Stick an inductance invalidation reason to basically be behaved in 5 respects, it is to be able to bear or endure respectively solder sex, solderability, solder undesirable, on the damaged of chance open a way, magnetic circuit invalidation that bring about, below put up with made an explanation this at 5 o’clock.

 

Before this, we understand inductance failure mode first, and the mechanism that sticks an inductance invalidation.

 

Inductor failure mode: Inductance measures the out of tolerance with other property, open a way, short circuit.

 

Stick a reason of power inductance invalidation:

 

The mechanical stress that 1. magnetism core produces in machining a process is greater, did not get releasing;

 

There is foreign matter inside 2. magnetism core or itself of material of empty magnetism core is inhomogenous, affect the magnetic field condition of magnetism core, make the magnetism conductance of magnetism core produced deviation;

 

The agglomeration crackle that 3. produces as a result of agglomeration hind;

 

When 4. copper cash and copper take immersed solder to join, coil part splashs stannic fluid, melted the insulation layer of enamel-insulated wire, cause short circuit;

 

5. copper cash is fine, when taking join with copper, cause false solder, open circuit invalidation.

 

One, be able to bear or endure solder sex

 

The feeling after low frequency sticks a solder of circumfluence of power inductance classics measures ascendant <20 ％ .

 

Because the temperature of circumfluence solder exceeded low frequency to stick the Courier temperature of an inductance material, occurrence demagnetization phenomenon. After sticking an inductance demagnetization, the magnetism conductance that sticks an inductance material restores maximum, feeling volume rises. The control limits of general requirement is to stick an inductance to be able to bear or endure solder after heat, feeling volume ascendant range is less than 20% .

 

Be able to bear or endure the problem that solder sex may create is sometimes when solder of small lot handiwork, circuit function is all and eligible (stick an inductance right now not whole heats, feeling volume rises small) . But large quantities of quantities stick a short while, discovery has partial circuit function to drop. Because cross circumfluence solder,this may be hind, stick an inductance feeling quantity to be able to rise, affected the performance of circuit. Estimating the place with precision stricter requirement to sticking an inductance to feel (if signal receives emissive circuit) , should increase be able to bear or endure to sticking an inductance the attention of solder sex.

 

Detect method: Measure first stick an inductance the feeling value of a quantity when normal temperature, in the soldering tin canister that will stick an inductance immerge to fuse again 10 seconds or so, take out. Wait for after sticking an inductance to cool thoroughly, measure stick the feeling value of a quantity with a new inductance. The percentage that feeling quantity increases is what should stick an inductance to be able to bear or endure already solder sex size.

 

2, solderability

 

When the temperature that reachs circumfluence solder, the metal is silver-colored (Ag) can follow metallic stannum (Sn) reaction is formed in all frit content, because this is sticking the silver-colored termination of an inductance,go up direct tin-plating. Go up in silver-colored termination however first plating nickel (2 ｕ M is controlled) , form isolation layer, next again tin-plating (4 – 8 ｕ M) .

 

Solderability detects

 

Will wait for the detected termination that sticks an inductance to be cleaned clean with alcohol, will stick an inductance in fused soldering tin canister immerge is controlled 4 seconds, take out. If stick the soldering tin of an inductance termination to enclothe,lead achieve 90 ％ above, criterion solderability is eligible.

 

Solderability is undesirable

 

1, termination oxidizes: Should stick an inductance to get gas of high temperature, damp, chemical, oxidisability (SO2, NO2) influence, or save time to grow too, cause the metallic Sn oxidation that sticks an inductance termination to go up to become SnO2, stick an inductance termination to pale. Do not wait with Sn, Ag, Cu as a result of SnO2 generate in all frit content, bring about stick an inductance solderability to drop. Stick an inductance product expiration period: Half an year. If stick an inductance termination to be polluted, for instance oily material, solvent, also can cause solderability to drop.

 

2, plating nickel layer is too thin: If when plating nickel, nickel layer is too thin cannot have segregation effect. When circumfluence solder, the Ag that sticks a Sn on inductance termination and oneself reacts above all, and affected the Sn that sticks an inductance termination to go up and solder dish the solder that go up creams in all frit, create appearance taking silver, the solderability that sticks an inductance drops.

 

Judge a method: In the soldering tin canister that will stick an inductance immerge to fuse a few seconds, take out. If discover circumstance of termination occurrence pothole, appear even porcelain body appears, can be being judged is to appear of phenomenon taking silver.

 

3, solder undesirable

 

Internal stress

 

If stuck an inductance to produce greater in-house stress in the process that make, and did not adopt measure to eliminate stress, in circumfluence solder process, had stuck stick an inductance to because the influence generation of internal stress stands,be met piece, common says to establish tablet effect.

 

 

Judgement sticks an inductance to whether be put in greater internal stress, can adopt a simpler method:

 

Take hundreds of stick an inductance, put into general oven or microtherm furnace, warm up to be controlled to 230 ℃ , heat preservation, observe the condition inside furnace. If hear Pi Pi noise, have the voice that film start comes to even, explain the product has greater internal stress.

 

Component is out of shape

 

If stick an inductance product to have,bend be out of shape, the meeting when soldering has enlarge effect.

 

Solder solder of undesirable, empty

 

Solder to be like a graph normally

 

 

Solder dish the design is undeserved

 

A. Solder dish two end should be designed symmetrically, avoid size differ, otherwise wet force of the melt time of two end and embellish will be different.

 

B. The length of seam is in 0.3mm above (the metallic termination that sticks an inductance namely and solder dish coincide length) .

 

C. Solder dish the length of leeway as far as possible small, do not exceed 0.5mm commonly.

 

D. Solder dish itself width shoulds not be too wide, its are reasonable width and MLCI width photograph are compared, unfavorable exceed 0.25mm.

 

Stick piece undesirable

 

Should stick piece fill up because of solder rough or what solder creams is slip, and cause stick an inductance deflection when θ horn. Because solder fills up the embellish wet force of the generation when melt, the likelihood forms above 3 kinds of circumstances, return to be being given priority to by oneself among them, but can appear sometimes those who pull is more inclined, only perhaps place is pulled circumstance, stick an inductance to be pulled to a solder dish on, be pulled even, inclined stand or erect (phenomenon establishing tablet) . Take what vision of θ horn deflection detects to stick a machine to be able to reduce the happening of this kind of invalidation at present.

 

Solder temperature

 

Of circumfluence welder solder the requirement set that temperature curve fibril occupies solder, should assure to stick an inductance as far as possible the solder of two end at the same time melt, differ in order to avoid the time that two end produce embellish wet power, bring about stick an inductance soldering shift appears in the process. If appear,solder undesirable, can affirm first, whether does circumfluence welder temperature appear unusual, or solder is changed somewhat.

 

Inductance issues easy damaged in the circumstance of urgent cold, urgent heat or local heating, solder because of special attention answering when this solders the control of temperature, shorten as far as possible at the same time solder osculatory time.

 

4, on solder of empty of chance open a way, solder the contact is undesirable

 

From circuit board on get off stick an inductance test, it is normal to stick an inductance function.

 

Electric current is burned wear

 

If choose stick an inductance the rated electric current of magnetism bead is lesser, or the impulse current with the large presence in circuit can cause electric current to burn wear, stick an inductance or magnetism bead invalidation, bring about circuit open a way. From circuit board on get off stick an inductance test, stick an inductance invalidation, have burned-out mark sometimes. If appear,electric current is burned wear, the product measure of invalidation will be more, product of the invalidation in be the same as batch is achieved commonly 100 classification above.

 

Solder open circuit

 

When circumfluence solder urgent cold urgent heat, make stick an inductance interior to produce stress, the sticks an inductance defect that causes the hidden trouble of in-house existence open a way that has few share greatens, cause stick an inductance open a way. From circuit board on get off stick an inductance test, stick an inductance invalidation. If appear,solder open circuit, the product amount of invalidation is average less, product of the invalidation in be the same as batch is less than commonly 1000 classification.

 

5, magnetic body damaged

 

Magnetic body intensity

 

Stick an inductance agglomeration bad or other reason, cause strength of porcelain body whole insufficient, brittleness is big, sticking a short while, or the product suffers outside force concussion to cause porcelain body damaged.

 

Add exert oneself

 

If stick the adherent force of an inductance termination silver-colored layer to differ, when circumfluence solder, stick an inductance urgent cold urgent heat, heat bilges cold shrink generation stress, and porcelain body suffers outside force concussion, all can cause likely stick an inductance termination and porcelain body depart, fall off; Or solder dish too big, when circumfluence solder, the embellish wet muscularity of the generation when solder creams melt and termination react adheres to at termination force, cause termination to destroy.

 

Stick an inductance to pass to burn or be born burn, in perhaps making a process, interior produces micro-crack. When circumfluence solder urgent cold urgent heat, make stick an inductance interior to produce stress, occurrence brilliant is cracked, or micro-crack expands, create the situation such as magnetic body damaged.