Hot Wire Cutter

A mobile hot wire cutter to make small figures out of foamed material cut the foam edges or any other foamy things you can imagine.

This one as in many of my other projects is a very customized build that is hard to imitate. The 3D printed part I designed for this wire cutter presupposes an angle bracket of a particular dimension.

The reason for this is that I like to utilize things laying around that otherwise would have never been used and probably thrown away.

I will however provide you with the CAD file for the handle which is the only printed part of this project. So you can play around with it or change dimensions to your needs and make one for yourself.

Download: Hot Wire Cutter CAD Files
Archived in: 7zip
Content: Freecad Project File (FCStd) and STL File 
Password: hotwire

Preview:

Technically this is an amazingly simple build. It just has to move enough current through a tantalum wire and make it hot.
And yeah, I don’t want to care about any current regulation stuff or any other electronic things. This extra work will be done by my lab power supply.

Here is an overview of the parts I needed at least to make it work. All the extra you see on other images or in my video are just face lifting

• 3D printed handle or housing
• Tantalum wire that gets very hot and cuts through foamed material
• Two angle brackets made of conductive steel to hold and strain the tantalum wire
• Main power cord and an XT60 connector
• Many M3 Screws, nuts, and M3x9 sized rivet nuts

Preparing the angle brackets

The angle brackets play the role of holding and tightening the heating wire and transferring the current. Their great mass on the other hand protects the plastic housing from melting by absorbing the heat at the contact points to the wire and distributing it over its mass evenly.

I crimped rivet nuts into two holes on each bracket and soldered one end of a power cord to the rivet nut on the shorter side of the bracket.

Inserting the angle brackets

Now the brackets can be inserted into the housing. I also twisted the power cords and covered them with a protection sleeving

Closing the case

After the cord and protection sleeve are aligned to the notches, the housing can be closed with the other printed half.
To hold the housing tight we can insert rivet nuts into existing screw holes of the housing on one side and tighten it with screws from the other side

How to connect to a power source

For connecting it to my power supply I attached an XT60 connector to the end of the power cord, wrap it up with some tape, and covered it with shrink tubes

The hot part

This is the final part. Wiring up the tantalum heating element.
There is one hole on the angle bracket which is crimped up with a rivet nut. That one we use for tightening up the tantalum wire.
We screw a … screw together with a nut into each rivet nut …. OMG… then wrap the wire between the screw head and the screw nut and then tighten the wire by rotating the screw. I hope this was understandable.

The final product

The hot wire cutter is finished and ready to use. Looks pretty neat right?

The spare holes on the angle bracket where the heating wire goes through have an additional advantage. I can extend the length with other conductive metal parts easily. Thereby I can cut deeper into foamed material.

The tightening screw by the way never gets hot because the contact of the wire to the brackets restricts the current to only flow between the angle brackets over the wire. You can see it in the next image.