An entry sheet for drilling comprising: a metallic foil; and a layer of a resin composition on at least one surface of the metallic foil, the resin composition comprising a polyolefin resin (A) and a water-soluble resin (B), wherein a content of the polyolefin resin (A) is 25 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), a content of the water-soluble resin (B) is 50 parts by mass or more and 75 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), and the water-soluble resin (B) comprises a high-molecular-weight water-soluble resin (B-1) having a weight average molecular weight of 2×10.sup.5 or higher and 1.5×10.sup.6 or lower.

An entry sheet for drilling comprising: a metallic foil; and a layer of a resin composition on at least one surface of the metallic foil, the resin composition comprising a polyolefin resin (A) and a water-soluble resin (B), wherein a content of the polyolefin resin (A) is 25 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), a content of the water-soluble resin (B) is 50 parts by mass or more and 75 parts by mass or less based on 100 parts by mass of the total of the polyolefin resin (A) and the water-soluble resin (B), and the water-soluble resin (B) comprises a high-molecular-weight water-soluble resin (B-1) having a weight average molecular weight of 2×10.sup.5 or higher and 1.5×10.sup.6 or lower.

An assembly and method for drilling micro holes in a tube including an outer wall having opposing open ends and forming an inner channel. The method includes the steps of submerging the tube in water so the water fills the inner channel, retaining the water in the inner channel, freezing the water in the inner channel so as to form an ice backing in the inner channel, and drilling through the outer wall such that the ice backing supports the outer wall and prevents the outer wall from deforming or distorting near the hole location.

An assembly and method for drilling micro holes in a tube including an outer wall having opposing open ends and forming an inner channel. The method includes the steps of submerging the tube in water so the water fills the inner channel, retaining the water in the inner channel, freezing the water in the inner channel so as to form an ice backing in the inner channel, and drilling through the outer wall such that the ice backing supports the outer wall and prevents the outer wall from deforming or distorting near the hole location.

An assembly and method for drilling micro holes in a tube including an outer wall having opposing open ends and forming an inner channel. The method includes the steps of submerging the tube in water so the water fills the inner channel, retaining the water in the inner channel, freezing the water in the inner channel so as to form an ice backing in the inner channel, and drilling through the outer wall such that the ice backing supports the outer wall and prevents the outer wall from deforming or distorting near the hole location.

An assembly and method for drilling micro holes in a tube including an outer wall having opposing open ends and forming an inner channel. The method includes the steps of submerging the tube in water so the water fills the inner channel, retaining the water in the inner channel, freezing the water in the inner channel so as to form an ice backing in the inner channel, and drilling through the outer wall such that the ice backing supports the outer wall and prevents the outer wall from deforming or distorting near the hole location.

A precision pneumatic drill spindle and method provides reduced spin axis error and increased rate of forming holes in a microelectronic substrate. The spindle includes a press-fit collar that accepts drill bits and incorporates turbine blades around the collar, which is rotated by directing pressurized air through a number of nozzles distributed around the collar within a housing of the spindle. The collar is supported by air bearings above and below the collar. The turbine blades may be provided by concavities in the collar forming a Pelton wheel type rotation system that concentrates the air flow to improve energy transfer from the pressurized air directed by the nozzles to the collar, increasing the rotation rate of the collar. Exit air may be directed downward toward the tip of the drill bit by inclined channels within the lower air bushing assembly, improving the debris removal rate.

A precision pneumatic drill spindle and method provides reduced spin axis error and increased rate of forming holes in a microelectronic substrate. The spindle includes a press-fit collar that accepts drill bits and incorporates turbine blades around the collar, which is rotated by directing pressurized air through a number of nozzles distributed around the collar within a housing of the spindle. The collar is supported by air bearings above and below the collar. The turbine blades may be provided by concavities in the collar forming a Pelton wheel type rotation system that concentrates the air flow to improve energy transfer from the pressurized air directed by the nozzles to the collar, increasing the rotation rate of the collar. Exit air may be directed downward toward the tip of the drill bit by inclined channels within the lower air bushing assembly, improving the debris removal rate.

A method includes applying a force to elastically deform at least a portion of a superalloy turbine blade from a relaxed, initial position to an elastically deformed position. The at least a portion of the superalloy turbine blade has a curvature in the elastically deformed position not present in the relaxed, initial position. A hole is drilled generally span-wise through the at least a portion of the superalloy turbine blade in the elastically deformed position, and when the force is released, the superalloy turbine blade returns to the relaxed, initial position and the hole takes on a hole curvature within the at least a portion of the superalloy turbine blade.

A method includes applying a force to elastically deform at least a portion of a superalloy turbine blade from a relaxed, initial position to an elastically deformed position. The at least a portion of the superalloy turbine blade has a curvature in the elastically deformed position not present in the relaxed, initial position. A hole is drilled generally span-wise through the at least a portion of the superalloy turbine blade in the elastically deformed position, and when the force is released, the superalloy turbine blade returns to the relaxed, initial position and the hole takes on a hole curvature within the at least a portion of the superalloy turbine blade.