General video · Level C1 - Part 2

How It's Made Rubber Balls

A lot happens when an inflated rubber ball hits the ground. The rubber compresses and quickly snaps back to its round shape.

Level: C1 · 60 sentences

Transcript

1. A lot happens when an inflated rubber ball hits the ground.
2. The rubber compresses and quickly snaps back to its round shape.
3. That snapping back makes the ball bounce.
4. In addition, the air inside the ball acts as a tightly coiled spring, increasing the rebound.
5. When an inflated rubber ball falls to the ground, it bounces back,
6. and players catch it on the rebound.
7. This type of ball is at the heart of many games, from basketball to soccer to volleyball.
8. At the core is an inflated rubber bladder.
9. Making it starts with a sheet of natural rubber.
10. The factory worker folds it in a specific configuration.
11. He places a die on top and activates a press
12. to force it through the layers, which cuts out the shape.
13. He now has the bladder of a sports ball.
14. He brushes an adhesive around the hole in the bladder and inserts a plug.
15. Another worker inflates the rubber bladder as she places it in a spherical chamber.
16. It heats and cures the rubber for 5 minutes at a temperature of 284 degrees Fahrenheit.
17. The rubber bladder spins on a revolving cylinder, causing it to take up nylon threads.
18. The threads twist around the bladder and form a layer that both strengthens it and keeps it round.
19. The material that will form the exterior of the ball is made using colored synthetic rubber,
20. natural rubber, magnesium carbonate, and mineral oil.
21. Once it cures, a worker rolls it into thick sheets and slices it to a specific width.
22. He folds it several times.
23. This blue rubber will be used for volleyballs.
24. The folded rubber now travels between a series of rollers.
25. They flatten it and press it extremely thin,
26. and it becomes both lightweight and formable.
27. An automated blade slices the rubber into shorter pieces.
28. A metal pattern cutter will now be used to cut the rubber into strips,
29. which will fit together to form the outside of the ball.
30. These particular strips are for a basketball.
31. The worker places the pattern on several pieces of rubber.
32. A press forces the sharp-edged pattern through the rubber
33. to cut out fish-shaped strips that are designed to fit around the round bladder.
34. She lines the two halves of a bonding shaper with the strips.
35. She inserts the bladder and re-inflates it.
36. She closes the bonding chamber and activates it.
37. Inside, heat and pressure cause the strips to stick to the bladder.
38. To make a medicine ball, which is used for exercising, a different pattern cutter is used.
39. The forming process is the same,
40. but this ball has a unique visual impact very different from that of the basketball.
41. Back at the basketball station, a worker applies the brand name to the outer skin in two places.
42. Glue helps the decal stick to the rubber.
43. This mold will now transfer a pattern onto the rubber ball
44. while also baking the lettering into it.
45. Another worker places the ball in the mold and pumps more air into the bladder.
46. He closes the lid.
47. The mold applies heat and pressure to emboss the pattern onto the rubber.
48. The lettering has penetrated the rubber,
49. and the worker peels off the decal plastic.
50. Another worker replenishes the air that's been lost to make the ball completely full and round.
51. The ball is now ready to receive its stripes.
52. The worker paints black rubber into grooves that were formed during embossing.
53. This rubber quickly cures to become part of the ball.
54. Another worker inserts a fill valve into the hole.
55. Then mechanical fists squeeze the ball to deflate it.
56. This prepares it for packaging.
57. With the valve inside, it can be easily re-inflated by the customer.
58. A worker wraps it in plastic and ships it to the retailer.
59. Making this rubber basketball has only taken a couple of hours,
60. but it should be able to take a lot of knocks and bounce right back.