Reliability Assessment Based on Design and Manufacturing Tolerances for Control Burst Mechanism of Small Arms

  • S.K. Basu Armament Research & Development Establishment, Pune.
  • D.R. Sonawane Armament Research & Development Establishment, Pune.
  • A.M. Datar Armament Research & Development Establishment, Pune.
Keywords: Control burst mechanism, Aspiration level


Very often specified tolerance is made greater than process tolerance, depending upon (i) the manufacturing process capability, and (ii) the 'aspiration level' of the designer in effecting a specified tolerance. This applies to multiple components merging into an assembly. In assembly tolerance, errors due to mating are inherent. Common errors arise due to clearance, misalignment in planes and distortion that may cause side stack. Such errors affect the functional performance of the subsystem and consequently become the main cause of failure. Probability distribution of the assembly tolerance and probability distribution of stacked up tolerance of the Components in actual practice leave a common zone of interaction, based on which the in-built reliability changes. From the designer's tolerance, one may have an idea about the 'aspiration level' of assembly tolerance stacking error. Assuming both these parameters, viz., actual stacking error and designer's aspiration level of stacking error to follow the normal probability distribution, it is possible to get the reliability of the product assembly. The paper presents a real life case study for assessing the reliability of sub-assembly at the initial stages of development for control burst mechanism (CBM) of rifle.

Author Biographies

S.K. Basu, Armament Research & Development Establishment, Pune.
Prof SK Basu is Professor Emeritus at GoVernment College of Engineering, Pune. During 1959-61 , he worked in the Machine ToOls Research Institute (ENIMS), MoSCoW, ar UNESCO fellow and visited a large num ber of scienti tic and research insti tutions in USA and Gcrmany. under NSF and DAD scientists exchange scheme. He has about 150 techn.iIcal papers to.his credit published in
international/national journals and has guided 20 PhD students in the areas of tribology and machine tools. He is a winner of four prestikioUS awards of the Institution of Engineers, (India), for the tiest papers published. He won AIMTDR awards in 1982 and 1984 conferences and NRDC awards in 1976, 1977 and 1986. He has written five engineering tex~books and has a number of patents to his credit.
D.R. Sonawane, Armament Research & Development Establishment, Pune.
Mr DR Sonawane did his MSc (Statistics). For the past three years, he has been associated with assignments in reliability engineering from various defence laboratories. He is working mainly on mechanical systems, including hydraulic systems. He is also responsible for software development in related fields. He has published several technical papers.
A.M. Datar, Armament Research & Development Establishment, Pune.
Mr AM Datar is presently Dy Director, Aeronautical Research & Development Establishment (ARDE),I Pune. He has done his BE from College of Engineering, Pune and MSc (Gun System Design) from Royal Military College of Science (RMCS), Cranfield University, UK, where he also I won trophy for his performance. He has also obtained Master's Diploma in Business Administration. For the past 10 years, he has been working in the field of weapon design and has specialised in the ar~a of small arms. He is Chartered Engineer and a member of Institution of Mechanical Engineers (India).
How to Cite
Basu, S., Sonawane, D., & Datar, A. (2013). Reliability Assessment Based on Design and Manufacturing Tolerances for Control Burst Mechanism of Small Arms. Defence Science Journal, 47(4), 455-465.
Armaments & Explosives