Badminton Production Knowledge - Benqu
Badminton Learning Insights
Distribution of feather slices on the wings of geese and ducks: 1-3 slices are half feathers, 4-10 slices are blade feathers, 11-16 slices are round feathers.
Feather Collection - Plucking Method:
There are two methods for plucking feathers: dry plucking and wet plucking. Dry plucking is preferred. After slaughtering the goose or duck, while their body temperature has not yet cooled down, pluck the feathers immediately to maintain their original color and quality. However, most areas in China use wet plucking. Wet plucking involves immersing the slaughtered goose or duck in hot water around 70 degrees Celsius for 2-3 minutes before plucking the feathers. Note that the water temperature should not be too high, and the immersion time should not be too long to avoid curling, contraction, and dullness of the feathers. Feathers collected by wet plucking contain a lot of moisture and need to be dried before storage.
Classification of Badminton Feather Slices:
Badminton initially used goose blade feathers, but now it also uses pheasant duck feathers, water duck feathers, and Cherry Valley duck feathers, greatly enriching the supply of badminton feathers. The classification of badminton feathers is very complex, as there is no unified national standard for classification numbers yet. Each manufacturer produces badminton balls according to industry standards, but even if different manufacturers have products with the same standard, it does not mean that their quality is the same. First, classify the feathers by type into large, medium, small feathers, bent feathers, black washed white feathers, straightened bent feathers, etc.; then classify them by quality into first, second, third, fourth, fifth grades; then divide them into five standards based on the curvature of the feathers; finally, categorize similar feathers based on the thickness of the feather shafts. The 16 feathers used in the same badminton ball must be of the same category and as similar as possible. For higher-end products, the 16 feather slices must be more consistent to ensure the quality of the product.
Identification of Badminton Feather Quality:
High-quality badminton feathers must be made from premium goose feathers. Goose feathers have strength and resilience that are particularly suitable for badminton requirements. However, due to their high cost and limited supply, some manufacturers use duck feathers in lower-demand badminton production. It is difficult to distinguish between duck and goose feathers just by appearance, and well-crafted duck feather balls also perform well in flight. Since the structure and nature of the feather shafts of the two types of feathers are different, the durability of duck feather balls is much worse than that of goose feather balls, and they are prone to breakage during normal play. Duck feathers are much cheaper than goose feathers, so using duck feathers can effectively reduce costs.
How to calculate the number of slices per kilogram of feathers or determine the weight based on the number of slices?
① Weigh several sets of 16 feather slices to find the average weight m16.
② Calculate the number of slices or weight based on the ratio.
Example: A factory sells 500,000 feather slices packed in 10 bags.
① Average weight 1.70 grams/16 slices → number of slices per pound
x = 4706 slices/pound
② Each bag weighs 5.31 kilograms, containing 50,000 slices → kilograms.
Weight Balancing of Badminton Balls - Round Feather Slices (similar for other types):
① Take several groups of 16 feather slices after sorting by print, thickness, and curvature, weigh them (on an electronic scale), and find the average weight.
Approximately:
16 fine bones ≈ 1.4-1.5g, about 5000 slices/pound
16 medium bones ≈ 1.5-1.6g, about 4900 slices/pound
16 coarse bones ≈ 1.6-1.7g, about 4800 slices/pound.
② According to the weight requirements for left-hand and right-hand feather balls, match the appropriate cork head.
Left feather ball requires 3.9-4.0g, landing point at 76, 77
Right feather ball requires 4.0-4.1g, landing point at 76, 77
This requirement is under normal conditions of 24 degrees Celsius and 80% humidity. In winter or summer, the weight of the badminton ball should be adjusted accordingly. Generally, in winter, the temperature and humidity are low, so heavier corks are required. In summer, the climate is opposite, so the ball needs to be lighter. Finally, the customer's requirements must be considered comprehensively.
③ Weight balancing also considers mechanical drilling, which removes 0.1-0.2g of cork shavings.
Difference in Badminton Glue:
The quality of glue directly affects the sturdiness and durability of the badminton ball. There are two main types of glue used in badminton production: high-grade resin glue and chemical glue (nitrocellulose). Nitrocellulose glue requires mixing with natural water (acetic acid solution, toxic), is thin and transparent, dries quickly (about 15 days), is flammable and prone to yellowing, and is inexpensive but dangerous. Resin glue requires mixing with alcohol, is thick, dries slowly (about 30 days), does not discolor over time, is hard, and is expensive. High-grade resin glue is superior in hardness and sturdiness compared to chemical glue but is more costly and is generally used in high-end badminton production. Other varieties and types of badminton balls use high-strength chemical glue. To ensure quality, all varieties of badminton balls have glue content exceeding national standards.
Main Components and Parameters of Badminton Balls:
Ball diameter: 75-80mm, generally 78-79mm, feather slice length: 63mm (after insertion).
Total feather slice length: 76.5mm
Ball heads are generally divided into: full cork, double cork (upper layer is synthetic fiber, lower layer is cork),
Triple-layer (upper and lower layers are cork, middle layer is synthetic fiber),
Synthetic fiber (upper layer is 11mm or 14mm synthetic fiber, lower layer is cork powder),
Foam plastic
Cork weight: 2.1g-2.8g (normal weights are 2.2g, 2.4g, 2.5g)
Glue weight: 0.7g-0.9g
Dry glue weight after gluing: 0.2g
A typical glue injector can handle 50 balls.
Drying time after gluing is approximately one day.
Drying room temperature after gluing: 20~22°C, humidity:
Ball diameter after stringing (before brushing glue): Left hand: 68mm, Right hand: 69mm
Glue weight for brushing line glue: 0.1g
Length of knot after tying should not exceed 3mm.
Test balls are mainly divided into: A, B, C, D, and route balls.
Standard for A balls: Stable flight, stable rotation speed.
Standard for B balls: Stable flight, slightly slower rotation speed, slight sway.
Standard for C balls: Slow speed, slight sway.
Standard for D balls: Large sway.
Standard for route balls: Ball head sways during flight.
Lower limit for A balls: Slightly better than B balls.
Lower limit for B balls: Slightly better than C balls.
Standards for A and B balls: Mixed A and B balls.
Standards for B and C balls: Mixed B and C balls.
Standards for A, B, and C: Mixed A, B, and C balls.
Swing balls need to be re-weighted, brushed with glue, and maintained for a week (due to glue dryness) before testing again.
Ball weight: Left hand 4.9g; Right hand 5.0g; Landing point at 77. (Small diameter becomes 78; Large diameter becomes 76.)
Left hand 4.8g; Right hand 4.9g; Landing point at 76. (Small diameter becomes 77; Large diameter becomes 75.)
Ball weight = Cork head weight + 16 feather slice weights + 1.0g (including string and glue weights)
Drying room temperature after rolling glue: 30℃ Humidity: 60%
Check for uniformity of glue between lines and inside/outside after rolling glue, parallel line loops, no glue on feather leaves or ball heads.
Each ball contains dry glue weight after rolling glue: 0.5~0.7g.
Each ball contains dry glue weight after injecting glue: 0.25~0.3g.
Ball weight requirement is between 3.8g~3.9g, so the final finished ball total weight is: 4.9g~5.0g.
Generally, 0.5g of wet glue weight is equivalent to about 0.15g of dry glue weight.
String gauge for ball diameter: Left hand: 68mm, Right hand: 69mm.
Semi-finished ball, its tube diameter: 73.5mm, length 400mm.
Finished ball paper tube diameter: 64±0.5mm
Length: 390mm~393mm
Finished ball diameter: Left hand: 65mm, Right hand: 66mm.
Badminton weight source:
Feather slices: (1.8g~2.0g) 16 feather slice weights
Cork head: Finished ball in 2.1g~2.6g
Base glue: Dry glue weight after injecting glue is 0.2g.
Brushing glue: Dry glue weight for the first manual brushing of line glue: 0.1g.
Rolling glue: Dry glue weight after two rolls: 0.4~0.5g.
Bright glue: Final brushing step to enhance glue brightness.
Color tape and string: This weight already includes offsetting the drilled hole weight.
General finished ball requirement: Mainly within the range of 4.8g~4.9g for the left hand,
Mainly within the range of 4.9g~5.0g for the right hand.
For example, if the landing point is 77, then the left hand is 4.9g, the right hand is 5.0g,
If the landing point is 78, then the left hand is 5.0g, the right hand is 5.1g.
Quality Testing Items for Finished Badminton Balls:
Testing items generally include: stability, durability, weight, diameter, speed, adhesive firmness, string firmness, etc. These items are usually not tested individually by manufacturers, and consumers can test and compare prices based on their most concerned characteristics when purchasing badminton balls.
Differences Between High-end and Low-end Products:
Apart from appearance, the main difference lies in the flight performance of the ball, i.e., the stability, speed, deformation degree upon impact, and rotational properties during flight. High-end badminton balls require high-quality feather slices, where the 16 feather slices on a single ball must be almost identical in shape and quality to ensure high-standard requirements, thereby increasing the price. Low-end badminton balls, priced below 20 yuan per dozen, are generally not tested for performance by manufacturers before leaving the factory, and the feather slice grade is usually below level 3, significantly reducing costs. However, they are still good enough for general amateur enthusiasts.
Relationship between Badminton Speed, Weight, and Diameter:
The flight speed of badminton in the same region mainly depends on its overall weight, diameter, feather type, distinction between left and right feathers, and the weight ratio between the cork head and the ball body. Generally, the diameter of badminton balls produced by the same factory is fixed, usually between 66-67mm. At this point, the main factor determining the ball speed is the overall weight of the ball and the weight ratio between the cork head and the ball body. We strictly control the weight ratio between the cork head and the ball body to ensure the flight performance of the badminton. Therefore, the approximate flight speed can generally be determined by the overall weight of the ball, and thus its suitability for different regions.
What Kind of Badminton Should Be Chosen in Different Altitude and Climate Regions?
The basic requirement for playing badminton is that the speed or weight of the ball must be appropriate, otherwise, many techniques will be difficult to execute. The flight speed of the same important badminton ball varies greatly in different regions because the weight of the ball and the altitude and climate have a very close relationship. At high altitudes, the air density is smaller, and the air resistance encountered by the badminton ball during flight is smaller, so the weight of the badminton ball used in high-altitude areas should be reduced. At low altitudes, the air density is greater, and the air resistance encountered by the badminton ball during flight is greater, so the weight of the badminton ball used in low-altitude areas should be heavier.
In addition, the dryness and wetness of the air and the high and low temperatures also have a certain impact on the speed of the badminton ball, but the influence of altitude is the most obvious.
What Are the Drawbacks of Using Overweight or Underweight Badminton Balls on Rackets and the Human Body?
If the overall weight of the badminton ball is too heavy or the cork head is too heavy, the vibration caused during hitting is larger, resulting in greater impact on the racket and strings, reducing the service life of the racket and strings. The most obvious effect is the significant shortening of the string's lifespan. On the other hand, the vibration will be transmitted to the player's arm, causing some adverse effects on the arm over time. Moreover, if the badminton ball is too light, due to insufficient hitting distance, the player will exert more force to achieve the desired hitting distance, easily causing arm fatigue and injury. Therefore, choosing a badminton ball of appropriate weight not only allows you to enjoy the fun of badminton but also reduces the risk of injury.
Badminton Production Process Flow
Feather Slice Inventory → Sorting Feather Slices → Measuring Cork Heads → Measuring Feather Slices → Inserting Feathers → Inspection → Clamping Balls → Weighing Balls → Injecting Base Glue → Drying → Repairing Balls → Weighing Balls After Injection → Stringing → Tying Knots → Brushing Line Glue → Second Clamping → Rolling Glue → Drying → Weighing Balls → Maintenance → Wrapping Color Bands → Test Playing → Grading → Packaging
Parts Workshop:
A. Sorting Feather Slices. Sort out the levels of feather slices, select grade one to four feather slices, dirty feathers, waste feathers, thick, medium, thin stems, missing filaments, broken feathers, folded prints, modified feathers, etc.
① Main standards for grade one and two feather slices: White feather color, relatively straight feather bone, thick feather quality, complete feather shape.
② Main standards for grade three and four feather slices: Darker feather color, slightly yellow feather bone, thinner feather quality, complete feather shape.
③ Waste feathers: Some marks on the entire feather leaf's bone, but not broken.
④ Dirty feathers: Dirty and yellow feather leaves.
⑤ Missing filaments: Incomplete feather leaf parts, signs of decay.
⑥ Modified feathers: Feather shapes cut incompletely, modifiable feather slices.
⑦ Pig feathers: No groove on the feather bone like goose feathers, and the feather bone part is flat-shaped.
Note: The difference between goose feathers, duck feathers, and pig feathers is in the entire feather bone. Goose feathers have a groove on the feather bone, while duck feathers and pig feathers do not, and are round in shape. However, the feather bone of duck feathers is round in the feather leaf part, while pig feathers are flat-shaped.
B. Matching Feathers:
Further sort the feather slices by their curvature, arch, thickness, thinness, and color within graded feather slices.
Example: Straight feathers: Further sort out the degree of arch, thickness, thinness, and the color of the feather bone, place them in various categories, then use an electronic balance to weigh 16 feather slices to get the weight of the feather slices and match them with the weight of the finished ball head to prevent making overweight balls. Generally, the weight of left and right hands differs by 0.1g, with the right-hand ball requiring 3.8g~3.9g.
Left-hand ball requires 3.9g~4.0g.
C. Machine Drilling and Inserting Feathers:
After completing the process in item B, proceed to the drilling requirements. The drilling depth is approximately 14~13mm. When drilling left and right holes, the ball surface must remain flat. When inserting feathers, the feather bone must be placed in the machine's clamp position to insert the feather slice. The distance between the plane of each feather slice after entering the hole and the clamp is between 62mm~62.5mm. The angle and height between each feather slice must be the same.
D. Clamping Balls and Cutting Edge Feathers:
Check the angle of the ball, use a flat-nosed pliers to correct the feather bone part between the two wire loops, but remember not to reverse the angle. Straight feathers and slightly curved feathers are usually clamped once and then placed in a dedicated turnover drum (for maintenance and fixation) and rechecked the next day. If the angle hasn't changed and the heights are consistent, glue can be injected; however, feathers with moderate curves or more generally need to be cl