Rifle Barreleling Research Paper

Rifle Barreling (Rifling groove): There are several techniques to boring of rifle barrels wherein the rifle barrel must have groove, and it is summarized as follows below.

1. Single Point Cut: This process cuts one groove at a time, for as many time as required. This process is not popular and is not common anymore.

2. Broached Rifling: In this process, a broaching bit with cutters in a single tool is inserted into the barrel and pulled through. In this process, all the grooves are cut in a single pass using.

3. Button Rifling: This is very popular and accurate form of rifling using a tool called button. The button tool has an inverted form of the grooves on the tool and when pushed through the barrel bore, the grooves are formed on the inside of the barrel.

4.

Flow forming: In this process, a barrel is made to flow form over a mandrel with reverse image of desired grooves under high pressure with using rollers. This is a specialized process.

Stents used to support arteries in heart patients:

• Step 1: Material selection- The optimal material depending on the cost and durability are selected, in this article Nitonel, an alloy of nickel and titanium is used to make the stents. The raw material is in the form of tubes or fine wire.

• Step 2: Winding – A nitinol wire is wound on a jig to make the skeleton of the stent; the process is called wire braiding or knitting. Stents skeletons can also be made by cutting the desired pattern on small tubes of starting OD 0.5mm size using Nd:YAG laser systems. The image on the left shows the wire braiding process and the image on the right shows the laser tube cutting process. • Step 3: Heating - The skeleton is heated in an oven, to retain the shape memory in the metal.

• Step 4: Polishing – The stent is polished by mounting the stent in a special jig and rotating it through a container with abrasive grains, this removes micro cracks, residue and impurities on the stent