Superplastic forming for titanium implant enclosures

Abstract

A titanium alloy metal sheet is provided and heated to a superplastic forming temperature. A die has a plurality of housing forming areas each corresponding to one of the medical device housing portions. The heated titanium alloy metal sheet is forced onto the die and over each one of the plurality of housing forming areas, thereby superplastically forming a workpiece comprising a plurality of integrally formed implantable medical device housing portions.

What is claimed is: 
     
         1 . A method of manufacturing a plurality of titanium alloy implantable medical device housing portions, comprising the steps of:
 providing a titanium alloy metal sheet;   heating the titanium alloy metal sheet to a superplastic forming temperature;   providing a die comprising a plurality of housing forming areas configured as cavities each corresponding to one of said housing portions; and   forcing the heated titanium alloy metal sheet onto the die for engaging each one of the plurality of cavities simultaneously, thereby superplastically forming a workpiece comprising a plurality of joined and integrally formed implantable medical device housing portions formed simultaneously.   
     
     
         2 . The method of  claim 1 , wherein the titanium alloy is selected from the group consisting of Ti-6Al-4V ELI alloy and Ti-3Al-2.5V alloy. 
     
     
         3 . The method of  claim 1 , wherein the plurality of joined and integrally formed implantable medical device housing portions includes a plurality of front housing portions, and a plurality of rear housing portions that are different from the front housing portions. 
     
     
         4 . The method of  claim 1 , wherein the workpiece comprises at least twenty-five joined and integrally formed implantable medical device housing portions. 
     
     
         5 . The method of  claim 1 , further comprising the steps of:
 separating the plurality of joined and integrally formed implantable medical device housing portions into separate housing portions;   trimming the plurality of separate housing portions; and   acid etching the plurality of implantable medical device housing portions before and/or after performing the step of separating.   
     
     
         6 . The method of  claim 1 , wherein each housing portion includes a first edge portion located between a first set of rounded corners, and a second edge portion located between a second set of rounded corners, and wherein a radius for the second set of rounded corners is at least three times larger than a radius for the first set of rounded corners,
 wherein the first edge portion extends along a substantially straight line between the first set of rounded corners, and the second edge portion extends along a curve between the second set of rounded corners,   wherein each housing portion includes third and fourth edge portions extending between the first set of rounded corners and the second set of rounded corners, and wherein the third and fourth edge portions are curved.   
     
     
         7 . The method of  claim 6 , wherein each housing portion includes a deep portion having a first depth, a shallow portion having a second depth, and a transition portion joining the deep portion and the shallow portion, and wherein the first edge portion is located along the shallow portion and the second edge portion is located along the deep portion, the method further comprising the step of cutting a plurality of feed through holes into the shallow portion of each housing portion. 
     
     
         8 . A method of manufacturing a plurality of titanium alloy implantable medical device housing portions, comprising the steps of:
 providing a titanium alloy metal sheet;   heating the titanium alloy metal sheet to a superplastic forming temperature;   providing a die comprising a plurality of housing forming areas each corresponding to one of said housing portions; and   forcing the heated titanium alloy metal sheet onto the die for engaging each one of the plurality of housing forming areas simultaneously, thereby superplastically forming a workpiece comprising a plurality of joined and simultaneously integrally formed implantable medical device housing portions,   wherein each housing portion includes a first edge portion located between a first set of rounded corners, and a second edge portion located between a second set of rounded corners, and wherein a radius for the second set of rounded corners is at least three times larger than a radius for the first set of rounded corners,   wherein the first edge portion extends along a substantially straight line between the first set of rounded corners, and the second edge portion extends along a curve between the second set of rounded corners, and   wherein each housing portion includes third and fourth edge portions extending between the first set of rounded corners and the second set of rounded corners, and wherein the third and fourth edge portions are curved.   
     
     
         9 . The method of  claim 8 , wherein the titanium alloy is selected from the group consisting of Ti-6Al-4V ELI alloy and Ti-3Al-2.5V alloy. 
     
     
         10 . The method of  claim 8 , wherein the plurality of housing forming areas comprises a plurality of contoured projections from a surface of the die. 
     
     
         11 . The method of  claim 8 , wherein the plurality of housing forming areas comprises a plurality of cavities into which respective portions of the heated titanium alloy metal sheet are forced. 
     
     
         12 . The method of  claim 8 , wherein each housing portion includes a deep portion having a first depth, a shallow portion having a second depth, and a transition portion joining the deep portion and the shallow portion, and wherein the first edge portion is located along the shallow portion and the second edge portion is located along the deep portion. 
     
     
         13 . The method of  claim 12 , further comprising the steps of:
 separating the plurality of integrally formed implantable medical device housing portions into separate housing portions, and   cutting a plurality of feed through holes into the shallow portion of each housing portion.   
     
     
         14 . The method of  claim 13 , further comprising the steps of:
 installing pulse generation circuitry into the separate housing portions including aligning feed through pins with the plurality of feed through holes cut into the shallow portion of each housing portion; and   welding each housing portion to another housing portion from said or another workpiece.   
     
     
         15 . The method of  claim 14 , further comprising the step of adhering a header to the shallow portion to form a sealed implantable medical device, wherein the header encloses at least one connector comprising contact blocks that are respectively electrically connected to the feed through pins. 
     
     
         16 . A method of forming a plurality of titanium alloy implantable medical device housing portions, comprising the steps of:
 providing a titanium alloy metal sheet;   heating the titanium alloy metal sheet to a superplastic forming temperature;   providing a die comprising a plurality of housing forming areas each corresponding to one of said housing portions;   forcing the heated titanium alloy metal sheet onto the die for engaging each one of the plurality of housing forming areas simultaneously, thereby superplastically forming a workpiece comprising a plurality of joined and simultaneously integrally formed implantable medical device housing portions;   separating the plurality of integrally formed implantable medical device housing portions into separate housing portions;   cutting a plurality of feed through holes into at least one of the housing portions.   
     
     
         17 . The method of  claim 16 , wherein the titanium alloy is selected from the group consisting of Ti-6Al-4V ELI alloy and Ti-3Al-2.5V alloy. 
     
     
         18 . The method of  claim 16 , wherein the plurality of joined and integrally formed implantable medical device housing portions includes a plurality of front housing portions, and a plurality of rear housing portions that are different from the front housing portions. 
     
     
         19 . The method of  claim 16 , further comprising the steps of:
 installing pulse generation circuitry in each of the feed through holes, including aligning feed through pins with the plurality of feed through holes;   welding the at least one of the housing portions to another housing portion from said or another workpiece; and   attaching a header to the at least one of the housing portions, wherein the header encloses at least one connector comprising contact blocks that are respectively electrically connected to the feed through pins.   
     
     
         20 . A method of providing a therapy to a patient, comprising:
 providing a titanium alloy metal sheet;   heating the titanium alloy metal sheet to a superplastic forming temperature;   providing a die comprising a plurality of housing forming areas each corresponding to one of said housing portions;   forcing the heated titanium alloy metal sheet onto the die and over each one of the plurality of housing forming areas simultaneously, thereby superplastically forming a workpiece comprising a plurality of joined and simultaneously integrally formed implantable medical device housing portions;   separating the plurality of integrally formed implantable medical device housing portions into separate housing portions;   cutting a plurality of feed through holes into at least one of the housing portions and installing pulse generation circuitry therein, including aligning feed through pins with the plurality of feed through holes;   welding the at least one of the housing portions to another housing portion from said or another workpiece;   attaching a header to the at least one of the housing portions thereby forming an implantable medical device, wherein the header encloses at least one connector comprising contact blocks that are respectively electrically connected to the feed through pins;   implanting the implantable medical device and an electrode into a body of a patient;   generating electrical pulses by the implantable medical device; and
 transmitting the pulses to a portion of the body by the electrode.