Methods for fabricating composite face plates for use in golf clubs and club-heads for same

Abstract

Methods are disclosed for making composite face plates for club-heads of golf clubs. In an exemplary method a lay-up is formed having multiple prepreg layers, each including at least one layer of respective fibers at a respective orientation. The at least one fiber layer is impregnated with a resin. The lay-up is exposed to an initial tool temperature T i and an initial pressure P 1 . At time t 1 the resin has minimal viscosity, and the lay-up temperature and pressure are increased from T i and P i , respectively. During an interval from time t 1 to time t 2 , the lay-up temperature and pressure are increased to T s >T i and P 2 >P 1 , respectively. During the first interval the resin experiences a relatively rapid progressive increase in viscosity. During a second interval between t 2 and a later time t 3 , the lay-up is maintained substantially at T s and substantially at P 2 , which allows the resin to experience a relatively slow progressive increase in viscosity to a specified pre-cure viscosity level.

1 . A method for fabricating a composite face plate for a club-head of a golf club, the method comprising:
 forming a lay-up comprising multiple prepreg layers, each prepreg layer comprising at least one layer of respective fibers at a respective orientation, the at least one fiber layer being impregnated with a resin;   exposing the lay-up to an initial tool temperature T i  and an initial pressure P 1 ;   beginning at a time t 1  at which the resin exhibits a minimal liquid viscosity, commencing an increase in temperature of the lay-up from T i  and an increase in pressure of the lay-up from P 1 ;   during a first interval between the time t 1  and a later time t 2 , increasing the temperature of the lay-up to T s >T i  and increasing the pressure of the lay-up to P 2 >P 1 , during which first interval the resin exhibits a relatively rapid progressive increase in viscosity; and   during a second interval between the time t 2  and a later time t 3 , maintaining the lay-up substantially at the temperature T s  and substantially at the pressure P 2 , thereby allowing the resin to undergo a relatively slow but continued increase in viscosity to a specified pre-cure viscosity level.   
   
   
       2 . The method of  claim 1 , wherein:
 the increase in temperature of the lay-up from T i  is ramped; and   the increase in pressure of the lay-up from P 1  is ramped.   
   
   
       3 . The method of  claim 2 , wherein, between the times t 1  and t 2 :
 the temperature of the lay-up is ramped up to T s >T i ; and   the pressure of the lay-up is ramped up to P 2 >P 1 ,   
   
   
       4 . The method of  claim 1 , wherein, between the times t 1  and t 2 :
 the temperature of the lay-up is ramped up to T s >T i ; and   the pressure of the lay-up is ramped up to P 2 >P 1 ,   
   
   
       5 . The method of  claim 1 , further comprising, after the time t 3 , decreasing the temperature from T s  and decreasing the pressure from P 2 . 
   
   
       6 . The method of  claim 4 , further comprising shaping the lay-up to have specified dimensions and shape for use as a face plate for a club-head. 
   
   
       7 . The method of  claim 1 , further comprising, after the time t 3 , completing a full-cure of the lay-up, the full-cure being characterized by the resin exhibiting a maximal viscosity. 
   
   
       8 . The method of  claim 7 , further comprising shaping the full-cured lay-up to have specified dimensions and shape for use as a face plate for a club-head. 
   
   
       9 . The method of  claim 1 , wherein the lay-up is formed in a tool configured to hold the lay-up as the lay-up is being exposed to the temperatures T i  and T s  and to the pressures P 1  and P 2 . 
   
   
       10 . The method of  claim 9 , further comprising removing the lay-up from the tool when the lay-up has reached the specified pre-cure viscosity level. 
   
   
       11 . The method of  claim 8 , further comprising shaping a contour of the lay-up while the lay-up is in the tool. 
   
   
       12 . The method of  claim 1 , wherein the pressure P 1  is within a range 0-100 psig. 
   
   
       13 . The method of  claim 1 , wherein the pressure P 1  is within the range 0-100 psig±ΔP, wherein ΔP is a maximum of 50 psi. 
   
   
       14 . The method of  claim 1 , wherein the pressure P 2  is within a range 200-500 psig. 
   
   
       15 . The method of  claim 1 , wherein the pressure P 2  is within a range 200-500 psig±ΔP, wherein ΔP is a maximum of 50 psi. 
   
   
       16 . The method of  claim 1 , wherein the temperature T s =T r ±ΔT, wherein T r  is a manufacturer's recommended cure temperature for the resin, and ΔT is a maximum of 75° F. 
   
   
       17 . The method of  claim 16 , wherein the temperature T i =T s /2±ΔT. 
   
   
       18 . The method of  claim 1 , wherein, at the time t 1 :
 the minimum viscosity of the resin is in a range of ±Δx;   Δx is a maximum of 25%;   the time t 1  is in a range of ±Δt; and   Δt is a maximum of 10 minutes.   
   
   
       19 . The method of  claim 1 , wherein, at the time t 2 :
 the resin has reached 80% of its maximum viscosity X m ;   X m  is in a range of ±Δx; and   Δx is a maximum of 25%.   
   
   
       20 . The method of  claim 1 , wherein:
 the time t 2  is in a range of ±Δt; and   Δt is a maximum of 10 minutes.   
   
   
       21 . The method of  claim 1 , wherein, at the time t 3 :
 the resin has reached 90% of its maximum viscosity X m ;   X m  is in a range of ±Δx; and   Δx is a maximum of 25%.   
   
   
       22 . The method of  claim 21 , wherein:
 the time t 3  is in a range of ±Δt; and   Δt is a maximum of 10 minutes.   
   
   
       23 . The method of  claim 1 , wherein:
 the pressure P 1  is within the range 0-100 psig±ΔP, wherein ΔP is a maximum of 50 psi;   the pressure P 2  is within a range 200-500 psig±ΔP, wherein ΔP is a maximum of 50 psi;   the temperature T s =T r ±ΔT, wherein T r  is a manufacturer's recommended cure temperature for the resin, and ΔT is a maximum of 75° F.;   the temperature T i =T s /2±ΔT; and   at the time t 1  the minimum viscosity of the resin is in a range of ±Δx, wherein Δx is a maximum of 25%, the time t 1  is in a range of ±Δt, and Δt is a maximum of 10 minutes.   
   
   
       24 . The method of  claim 23 , wherein, at the time t 2  the resin has reached 80% of its maximum viscosity X m , X m  is in the range of ±Δx, and the time t 2  is in the range of ±Δt. 
   
   
       25 . The method of  claim 24 , wherein, at the time t 3  the resin has reached 90% of its maximum viscosity X m , X m  is in the range of ±Δx, and the time t 3  is in the range of ±Δt. 
   
   
       26 . The method of  claim 1 , wherein the pressure is increased from P 1  to P 2  at a rate in which the pressure P 2  is reached before the resin viscosity ceases its relatively rapid increase. 
   
   
       27 . The method of  claim 1 , wherein the prepreg layers comprise carbon fiber and epoxy resin.