- February 4, 2021
- Posted by: AQI Service
- Category: Inspection standards
We shared with you the basic knowledge and process flow of imitation jewelry in the previous part (Imitation Jewelry Quality Control Inspection – Part A). In this part, we will share with you the on-site inspection of imitation jewelry, including some key points and testing contents that need attention.
1. Appearance Inspection
1.1 Appearance Inspection of Necklaces, Bracelets, and Anklets
- a. For necklaces, bracelets, and anklets
An overall inspection of the ring chain is required. Extend hands to both sides, observe whether the chain is broken and knotted, and particularly examine whether there are miscellaneous accessories on the chain (such as a half-cut ring, etc.). Check whether the overall product looks good, whether the color of the coating is normal, whether the coating peels off, whether the coating is contaminated, and whether the cladding layer is missing.
- b. For the lobster clip, snap buckle, rolling buckle, and pendant,
Check whether the switch functions normally, unlock the switch on the lobster clip, spring buckle, rolling buckle, and pendant repeatedly, and observe whether the lock can be flexibly opened and closed.
- c. Check the hanging parts. Pull the hanging parts gently to observe whether it is installed firmly.
- d. Check the casting. Check whether its quality is good, and there should be no trimming, pouring port, scratches, abrasions, etc.
- e. Check the small connecting pieces. Check whether different kinds of small connecting pieces (such as eye-pin, tin-pin, jump ring, bail, oval ring, etc.) are in good connecting condition and whether the joints are neat without gaps.
- f. Check decorative materials:
- Check whether the color of the gemstone meets the requirements, whether it is installed in the middle without excessive glue, and whether the gemstone is installed evenly.
- Check whether the epoxy looks good without excess epoxy, no flowing.
- Check whether other decorative parts are in good condition and the method is roughly similar as above.
1.2 Appearance Inspection of Earrings
- a. Pairing inspection: for earrings with separate parts, left-left pairing or right-right pairing are not allowed.
- b. Check whether overall earrings are good: check whether the overall appearance of the product is good, whether the color of the coating is normal, whether the coating peels off, whether the coating is contaminated, and whether the cladding layer is missing.
- c. For fishhook earrings, surgical earrings, lever back earrings, and lever spring earrings, check whether the overall ear clip is good.
- d. For fishhook earrings: the length should meet the requirements (generally 5% deviation is allowed), and ear-nuts cannot be too loose or too tight.
- e. For surgical earrings: they should be welded to the casting vertically, without tilting or bending, and ear-nuts cannot be too loose or too tight.
- f. For lever back earrings: the needle part cannot be bent; the hinge, the closing part, and the mechanical part must work flexibly without stiffness.
- g. For lever spring earrings: the mechanical part must be flexible and can be switched freely.
- h. For ear clip earrings: when wearing, earrings cannot be too loose or too tight. The mechanical part must be flexible and can be switched freely.
2. Imitation Jewelry On-site Test
The imitation jewelry is mainly ornaments processed and assembled with plastic, shells, and glass.
2.1 Drop test
Drop test is to check the fastness of the combination of gems or other parts.
Test method: the test can be conducted on the iron or wooden board at a certain height according to the customer’s specific requirements, and we can observe whether gems or joint parts drop during the fall.
The first step is to distinguish between precious metals (use a wood board) and base metals (use steel plate). After gluing for 72 hours, prepare a steel plate of min 5/8” (1.5cm), set the sampling number as S-1, at the height of 36, and there should be at least 10 drops. For the first drop, with the stone facing down, check whether the stone falls off every time. Judge whether it is qualified and score on the form. The kits must be tested separately. Glass, stone, and shells shall automatically go through board test. Judge whether it is qualified according to the second drop score.
2.2 Coating test
The coating test is to make sure that the product is thoroughly coated.
Generally, because the surface of the silver-plated or copper-plated product is easily oxidized and discolored, a layer of varnish will be attached to the surface of most imitation jewelry for air isolation effect. We can use a multimeter to confirm whether the surface coating is in good condition and whether the coated surface conducts electricity. If it is conductive, the multimeter will sound.
2.3 Jewelry adhesive test
Jewelry gluing test is to check the fastness of gem adhesive.
Test method: Inlay the whole gem surface on the Stik-Tak adhesive, then lift the product quickly to check whether any gems fall on the adhesive.
2.4 Tension test
Tension test to check the structural strength of necklaces and bracelets.
Test method: firstly, test all samples by hand with a normal force of 3-4lbs. If all pass the test, then select 2pcs to test with a pound scale. If 1pc fails, then 3pcs will be sampled. Among a total of 5pcs, only 1pc failure is allowed.
If samples fail in the normal force test, then 20pcs shall be sampled for checking a pound scale. 19pcs’ pass is deemed as qualified. The test value for base metals is 8lbs and 5lbs for precious metals. 1lbs/seconds are used for the pound scale and there is a need to keep the number of seconds. The tail chain should be connected and pulled together. For multiple chains: pull the inner chain with the force of 8lbs, and pull the outer chain with the force of 5lbs.
2.5 Bungee cord elongation test
The test is to check whether the elongation of the bungee cord is qualified.
Test method: stretch the bungee cord to twice its original length for 5 times, no breaking or dimension change is allowed.
2.6 Accelerated Test of Nickel
The test is to check whether the product contains nickel.
Because people in some countries have a skin allergy to nickel, it is stipulated that related jewelry shall be nickel free. According to the chemical principle of displacement reaction, the metal coating on the surface of imitation jewelry is removed. Then, wipe the surface of the product with test paper. If it contains nickel, the test paper will turn red. (Power on for 3 minutes under 3V direct current in a solution with a pH of about 3.5, the product is connected to the anode, the negative electrode is connected to the cathode, and exchange the electrode after 10 seconds)
2.7 Vulcanization/ Te test
The test is to check whether the surface coating of the silver-plated product meets the standard.
Test method: Put the silver-plated surfaced product with a coating into a potassium sulfide solution with a concentration of 3% to soak for 2 minutes. Then wash it with water and check the area of the blackened. (Copper plated products or silver burning products can be put in 10% hydrochloric acid mixed with 0.25% TeO2 solution for 10 seconds to check the area of the blackened.)
Method: (take sampling S-1:5pcs as an example)
Discoloration area of any pc >50%: Fail
Discoloration area of 2 pcs of 20-50%: Fail
Discoloration area of 1 pc of 20-50%: Pass
Discoloration area of all pcs<20%: Pass
2.8 Gold plating test
The gold plating test is to check the thickness of the coating on the surface of the coated product.
Test method: Scan the surface of the electroplated product with an X-Ray coating machine (Search XRF Gold Tester) to measure the thickness of the coating.
2.9 Torsion test
A torsion test is to check the welding strength of the metal welding point.
Test method: Check the welding strength with a torque device with 2inch per pound (0.2NM) clockwise at first and then anticlockwise. If the part is deformed, it can only be twisted to the maximum value of 90%. No breakage will be deemed to pass. If not reaching the test value after being twisted to 90 degrees, it is considered to pass.
It is necessary to pay attention to different points during an on-site inspection of imitation jewelry with different types, different processes, and different materials. Undoubtedly, customers’ inspection requirements must be considered to ensure that the products can meet customers’ quality requirements before delivery.
Author: AQI Service as a professional quality control service company in China specialized in providing a complete range of quality inspection and testing certification services in China & Asia for global importers, buyers, retailers, and sellers.
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