Hotend Becomes The Z Probe With A Kinematic Coupling

November 13, 2018 by Sonya Vasquez 5 Comments

3D Printer tool changers are bedazzling to watch, but even failed attempts at tool changers can yield something marvelous. Such is the case for [Raymond] who transformed a tool changer attempt into a perfectly capable z-level probe that uses the hotend itself as a limit switch.

The secret sauce behind this mechanism: a kinematic coupling. This coupling takes two planar surfaces and perfectly constrains them relative to each other by mating them together at exactly 6 points of contact. The result is that repeatedly separating and joining the two surfaces will always land them in the same spot within a few microns. To transform these surfaces into a switch, we need only run a small current between the points of contact. That was easy since there were all-metal balls and pins making the connection. Both surfaces are held together with magnets with the upper surface holding the hotend. To trip the limit switch, the printer simply lowers the z-height until the hotend “probes” the bed, defeating the magnets and breaking the current. Presto! No switches or P.I.N.D.A. probes. Just good old fashioned electricity and steel pins.

With so much focus on pricey probes and repeatable switches, it’s great to see some good old-fashioned geometry guiding the precision behind this printer’s sensing. It’s also heartwarming hear that the whole project was actually inspired by another coupling-equipped 3D printer that landed here a few years ago! Finally, if you’re curious to see some other folks getting some more mileage out of kinematic couplings, have a look at this homebrew CNC touch probe.

3D-Printer Extrudes Paper Pulp Instead Of Plastic

November 11, 2018 by Dan Maloney 33 Comments

We’ve seen all sorts of 3D-printers on these pages before. From the small to the large, Cartesians and deltas, and printers that can squeeze out plastic, metal, and even concrete. But this appears to be the first time we’ve ever featured a paper-pulp extruding 3D-printer.

It’s fair to ask why the world would need such a thing, and its creator, [Beer Holthuis], has an obvious answer: the world has a lot of waste paper. Like 80 kg per person per year. Thankfully at least some of that is recycled, but that still leaves a lot of raw material that [Beer] wanted to put to work. Build details on the printer are sparse, but from the photos and the video below it seems clear how it all went together. A simple X-Y-Z gantry moves a nozzle over the build platform. The nozzle, an order of magnitude or two larger than the nozzles most of us are used to, is connected to an extruder by a plastic hose. The extruder appears to be tube with a stepper-driven screw that lowers a ram down onto the pulp, squeezing it into the hose. [Beer] notes that the pulp is mixed with a bit of “natural binder” to allow the extruded pulp to keep its shape. We found the extrusion process to be just a wee bit repulsive to watch, but fascinating nonetheless, and the items he’s creating are certainly striking in appearance.

This may be the first pulp printer to grace our pages, but it’s not the first pulp hack we’ve featured. Pulp turns out to be a great material to keep your neighbors happy and even makes a dandy fuel.

Continue reading “3D-Printer Extrudes Paper Pulp Instead Of Plastic” →

A 3D-Printed Egg-Shaped Speaker Cabinet

November 8, 2018 by Jenny List 21 Comments

There are few limits to the extent audiophiles will go in their quest for the perfect sound. This applies in particular to the loudspeaker, and with that aim [Heine Nielsen] has created an eye-catching set of 3D-printed egg-shaped enclosures.

The theory of a loudspeaker enclosure is that it should simulate an infinite space behind an infinite plane in which the speaker driver is mounted, and the reasoning behind spherical or egg-shaped enclosures goes that they better achieve that aim through presenting a uniform inner surface without the corners of a more conventional rectangular enclosure. [Heine]’s enclosures 3D-printed ported enclosures achieve this more easily than traditional methods of building this shape.

A loudspeaker enclosure is more than just a box though, whatever material it is made from must adequately dampen any resonances and absorb as much energy as possible. Conventional speakers try to achieve this by using high-mass and particulate materials, but 3D-printing does not lend itself to this. Instead, he created a significant air gap between two layers which he hopes will create the same effect.

This is an interesting design and approach to speaker cabinet construction, but we think from an audio perspective its one that will be well served by more development. What would be the effect of filling that air gap with something of higher mass, for example, and should the parameters of the egg shape and the port be derived for a particular driver by calculation from its Thiele-Small parameters. We look forward to more on this theme.

These aren’t the first 3D-printed enclosures we’ve seen, but if you’re after something truly unusual how about an electrostatic?

An OpenSCAD Mini-ITX Computer Case

November 5, 2018 by Tom Nardi 18 Comments

We’re no strangers to 3D printed enclosures here at Hackaday. From the plethora of printed Raspberry Pi cases out there to custom enclosures for electronic projects, small plastic boxes turn out to be an excellent application for desktop 3D printing. But as printers get bigger and filament gets cheaper, those little boxes don’t always need to be so little. We aren’t talking about running off boxes for your sneaker collection either, if you’ve got the time and the print volume, you could whip up an enclosure for your PC.

[Nirav Patel] writes in to share his impressive 3D printed Mini-ITX computer case project, which would be a neat enough trick in its own right, but he took the concept one step farther and made it a parametric design in OpenSCAD. This allows the user to input their particular hardware configuration and receive STL files for a bespoke case. The list of supported hardware isn’t that long yet, but with the OpenSCAD code up on GitHub and released under the BSD license, hopefully the community can improve on that as time goes on.

To keep things simple (and strong), [Nirav] implemented what he refers to as a “bucket” design. The majority of the case is a single print, which does take a long time (just shy of 40 hours on his Prusa i3 MK3), but nearly eliminates any post-printing assembly. Only the optional feet and the lid need to be printed separately. Threaded inserts are used throughout the design for mounting hardware, so you don’t run the risk of blowing out the printed holes during hardware changes or upgrades.

A particularly neat feature, and a testament to the power of OpenSCAD, is the fact that the case’s internal volume is calculated and embossed into the side of the design. Does this have any practical purpose? Not exactly, but [Nirav] thought it would be appealing to the Mini-ITX case modding community which apparently measures their accomplishments in liters of volume.

We’ve seen a 3D printed computer case before, but it used acrylic sheets and couldn’t be made without a large format printer. There’s something to be said for a project that can be completed on the hacker community’s favorite printer.

Better 3D Printing Through Magnets

November 5, 2018 by Al Williams 21 Comments

Just like Goldilocks found some porridge too hot and some too cold, 3D printers often have beds that don’t stick well enough or stick too well. A few weeks ago I switched two of my three printers to use magnetic beds and thought I’d share with you how that worked out. Spoiler alert: like most things it has its plusses and minuses.

It isn’t a secret that 3D printing is not a plug-and-play operation, especially at the price most of us are willing to pay for printers. There are lots of variables to get right: temperature, speeds, bed leveling, and a bunch of other things. However, one of the things that vexes many people is the relationship between getting that first layer to stick and being able to get the print off the bed when you are done. It is hard to find a happy medium. If the first layer won’t stick, you print is doomed. If the first layer sticks too well, you are likely to damage the part or your fingers getting it removed. I switched to BuildTak surfaces long ago, and many people like PEI. But it is sometimes hard to get a big part removed. A few weeks ago, I took the plunge and bought some magnetic build surfaces for two of my printers. These were “no name” inexpensive affairs from Ali Express.

The idea is simple. There are two sheets that look like a rubberized plastic and have magnetic properties. One piece has some 3M adhesive on the back. The other has one surface that resembles BuildTak. Once you glue down the one sheet you leave it alone. Then you put the other sheet on top and print on it. When you are done, you can pull the sheet out and flex it to pop the print off. That’s the theory, anyway. Continue reading “Better 3D Printing Through Magnets” →

ESP8266 Monitor Keeps An Eye On OctoPrint

November 5, 2018 by Tom Nardi 8 Comments

At this point, you’ve almost certainly heard of OctoPrint. The web-based control interface for 3D printers is especially popular for those who’s primary computers run on an operating system that has a penchant for occasionally imploding. Even if you aren’t laboring under that common software handicap, OctoPrint offers a wide away of compelling features. Perhaps chief among them the ability to monitor your printer over the network, and if you insist, over the Internet. But while OctoPrint provides the server side for getting your printer on the net, you’re on your own for the client.

Rather than using a web browser like some kind of peon, [David Payne] has come up with a very slick desktop OctoPrint monitor using the WeMos D1 Mini ESP8266 board. With an exceptionally low part count and housed in a (what else) 3D printed enclosure, this is a cheap and easy OctoPrint accessory that we suspect will be decorating many a hacker’s desk before too long.

The electronics are simple to the extreme, just hook the 4 wires of an 128×64 OLED I2C display to the appropriate pins of the ESP8266 board, and you’re ready to upload the Arduino code [David] has come up with.

His code is very polished, from using WiFiManager for initial network setup to providing its own web-based configuration menus to get the device linked up to your OctoPrint instance, [David] clearly wanted this to be as smooth an experience as possible for the end user. When the 3D printer isn’t working on a job, the monitor will even switch over to showing you the time and weather. We’ve seen commercial products that weren’t this user-friendly.

We also love the case design on this little gadget. While the aesthetics are perhaps debatable (sort of reminds us of the little fellows from Darwinia), we appreciate any functional print that doesn’t require supports. You’ll need to provide a couple of little screws to keep the back panel on, but other than that everything snaps into place.

Of course, you could always just use your smartphone to keep an eye on OctoPrint, and even if the remote management capabilities don’t grab your interest, there’s plenty of interesting plugins to keep you occupied.

Continue reading “ESP8266 Monitor Keeps An Eye On OctoPrint” →

Living Hinges At The Next Level

November 4, 2018 by Brian McEvoy 13 Comments

First of all, a living hinge is not a biological entity nor does it move on its own. Think of the top of a Tic Tac container where the lid and the cover are a single piece, and the thin plastic holding them together flexes to allow you to reach the candies disguised as mints. [Xiaoyu “Rayne” Zheng] at Virginia Tech designed a method of multimaterial programmable additive manufacturing which is fancy-ese for printing with more than one type of material.

The process works under the premise of printing a 3D latticework, similar to the “FILL” function of a consumer printer. Each segment of material is determined by the software and mixed on the spot by the printer and cured before moving onto the next segment. Like building a bridge one beam at a time, if that bridge were meant for tardigrades and many beams were fabricated each minute. Mixing up each segment as needed means that a different recipe results in a different rigidity, so it is possible to make a robotic leg with stiff “bones” and flexible “joints.”

We love printing in different materials, even if it is only one medium at a time. Printing in metal is useful and could be consumer level soon, but you can print in chocolate right now.

Via Phys.org. Thank you again for the tip, [Qes].