How Racket String Is Made
By Steve Crandall
Vice President, Sales & Marketing
Ashaway Racket Strings
Maybe I'm just a bit too close to the subject to be entirely objective, but I find racquet string fascinating, and I just don't get it when otherwise serious racquetball players ignore their most important piece of equipment. But even among players who restring frequently, few give any thought to how string is made.
String manufacturing relies on century-old techniques, with a healthy dose of high-tech mixed in. Some of the equipment at Ashaway dates from the earliest years of the 20th Century, but it's still the best technology available for turning the latest polymer yarns from suppliers like DuPont and ICI into high-tech racquet strings. Every step in the process plays an important role in the construction of high-quality string. Here's how it works.
Step 1 -- The first step is to build the string's core, using mono- or multifilament nylon, Kevlar®, or Zyex® yarns. The yarns come off the stationary bobbins at the top of the twisting frames, and are twisted together on one of the fast-spinning bobbins at the bottom. By varying the number of twists put into the yarn for each inch of core produced, Ashaway controls the amount of elongation and resiliency. When full, the bottom bobbins hold 3,500 feet of core.
Step 2 -- A worker sets up a machine that braids the string's jacket or wear layer. As the core rises through the center of the machine, bobbins containing yarns for the jacket weave in and out around it. Differences in jacket construction can alter the string's durability, control, ease of stringing, and appearance. We can even run the string through the braider twice to produce two jacket layers.
Step 3 -- A chemical wear coating is then applied for abrasion resistance. The string unreels from the right, enters the coating bath, then rises over pulleys forty feet straight up into the drying tower, seen at center. (The bath is just below the tower.) The string is then re-wound on the takeup reels at left. It may go through this process six times to apply the right thickness of coating.
Step 4 -- An ink-jet prints the Ashaway name on the string at a rate of 3,000 feet per minute. Next, the string dips through another coating bath to make it easier to string into rackets. Then it's inspected by hand, cut to length, packaged, and shipped to distributors, stringers, or retail outlets worldwide.