What is included in the quality inspection of electroplated products


Quality inspection of electroplated products is an indispensable task, and only products that pass the inspection can be handed over to the next process. Common inspection items are: film thickness, adhesion, solderability, appearance packaging and salt spray test, for products with special requirements for drawings, there is a porosity test (30U ") gold using nitric acid vapor method, plating Palladium nickel products (using gel electrolysis) or other environmental tests.



A. Film thickness:

1. The film thickness is a basic item for electroplating inspection. The basic tool is a fluorescent film thickness meter (X-RAY). The principle is to irradiate the coating with X-rays, collect the energy spectrum returned by the coating, and identify the thickness and composition of the coating.

2. Cautions when using X-RAY:

1) Spectrum calibration is required every time the device is turned on
2) Do crosshair calibration every month
3) Gold and nickel calibration should be done at least once a week
4) Test files should be selected according to the steel used in the product.
5) There is no test file for new products, test files should be established

3. The significance of the test file:

Example: Au-Ni-Cu (100-221 sn 4%@0.2 cfp
Au-Ni-Cu ---------- Test the thickness of nickel-plated base and then gold-plated on copper substrate.
(100-221 sn 4% ------- AMP copper material number, copper material containing 4% tin)



B. Adhesion:

Adhesion testing is a basic testing item for electroplating. Poor adhesion is one of the most common undesirable phenomena in electroplating. There are two detection methods:

1. Bending method: First use a copper sheet of the same thickness as the required test terminal to pad the bend, and use flat-nose pliers to bend the sample to 180 degrees. Use a microscope to observe whether the curved surface is peeled and peeled.

2. Adhesive tape method: Use 3M adhesive tape to stick firmly on the surface of the sample to be tested, 90 degrees vertical, quickly tear the adhesive tape, observe the peeling metal film on the adhesive tape. If you can't observe clearly by visual observation, you can use 10x microscope to observe.

3. Result judgment:
a) Do not drop metal powder and sticky tape.
b) There should be no peeling of metal plating.
c) When the substrate is not broken, there must be no severe cracking or peeling after bending.
d) No blistering
e) Under the condition that the substrate is not broken, there should be no exposed underlying metal.

4. For poor adhesion, you should learn to distinguish the position of the peeled layer. You can use the microscope and X-RAY test to determine the thickness of the peeled layer, and use some stations to find the problem.

C. Solderability

1 Solderability is the basic function and purpose of tin-lead and tin plating. If required after welding, poor welding is absolutely unacceptable.

2. Basic method of solder test:
1) Direct tin dipping method: According to the drawing, directly dip the solder part into the required flux, dip it into a 235 degree tin furnace, and take it out slowly at about 25MM / S after 5 seconds. After taking out, use a 10x microscope to observe and judge when cooling to room temperature: the area where tin is eaten should be more than 95%, and the area where tin is eaten should be smooth and smooth without solder rejection, desoldering, pinholes, etc.

2) After aging and welding, for products with special requirements on some force surfaces, the samples should be aged with a steam aging tester for 8 or 16 hours before the welding test, in order to judge the product's Welding performance.

D. Exterior:

1. Appearance inspection is the basic function of electroplating inspection. From the appearance, we can see the suitability of electroplating process conditions and possible changes in electroplating chemicals. For different customers, there are different requirements for appearance. For plated terminals, they should always be observed with a microscope at least 10 times. For the defects that have occurred, the larger the magnification, the more helpful it is to analyze the cause of the problem.

2. Inspection steps:
- Take the sample under a 10x microscope and illuminate it vertically with a standard white light source:
- Observe the surface condition of the product through the eyepiece.
- Measure to judge:
1. The color is uniform, and there should be no dark or light colors, such as black, redness, and yellowing. Gold plating should not have serious color difference.

2. Do not stick to any foreign matter (hair dust, dust, oil, crystals)

3. Must be dry and free from moisture

4. Good smoothness, no pits and particles

5. There must be no deformation, such as crushing, scratching, crooking, and damage to the plated parts.

6. There must be no exposed bottom layer. Regarding the appearance of tin and lead, a little (not more than 5%) pits and pits are allowed without affecting solderability.

7. The coating should not have poor adhesion such as blistering and peeling

8 The plating position shall be performed in accordance with the provisions of the drawings. Under the premise of not affecting the use function, the QE engineer may decide to appropriately relax the standard.

9. For suspected appearance defects, QE engineers should determine limit samples and appearance assistance standards

E. Packaging

Packaging represents the image of the product and should be given sufficient attention.
Packaging requires the packaging direction is correct, packaging tray, box is clean and tidy, no damage: complete and correct label, the same number of internal and external labels.

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