NiChrome Hot Wire Cutter for Acrylic

Acrylic sheet is always a go-to for me when building something. It's relatively cheap, durable, and able to be used for a variety of applications. For the past few years, I've been using a Dremel rotary tool to cut the plexiglass, which gets messy, takes forever, and doesn't provide very clean edges. This project seeks to provide a better way of cutting parts out of plexiglass.

When I was an AiR at Instructables, I was spoiled with laser cutter. When I thought of how the laser is actually "cutting" the plastic, I realized that in reality, the laser is heating up and vaporizing the plastic, only a very small amount at a time. After doing some quick research, it became apparent that a nichrome wire could be made hot enough to vaporize the plastic, and was easily available in extremely thin diameters. I've deemed this project a "vocutter", or Vaporization On Contact, (VOC) Cutter because of this cutting method. I'm very happy with the results that this cutting method produces, and will be using it in the future unless if someway by the grace of God I get a laser cutter.
(What is this!? Instructables has a contest with a laser cutter as a prize!? Vote for me if you like this project. Thanks!)

Check out the next step to see what it looks like to cut things with a Vocutter, or head to step 3 to get started on the build!
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UPDATE 5/7/14: I added a foot switch which greatly improves the cutting process! See step 6!

Step 1: Videos!

There are two videos here. The first one shows off different materials that can be cut with a nichrome Vocutter, and the second shows my first attempts at cutting designs out of plexilglass that I would have otherwise used a laser cutter for.

Step 2: Tools and Materials

A variety of tools and materials are needed to complete this project:

Tools:

• Drill
• Dremel Rotary Tool
• Tap set
• Car battery charger
  • If you don't have one laying around, Harbor Freight is probably your best bet.
• Hot glue gun

Materials:

• 1/2" thick particle board
• 1/2" wide steel bar
• Nichrome wire
  • Easily available online in every thickness. 30 Gauge worked best for me for this project.

Let's get started!

Step 3: Build: Frame

We need a sort of "C" shape to run the wire from one side to the other. The wire will get charged with electricity and become hot, and by moving our material through the wire inside the "C", we will be able to cut things.

My frame is cut from 1/2" thick particle board I had laying around. The gap between the two bars is roughly 5". This distance was determined by running tests with different power supplies beforehand. The depth of the C-frame is about 8 inches, to give some room to work the material. The thick part at the back is about 3" deep. I made it that depth so that if I want to add any improvements in the future, I'll have some room to mount components. Cutting was done by hand with an oscillating cutter.

I later cut a Back Plate roughly 5" wide out of the 1/2" thick particle board, and glued it to the C-frame. This allows the cutter to sit horizontally, and be clamped to a table either horizontally or vertically. A small piece of 1/4" thick plywood was cut to act as a Base Plate to help keep any materials level during cutting if necessary. See the images notes in the last picture.

Step 4: Build: Metal

Two 3" sections of 1/2" steel bar stock were cut using a Dremel Rotary tool.

1/4" holes were drilled and tapped (threaded) so that screws could be threaded into them, and a nut could be used to hold the wire in place.

Two 1/8" holes were drilled on each piece so that small screws could be used to attach each metal piece to the C-frame. Be careful to attach each metal piece so that they are parallel, and the wire will run as close to a 90-degree vertical as possible.

I think the pictures do a good job of showing what needs to be done in this step.

Step 5: Using the Vocutter and Conclusion

Cut and attach a piece of nichrome wire in between the two screws on either side of the C-frame. A car battery charger is plugged into the wall, and the positive and negative leads are attached to each piece of metal on the C-Frame. The wire then becomes hot, and the settings on the car battery charger can be adjusted to get the best results.

Cutting things like paper, foam, cardboard, etc., is as easy as gently guiding the material through the wire. There's virtually no resistance.

Cutting things like wood and plexiglass can be a little more difficult, and especially with thicker materials, dragging the material along the wire eases the process substantially, as the hottest part of the wire is able to contact the material. Dragging it along the wire and lose some of the accuracy in the cut, but as long as you're careful quality results can be had.

I've attached pictures of some of different materials after they've been cut. 1/16" Plexiglass, 3/32" Plexiglass, 1/8" foam rubber, and 1/4" birch plywood. There are also pictures of designs I made in Inkscape, as I would to be laser cut, but cut with this method instead by printing out, cutting, and taping them in place. The pictures show how close I was to the actual design, and all they need is some sanding to clean up.

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Thank you for reading! If you have any questions or comments, please leave them in the comments! I enjoy reading them. I look forward to using this as a new tool to produce higher quality projects more quickly.

Step 6: Addition: Foot Switch

I added a foot switch so that the device could easily be turned on and off while cutting. This was done using a short section of 2x3", and some 1/4" plywood I had laying around. A simple pushbutton switch from Radioshack was found and wired up. The entire process only involved some drilling, cutting, and soldering. A drill, oscillating cutter, and soldering iron were used. Take a look at the pictures, and the video to see it in action.

Comments

[Monikalea]

As a picture framer, I can tell you that the best way to cut acrylic is similar to cutting glass. You score it and snap it. You can score it with a straight edge and a box cutter blade. You snap it by laying it upside down from where you scored it and bend it back. Curves are often made by scoring it and snapping off small pieces like working with stained glass.

Safety first my friends: Avoid Poisonous vapors, white hot wires , plus you get a straight line.

How to score and snap plexiglass:

https://www.youtube.com/watch?v=AsBrJRNvdyA

[Shadenf]

Thanks for this comment it, was really helpful. I was missing the wire for this project so was a bit stuck. I used your suggestion and I have just managed to reshape my motorbike's windshield to fit the front fairing.

[Monikalea]

As a picture framer, I can tell you that the best way to cut acrylic is similar to cutting glass. You score it and snap it. You can score it with a straight edge and a box cutter blade. You snap it by laying it upside down from where you scored it and bend it back. Curves are often made by scoring it and snapping off small pieces like working with stained glass.

Safety first my friends: Avoid Poisonous vapors, white hot wires , plus you get a straight line.

How to score and snap plexiglass

[MikeB565]

Hey man, awesome video you made, thnx a lot! Do you know how hot the wire will get if you power it with 12V? I'm trying to make a hot dog machine so i need a heat source. I haven't done anything with electronics and heat though. Do you think this wire can heat up a hot dog if winded up in a coil shape (but with space in between the wires) so yes, from what distance and will the wire be able to resist standing on for a long time? already thanks a lot! :)

[rimar2000]

Great idea! I have done polystyrene foam cutters many times, but did not know you can use them to cut other materials, giving it higher temperature.

I have a suggestion for you: add a steel spring to and end of the wire, in order to keep it tense when is hot. The contacts should not vary, only the wire should pass loose over one of them, sliding when dilates.

If you don't understand (my English is very poor) I could put a drawing.

I suppose you have a pedal switch, it is almost indispensable.

[fozzy13]

Thank you for the suggestions! I have actually thought of adding both a spring to hold the wire tight, and a foot pedal switch! Those will likely be added later.

The one issue with adding a spring is that a fair amount of pressure is already put on the wire when cutting thicker materials. A spring could just make the wire less stable, although I should run some tests.

[AndiR1]

May I just say that the spring actually helps maintaining the stability of the wire, making it less flimsy. The wire expands and contracts when heating and cooling, so if you want to be able to have a more reliable straight wire to cut with, that doesn't bend AS much, put some springs on it :)

I've seen another guy doing this with the spring: https://www.instructables.com/id/Plywood-Hot-Wire-...

Oh BTW, I also wanted to add that your wire WILL hold, because if you're using force to push the object through, it doesn't get hot enough and/or you, well honestly, WE are too impatient ;)

[rimar2000]

The spring must have a lever to control its force. It is very easy to do. But I never worked with too high temperature, maybe the wire could stretch and cut if the spring is too strong. A pedal switch could be a simple bell switch, fastened on a piece of wood.

[fozzy13]

I thought I'd mention that I added that foot pedal! Step 6!

[rimar2000]

Great! Pardon, I didn't see that.

[Battlespeed]

Just curious - have you experimented with kanthal wire? I understand that it gets a bit hotter than nichrome.

[AndiR1]

I've used Kanthal A1 before, and it works just fine.
If you want a specific build or setup, i would go for nichrome because it has an easier readout of it's ohm/resistance per cm/inch etc. So it's easier to calculate how much power you should have running through the length of wire you use, depending on how hot you want it to get.

I'm currently in the making of a high-end-diy hot wire cutter with variable power and I'm planning to use nichrome, but i might switch to titanium wire so it could be temperature controlled.

[fozzy13]

I have not! I noticed a few different alloys used for this sort of thing during the research phase, but chose NiChrome because I knew it was widely used, and it was cheaply and easily available. I'd be interested in seeing how kanthal compares! Thank you for the comment!

[Seán Walsh]

Very interesting and I see potential for it for complicated shapes, but honestly I could cut the shapes shown in the two videos using a handsaw just as fast and there wouldn't be any burn marks / melted plastic on the edges.. Still, it's pretty cool.. (or hot..)

[fozzy13]

Thank you! I often find myself cutting complicated shapes out of plexiglass. The burn marks I think are nearly an aesthetic choice, as they would be if you made the cuts on a laser cutter. The melted plastic is really negligible on the edges because of how thin the wire is. I'm pretty happy with it. Thank you for commenting!

[JohnathanW15]

do you find this accurate enough to knotch a usb sized hole at an arbitrary place and have a nice square ish cut?

[JohnathanW15]

I doubt you could at 2am on a work night in a large apartment complex... at least from the comfort of your desk/work bench in the unit. ie the hot knife wont disturb the neighbors like a rickety desk transfering the momentum of your saw into the floor. It also doesnt require clamping each piece

[lenink1]

it's a nice project.. and simple to built... this cutter can cut various thickness plexiglass es.. and how to get nicrome wire... kindly tell me as soon as possible

[JohnathanW15]

google "how to use a search engine" , then go from there.

[philipmarshal]

Wow.. this cutting process is very useful to my final year project.. I'm using this Nichrome hot wir to cutting the various designs but not using CNC I'm using mechanism.. now i want to clamp the work piece i mean sheets .sir can u tell me how can i clamp the sheet without disturb the cutter paths.