All of us has encountered a hypodermic needle at some point in our lives. It may have been in the doctor's office, as a child, getting our vaccinations in time for school, or as an adult, getting a needed shot, like tetanus. The uses for hypodermic needles are varied, ranging from the obvious medical applications, to industrial processes. But, did you ever wonder exactly how they were made? We will explain the entire hypodermic tube beveling process, and how it is used to create these marvelous devices.
Step One: Tube drawing
The first phase in hypodermic tube beveling is taking stainless steel tubing, and putting it through a process known as tube drawing. Tube drawing is a process in metalworking where stainless steel tubing or other materials are drawn through a series of dies in order to shrink its diameter. The process as a whole is simple: start out with a larger diameter, soften, and pull it through a smaller die to create a smaller diameter. The process is repeated until the desired diameter is reached.
Tube drawing produces a high quality product, with precise dimensions, a quality surface finish, and the added element of greater strength, thanks to using cold working as part of the whole process. There are several techniques that can be applied to tube drawing, and they include: tube sinking, mandrel drawing, stationary mandrel, moving mandrel, and floating mandrel. A mandrel, for those who do not know, is a tool used to prevent the buckling or wrinkling of the material while it is being worked.
Step Two; Beveling
After the desired diameter has been reached on the stainless steel tubing, following the tube drawing process, it is now time to begin beveling the stainless steel tubing to create the angles that will eventually form the needle point. The typical needle point actually will consist of three bevels: the primary bevel, and two side bevels. The primary bevel is the surface that will be formed by grinding the metal tubing at a specific angle. The two secondary bevels are ground on either side of the primary, creating a sharp point with a cutting edge.
The secondary bevels on shorter needles would be ground on the underside of the primary, and are often referred to as back bevels. Bevel length, in this application, is the longest measure from the tip of the needle point, to the approximate area of grinding behind the heel of the primary bevel. The heel is the area directly behind the narrower beveled tube whose end has formed the needle point. It is often expressed in degrees, and designated A, B, or C. An A bevel is equal to 12 degree angled point, B is equal to an 18 degree angle, and C is equal to a 30 degree angled needle point.
Step Three: Final assembly
After tube drawing and beveling comes final assembly. Non-disposable needles sturdy stainless steel locking ring assemblies that fit around the heel of the needle. These are referred to as hubs. The hubs, in use, will be attached to the body of the hypodermic, and will be used to draw medium through the needle, and into the hypodermic. In disposable needle assemblies, the hub will be made of plastic or aluminum, instead.
Before they are packaged, all finished products that have undergone hypodermic tube beveling will be gauged to determine the diameter of the needle. All needles are sold according to their gauge, and for common medical use, they will range from 7, the largest diameter, or bore, to 33, which is the smallest diameter possible.
Step One: Tube drawing
The first phase in hypodermic tube beveling is taking stainless steel tubing, and putting it through a process known as tube drawing. Tube drawing is a process in metalworking where stainless steel tubing or other materials are drawn through a series of dies in order to shrink its diameter. The process as a whole is simple: start out with a larger diameter, soften, and pull it through a smaller die to create a smaller diameter. The process is repeated until the desired diameter is reached.
Tube drawing produces a high quality product, with precise dimensions, a quality surface finish, and the added element of greater strength, thanks to using cold working as part of the whole process. There are several techniques that can be applied to tube drawing, and they include: tube sinking, mandrel drawing, stationary mandrel, moving mandrel, and floating mandrel. A mandrel, for those who do not know, is a tool used to prevent the buckling or wrinkling of the material while it is being worked.
Step Two; Beveling
After the desired diameter has been reached on the stainless steel tubing, following the tube drawing process, it is now time to begin beveling the stainless steel tubing to create the angles that will eventually form the needle point. The typical needle point actually will consist of three bevels: the primary bevel, and two side bevels. The primary bevel is the surface that will be formed by grinding the metal tubing at a specific angle. The two secondary bevels are ground on either side of the primary, creating a sharp point with a cutting edge.
The secondary bevels on shorter needles would be ground on the underside of the primary, and are often referred to as back bevels. Bevel length, in this application, is the longest measure from the tip of the needle point, to the approximate area of grinding behind the heel of the primary bevel. The heel is the area directly behind the narrower beveled tube whose end has formed the needle point. It is often expressed in degrees, and designated A, B, or C. An A bevel is equal to 12 degree angled point, B is equal to an 18 degree angle, and C is equal to a 30 degree angled needle point.
Step Three: Final assembly
After tube drawing and beveling comes final assembly. Non-disposable needles sturdy stainless steel locking ring assemblies that fit around the heel of the needle. These are referred to as hubs. The hubs, in use, will be attached to the body of the hypodermic, and will be used to draw medium through the needle, and into the hypodermic. In disposable needle assemblies, the hub will be made of plastic or aluminum, instead.
Before they are packaged, all finished products that have undergone hypodermic tube beveling will be gauged to determine the diameter of the needle. All needles are sold according to their gauge, and for common medical use, they will range from 7, the largest diameter, or bore, to 33, which is the smallest diameter possible.
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