ARTICLE INFO Laser welding technology for high precision fixing is widely used as it provides Lon... more ARTICLE INFO Laser welding technology for high precision fixing is widely used as it provides Long term stability and is preferred method for hermetic sealing of explosives filled components. Furthermore, it provides means for semiautomatic, high speed, high yield production. The mechanism of deep penetration welding is by heat transfer via keyhole which acts as a blackbody. The keyhole is filled with gas or vapours created due to continuous vaporization of wall material by the laser beam. When laser beam moves with respect to the substrate, successful deep penetration weld is only possible when movement of this cavity and molten zone achieve a steady state, minimizes the heat affected zone (HAZ). As welding is carried out, the Heat will be generated which can cause the explosion inside the component, so heat generation is required to be controlled. For this Nd:YAG Laser is an appropriate solution which has a proper concentration of energy and also less Heat Affected Zone (HAZ) instead of other Laser like CO2 laser. Here the use of Laser welding is done since it can be efficiently used to weld very small parts, quality of weld achieved is better than other types of welding processes, takes very less time to cool after welding is stopped, the process is noncontact type hence filler material is not required. The Project has a wide scope in studying and analyzing the 'Heat Affected Zone', the 'Quality of Weld'.
A semiconductor bridge (SCB) igniter used to explosives typically require a tenth of the energy i... more A semiconductor bridge (SCB) igniter used to explosives typically require a tenth of the energy input as compared to a bridge wire with the same current and is capable of igniting in tens of microseconds. Hence, it has become a popular c commercial and military applications. Testing the performance and suitability of these devices in snow filled terrains and low temperature environment on a SCB igniter, where its electrical properties were studied over a wide range of temperature and frequency using complex impedance spectroscopy (CIS). Our results show that the resistance of a 3.2 Ω device increases by 25% as temperature decreases from 300 to 70K. Also, for any temperature the impedance remains constant up to 5 orders in frequency beyond which the inductive reactance increases. In addition the time required to fire the device is increased marginally at 77K when com environments.
Presentations slide of my lecture at "Make in India Workshop" at Suryadutta College of Managemen... more Presentations slide of my lecture at "Make in India Workshop" at Suryadutta College of Management, Bavdhan Pune -411021 in 2017.
ARTICLE INFO Laser welding technology for high precision fixing is widely used as it provides Lon... more ARTICLE INFO Laser welding technology for high precision fixing is widely used as it provides Long term stability and is preferred method for hermetic sealing of explosives filled components. Furthermore, it provides means for semiautomatic, high speed, high yield production. The mechanism of deep penetration welding is by heat transfer via keyhole which acts as a blackbody. The keyhole is filled with gas or vapours created due to continuous vaporization of wall material by the laser beam. When laser beam moves with respect to the substrate, successful deep penetration weld is only possible when movement of this cavity and molten zone achieve a steady state, minimizes the heat affected zone (HAZ). As welding is carried out, the Heat will be generated which can cause the explosion inside the component, so heat generation is required to be controlled. For this Nd:YAG Laser is an appropriate solution which has a proper concentration of energy and also less Heat Affected Zone (HAZ) instead of other Laser like CO2 laser. Here the use of Laser welding is done since it can be efficiently used to weld very small parts, quality of weld achieved is better than other types of welding processes, takes very less time to cool after welding is stopped, the process is noncontact type hence filler material is not required. The Project has a wide scope in studying and analyzing the 'Heat Affected Zone', the 'Quality of Weld'.
A semiconductor bridge (SCB) igniter used to explosives typically require a tenth of the energy i... more A semiconductor bridge (SCB) igniter used to explosives typically require a tenth of the energy input as compared to a bridge wire with the same current and is capable of igniting in tens of microseconds. Hence, it has become a popular c commercial and military applications. Testing the performance and suitability of these devices in snow filled terrains and low temperature environment on a SCB igniter, where its electrical properties were studied over a wide range of temperature and frequency using complex impedance spectroscopy (CIS). Our results show that the resistance of a 3.2 Ω device increases by 25% as temperature decreases from 300 to 70K. Also, for any temperature the impedance remains constant up to 5 orders in frequency beyond which the inductive reactance increases. In addition the time required to fire the device is increased marginally at 77K when com environments.
Presentations slide of my lecture at "Make in India Workshop" at Suryadutta College of Managemen... more Presentations slide of my lecture at "Make in India Workshop" at Suryadutta College of Management, Bavdhan Pune -411021 in 2017.
Microelectric Detonators (MED) is the new and emerging field in the miniaturize electro explosiv... more Microelectric Detonators (MED) is the new and emerging field in the miniaturize electro explosive devices. MEDs are used in field with extremely sensitive primary explosive material for initiating secondary explosives. To use MEDs in field we have to put slurry of primary or secondary explosive materials on the surface of MED for making physical contact between primary explosive and MED. MED can be initiated by imparting sufficient electrical energy to produce plasma on the surface of MED and it in turn initiates the high sensitive primary explosive pasted on its surface. In view of this we have designed and developed three axis stage including X,Y and Z axis control with dispensing control mechanism. Mechanical parts with linear actuator, lead screw and linear guide has been designed by us and fabricated for X, Y and Z axis stages. All mechanical parts are integrated to make standalone semi-automatic dispensing system. For dispenser design we have modified a manually operated bottle top dispenser such that its dispensing action can be automatically controlled from PC. For ontrolling mechanical movement of dispenser, stepper motors with linear actuator having different holding torque, weight and current has been used for X, Y and Z axis. We have fabricated slurry filling system having three stepper motors for controlling X axis, Y axis, and Z axis (piston bottle top dispenser) movement respectively.We have also designed 2 Amp stepper motor driver having option to select half and full step pulse sequence to be applied for stepper motor.The driver can precisely drive the stepper motor with the minimum resolution of 3 µm. The driver has been tested with stepper motor with linear guide assembly for every axis separately. Whole assembly is integrated with embedded system to automatically control its operation through PC. The embedded software is designed and tested with the slurry filing system. This report also contains detailed SOP on preparation of various Nano explosive inkusing different techniques such as Supercritical fluid precipitation processes, Gas anti – solvent (GAS) Method, Rapid Expansion of Supercritical Solution into Aqueous Solution (RESS– AS) Method, Crystallization Method, Sonocrystallization Method, Cooling crystallization Method, Nozzle assisted Solvent/nonsolvent Method, Prefilming twin-fluid nozzle assisted solvent/nonsolvent Method, Spray drying Methods, Ultrasonic Spray Method, Spray freezedrying Method, Spray freezing into liquid (SFL) Method, Electrospray crystallization Method, Sol-gel processing, Template technique, Rigid template, Wet chemical-assisted soft template, Physical vapor deposition (PVD) and Inkjet printing. Hence this document can be used for design & development of production grade automated explosive slurry filing system i
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Papers by Dr Virendra Kumar Verma
standalone semi-automatic dispensing system. For dispenser design we have modified a manually operated bottle top dispenser such that its dispensing action can be automatically controlled from PC. For ontrolling mechanical movement of dispenser, stepper motors with linear actuator having different holding torque, weight and current has been used for X, Y and Z axis. We have fabricated slurry filling system having three stepper motors for controlling X axis, Y axis, and Z axis (piston bottle top dispenser) movement respectively.We have also
designed 2 Amp stepper motor driver having option to select half and full step pulse sequence to be applied for stepper motor.The driver can precisely drive the stepper motor with the minimum resolution of 3 µm. The driver has been tested with stepper motor with linear guide
assembly for every axis separately. Whole assembly is integrated with embedded system to automatically control its operation through PC. The embedded software is designed and tested with the slurry filing system.
This report also contains detailed SOP on preparation of various Nano explosive inkusing different techniques such as Supercritical fluid precipitation processes, Gas anti – solvent (GAS) Method, Rapid Expansion of Supercritical Solution into Aqueous Solution (RESS–
AS) Method, Crystallization Method, Sonocrystallization Method, Cooling crystallization Method, Nozzle assisted Solvent/nonsolvent Method, Prefilming twin-fluid nozzle assisted solvent/nonsolvent Method, Spray drying Methods, Ultrasonic Spray Method, Spray freezedrying
Method, Spray freezing into liquid (SFL) Method, Electrospray crystallization Method, Sol-gel processing, Template technique, Rigid template, Wet chemical-assisted soft template, Physical vapor deposition (PVD) and Inkjet printing. Hence this document can be
used for design & development of production grade automated explosive slurry filing system
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