What part of the tennis racket manufacturing process causes thr varaibility in weights/swing weights?
- Thread starter Arjuntino
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ouch_my_shoulder
New User
Here's one example, there are a few others on Youtube:
From what I understand, there's a lot of manual handling and assembly in racquet manufacturing. You've got variation in the thickness and orientation of the fibers and resin, when they're in the flat state (the "prepreg" material). Then that needs to be cut into pieces, which will have dimensional tolerances & variation. Then you've got variation in the assembly of the layup, which seems to be done manually. You could have variation in the air pressure applied during the curing process. If the racquet gets filled with foam, there would be some variation and potential for voids there too.
In the end, manufacturers are only going to put tight controls on parameters that affect the perceived quality of the product, for the intended customer. If it's something that most customers would not notice or care about, it's probably not worth spending a bunch of extra money to control more tightly.
I've never worked on racquets specifically, but I have some experience with laminated fiberglass prepreg, being wound over a steel bar with additional resin. So pretty similar to the initial process steps. It can be a challenge just to control the needed thickness, orientation of layers, voids, etc.
From what I understand, there's a lot of manual handling and assembly in racquet manufacturing. You've got variation in the thickness and orientation of the fibers and resin, when they're in the flat state (the "prepreg" material). Then that needs to be cut into pieces, which will have dimensional tolerances & variation. Then you've got variation in the assembly of the layup, which seems to be done manually. You could have variation in the air pressure applied during the curing process. If the racquet gets filled with foam, there would be some variation and potential for voids there too.
In the end, manufacturers are only going to put tight controls on parameters that affect the perceived quality of the product, for the intended customer. If it's something that most customers would not notice or care about, it's probably not worth spending a bunch of extra money to control more tightly.
I've never worked on racquets specifically, but I have some experience with laminated fiberglass prepreg, being wound over a steel bar with additional resin. So pretty similar to the initial process steps. It can be a challenge just to control the needed thickness, orientation of layers, voids, etc.
Funny, I was just thinking about that the other day. The manufacturers arrange pre-preg sheets of carbon fiber in a press. Getting the weight right really should be pretty easy if the sheets are relatively consistent. All you would need to do is make sure you source consistent materials and use the same size of sheets each time. The variability would be around the consistent arrangement, which would impact balance and swing weight, not total weight. I would guess that the manufacturing variability is around the handle and/or foam filler if the racquet has that.
lazywombat
Rookie
I've read somewhere that the main problem is even distribution of resin inside mold that relies on preheating and sustaining exact temperature. The whole proces is designed to be as fast and cheap as possible, precision is just not top priority.
Grafil Injection
Hall of Fame
During the baking process the pre-preg (which is partially cured already) fully cures, which means the epoxy changes to a solid orientation, at around 250 degrees, or a lower temperature like 160 degrees if pressure is also applied. At that point the epoxy and graphite are fused. In order to ensure that process works, the pre-preg must be impregnated with an excess of epoxy before baking. That excess seeps out of the mould and some ends up attached as 'flash', which also must be removed. Since the typical hairpin is 220-280g of cured graphite, and given the amount of epoxy that will bleed out inevitably varies, keeping the variation in weight down to about 15g is actually quite impressive.
Having said that, I would expect it would be possible to over-and-under the weights of grips, butt-caps, grommets and headguards somewhat more.
Having said that, I would expect it would be possible to over-and-under the weights of grips, butt-caps, grommets and headguards somewhat more.
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DropvolleysRhard
Rookie
Paint. We send rackets from our shop to a company in FL for custom painting. They strip them and it’s crazy the difference in two same model rackets before and after paint. They then match the raw frames repaint them keeping them matched.
socallefty
G.O.A.T.
It costs more to have tighter manufacturing and material tolerances whatever product you are making. So, you are not going to set it much higher than what you think the majority of consumers/users need and/or what you deem necessary to outsell competitors. In the case of tennis racquets, the average consumer doesn’t measure specs, doesn’t have multiple versions of the same racquet, doesn’t care about spec differences etc. and so the manufactures set their tolerances accordingly.
I’ve been playing tennis for more than 45 years and never felt the need to worry about spec differences between my identical racquets or measure any specs myself. Whatever differences there are between my racquets, I likely compensate for with my swing speed during the warmup and then play accordingly just like I have to compensate for differing age of stringjobs even if my racquets are strung identically. I’m probably more reflective of the average consumer than the few who care about these things and post on TTW.
I’ve been playing tennis for more than 45 years and never felt the need to worry about spec differences between my identical racquets or measure any specs myself. Whatever differences there are between my racquets, I likely compensate for with my swing speed during the warmup and then play accordingly just like I have to compensate for differing age of stringjobs even if my racquets are strung identically. I’m probably more reflective of the average consumer than the few who care about these things and post on TTW.
