When it comes to 3D printing, the sky is the limit. As 3D printing technology continues to advance, applications can be as far reaching as airplane and automobile parts to medical devices and even anatomically correct, biocompatible models. Although 3D printing technology is developing at a rapid pace, the technology itself is not new. It emerged in the 1980s as a means of creating rapid prototypes. In recent years the applications for 3D printed models have evolved with the available hardware, software, and printable materials. Evolving technology, paired with the creative and innovative minds of scientists, engineers, and physicians, has been the launching pad for developments within 3D printing technology specific to healthcare. One way 3D printing technology is poised to create better patient outcomes is in creating an anatomically and patient-specific models to aid in surgery and medical procedures. With the capability to 3D ...
A polymer-and-rubber buff would love to know what gives tennis balls their bounce. But according to a The Wall Street Journal article, manufacturers aren’t telling.
Organizers of the French Open this year (May 17 to June 5)Â have switched from the Dunlop brand of tennis balls to the Babolat ones. Players like Novak Djokovic, the men’s No. 2 seed, and Roger Federer, a 16-time Grand Slam winner, have noticed how much faster are the new balls. Faster and harder to control. The ball may wind up favoring the servers and the big hitters.
Babolat is known for manufacturing strings and only has entered the tennis ball business in 2001. But it appears no matter how hard Tom Perrotta pushed during the reporting of this story, he couldn’t get his sources to reveal what goes into a tennis ball:
Kai Nitsche, vice president of racket sports at Dunlop, said laboratory tests can’t tell you everything about a ball — especially how it feels.‘There really would have been no way to duplicate our ball unless they had our formula,’ Nitsche said. ‘The core itself, while natural rubber is the main component, has 14 additional ingredients.’ Nitsche politely declined to reveal the ingredients.‘We’ve been making balls for over 100 years,’ he said. ‘That’s certainly not something we’re going to give away.’
Perrotta was able to find out that The International Tennis Federation (ITF) has regulations for tennis balls but those regulations oversee compression, mass, size, deformation, rebound, and durability. The ITF doesn’t investigate the materials in the balls and what gives them their characteristics.
The ITF’s website has an intriguing insight into the history of tennis balls and what they used to be made from. Tennis balls at one time were made from leather or cloth stuffed with rags, horsehair, or similar material. From the beginning of lawn tennis in the 1870s, India rubber, made from a vulcanization process invented by Charles Goodyear in the 1850s, was used to manufacture lawn tennis balls.
The balls were initially only made of rubber. However, the balls lasted longer and played better when the rubber was covered with flannel. Further developments in ball design included:
Originally, core manufacture was based on the ‘clover-leaf’ principle whereby uncured rubber sheet was stamped into a shape resembling a three-leaf clover and this was assembled into a roughly spherical space by machinery adapted for the purpose. Chemicals generating pressurising gas were added prior to closing the assembly and these were activated on moulding the core to a spherical shape in heated cavities. The process was used for many years until the precision of the game demanded a higher degree of uniformity (particularly relating to wall thickness) than could be obtained with the clover-leaf method. Now it is usual to compression mould two separate ‘half-shells’ which are assembled together to produce a ‘core’. The original flannel cloth was replaced by special ‘melton’ cloth made specifically for the purpose and the stitching has been replaced by a vulcanised rubber seam.
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