Laser cutters are impractical and expensive for a noob project. however, we can all have home robot-cutting tools for a great price: Instead of lasers, we can use a 0.5mm wide filament of tungsten carbide, make it red hot, and then CNC some shapes into thermoplastics, cardboard, and even wood. the total cost of the hot filament cutter would be around 20 euros, and hopefully it would fix under an existing reprap extruder.

It would be pretty fun to cut things using a hot filament and a reprap
[www.ebay.co.uk]

Edited 2 time(s). Last edit at 03/24/2015 10:27AM by skynetprinter.

Good theory.

Why do you think tungsten carbide? I know it's quite tough but why not any other metal?

Any thoughts on a heater? Induction perhaps? Could be controlled with standard reprap stuff with the right sort of thermocouple and amplifier.

-a

I can't reach your link, country restrictions...

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

The only thing you are going to cut with a hot wire is foam.

I just machined some PE board by mistake after reading online that it was a good substrate for ABS, the nozzle of the printer melted a perfectly regular machined outline into the top of it, with very accurate super straight lines, it's great!... So i realized that if i had a thin hot rod at 200 degrees, and set the printer to go very slowly, i could cut any thermoplastic very accurately, not just foam, anything that melts and that can be cut using a hot knife, it just takes a while.

It's brilliant, the metal tip just dives into the metal at a rate of 1-2 millimeters a second, it's just like a hot knife that robot precision, it takes insanely long to cut 1cm thick HDPE board, but it's totally possible... how could it fail? perhaps one mm every second, and after 20 minutes, can drill absolutely loads of things.

Perhaps there are steel alloys that are better than tungsten for strength and thermal transmission, i thought that tungsten could go to 1000 degrees and cut very fast and it's twice as strong as steel. Maybe a copper alloy would cut faster. I'm pretty sure that if you jammed a strand of welding copper rod into the extruder you would probably have a laser cutter equivalent that would cut anything given enough time, same as a hot knife just with machine precision.

Quote
Zavashier
I can't reach your link, country restrictions...

Here it is.
the (I hope the) same on amazon

Greetings Mr Tchitchou. I have run a shaky video on YT but it's viewable.

[www.youtube.com]

I dont know what plastic i had, but be warned that this project generates alot of hazardous fumes, so 3d print an extraction fan to stick next to the filament with some reactive substance to take away the fumes.

Edited 1 time(s). Last edit at 03/25/2015 06:56AM by skynetprinter.

Thanks for the link (that works this time)

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skynetprinter
but it's totally possible... how could it fail?

Here is why this will fail. Whith hot wire technology, even foam has its limits. The good point about styrofoam, is that retracts far from the hotwire, so it stays dry. Seccond, styrofoam can retract until a few percentage of the initial volume. Because that material density is very low. If the material density grows, the retractation decreases, and so the ability to cut it. If you try to melt foam, you will notice than up to 20-25% of rectactaction, it forms a hard skin which is more difficult to be melted. So if you need to cut a "T", the seccond path will be much harder to cut than the first one. And you will never be able to remove a pocket. But, much more important : What will you do with the material fused by your path ? If you don't remove it, it will flow or clogg. That's the most important reason why it will fail.

I love today's "inventors", whom most of the time invents nothing. You can't reinvent the wheel. Most of what you can do or say about physics and technology has been told a long time ago. There's numbers generations of graduated engineers worldwide that have already explored all the possible paths. If it looks as simple as a hot carbide tip, why can't you already buy at last an expensive industrial version ? What you can do, like Adrian Bowyer and other did, is to apply existing technology in a different way or for a closer use. It's not realy inventor's time, but hacker's time today.


Inventor's time, another century another time...

Edited 4 time(s). Last edit at 03/25/2015 08:50AM by Zavashier.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Indeed it wouldn't be very high quality. You haven't proved that it would fail. Nothing resists the path of the wire through the plastic, so it can cut the shape. so you say it will cut it badly. it depends how many T shapes you want in an object. The excess material forms a sheer wave same as the front of a boat, it doesnt climb infinately high up the wire, it flows around the wire. When you pour water in a cup, it becomes the cup. When you pour water in a bottle, it becomes the bottle. When you pour water in a teapot, it becomes the teapot. Water can drip and it can crash. some materials would cut better than others because the material just retratracts i know it isnt a very genius invention.

The issue is that it would cut the shape, but it would leave blobs everywhere? even 1 cm plastic, the hot stuff has the consistency of syrup the shape would kindof get there slowly? if you cut plastic with a knife it's the same. you will make me have a go with a 1cm plastic just to prove it?

Edited 1 time(s). Last edit at 03/25/2015 11:05AM by skynetprinter.

I can appreciate your endeavor skynetprinter.

I once made an evaporative cooler from a desk fan, a scrap of fabric, a bowl and a fountain pump. This was by no means a replacement for a whole room/house cooling system, and could not even hold a candle to the efficiency of even cheaply made manufactured units. But I had a little fan that made my desk a little bit cooler than it was before, and being an engineering student at the time I spent many hours in one spot doing homework, so the utility and cost were on par with functionality so I couldn't have been happier.

For your hot wire/point.

Thermal conductivity of Tungsten Carbide is only 84 W/mK.
Copper thermal conductivity is 400 W/mK

Copper would conduct heat to the end of the wire much faster, but it not nearly as rigid which could cause bending if you move too fast.

Will this work for all materials in all thicknesses, definitely not, no tool is compatible with all possible applications. But it may have its uses, even if that use leads to the creator getting frustrated with it not working the way he wants it and re-designing a little different after some experimentation.

You mention a hot knife. Have you considered mounting one of these in place of your extruder. [www.harborfreight.com]

You could strip it down and find a way to put that 130 watt heating element to use.