Inspection standards for electroplating products.
The inspection of electroplating terminal products is an indispensable work for electroplating products after the electroplating is completed, and only the electroplating products that pass the inspection can be handed over to the next process.
Usually the inspection items of electroplating products are:Thickness, Adhesion, Solder Ability, Appearance, Package, Salt Spray Test. For products with special requirements in the drawings, there are porosity tests (30u) gold using nitric acid vapor method, palladium-nickel plating products (using gel electrolysis method) or other environmental tests.
1.Film thickness is the basic item of electroplating inspection, and the basic tool used is fluorescent film thickness meter (X-ray), the principle of which is to use X-rays to irradiate the coating, collect the energy spectrum returned by the coating, and identify the thickness and composition of the coating.
2.Precautions for using X-ray:
1) Spectral calibration is required every time the machine is turned on.
2) Do a crosshair calibration every month.
3) Gold and nickel calibration should be done at least once a week.
4) The test file should be selected according to the steel used in the product during the measurement.
5) If there is no test file for new products, a test file should be established.
3.Significance of the test dossier:
Example: au-ni-cu (100-221 sn 4%@0..)2 cfp
Au-Ni-Cu ——— test the thickness of nickel plating and gold plating on a copper substrate.
100-221 sn 4% - sample copper with 4% tin).
Adhesion inspection is a necessary inspection item for electroplating products, and poor adhesion is the most common defect in electroplating product inspection, and there are usually two inspection methods:
1.Bending method: First, use a copper sheet of the same thickness as the required detection terminal to pad the bending place, bend the sample to 180 degrees with flat pliers, and observe whether the bending surface has plating peeling and peeling off with a microscope.
Tape method: Firmly paste the 3M tape on the surface of the sample to be tested, 90 degrees vertically, quickly tear off the tape, and observe the peeling off metal film on the tape. If it is not possible to observe clearly visually, a 10x microscope can be used.
3.Verdict:
a) Do not drop metal powder and patch tape.
b) There should be no peeling of the metal plating.
c) If the substrate is not broken, there should be no serious cracking and peeling after bending.
d) No blistering.
e) If the substrate is not broken, there shall be no exposure of the underlying metal.
4.When adhesion is defective, you should learn to distinguish the location of the peeling layer, and you can use a microscope and X-ray to test the thickness of the peeled coating, and use some stations to find out the problem.
1.Solderability is the basic function and purpose of tinning, lead and tinning, if there is a post-welding process requirements, poor soldering is a serious defect.
2.The basic method of solder test:
1) Direct solder dipping method: According to the drawing, the solder part is directly immersed in the required flux, immersed in a 235 degree sin pot, and slowly taken out at a speed of about 25mm s after 5 seconds. After taking it out, when it is cooled to room temperature, it is judged by 10 times microscope observation that the tin eating area should be greater than 95%, and the tin eating part should be smooth and clean, and there should be no rejection of soldering, desoldering, pinholes and other phenomena.
2) Aging first and then welding, for products with special requirements for some force surfaces, the sample should be aged for 8 or 16 hours by using a steam aging testing machine before the welding test to judge the welding performance of the product in the harsh use environment.
1.Appearance inspection is the basic inspection item of electroplating inspection, and the suitability of electroplating process conditions and the possible changes of electroplating solution can be seen from the appearance. Different customers will have different requirements for appearance, and the electroplated terminals should be observed with a microscope of at least 10 times. For defects that have occurred, the higher the magnification, the more helpful it is to analyze the cause of the problem.
2.Inspection Steps:
1).Take the sample and place it under a 10x microscope and irradiate it vertically with a standard white light source
2).Observe the surface condition of the product through the eyepiece.
3.Determination method:
1).The color is uniform, there can be no dark and light colors, different colors (such as blackening, redness, yellowing), and there can be no serious color difference in gold plating.
2).Do not stick to any foreign matter (dander, dust, oil, crystals).
3).It must be dry and not wet with moisture.
4).Good smoothness, no holes, particles.
5).There shall be no crushing, scratching, scratching and other deformation phenomena and damage to the plating parts.
6).There shall be no phenomenon of exposing the lower layer, and a little (no more than 5%) pitting and pitting are allowed without affecting the appearance of tin and lead without affecting the solderability.
7).The coating should not have blistering, peeling and other poor adhesion.
8).The electroplating position is carried out in accordance with the provisions of the drawing, and the standard can be appropriately relaxed by the QE engineer without affecting the use function.
9).For the suspicious appearance defects, the QE engineer should set the limit sample and appearance auxiliary standards.
The packaging inspection of electroplating products requires that the packaging direction is correct, the packaging tray and box are clean and tidy, and there is no damage: the label is filled in completely and correctly, and the number of internal and external labels is consistent.
Unqualified electroplating parts, after the salt spray test, the surface will be blackened, red rust, etc. Of course, different types of electroplating will produce different results.
The salt spray test of electroplating products is divided into two categories: one is the natural environment exposure test; The other type is the artificial acceleration simulation of salt spray environment test. The artificial simulated salt spray environment test is to use a test equipment with a certain volume space - salt spray test chamber, in which the volume space is artificially created to create a salt spray environment to assess the salt spray corrosion resistance performance and quality of the product.
Artificial simulated salt spray tests include:
1) Neutral salt spray test (NSS test) is the earliest and most widely used accelerated corrosion test method. It uses a 5% sodium chloride brine solution with a pH in the neutral range (6 7) as a solution for spraying. The test temperature is 35, and the sedimentation rate of salt spray is required to be 1 2ml 80cmh.
2) The acetate spray test (ASS test) is developed on the basis of the neutral salt spray test. It is to add some glacial acetic acid to the 5% sodium chloride solution, so that the pH value of the solution drops to about 3, the solution becomes acidic, and the final salt spray also changes from neutral salt spray to acidic. It corrodes about 3 times faster than the NSS test.
3) Copper salt accelerated acetate spray test (CASS test) is a kind of rapid salt spray corrosion test recently developed abroad, the test temperature is 50, and a small amount of copper salt - copper chloride is added to the salt solution to strongly induce corrosion. It corrodes about 8 times faster than the NSS test.
The above are the inspection standards and inspection methods for electroplating products, including electroplating productsFilm thickness inspection, adhesion inspection, weldability inspection, appearance inspection, packaging inspection, salt spray test, more electroplating inspection and method finding library (www.).testcoo.com)。