Inspection and testing of metal ornaments

I. Appearance inspection

1. Check the appearance of necklaces, bracelets and anklets

a. Check the necklace, bracelet and anklet as a whole. Stretch the chain with both hands to both sides, and observe whether it is broken. Check the product, especially whether there are any external accessories on the chain (such as the half-cut ring, etc.). Check the overall good appearance of the product, the coating color is normal, and there is no coating peeling off, dirty coating and plating leakage.

b. Whether the functions of lobster buckle, spring buckle, flip buckle or switch on the pendant are normal, open the switch on lobster buckle, spring buckle and pendant repeatedly, and observe whether the lock can open and close flexibly.

c. Suspension components Check whether the light pull pendant is securely installed.

d. Casting inspection Check the casting for good quality, such as no flanges, castings, scratches, scrapes, etc.

e. Small connector inspection, check all kinds of small connectors are in good condition (such as: eye-pin, tin-pin, jump ring, bail, oval ring, etc.) neat and clean, no gap.

f. Inspection of decorative materials:

• Check that the gemstone color meets requirements, the installation position is centered, there is no excessive glue, and the gemstone is installed evenly.

• Check epoxy with good appearance, no redundant epoxy, no flowing epoxy.

• Check that other decorative parts are in good condition, roughly as above.

2. Appearance inspection of ear studs

a. Pairing check: For left and right studs, left and right studs are not allowed.

b. The overall inspection of the stud is good: check the overall appearance of the product, the coating color is normal, no coating falling off, dirty coating, coating leakage phenomenon.

c. Fish hook type ear needle, scalpel type ear needle, lever type ear needle, lever spring type ear hook, ear clip overall check is good:

• For fishhook type earpins, the length of earpins shall meet the requirements (generally 5% deviation is allowed), and the earplugs shall not be too loose or too tight.

• For scalpel type ear needle, the ear needle should be welded on the casting in a vertical state, not tilted, not bent, ear plug should not be too loose or too tight.

• For lever type ear needle, the part of the ear needle is not bent; Hinge and closing part, mechanical part can work flexibly, not stiff.

• For lever spring type stud, the mechanism is flexible and can be switched freely.

• The ear clip type stud should not be too tight or too loose when wearing. The ear clip mechanism is flexible and can be opened and closed freely.

2. Field test

1. Drop test

A drop test is to check the binding strength of a gemstone or other part.

Test method: We can test on the iron plate or board according to the requirements specified by customers in accordance with a certain height to observe whether there are gems or binding parts in the process of falling.

First distinguish between precious metals and base metals, base metals with steel plates, precious metals with wood. After 72 hours of adhesive, prepare Min5/8 "(1.5cm) steel plate, sampling number is S-1, 36" x10 times, once the stone is down, check whether the stone falls off each time, and judge whether it is qualified according to the score of the table. Kits are tested separately. Glass, stone, shell rupture automatic board test, according to the second drop score to judge whether qualified or not.

2. Coating test

Coating testing is to ensure that the coated product is well coated.

Generally speaking, the surface of silver-plated or copper-plated products is prone to oxidation and discoloration, so most of the simulation jewelry will attach a layer of varnish on its surface, to achieve the effect of isolation from the air. We can determine whether the product surface coating state is good through the multimeter, the coated surface is not conductive. If it conducts electricity, the multimeter will beep.

3. Gemstone adhesive test

The gemstone adhesive test is to check the fastness of gemstone adhesive.

Test method: Set the entire gem face into Stik-Tak clay, then quickly lift the product to check if any gems fall on the clay.

4. Tension test

Tensile test is to check the structural strength of necklaces, bracelets, etc.

Test method: All samples were tested by hand for normal force, 3-4 LBS. If all the samples passed the normal force test, then 2pcs were selected for pound test, 1pc failed, and then 3pcs were selected for a total of 5pcs. Only 1pc was allowed to be unqualified.

If the normal force test is found to be not passed, then 20pcs will be selected to check with the puller, and 19pcs are required to pass as qualified. The test value is base metal: 8lbs; Precious metal: 5lbs. 1lbs/seconds pounds, no need to hold seconds. The tail chain should be connected to pull together, Multiple chain: inner chain pull 8lbs, outer chain pull 5lbs.

5. Elongation test of elastic rope

The elongation test of elastic rope is to check whether the extension rate of elastic rope is qualified.

Test method: Stretch the elastic rope to 2 times the original length for 5 times without breaking or size change.

6. Accelerate nickel testing

An accelerated nickel test detects whether a product contains nickel.

In some countries, people's skin is allergic to nickel, so the relevant jewelry is not allowed to contain nickel. This method is to remove the metal coating on the surface of the simulated jewelry by using the chemical principle of displacement reaction, and wipe the surface of the product with a test paper. If the product contains nickel, the test paper will turn red. (3V DC, energized for 3 minutes in a solution with a PH value of about 3.5, the product is connected to the positive electrode and the negative electrode is connected to the carbon rod, and the polarity is exchanged after 10 seconds)

7. Vulcanization /Te test

The vulcanization /Te test is to check whether the surface coating of silver-plated products is up to standard.

Test method: Put the coated products on the silver-coated surface into the potassium sulfide solution with a concentration of 3% for 2 minutes, and then check the blackened area after cleaning with water. (For products such as copper plating or silver burning, the blackening area can be checked by adding 10% hydrochloric acid and 0.25% TeO2 solution 10S)

Judgment method: (Take sampling S-1:5pcs as an example)

Any having a discolored area. 50% : Fail

2pcs discolored area of 20-50% : Fail

1pc discoloration area 20-50% : Pass

All color changing area

8. Gold plating test

Gold plating test is to test the coating thickness on the surface of the coated product.

Test method: X-Ray coating machine is used to scan the surface of electroplating products and measure the coating thickness.

9. Torque test

Torsion test is to check the welding strength of metal welding points.

Test method: Welding strength is checked by torsion device. 2inch per pound(0.2NM), first homeopathic needle, then counterclockwise, if the component deformation, can only be twisted to 90% of the maximum value, no fracture for passing. If the twist is 90 degrees and it doesn't reach the test value, it is considered to be passed.