Quality inspection method for watches
In the process of watch inspection, in addition to verifying the number, style, and model of the product, a visual inspection of the watch's appearance and function of the watch must also be tested. NBN's inspection standard is in accordance with AQL 0 / 1.5 / 2.5 or according to the standard specified by the customer.
Of course, the too harsh AQL standard will increase the probability of rejection of the goods, resulting in delayed shipment. This needs to be determined based on factors such as product positioning, price, and market.
Here we share the visual inspection of the watch and the necessary performance test:
A. Watch glass (watch glass)
(1) Observation under natural light in the room allows slight scratches and ripples to be seen.
(2) Spots: There are four shift points with a diameter not greater than 0.3 mm, and two are allowed in the center plane. There is no limit to the number below 0.3 millimeters. The distance between spots should be greater than 5 mm.
(3) Scratch: No obvious scratches are allowed inside the glass, and light scratches and scratches are allowed on the edges: Severe scratches, scratches, edges and cracks are not allowed.
(4) Reflective circle (inner shadow): No obvious scratches, discoloration and plating off are allowed.
B. Dial (surface)
(1) Scratches are not allowed to have a width greater than 0.03 mm and a length greater than 1.2 mm, and the distance between scratches should be greater than 3 mm.
(2) Disk pits: those with a diameter greater than 0.25 mm are not allowed, one with an internal diameter less than 0.25 mm, and three with a diameter less than 0.15 mm.
(3) Drum: No obvious drums and drums with debris adhering to the disk are allowed. Three diameters less than 0.09 mm are not allowed to exist at the same time, and those below 0.05 mm are not counted.
(4) Heterochromatic spots: (not metamorphic) One with a diameter of 0.3 mm is allowed, and one with a diameter of less than 0.3 mm is allowed, but the distance should be greater than 3 mm.
(5) Dial deterioration, peeling, severe ripples and scratches are not allowed.
(6) Trademarks, disks and varnishes are allowed to have slight ripples and injuries, scratches, stains and air bubbles observed with the naked eye, but there must be no obvious scratches, missing plating, discoloration and bubbles.
(7) Sub-scale: slight line breaks are allowed, but no obvious line breaks, missing lines, or heavy lines are allowed.
(8) Noctilucent: There is no shortage of fall-offs, and nocturnal points are allowed to be slightly incorrect, but no more than 1 division to the left and right (calendar window holes and 6 no-luminous points are not missing).
C. Watch hand
(1) No obvious scratches, missing plating, discoloration, rust and night light fall off are allowed.
(2) The hour, minute, second hand and dial face are parallel to each other. When setting the hands, the hands must not be high on one side or low on the other side.
(3) When the hour hand coincides with the scales at 3, 6, 9, and 12 o'clock, the minute hand deviating from the 12 o'clock "scale" should be less than 3 divisions of the soil.
(4) Positive and negative setting, smooth and suitable. (5) The gap between the hour hand and the trademark is 0.05-0.15 mm: the gap between the hour hand and the minute hand, and the minute hand and the second hand is 0.15-0.25 mm. (0) The second hand must not be given a watch glass. Press the hand to rotate the hour hand-the circle must not have a gift plate, rubbing scales, or touch hands.
(1) There are slight scratches and missing sections on the front, no trachoma and obvious scratches, bumps, knife wounds and pits or lack of material.
(2) Slight bruises, scratches, and pits are allowed on the sides, but not more than 0.5 mm, and there must not be two places on each side.
(3) Slight bruises, lack of material and trachoma are allowed on the back, and no more than 2 of which are larger than 0.5 mm in diameter.
(4) The spring-loaded eyes of the watch band are allowed to be slightly skewed, but no defects such as bulging or open eyes are allowed.
(5) The back cover is allowed to have light trachoma, abrasions, scratches, and discoloration (brown yellow), and slight scratches and knife marks are allowed at the opening part, but no serious scratches or trachoma are allowed on the rear surface.
(6) The gap between the crown and the case is 0.10 ~ 0.20 mm.
E. Other inspection items
In addition to appearance inspection, travel quality and waterproof performance are more important inspection items. The mechanical watch should be full of clockwork, correct the time and calendar, and actually take a travel time length (the mechanical watch is less than 36 hours to stop the watch), check the calendar to change the day and the performance is normal, only to be able to store. If possible, the instrument should be used to test the watch's travel time accuracy and waterproof performance. Mechanical watch test: full swing (plane 260-30) 0, travel accuracy (+25 seconds / day). Quartz watch test: travel time accuracy (month difference: 15 seconds or daily difference t0.5 seconds). Waterproof test: According to the standard indicated by the hand (minimum 3 atmospheres).