Additive manufacturing for field repair and maintenance of the assault rifle AK5C – a feasibility study

Sammanfattning: The main purpose of this thesis is to see if it is possible to use additive manufacturing(AM) for field repair and maintenance of the assault rifle AK5C, by finding a suitableadditive manufacturing process and make a functional evaluation of the additivemanufactured components: hammer axis, gas cylinder and the magazine follower. TheSwedish Defense Materiel Administration (FMV) is an administration that supplies theSwedish armed forces with materiel. Therefore, it is in their interest to investigate if itis possible to use AM for field repair and maintenance in example Mali or Afghanistan.Based on a survey, and the fact that the components are purelystructural Powder Bed Fusion AM was selected. The hammer axis was made in amargining steel MS1, the gas cylinder in the nickel-alloy called Inconel 718 and themagazine follower was made in a polymer called nylon 12.The functional evaluation of the components took place at Saab in Östersund, whereeach component was placed in the rifle. The rifle was fired 1000 rounds with thehammer axis, 1000 rounds with the gas cylinder and 500 rounds with the magazinefollower. The functional test for the components was successful, there were also nomajor changes in dimensions and weight except for the hammer axis. The diameterfor the hammer axis went from 5,00 mm before the functional test to 4,98 mm afterthe functional test. The microscope images showed thatabrasion had occurred, not only for the hammer axis but also for the magazinefollower, due to friction. Firing speed was also measured and it should be over 600rounds/min, if everything works properly. The hammer axis had a firing speed of 639rounds/min which is good while the gas cylinder only had a firing speed of 595rounds/min. This was because the inner diameter of the cylinder was too big, causinggas leaking and pressure drop inside the gas cylinder.In conclusion, additive manufacturing does allow for fabrication of functional spareparts – at least these evaluated here.