Quality Inspection Handbook

Quality Control

Quality underpins everything we do at TTT Jewelry, and we want to ensure that the products you receive from us consistently exceed your expectations. That’s why we have rigorous controls in place that cover all aspects of our production, from workmanship to the grading of the materials used. 

We provide greater detail on materials and processes further down, but in general terms, our quality checks include the following:

  • That there are no scratches, marks, or inexpertly applied solder or glue in any of our items.
  • That all stone fittings are secure.
  • There are no mismatched colors or discoloration in any of our products.
  • That there are no sharp edges or joins that may cause injury.

Tests are also conducted to ensure the strength, thickness, and durability of our jewelry so that you can have complete confidence in the products that you purchase from us.

Basic Knowledge and Quality Testing of Accessories

1. Leather

Leather can be divided into real leather made from animal hides, imitation leather (artificial leather), and silica leather.

Brown Leather Belts for Jewelry

Type

  • Real leather is made from the dermis layer of the skin of an animal and has pores and skin texture on the surface layer, and is a naturally strong and durable material. It should feel smooth, soft, and elastic to the touch. Commonly used hides come from cows and calves, sheep, goats, and pigs. 
  • Imitation leather (artificial skin) can be made from PVC, although more modern imitation leathers are now made with a polyurethane coating and are called PU imitation leather. Imitation leather can feel harsh, rigid, and less soft than real leather. It may also have a plastic smell which is more pungent when burned. 
  • Silica leather, also known as polysiloxane resin, is an environmentally friendly alternative to imitation leathers made from polyurethane and vinyl while also providing a vegan alternative to real leather.

Testing of Leather

  • Color test: The color of the leather should meet your requirements based on color cards or templates. Any color difference, a common phenomenon in real leather, must be confirmed before accepting the product.
  • Thickness test: Generally, the thickness of leather is tested at three points; the head, middle, and tail of the piece of material. The acceptable level of variation between the three points is 0.4 mm for double-layer and 0.2 mm for single-layer.
  • Colorfastness test: Adhesive tape can be used to perform a peel test (stick the tape to the leather in the same place five times), or use a white cloth to rub the leather repeatedly (in the same position rub back and forth ten times). The leather should not fade.
  • Environmental testing: According to European and American standards, leather must not contain DMF (dimethylformamide) or have a lead content that is greater than 0.1mg. More than 22 carcinogenic dyes are banned and must not be used. Formaldehyde content and mold inhibitor content requirements must be met depending on the specific customer requirements.

2. Semi-precious Jewels

Defects such as cracks, sand holes, impurities, variegation, and other problems must be assessed as to whether they are acceptable. Because semi-precious stones are made from natural materials, there may be color differences once dyed or plated. These should be referenced against the standards of pre-agreed samples, and customers with special requirements should explain them in advance.

(1) Cat’s Eye/Tiger Eye Stone

Tiger Eye Stone
  • It must have a good cat’s eye gem effect, not too thorough, although the grain thickness and direction should be unified.
  • There should be no impurities, raindrops, defects, variegation, or other issues.
  • Half of the surface of the stone needs to be fitted into the jewelry piece, so first check whether it can be fitted and that the cat’s eye stone color has a variegation of less than 10%
  • The color spectrum may appear different when the same material is used to make different shapes/sizes of products
  • The color of the paint needs to be unified, and the oil color should be uniform and bright. In addition, the surface should not have dust or impurities.

(2) Zircon

  • Domestic zircon is most commonly mined in Wuzhou, Guangxi, and should not be confused with the synthetic stone, cubic zirconia.
  • Common colours in zircon stones are colorless, purplish red, violet, golden yellow, pomegranate red, olive green, champagne, pink, and apple green. The following colors resist discoloring even at high temperatures; smoked zircon, coffee zircon, blue zircon, black zircon, and green zircon. There can be certain chromatic aberration in different grades, especially after high-temperature wax is inlaid.
  • Zircon is mainly divided by quality into A (AA, AAA) and B stones. TTT Jewelry currently purchases AAA zircon, where there is no color variation. The pavilion and baseplate surface is uniform, with no bottom leakage or sanding angle. The size control error is + 0.03 mm.

(3) Other Beads

Pearls/Glass Pearls

  • The size of glass pearls should be the same, and they should also be uniform in color. In addition, the surface must be smooth and bright, with no staining, scratches, or color variation. 
  • Natural pearls can vary in size and shape and contain some minor blemishes. Color will sometimes appear uneven when natural pearls are dyed. Differences in color within batches of the same color pearls are normal.
Sterling Silver Pearl Cubic Zirconia Earrings

Plastic Beads/Acrylic Beads 

  • The following features are allowed: a parting line, slight shrinkage, gas and water-marks, small bubbles, scratches, impurities, variegation, and other minor defects.
  • Defects that should not be present are visible glue marks, pronounced burring or scorching, or severe shrinkage. Prominent gas or water-marks, small bubbles, scratches, impurities, or variegation.

Silica gel Beads

  • The color should meet the requirements according to the color card or template. The surface should be free from impurities and stains, and there should not be a noticeable smell. The mold line is uniform and not thick. The environmental requirements are specific to the provisions of customers.

Basic Knowledge and Test of Workmanship

1. Polishing

There should be no sand holes, die lines, or pockmarks. Smooth polished surfaces give a mirrored effect, so they must not be worn or deformed. Corners must also be polished, and joins must be kept smooth.

2. Burning and Welding

Soldering should be firm and the welding position unified. A suitable solder should be used according to the quality and material of the piece (tin, copper, silver). The size of the solder joint should be moderate, and there should be no big welding scar. The non-back or concealed solder joints need to be polished strictly.

3. Stone Settings

  • Prongs should be evenly spaced and sit flat against the stone to securely hold it in place. 
  • Prongs should be rounded, polished, and completely smooth. The fitting should not prevent light reflection, and the prongs should not damage the stone. 
  • The heal of the prong must be at least half as thick as the entire prong to ensure that it has durability and will not crack. 
  • There should be no movement in the stone setting.
TTT-Jewelry-Craftsman-Setting-Stone-on-the-Ring

4. Glued Stones(Rhinestone)

Small stones are stuck down using a slow-dry transparent AB adhesive. The glue must be applied carefully and should not be visible. Once the stone is in place, it should be attached firmly and be able to pass a drop test

5. Adhesive Glue

Glue Class

  • The glue is applied after electroplating.
  • The color of dropping glue should meet the standards of a color card or sample.
  • Flat and arced surfaces can be achieved depending on the effect selected. The plane should not be too convex or shallow, and there should be no pores or impurities.

6. Leather Oil Edge

The oil edge should be smooth and uniform, and there should be no color mismatch with the main item. Additionally, there should be no noticeable poring or a convex finish.

7. Choice of Glue

Our selection of glue directly affects the quality and lifespan of the product. So we do not use double-sided adhesive, quick-drying glue, or other adhesives which have low viscosity, are brittle, and age rapidly. Instead, the adhesive is applied correctly and firmly, and all items can pass the drop, aging, and tensile test.

8. Packaging

  • Typically, the finished goods box must be marked with its size, net weight, gross weight, number (color), quantity, PO#, guest mark, and origin. The gross weight cannot exceed 25KG.
  • All packaging must contain desiccants.
  • Packaging should always meet the customer’s specifications. 

Electroplating Quality Control

1. Water Electroplating

(1) Poor Electroplating

The following are all evidence of poor electroplating:

  • Blistering: surface bulging caused by gas expanding through the pores of the item, pressing against the plating.
  • Peeling and flaking: caused by poor adhesion, the coating peels away from the metal substrate.
  • Scorching: appears as a difference in color between the plating and other surface coatings, and the surface feels rough to the touch
  • Uneven color: localized color difference.
  • Impurities: metal particles become attached to the plating, resulting in a rough surface.
  • Blue film (color): presents as a blue reflection in the plating.
  • Exposed substrate: the surface of the product is not entirely covered by the coating.

(2) Non-electroplated Surface Defects

The following are examples of non-electroplated defects:

  • Collision: a raised mark on the surface of the coating caused by an impact with another object
  • Scratch: marks made on the coating surface by other sharp objects.
  • Scraping: abrasion marks on the coating caused by another object.
  • Watermarking: caused by solution left on the coating surface after electroplating.
  • Wavy surface appearance: the surface of the product is not smooth, and this can be seen as a wavy appearance in the coating following electroplating.
  • Sand hole: an imperfection in the item that electroplating does not cover up.

(3) Water Electroplating Quality Control

Salt-Spray-Test-Picture-From-TTT-Jewelry
  • Environmental protection requirements such as lead and nickel testing should be carried out. Electroplating manufacturers have environmental protection assurance in place.
  • Thickness testing; reports should be provided in line with customer requirements.
  • Protective layer testing; potassium sulfide, ammonium sulfide, sweat, or salt spray tests should be done as per the relevant requirements.

2. Vacuum Electroplating

(1) Poor Electroplating

Poor electroplating will present as:

  • Discoloration, blackening, and a lustreless finish.
  • Non-uniform coloring in the plating.
  • Oil present on the surface of the product.
  • Fine scratches but no deep scratching.
  • Hard or deep scratches
  • Bruising; damage to the surface of the product caused by external objects.
  • Leakage; the product does not dry and water is present (hollow products)
  • Pocked surface; where granular defects are present on the plating surface.
  • Coke; due to excessive plating.
  • Rough surface coating.

(2) Vacuum Test Project

  • Wear resistance, 24-48 hours wear resistance test.
  • Colorfastness, 24-72 hours salt spray test.

Product Detection

1. Rings

Sterling-Silver-Pear-Cut-Sapphire-CZ-Ring-From-TTT-Jewelry
  • The ring perimeter measurement has a US standard (such as 6#/7#/8#)
  • The standard error is ±0.1 according to US standards. Other requirements are customer-oriented.
  • The standard ring size is 7#

2. Bracelets

TTT-Jewelry-Sterling-Silver-Pear-Cut-Sapphire-CZ-Ring
  • The internal diameter error of a circular bracelet is ±1mm.
  • The inner diameter error of a C-shaped open bracelet is ±5mm, and the opening error is ±5mm.
  • As bracelets are delicate items, they should have a good degree of hardness and be made from a pure alloy form.
  • The length of the two ends of an adjustable spring bracelet should be the same, with good elasticity and a static inner diameter error of ±2 mm.

3. Hand Chain

18K-Gold-Plated-Cuban-Link-Chian-Bracelet
  • The length of a conventional hand chain is 7.5″. The length error is between -0.15″ and + 0.25″.
  • The average length of an extension chain is between 2” and 3”.
  • All hand chains must pass a tensile test of more than 2 kg (about 5 pounds)
  • All single laps should be closed, and a 0.5mm single lap should be spot welded. 
  • The elastic used should be in line with the size of the beads or, otherwise, follow the customer’s requirements.

4. Earrings

Gold-Drop-Earrings-Green-AB-Glass-TTT-Jewelry
  • The earring head (including hook) should be hypoallergenic and smooth.
  • Earrings should match when they are displayed apart.
  • Plastic and bullet clutch earring backs should have a soft to medium elasticity, and a butterfly back should be flexible and smooth.
  • Earring clips are usually white and should not exceed the earrings.
  • No parts of the earrings should be sharp or able to cause injury.

Related Test Requirements

We may perform other tests according to the product’s characteristics or the requirements of our customers and their industry.

1. Colorfastness Test

Mainly for sprayed or dyed materials: an alcoholic solution is applied to the product’s surface and wiped away with a white cloth. If there is no fading or color transference, the test is passed.

2. Electroplating Protection Test (See Electroplating Quality Control Above)

Can be sent to third parties for the salt spray test as required by the customer

3. Safety Packaging Test

The finished item’s box is raised 1 m from the ground to perform drop tests on all sides of the box; upper, lower, front, rear, left, and right. The product is inspected, and if it is not damaged, the packaging is passed. If the item is damaged, it fails. (Similar products and packaging can be combined for this test). The total weight of each package should not exceed 13 kg, and special heavy items should not exceed 20 kg.

4. Tensile Test

  • Necklaces are tested under a 2 kg pulling force.
  • Bracelets are tested under a 2 kg pulling force.
  • Earrings are not generally subject to this test, but specific customer requirements determine this.

5. Drop Test (Impact Resistance)

Finished products or accessories are dropped without packaging to the ground (hard floor) from a distance of 0.9-1.2 m, four times. The material must remain intact to pass.

6. Anti-aging Test

The jewelry item is baked for 30 minutes in an oven at a temperature of 65°C and then frozen (below 0°C) for 4 hours. The material is then inspected to ensure it keeps its original quality.

The item is also exposed to direct sunlight for 4-8 hours in the sun to check whether the appearance and color of the object are obviously changed. 

7. Attachment Strength Test

  • The scope of this test is oil injection, transfer printing, bronzing, silk printing, and clay stone parts.
  • For dyed and spray-painted items: 3M adhesive paper is applied to the surface and torn off at 45 degrees to see if the tape is discolored.
  • Clay Stone: 3M adhesive paper is applied to the surface and torn off at 45 degrees to look for any stone residue. 
  • Before testing, the surface of the test object must be completely dry.

8. Heavy Metal Test

This test is carried out by SGS or another designated organization for testing according to the customer’s requirement. The specific tests required can also be agreed with the customer. 

Products that fail this test must be approved by the company’s general manager before they can be shipped. Items cannot be approved for shipping without this authorization.

Requirements for Revision of Quality Control Procedures and Quality Manuals

  • All internal and external inspections should be carried out in accordance with the company’s quality control procedures.
  • Other product specifications and testing requirements not yet compiled in this manual can be carried out according to the company’s usual quality activities.
  • The final revision authority of this manual is the responsibility of the Quality Department of the company.

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