Cast urethane versus injected urethane

[Donn lost in San Diego]

What is the difference between cast urethane and injected urethane?  Both in terms of what it actually means and how it is made, and, on the course what is diff in feel or performance?

[GregGarner]

For 99% of us? No difference at all on course. In terms of manufacturing what's different? Just different processes to get to a pretty similar end result. The casting process is a little more expensive, so die-hard supporters will tell you it gives you a thinner, softer finished product. Almost all of the Tour balls from the big manufacturers are cast (I believe Srixon and Bridgestone are injection?)

If you want the Titleist take on it, they have a good promo piece that nerds out a bit - https://www.titleist.com/teamtitleist/team-titleist/f/the-clubhouse/48136/did-you-know-not-all-urethane-covers-are-the-same

(Worth noting after you watch that... The Titleist Tour Speed is injection-molded.)

[storm319]

Cast thermoset urethane: chemical components are added to the mold separately where a chemical reaction crosslinks at a molecular level. Once cast the material cannot be recycled (as a result there tends to be more scrap which adds to the cost). The casting process takes longer to deliver a completed cover also adding cost, but the result tends to be a more durable, softer, thinner cover. Only 5 facilities on the planet that support this production process in a meaningful capacity (two owned by Acushnet, two owned by Taylormade, and Foremost who is independent though Taylormade also has a stake in that factory). As of today brands are pretty much limited to Titleist, Taylormade, Vice, Maxfli, and Wilson. 

Injection molded thermoplastic urethane (TPU): chemical components premixed and injection molded similar to other thermoplastics (ionomer/surlyn balls are produced the same way). Process is faster, cheaper, and material can be melted back down and reused once formed. Finished covers tend to be harder, thicker, and less durable than thermoset urethane, but still thinner and softer than ionomers. Big brands that use this production method are Bridgestone, Callaway, Srixon and then pretty much every other white label factory other than Foremost that produce balls for the majority of the smaller DTC brands (Acushnet also uses this method for the Titleist Tour Speed). 
 

TLDR: All other variables equal, thermoset urethane covers should be softer/thinner (tends to produce more spin) and tend to be more durable. With that said, other variables can be adjusted to account for the cover difference, granted it is difficult to make up for feel for those that a sensitive to cover hardness.

Edited December 7, 2023 by storm319

[Golf2Much]

On 12/6/2023 at 9:37 PM, storm319 said:

Cast thermoset urethane: chemical components are added to the mold separately where a chemical reaction crosslinks at a molecular level. Once cast the material cannot be recycled (as a result there tends to be more scrap which adds to the cost). The casting process takes longer to deliver a completed cover also adding cost, but the result tends to be a more durable, softer, thinner cover. Only 5 facilities on the planet that support this production process in a meaningful capacity (two owned by Acushnet, two owned by Taylormade, and Foremost who is independent though Taylormade also has a stake in that factory). As of today brands are pretty much limited to Titleist, Taylormade, Vice, Maxfli, and Wilson. 

Injection molded thermoplastic urethane (TPU): chemical components premixed and injection molded similar to other thermoplastics (ionomer/surlyn balls are produced the same way). Process is faster, cheaper, and material can be melted back down and reused once formed. Finished covers tend to be harder, thicker, and less durable than thermoset urethane, but still thinner and softer than ionomers. Big brands that use this production method are Bridgestone, Callaway, Srixon and then pretty much every other white label factory other than Foremost that produce balls for the majority of the smaller DTC brands (Acushnet also uses this method for the Titleist Tour Speed). 
 

TLDR: All other variables equal, thermoset urethane covers should be softer/thinner (tends to produce more spin) and tend to be more durable. With that said, other variables can be adjusted to account for the cover difference, granted it is difficult to make up for feel for those that a sensitive to cover hardness.

As a plastics engineer by trade, very good explanation @storm319! 

If I could add layman's examples of thermosets and thermoplastics that may help people not familiar with the terms.  As mentioned, in thermoset a chemical reaction takes place where the polymer bonds crosslink or connect to one another.  This reaction is permanent and cannot be reversed.  The best example would be an egg.  Once hard boiled, the egg's protein structure has changed and cannot be reversed to the egg's initial state.  Thermoplastics on the other hand are more like an ice cube.  By adding heat you can melt the ice cube into water, by adding pressure you can flow the water it into a new shape and that shape is retained once cooled to the proper temperature.  If you don't like the shape, you can repeat the cycle of heating, shaping and cooling process over and over again until you get it right.  

I hope this might help a little.