Knife, Sharp Tool, Pointed Tool or Drill; cut/bore away from your body or finger/leg not towards.
Use Long Riding Leather/Synthetic Boots when working in chemical plants and heavy industry.
Cross Ventilation and exhaust fans important if even little chemical fumes are generated in your work.
Soldering, plastic forming and even for some kinds of material processing. Good Ventilation or Masks needed.
Fire hazard and Air pollution in the workplace is the most important two dangers, Electricity is third.
Use Leather Boots when working with high voltage, also silicone flexible gloves or Latex Gloves.
My Recent Lessons –
I have long stopped using power tools as the injury is more in that. I have again started using small tools. Some notes.
Wear ear muffs when Noise present in surroundings to avoid distraction. When your own tools/work create too much noise, then also ear muffs protect ears, give some allowance/filter for audio feedback .
Cut away from you, not towards. Sharp tools and Power tools keep job at a distance. Watch for Splinters.
Both Legs and at least one hand insulated when working with High Voltage.
Use the right tool for the right job. Do not use cutting plair like a hammer.
Do not use Teeth, Legs etc. as tools. Only Iron and Steel should face the Job.
Ergonomics and Manpower the Engine of Growth – A Worker in One Firm is a Customer for another Firm. Healthy and Safe Workers implies a strengthening Consumer base.Just imagine what wonders it can do for the economy, when you broaden your view, think togetherness, as a Whole; not in isolated competitive groups, not in parts.
Ergonomics reduces Worker Stress. Helps in keeping good Mental and Physical Health. Safety is very important. His Limbs, Eyes and Ears are assets that a firm hires.
A good Manager knows that Manpower is the Foremost Asset of any Company.
First Aid and Flame Resistant Uniforms Tools and Apparel to make workplace safe. First Aid and Safety, Fire Protection and Flame Resistant Clothing. Cleanrooms are very important for Microelectronics, MEMS and Precision Instrumentation.
In spite of “Prevention better than cure”, a worker can get injured, more so on the field, where preventive measures may not be in place. A Portable First Aid Kit that should be in Service and Commissioning Departments. A stitch in time saves nine. in reference to: “Your employees may require first aid at remote worksites, too.”
Worker Safety and Health Education
When we educate ourselves about a Hazard, that awareness is the first step of defense. Resources like this should have a Kids Section. Just like Nasa and Fcc have. We have to catch them young, Interactive tutors and Activities will prepare them for a Safe and Sensible future. Home, Garden, Transport and School are also like a Workpace.
Kids of recent generations are degrading intellectually, it is more so in the developed countries. Education has to be emphasized, Hobby DIY activities encouraged. Hardships simulated, so they become responsible Young Citizens.
Rockefeller Jr. (A Philanthropist) was brought up with such discipline, he was not allowed entertainment when he was young. His father the richest man in the US at that time.
Intrinsic Safety and Zener Barriers Designing and Building Intrinsically safe Industrial Systems is of paramount importance as Human Safety is involved. Even in Switching Loads some contactors, relays, circuit breakers and motors are hazards as some sparking becomes inevitable.
Solid State Relays are safer but on an overload even these can pose a fire hazard if a HRC fuse is not used. Sensor measurements must employ low voltages and currents. Even cabling management and hermetically sealed enclosures may be required when volatile fluids are close by.