SMT production line anti-static times the speed of the chain with the key points of analysis

​Why is your SMT line always losing money? Chip capacitors inexplicably cracked, IC soft breakdown rework over 200,000?Eighty per cent of the time, the chain of static protection is not equipped with the right! Newbie can't figure out the three big potholes of grounding materials, humidity control, and personnel operations? Don't panic, this nanny guide allows you to save 30% return cost -

First, grounding system: independent grounding + double insurance design (save 200,000 rework costs of the core)

​sore point: PCB generated by friction of metal rollers8000V static electricityAnd a MOS tube 30V on the breakdown. A factory in Dongguan due to grounding shared lightning ground, the whole batch of motherboard IC soft breakdown lost 200,000 yuan.

​correct configuration::

1. ​Individual grounding: Must be separated from power ground! Usethree-phase, five-wire system (TCM)Grounding resistance≤4Ω(National Standard Hard Targets)
2. ​dual path bleed (computing)::
   • Speed Chain Metal Skeleton Direct Connect Ground Wire (Hard Ground)
   • Tooling boards pass through1MΩ current limiting resistorGrounding (soft ground to prevent damage to the chip from >5mA current)
3. ​Material Selection: Static dissipative materials for chain surfaces (surface resistance)10⁵-10⁸Ω-cm), such as rubber mixed with conductive carbon black

​White man avoiding pitfalls: Cross-sectional area of earthing conductor≥1.25mm²! Replacing copper core wire with iron wire? It's just waiting to be put up.

Second, environmental control: humidity + ion neutralisation double kill (electrostatic pressure straight down 90%)

​sore point: Humidity below 30%, human static electricity spikes to2kV+; Winter humidity in northern workshops 20%, PCB static voltage8kVResulting in bulk cracking of SMD capacitors.

​key operation::

• ​Humidity control: Workshop constant humidity45-70%RH(Temperature 23±3°C), the humidifier must be usedpurified water(Chlorine in tap water corrodes circuits)
• ​Ion blower deploymentInstallation: at the entrance of the speed chain, next to the bonder, specialising in the treatment of static electricity in plastic packaging film.
• ​Low-cost programmes: Can't get the humidity up? Installation on both sides of the doubler chainAtomised humidifying curtains(Lower cost than central air conditioning 70%)

Third, the personnel operating norms: anti-static equipment + action red line (to eliminate 6000V human bomb)

​lesson learnt through blood and tears: Employees did not wear wristbands for debugging, hand touching the chip instant production line downtime for 4 hours; chemical fibre clothing friction static electricityOver 6000V!

​Rules that must be enforced::

1. ​Fully clothed: Antistatic clothing/shoes (sole resistance)10⁶-10⁸Ω) + wrist strap (system resistance)1-10MΩ), mandatory pre-shift testing
2. ​operating ban::
   • Prohibit placing plastic bags/fast food containers on the speed multiplier chain (frictional electricity easily breaks 10,000 volts)
   • PCB must use anti-static crates, bare boards stacked with anti-static partitions
3. ​Movement Standard: Take and put PCB "a take and a test", touch the grounding point before contacting the device.

Four, doubling chain selection guide: chain + work plate golden combination (to avoid the risk of breakage)

​The wrong choice is a straight up turnover.::

• ​Chain type::

  • 2.5x speed chain: load bearing1-2 tonnesSuitable for mobile phone patching (plastic rollers are prone to wear and tear)
  • 3x speed chain: load bearing3-5 tonnesThe air-conditioning motor line is a must (steel wheels are twice as expensive, but they can be built).

• ​Workplace board materials::

  Material type	Anti-static effect	weight-carrying capacity	(manufacturing, production etc) costs	Applicable Scenarios
  ​Anti-static PVC​	★★★★	middle	lower (one's head)	Mobile phone/headset assembly line
  ​Carbon steel with anti-static paint​	★★★★★	your (honorific)	middle	Power supply motherboard cable
  ​plywood​	✘	lower (one's head)	lowest	Never use it!

​soul searching: What should I do if the anti-static coating wears off? → Coat monthlyAntistatic conditioner(Don't use floor wax!) (Don't use floor wax!) The resistance value can be returned to 10⁷Ω.

V. Maintenance monitoring: real-time early warning + low-cost life-preservation programmes (small plants can also copy operations)

​Neglect = wasted effortA factory's grounding wire was crushed by a shelf for 3 months without discovery, resulting in a 40% drop in yield for the whole month!

​Landing Configuration::

1. ​must-do: Pre-shift inspection of wristband testers, 1 thermo-hygrometer per work station (<40%RH Auto Alarm)
2. ​Monthly Hard Targets: Measurement of earth resistance by megohmmeter (check for corrosion immediately if it exceeds 4 Ω)
3. ​Poor Plant Programme: Priority protection of three pieces -Copper core grounding wire + ion fan + anti-static wrist strap, solving the 80% problem
4. ​landlord's addition: On-line static monitor with automatic power-off above threshold (save 30% hidden failure cost)

​lit. my editor slaps the tableDon't be fooled by "Stainless Steel Speed Chain"! I've seen too many factories spend money to buy high-end chain, the result of grounding with a wire casually wrapped---Copper core wire + daily spot checksIt's more real than anything else. Remember ah, electrostatic protection is not to cope with the audit, less bad a board enough to buy six months of supplies!