1. Classification of headphones
According to the product structure, it can be divided into: open type, semi-open type and closed type; According to the wearing method, it can be divided into: head-mounted type, ear-plug type, in-ear type, rear-mounted type, ear-mounted type;
According to the principle of conversion, it is divided into:
Dynamic and electrostatic
The composition of the headset:
Headband: Headbands are generally divided into two types: steel headbands and plastic headbands. The steel headband is generally equipped with a steel beam inside a PVC hose, and there are also double headbands and single headbands. Headphones with a steel headband structure are generally equipped with an elastic leather headband outside the steel beam to adjust the wearing comfort. The plastic headbands are generally made of PP material. The plastic of this material is soft and flexible.
Locking plate:
Plastic/steel bar (metal); only available with headband headphones
Bracket: plastic/steel bar (metal); only available for headband headphones
Ear shell: The material of the ear shell is generally plastic, metal and wood. Surface spray paint is generally divided into ordinary paint, UV paint, rubber paint.
UV paint is to spray a transparent and bright UV oil on top of ordinary paint to make the surface texture of the product smoother and brighter. Rubber paint is to spray a rubber oil on top of ordinary paint to make the surface texture of the product softer.
earmuffs:
Earmuffs are generally made of sponge, flannel, leather, and silicone.
Sponge earmuffs are breathable and cheap, but are more easily damaged;
Flannel earmuffs are comfortable to wear, but easy to get dirty;
The leather earmuffs have a good texture and feel more upscale, but they are not breathable and are not suitable for summer wear; the silicone earmuffs are cool to wear and suitable for use in summer.
Speaker:
NdFeB material, caliber: generally f9, f10, f30, f40, f50.
External microphone/line microphone:
Plastic microphone rod (gooseneck), microphone head (plastic);
Garnish:
Small accessories for decoration on earphones;
Wire: Length :
The walkman is about 1.2 meters, and the home computer is about 2.2 meters; Material: The plug is generally divided into two types: leather wire and braided wire (wiring). The leather thread has good texture, softness and elasticity; the braided thread is more resistant to abrasion and stretching, but the elasticity is insufficient.
The plug-in cable of the microphoneless headset is generally 3 cores:
ground, left, right
Signal line; there are generally two specifications of 4-pin and 5-pin plugs for earphones with microphones. The 4-core patch cord is shared by the left and right bottom wires, and the effect is not as good as the 5-core patch cord. The general brand of earphone wire will have anti-break wire. If there is no anti-break wire, the earphone will be scrapped in less than a month. This kind of earphone will not be available abroad, you know.
plug:
The headphone plugs are divided into four types: 6.35mm, 3.5mm, 2.5mm, and USB. The surface of the plug is divided into gold-plated and nickel-plated, and gold-plated has better oxidation resistance. We see the most 3.5mm, USB heads are used on the computer, all with their own sound card.
Wire Control:
To adjust the volume, there is a tuning button on it;
mouse tail:
Connect the apron (guard coil) between the two parts;
Splitting glue:
One line divides the solid rubber between two lines;
2. Important parameters of the headset
(1) Impedance Common standard: 16/32 ohm ± 3-15% (see customer requirements)
Headphones with low impedance are easy to be driven by audio equipment. Since the power of CD and MP3 itself is not large, it is suitable to choose low-impedance headphone products, usually below 32 ohms;
(2) Sensitivity Common standard: 90-120db
For portable players such as MP3, the higher the sensitivity, the more music details can be heard at the same volume. For a widely applicable earphone, the sensitivity should preferably be above 100d;
(3) Frequency response range Common standard: 20-20KHz
The sound range that normal human ears can hear is 20-20KHz, so the closer the frequency response range of the headset is to this range, the more complete the sound that can be "heard". It is reflected in the listening effect, that is, the richer the details.
2. General Inspection Specification for Headphones
(1) Inspection tools
Ruler, vernier caliper, plug gauge, comparison sheet, barcode gun, anti-static gloves or finger cots, dust cloth, alcohol, knife, sealing tape, transparent tape.
(2) Inspection conditions
Vision: The inspector's vision requirement is not less than 1.0 (including corrected vision);
Distance: The distance between the human eye and the surface of the mobile phone under test is 300mm±50mm; Illumination: cool white fluorescent lamp (the light source is directly above the detector), and the illuminance is 1000±200Lux;
Viewing angle: The product viewing surface and the desktop form a 45-degree angle, and rotate 45 degrees up, down, left, and right (as shown in the figure below):
(3) Definition of Defects
1. Definition of assembly defects of the whole machine
Level difference: The theoretical design of the assembly surface of the two parts is zero deviation. Due to the machining error, the dislocation deviation caused by the actual assembly surface.
Surplus: in normal use, face the level difference seen on the face of use.
Deficit: In normal use, face the level difference that cannot be seen on the face of use.
2 Definition of bad defects of plastic parts
Point Defect: A defect in the shape of a point, the largest diameter of which is measured when measuring.
Heterochromatic spots: Colors that appear on the surface of a plastic part are different from surrounding spots.
Bubble: Because the raw material is not fully dried, there are shrinkage holes inside the product after molding.
Multiple glue points: There are small plastic bumps on the surface of the product due to damage to the mold.
shrink:
When the plastic melt passes through a thinner section, its pressure loss is very large, and it is difficult to continue to maintain a high pressure to fill the pits formed in the thicker section.
Bright spots:
For non-smooth plastic parts, due to the uneven wall thickness, local luminescence occurs at the sudden change of wall thickness. Hard Scratches: Deep scratches on the surface of plastic parts due to friction with hard objects.
Fine scratches:
There are no deep scratches on the surface of the plastic parts.
Flash:
Plastic waste at the edge or parting surface of plastic parts due to injection molding parameters or molds.
Weld line:
When the plastic melt flows in the cavity and encounters obstacles (such as cores), the melt cannot be well fused after bypassing the obstacles, so an obvious line is formed on the surface of the plastic part, which is called welding. Wire.
Warpage: Plane deformation of plastic parts due to internal stress.
Top white/top protrusion: Due to the large packing force of the plastic parts, the top pin area is subjected to a white mark or protrusion caused by the strong ejection force.
Insufficient filling: The phenomenon of insufficient injection caused by insufficient injection pressure or poor exhaust in the mold cavity, so that the molten resin cannot reach a certain corner of the mold cavity.
Silver stripes: silver-white stripes appearing on the surface of plastic parts along the resin flow direction.
Flow pattern: The annual ring-like stripes appear on the surface of the product with the gate as the center.
Charring: Localized charring and blackening of plastic on the surface of plastic parts.
Side dragging: due to excessive injection pressure or uneven cavity, the edge scratches caused by demoulding.
Crack: Cracks or small cracks in the product due to internal stress or mechanical damage.
Chromatic aberration: The surface of the product exhibits a difference in color from the standard sample, which is called chromatic aberration.
Impurities: There are foreign matters mixed into the raw materials, etc., and spots appear on the surface of the product after molding.
Rainbow phenomenon: refers to the phenomenon of colored halos appearing in transparent areas under reflective conditions.
Deformation: Stress is formed inside the molded product due to uneven shrinkage of the molded product.
Crackling defect: Due to improper control of discharge time, current intensity or corrosion time of the potion, the bite pattern or pattern on the surface of the plastic part is different from that of the standard sample.
Poor transparency: refers to the phenomenon of blurring and poor transparency in the transparent area.
Light transmission: There are parts with missing printing in the printing area, which cause light to pass from the back to the front, which is called light transmission.
3. Definition of bad defects of painted parts
Point Defect: A defect in the shape of a point, the largest diameter of which is measured when measuring.
Particles: Fine particles adhering to the surface of painted parts.
Hard Scratches: Deep scratches on the painted surface due to friction with hard objects.
Fine scratches: There are no deep scratches on the surface of the painted parts, and they are not obvious.
Accumulation of paint: Local paint accumulation occurs on the surface of the painted parts.
Shadow: An area that appears on the surface of a painted or plastic part that is darker than the surrounding area.
Orange pattern: There are large and small undulations in the shape of orange peel on the surface of painted parts or electroplated parts.
Bottom penetration: The local paint layer is too thin on the surface of the painted part to expose the color of the substrate.
Fisheye: There are depressions or small pits on the surface of the painted parts due to the unfavorable evaporation rate of the solvent.
Overspray: Exceeds the spray area specified on the drawing.
Peeling: The phenomenon of coating peeling on the surface of the product.
Fluff: fibrous fluff that is contained in the paint itself, or that falls on the surface of the paint when the paint is not dry.
Color difference: The surface of the product exhibits a color difference from the standard sample (the customer acknowledges the sample), which is called color difference.
Poor gloss: The surface of the product exhibits a gloss inconsistent with the standard sample (the customer acknowledges the sample).
Fingerprints: Fingerprints that appear on the surface of a product or on the shiny side of a part.
Heterochromatic spots: Colors that appear on the surface of the product are different from surrounding spots.
Fog: The gloss of the entire product surface is not good, and it looks like a layer of fog.
Shrinkage: There is shrinkage on the surface of the plastic part, but it is not covered or more visible after painting.
Bubble: Because the raw material is not fully dried, there are shrinkage holes inside the product after molding.
Multiple glue points: There are small plastic bumps on the surface of the product due to damage to the mold.
Pockmarks: Dense granular point defects.
Uneven color: Due to spraying parameters or process problems, the surface gloss or color of the same product is inconsistent.
Poor light transmission: When the product shell is required to achieve light transmission, the surface light transmission effect is different from the expected light transmission
4. Definition of defective hardware defects
Missing plating: There is no plating where it should be plated.
Coating peeling off: There is separation between the coating and the substrate due to the poor adhesion of the coating.
Rust spots: Due to the lack of electroplating, a chemical reaction occurs between the substrate and the external environment.
Pit: The electroplating process is not well controlled, resulting in small pits on the surface of the electroplated parts.
Bump: The surface of the part is damaged due to external force.
Burr: Excess scrap at the edge of the part.
Bubble: There is a phenomenon in which the coating bulges in a local area on the surface of the part.
Shrinkage cavities: During the condensation process of die castings, irregular shapes and rough surfaces are caused by insufficient internal compensation.
Undercasting: The molten metal does not fill the cavity, and there are incompletely filled parts on the casting.
Rough: The coating surface is not smooth.
Fine Scratches: Scratches with no depth.
Hard Scratches: Deep scratches.
Uneven color: The gloss and color of the surface of the part are uneven.
Warpage/Deformation: The surface of the part is not flat.
Oil dirt: Oil dirt attached to the surface of parts.
Indentation point: a pit that is crushed on the surface.
Poor gloss: The surface of the product exhibits a gloss inconsistent with the standard sample (the customer acknowledges the sample).
Pockmarks: Dense granular point defects.
Color difference: The surface of the product exhibits a color difference from the standard sample (the customer acknowledges the sample).
Uneven color: Due to anode parameters or the design of the mold itself, the surface gloss or color of the same product is inconsistent
5. Definition of bad defects in printing/printing graphics
Printing Position and Alignment: Deviation from the specified printing position.
Inconsistent printing style: The printing patterns and specifications are inconsistent during printing.
Color and Hue Differences: Colors and shades deviate from specifications.
Thickness and Flatness Differences: Thickness and flatness deviate from specification requirements.
Missing corners: Graphic font defects.
Divergence: The edges of the image and text are blurred.
Thin line: The printed text or pattern line is not fully printed and the width becomes smaller.
Defects: Parts of printed text or pattern lines are not printed and appear incomplete, including at the edge or middle of the ink film.
Disconnected lines: The phenomenon in which the printed lines are interrupted and there is no ink (exposing the substrate).
Cracks: Small cracks and roughness appear on the surface of the printing ink film.
Screen marks: The phenomenon of screen marks on the printing ink film due to poor ink fluidity.
Burr: The phenomenon of a jagged ink film on the edge of the printed line due to the infiltration of ink in the air.
Ink bleeding: refers to the phenomenon of ink overflowing on the outside of the printed lines.
Orange peel: The surface of the printing ink film is not smooth, and the phenomenon of orange peel-like unevenness appears.
Overprinting: that is, overlapping ink films, which mostly appear on register printing.
Moisturizing: Spotted marks in the printed graphics and dark areas.
Flying ink: When the screen is separated from the substrate, the ink is drawn into filaments without breaking in time, and then slowly breaks and then falls to both sides, thus forming the phenomenon of filaments perpendicular to the imprint.
Overprinting: When printing more than two colors, the images and texts of each color separation plate can achieve and maintain the accurate position; Overprinting is inaccurate in the process of overprinting, the error of the overlap of the imprints - the printing position is not correct, resulting in dislocation and blank phenomenon .
Rubbing: Regional marks caused by rubbing of printed matter.
Ink bar: An obvious dark streak caused by the expansion of dots in a local area due to the instantaneous sliding friction of the ink roller in contact with the surface of the printing plate.
Water bar: Due to the instantaneous sliding friction when the water roller is in contact with the surface of the printing plate, an obvious light white stripe is produced by the reduction of dots in a local area.
Deep scratches: The scratches have a certain depth, and when you touch them with your hands, you can feel that they are obviously concave on the surface of the printed product. Slight scratches: The scratches on the surface of the printed product cannot be felt when touched by hand.
Detachment: The phenomenon that the surface cardboard and the pit paper are not firmly bonded.
Explosive knife line: When the product is formed, it cracks along the beer cutting indentation.
Color explosion/paint peeling: There is a phenomenon of ink peeling off the surface of the printed product.
Brittle: When the printed material is bent, the surface cracks.
Overline/Offline: The bonding position of the carton exceeds or does not reach the specified size position when the carton is glued.
Dirt: The printing ink printed on the substrate sticks to the back of another printed sheet, causing smudges.
Chromatic aberration: The surface of the product exhibits a difference in color from the standard sample, which is called chromatic aberration.
Air bubbles: There are small air bubbles on the surface of the coated color box.
Wrinkle: The phenomenon of wrinkling on the surface of the coated color box.
Streaks: streaks that appear on the surface of the print.
Heterochromatic spots: Colors that appear on the surface of a plastic part are different from surrounding spots.
Dirt: including fingerprints, oil stains, fingerprints, smudges, white fog and other undesirable phenomena.
Glue overflow: In the inherent processing technology of the color box, the glued part overflows the specified pasting area due to excessive glue, and the excess glue part. Residual glue/glue marks:
Streamline, glue pollution caused during operation, such as filamentous, strip, block, etc. erasable pollution formed after the glue on the operator's finger accidentally adheres to the surface of the color box and dries up.
QCANT™ Quality Control Service Provider,Partner of SGS,TUV,Intertek provide variety of professional inspection and auditing services with 180+ inspecters to ensure goods meet buyer requirements and regulations in the supply chains. QCANT Pricing begin with ALL included only $198/MD for Inspection in China, 5 minutes to make an online booking , get order scheduled and 99% receive report within 24 hours
QCANT™ Quality Control Service Provider,Partner of SGS,TUV,Intertek provide variety of professional inspection and auditing services with 180+ inspecters to ensure goods meet buyer requirements and regulations in the supply chains. QCANT Pricing begin with ALL included only $198/MD for Inspection in China, 5 minutes to make an online booking , get order scheduled and 99% receive report within 24 hours