OPTIMIZATION OF CENTRIFUGAL SPINNING MACHINE

: We were all living in the world of technology, where the science had been developing for each and every seconds such as new technologies, new inventions and new ideas. In which, we would like to introduce a new idea by using centrifugal spinning method. Where, it is has been recently used for the production of micro and nano-fibers and it is also a safer and more efficient method for producing micro and nano-fibers when compared to all the fibers production method. Our concept is to reduce the manufacturing cost of the centrifugal spinning machine. Because the manufacturing cost of the single machine in India is about Rs.2.5 to 3 lakhs, by the way we would like to produce a machine at a low cost and by using the machine we produce the mat which has the same efficiency as compared to the mat produced by the original machine.


INTRODUCTION
In the recent years, the use of nano-fibers has been widely used in all industries. In which, the nanofibers are those fibers within the diameter range of 1 to 100 nanometers. And it can be generated from different polymers which has different mechanical properties and applications based on what type of polymer we used to produce the nanofiber (or) mat. And it is widely used in real life applications like tissue engineering, drug delivery, cancer diagnosis, lithium-air battery, air filtration, oil-water separation, and sportswear textiles etc.
In which, many methods had been used by the industries to produce the nanofibers such as electrospinning, multi jet electrospinning, bi-component spinning, drawing, phase separation, force spinning (or) centrifugal spinning. Where, we choose centrifugal spinning method because it is the most efficient, more economical, low cost and safer method for producing nano-fiber. Where, we had modified the centrifugal spinning machine by introducing the top-down approach in which the molten polymer solution falls directly into the spinneret from the top of the barrel connected with the band heater, and it comes out through the orifice which is located in the bottom of the spinneret and collected in the collecting drum which is placed just 2 opposite to the spinneret. The following components are used in this machines are PID temperature controller, SSR, RTD sensor, 1 kilowatt mica band heater, 145 watts ac motor, rack and pinion gears, pillow block bearings etc. The PID temperature controller stands for proportional integral derivative controller. It uses closed control loop feedback mechanism. Where, it calculates an error value as the difference between a desired set point (SP) and a measured process variable (PV) and applies a correction based on proportional, integral and derivative terms. It is widely used in industrial control systems and a variety of other applications that require continuous modulation control. The SSR stands for solid state relay which is used for ON and OFF the band heater which is connected to the PID controller. The RTD temperature sensor stands for resistance temperature detector these are sensors used to measure Temperature.
They are normally constructed of platinum, copper, nickel and nickel iron alloy. It acts as an electrical transducer that converts and changes the temperature into voltage signals by the measurement of resistance.
Here, we are going to use PT -100 temperature sensor, it is a contact type RTD sensor. And we are going to use 1000 watts mica band heater it is an indirect form of industrial heating and it is used to heat the outer surface of drums (or) tubes for the gradual transfer of heat. We had chosen mica band heater, due to low cost and high efficiency. The rack is a type of linear actuator that includes a circular gear (the pinion) that engages a linear gear (the rack). It is used to translate rotational motion into linear motion and it is used for pushing the molten polymer solution manually to give some forces on the solution to hit the surface of the spinneret and comes out through the orifice. A collecting drum made up of stainless steel which has excellent corrosion resistance, very tough and scale resistance at high temperature which is used to collect the nano-fibers in the form of mat coming out from the orifice where it also acts as a protective barrier to prevent accidental damages.

METHODOLOGY
In this the mat is produced by using "centrifugal force" so, the following steps are used for preparing the mat by using the centrifugal spinning machine: a. First the polycaprolactone solution is prepared by dissolving (12wt. /v %) of PCL in TFE (2, 2, 2-Trifluroethanol) and stirring it in a magnetic stirrer to get uniform fibers for the centrifugal spinning process.
b. The centrifugal spinning machine consist of two segments the top segment consist of barrel connected with a band heater, PID temperature controller, rack and pinion, nozzle, SSR, RTD sensor and the bottom segment consist of spinneret, collecting drum, motor etc.
c. The melted polymer solution is poured into the barrel where, the barrel is maintained at a temperature of 60 degree Celsius by using the band heater connected to the PID controller through SSR.
d. The RTD sensor is connected to the band heater to give feedback for the PID controller. In which we have to maintain the temperature of the barrel at a constant rate because, to produce highquality of nanofibers the surface tension and viscosity of the fluid must be decreased by increasing the working temperature which led to the formation of nanofibers.
e. The evaporation rate, viscosity of the solution and surface tension affects the quality of nanofiber which can be minimized by maintaining a suitable working temperature.
f. The speed of the spinneret is maintained at a speed of 3000 to 4000RPM (rotational per minute) for the formation of nanofiber. Because, when the speed of the spinneret is low the centrifugal force cannot overcome the surface tension which may cause the solution to stuck in the spinneret itself.
g. The distance of the collecting drum is fixed about 15cm (or) 150mm from the spinneret. When the distance of the collecting drum is too short the fiber coming out from the spinneret will not stretch and the diameter of the fiber produced will be very large.
h. The diameter of the orifice in the spinneret can be made between 0.1 to 1mm. where we had chosen 0.5mm because it reduces beads and form fine dimeter.

4
i. Finally, the nanofiber in the form of mat is collected in the collecting drum and separated from it by manually by hands without using any chemicals to separate the mat from the collecting drum. Height of the rectangle = 30cm.
For finding the center of gravity, first we have to find the volume of all the three sections.
Here we take three sections namely,  Where, CIRCUMFERENCE = DISTANCE AROUND CIRCLE We are going to take, We need to convert revolution per minute to meter per second.
To find velocity, v process variable (PV) in the monitor. When the measured temperature goes above 60 degree Celsius the PID controller sends signal to the SSR module to cut off the current supply to the band heater and when the temperature goes below the 60 degree Celsius the PID controller sends signal to the SSR module to turn on power supply to the band heater to maintain at the same temperature. The PID temperature controller uses a closed control loop feedback mechanism.

RESULTS AND DISCUSSION
In this, the polycaprolactone mat is produced by using centrifugal spinning machine and the photographic image and scanning electron microscope (SEM) image are produced here, Figure. 10: left side shows the SEM image and the right side shows the photographic image of PCL mat.

COST ESTIMATION
The cost for manufacturing the centrifugal spinning machine is produced in the tabular column format where, the cost for manufacturing the machine is reduced and displayed here,

CENTRIFUGAL SPINNING METHOD
It is the most commonly used method when compared to all the nano -fiber production methods because it has many advantages when compared to them, the comparison between various nanofiber production methods are mentioned here,

CONCLUSION
In this paper, the nanofibers are produced by using the optimized centrifugal spinning machine and the production of nanofibers can be made for numerous numbers of conducive and non-conductive materials can be made by using centrifugal spinning method. Since the centrifugal centrifuge does not require high voltage, the system can alleviate safety related problems. In addition, centrifugal spinning can greatly improve production efficiency by increasing the rotational speed, enabling rapid and largescale production of nanofibers. The fibers obtained using this method have superior properties, and the process is free from the extra process of solvent recovery as no solvent is used. In this spinning process, the limitations of the electrospinning process, such as a very high electric field, low productivity, conductivity and high production costs are eliminated. Compared with the electrospinning process, centrifugal spinning allows nanofiber fabrication from the polymers at much higher concentrations, which decreases the use of solvent and lowers the production cost.

FUTURE SCOPE
In future it can be fully automated by the uses of sensors and other equipment's. Where, we can use hopper and level sensors, pneumatic cylinders. In this we are going to use polymers like gelatin, polyurethane and collagen granules which are loaded in a large barrels which is called as loading unit where it is connected to a hopper and the hopper is connected to a large tube with the level sensors connected at the top of the tube with the hopper's bottom end with a band heater of 1KW to 1.5KW which is called as heating unit and the fiber coming out from the spinneret is collected in a collector drum which is called as collecting unit and the fiber collected in the drum is changed by using robotic arms by changing the fiber collected drum with the empty drum and the fiber is separated from the drum and it is reused which is called as un -loading unit.
Where, the level sensor is a device that is used to determine the level (or) the amount of fluids, liquids (or) other substances flowing in an open (or) closed system. Like infrared sensors, level sensors are found in a wide range of industries. They are primarily known for measuring fuel levels, but are also used in companies that work with liquid materials. For example, the recycling industry, as well as the juice and spirits industry, rely on these sensors to measure the amount of liquid assets they hold.

FUNDING
This present work was jointly supported by Jenith Immanuel R, Harish B, and Prakash R. Funding sources were not involved in study design, data analysis and interpretation, report writing, and the decision to submit the article for publication.