Dieless drawing

DIELESS WIRE DRAWING

MEL335Prof. D. Ravi Kumar

Presented By:-Rohit Gothwal2010ME20796

Wire Drawing•It is manufacturing process of making a wire, generally froma rod or a bar.

• A bulky process involves a large amount of plasticdeformation is one of the oldest manufacturing processesknown.

•The conventional technique to draw wire is coldwiredrawing.

Conventional Wire DrawingThe wire is pulled through a conical aperture called a die to reduce its diameter.

cost is associated with pre-cleaning of the wire prior to entry to the die, tooling, and lubrication materials

Cemented carbide or diamond working surface

Problems associatedDie wear due to frictional and heating effects can rapidly diminish tool life.

High tooling costs associated with it.

Harder the material most is the cost.

Die-less Drawing ProcessThis innovative method is a semi hot or hot forming process.

This is a contact free process takes advantage of the temperature dependency of flow stress to reduce diameter of wire.

Wire enters into a heat measurement cooling unit instead of drawing die.

Basic ElementsAll die-less wire drawing systems must contain the some basic elements namely.

A heating device

oResistance heating

oLaser heating

oinduction heating

A cooling device

Purified water and an inert gas

Basic ElementsA method of applying a tensile force

Many methods of applying a tensile load have been utilised.

Use of rollers and pay-off wheels.

use of bearings and linear slides in a vertical fashion.

Machine Design and OperationDesigned to produce infinitely variable reductions in mild steel wire of maximum diameter, 5.0mm at temperatures between 400 and 900◦C at drawing speeds of up to 1.5m/s.

The wire is passed around both roller electrodes

Individual angular velocities are controlled to produce a tensile load in the wire parallel to its longitudinal axis.

The current to heat the wire was obtained from a 1600A power converter

The machine, which was controlled by an IBM PC.

Data Acquisition The instability of the die-less drawing process coupled with the complex nature of the machine operation necessitated the use of an automated data acquisition and machine control system.

Data was acquired for two purposes.

•Primarily, to record the test parameters of the wire.

•Secondly, to record data from the machine transducers to allow machine control and monitoring to be achieved.

• The system is designed to sufficiently control the roller angular velocities and wire temperature to achieve a desired reduction in the wire diameter.

• A PC based system was used to achieve the aforementioned requirement due to its cost-effectiveness and flexibility.

• The hardware was controlled by LabVIEW software.

• The user interface consisted of numerous controls and indicators. The controls allowed the user to input values and choices

Simplified flow chart of machine control and data acquisition program

ExperimentsExperiments are conducted on low carbon steel wire of nominal diameter 2.65mm.

Results:

Maximum drawing velocity of 1.4 m/s was attained without wire fracture during the drawing process.

Maximum reduction achieved in cross sectional area during a single pass was 72%. This reduction was obtained at a test temperature of 780 ◦C.

Variation in wire diameter with percentage reduction

Advantages•Absence of die makes the process less expensive as compare to conventional processes.

•Suitable for materials that have high strength and high frictional resistance.

•A large reduction of area can be achieved in single pass.

•Process can be applied to variable cross section bars.

Thank You