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How do you inspect solder joints?

How do you inspect solder joints?

After you’ve completed a solder joint, you should inspect it to make sure the joint is good. Look at it under a magnifying glass, and gently wiggle the component to see if the joint is stable. A good solder joint should be shiny and fill but not overflow the pad.

What are the signs of a good quality soldered joint?

What Constitutes Good SMT Solder Joint Quality?

  • component pin and footprint pad are aligned;
  • pad area is completely covered with solder;
  • component pin area in contact with pad is completely covered with solder;
  • no excess solder covers component;
  • solder joint is smooth;
  • solder joint does not contain voids; and.

What is the maximum amount of acceptable lead damage?

OSHA set a Permissible Exposure Limit (PEL) for lead in workplace air of 50 µg/m3 (8-hour time weighted average). OSHA mandates periodic determination of BLL for those exposed to air concentrations at or above the action level of 30 µg/m3 for more than 30 days per year.

How do you know if your solder joints are dry?

It is easy to identify dry joints. Unlike good solder joints that are shiny, dry joints have a dull or matt finish. Also when soldering them they appear to have a more granular appearance as the solder is melted.

What is a bad solder joint?

A solder-starved joint is just that: a joint that does not have enough solder. Despite making the necessary electrical contact, the insufficient solder weakens the joint and increases susceptibility to cracking and failure.

What does a bad solder joint look like?

A Disturbed joint is one that has been subjected to movement as the solder was solidifying. The surface of the joint may appear frosted, crystalline or rough. Often called a ‘Cold Joint’. They can look similar to a true cold joint, but the cause is different.

At what level is lead toxic?

Current standards define a lead blood level of 10 mcg/dL in the as being toxic in children. In adults, a level of 25 mcg/dL is considered toxic. Any level of lead can have toxic manifestations, and all health care practitioners should become familiar with the signs, symptoms, and treatment of lead poisoning.

What is stress relief in soldering?

Abstract: When a surface-mounted ceramic chip carrier is subjected to thermal cycling, complex stresses and strains are generated in the solder joints. At any temperature, the solder simultaneously undergoes creep and stress relaxation in a process We call “stress reduction.

What are three common causes of a poor solder joint?

Top 5 Reasons for Solder Joint Failure

  • Unintended Stresses from Potting, Underfills and Conformal Coatings.
  • Unexpected Temperature Cycling Extremes.
  • Mechanical Overstress Events.

What are the general requirements for through hole solder?

THROUGH-HOLE SOLDERING GENERAL REQUIREMENTS (cont.) Solder skip is the random non-formation of solder fillets, and is an indicator of poor process control. Solder skip may be caused by insufficient solder, contamination, non-solderability (oxide), improper flux, solder thieving, etc.

What are the characteristics of a good soldering system?

Component and board markings are clear and legible. Component leads exhibit proper bend radii and stress relief. Solder fillets are smooth and shiny with concave profiles. PREFERRED 100% SOLDER FILL (PTH)

What does a good solder fillet look like?

Solder fillets are smooth and shiny with concave profiles. Populated plated through holes (PTH) should exhibit a vertical solder fill of 100%, with a fully formed fillet on the solder side, and evidence of 100% wetting on the component side lead, barrel and pad.

Does solder have to extend into stress relief Bend?

SOLDER IN STRESS RELIEF BEND. Solder which extends into the stress relief bend of any leaded part shall not be cause for rejection if the topside bend radius is discernable, and if the solder does not extend within one (1) lead diameter of the part or end seal.