3D Printing With Nylon For A More Useful Objects

[taulman] over on Instructables has been working on his own version of a 3D printer. Unlike the usual PLA or ABS filament all the RepRaps and Makerbots use, this printer uses nylon to make parts with very interesting properties.

Most extrusion printers are designed to print with ABS (a very hard plastic that melts around 220-230° C) or PLA (a somewhat softer plastic that melts at about 180° C). [taulman] is using Nylon 6, a very slippery and bendable plastic that melts around 320° C (about 600 degrees Fahrenheit). He’s doing this with a hot end of his own design and a ‘spiky’ extruder bolt that allows high-temperature thermoplastics to be extruded into any shape imaginable.

For the longest time, the 3D printer community has been using low-temperature thermoplastics such as PLA and ABS. There are obvious benefits to these materials: it’s pretty easy to source a spool of filament, and the low melting point of these plastics makes building a printer easier and safer. Now that [taulman] has the high-temperature plastic nut cracked, he’s moving on to easily-machiniable Delrin and transparent Polycarbonate. Very cool, and hopefully in a year’s time we’ll have a choice of what material to run in our printers.

After the break, there are a few videos [taulman] put up showing his printer at work and the properties of his 3D printed objects. It looks like [taulman] can print objects that are impossible on any other 3D printer we’ve seen; the flexible iPhone case probably couldn’t be made on any other DIY machine.

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DIY CNC Touch Probe

diy_cnc_touchprobe

[Dennis] recently invested some money in the Tormach Tooling System for his CNC’d Sieg SX3 mill in order to make his tool changes easier. While the kit allows him to easily account for height offsets while changing tools, he has no quick, reliable means of locating the spindle in relation to his workpiece. Tired of manually finding the edges of his workpiece for each axis, he built himself a DIY touch probe to automate the process.

The theory behind the probe’s operation is pretty simple. In the probe’s housing, three conductive rods are mounted perpendicular to the probe tip. Each rod rests between two metal balls forming a complete circuit. When the probe touches the edge of his milling material, the circuit is broken, sending a signal to his CNC control box.

The probe is comprised of several different parts, milled from either aluminum or black delrin. [Dennis] says that after everything was assembled, the runout on the probe was unacceptable, so he made a few tweaks, and now the runout has been reduced to about 0.00025” – well within acceptable tolerance limits for any work he will be doing.

Be sure to check out his site, as there are plenty more pictures of the probe’s construction, as well as additional video.

In the meantime, continue reading to see a quick video of the finished probe in action.

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Nerf Gun Converted To CO2 Powered Semi-automatic

[Philysteak527] modified a Nerf rifle, making it semi-automatic thanks to the powers of compressed air. This is not a simple change to make, and rests on his ability to design and manufacture a bolt-action that fits in the gun, works with the Nerf ammo, and uses a CO2 canister and solenoid valve for the firing action. Knowing that, it’s not surprising to find that he’s an engineering student at Stony Brook University. He started with some POM, or polyoxymethylene plastic sold under the brand name Delrin, and used a CNC lathe to machine the parts for the bolt. Add in some brass fittings, a solenoid, tubing, and the electronics and you’re in business.

We’ve embedded the test footage after the break. Looks like the new internals allow a rather fast firing rate (maybe 2-3 shots per second?) and achieve a distance between seventy and one hundred feet.

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