Sunday, April 14, 2013

Electronically Controlled Nichrome-Wire Cutter

Nichrome-Wire Cutter is an essential tool for model aircraft constructions. We mainly use Nichrome-Wire Cutters to fabricate model aircraft wing assemblies, other than that Nichrom-Wire Cutters are used to cut wax, polystyrene materials and other similar kind of materials.

In this project we construct electronically Controlled Nichrome-Wire Cutter. The main feature of this cutter is its (non mechanical) variable temperature controller. The temperature of the Nichrome-Wire is controlled using TL494 PWM controller. In this design TL494 is oscillated with fixed frequency and only varying factor is its duty cycle, in this given design R2 is used to control the duty cycle of the frequency.

Duty cycle variation with R2 potentiometer

This Nichrome-Wire Cutter requires 8V to 20V – 3A DC power source and 16.5V – 3A is recommended supply for this system. When constructing this system makes sure to solder and connect all the components properly, improper connections may cause oscillations and instabilities in output.

Recommended wire for this system is 1m of 24 S.W.G Nichrome-wire (generally with mix of 60% nickel, 16% chromium, 24% iron) with approximately 6Ω resistance. When constructing this system take special care about this Nichrome-wire. Improper wiring/mounting may cause severe burns, fire and/or permanent damage to the equipments.

The schematic, PCB and all the other materials related to this project are available to download at elect.wikispaces.com under the terms of Creative Commons - Attribution 3.0 Unported license.

4 comments:

Anonymous said...

It would be cool if it measured current and voltage drop across the nichrome wire and was a constant power controller... This way it will account for the cooling of the wire as it melts the foam. Think of it as trying to keep a constant resistance of just the wire, since the wire has a temp. coefficient. Something I've been meaning to try for a while now.

Dilshan Jayakody said...

agreed! Like always, feedback systems provide more accuracy and reliability to the system, but in here I omit current and voltage (or altogether resistance) variations of the NiCr wire because it need more components and space :(. In here my plan in is to make some low cost, less complex and customizable (adjustable) NiCr wire base cutter.

Anonymous said...

where can I buy nichrome wire(specific gauge) in Colombo?

Dilshan Jayakody said...

NiCr wires are available to purchase at shops which sold scientific instruments and chemicals. (Most of these shops are located at Bankshall Street - Colombo 11)