Hackaday Prize Entry: 3D Printed Mini-Lathe

May 31, 2017 by Lewin Day 20 Comments

Lathes can be big, powerful, dangerous machines. But sometimes there’s a call for making very small parts out of soft materials, like plastic and wood. For jobs like this, you could use something like this 3D printed mini-lathe.

The benefits of 3D printing a tool like this are plentiful. The design can be customized and refined by the end user; [castvee8] notes that the machine can be made longer simply by increasing the length of the lead screw and guide rails. The machine does rely on some metal parts and a motor; but the real power here is that if you can’t source the exact components, you can always customize the files to suit what you have on hand.

[castvee8] aimed to make the entire build as easy as possible for the novice – even the motor and speed controller are off-the-shelf modules. It’s a testament to the golden age we live in that an entire lathe can be built out of modules and 3D printed parts. The project makes up another member of the family of 3D printed tools [castvee8] is showing off on Hackaday.io.

Practical Enclosure Design, Optimized For 3D Printing

May 24, 2017 by Donald Papp 36 Comments

[3D Hubs] have shared a handy guide on designing practical and 3D printing-friendly enclosures. The guide walks through the design of a two shell, two button remote control enclosure. It allows for a PCB mounted inside, exposes a USB port, and is optimized for 3D printing without painting itself into a corner in the process. [3D Hubs] uses Fusion 360 (free to hobbyists and startups) in their examples, but the design principles are easily implemented with any tool.

One of the tips is to design parts with wall thicknesses that are a multiple of the printer’s nozzle diameter. For example, a 2.4 mm wall thickness may sound a bit arbitrary at first, but it divides easily by the typical FDM nozzle diameter of 0.4 mm which makes slicing results more consistent and reliable. Most of us have at some point encountered a model where the slicer can’t quite decide how to handle a thin feature, delivering either a void between perimeters or an awkward attempt at infill, and this practice helps reduce that. Another tip is to minimize the number of sharp edges in the design, because rounded corners print more efficiently and with smoother motions from the print head.

The road to enclosures has many paths, including enclosures made from FR4 (aka PCB material) all the way down to scrap wood with toner transfer labeling, and certainly desktop 3D printing has been a boon to anyone who’s had to joylessly drill and saw away at a featureless plastic box.

DIY USB Power Bank

May 21, 2017 by Eric Evenchick 47 Comments

USB power banks give your phone some extra juice on the go. You can find them in all shapes and sizes from various retailers, but why not build your own?

[Kim] has a walkthrough on how to do just that. This DIY USB Power Bank packs 18650 battery cells and a power management board into a 3D printed case. The four cells provide 16,000 mAh, which should give you a few charges. The end product looks pretty good, and comes in a bit cheaper than buying a power bank of similar capacity.

The power management hardware being used here appears to be a generic part used in many power bank designs. It performs the necessary voltage conversions and manages charge and discharge to avoid damaging the cells. A small display shows the state of the battery pack.

You might prefer to buy a power bank off the shelf, but this design could be perfect solution for adding batteries to other projects. With a few cells and this management board, you have a stable 5 V output with USB charging. The 2.1 A output should be enough to power most boards, including Raspberry Pis. While we’ve seen other DIY Raspberry Pi power banks in the past, this board gets the job done for $3.

Endstops That Stay Out Of The Way

March 30, 2017 by Donald Papp 7 Comments

In the course of building a new delta printer, [thehans] decided he needed his own endstop design that used minimal hardware. Endstops are just switches that get hit when the printer moves at the extreme of an axis, but [thehans] wanted something with a bit of refinement for his BigDelta 3D Printer build.

The result is a small unit that cradles a microswitch and needs only a single zip tie that mounts flush, resulting in a super tidy looking piece. In addition, it mounts on the delta’s v-slot rails such that the mount does not take up any of the machine’s range of motion, because the carriage can travel past it. It is a parametric design made in OpenSCAD, so feel free to modify it to accommodate other types of switches.

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Walter Is The Slickest Retro-Futuristic Robot Arm

March 9, 2017 by Elliot Williams 11 Comments

[Jochen Alt] is on a roll. We just covered his ball-balancing robot, Paul, only to find his phenomenal six-DOF robot arm in full retro style. Its name is “Walter” and it’s done up in DDR style (the former East Germany), in painted, 3D-printed plastic. The full design and build documents are an absolutely amazing resource if you’re into robot arm or legs.

In particular, the sections on trajectory planning and kinematics are fantastic. If you’re interested in robot motion planning by Bezier curves, you know where to go. (We’ve always wanted a Bezier-curve 3D printer slicer, but that’s another story.) The construction is also top-notch here, and the attention to detail that went into this arm is phenomenal. It’s all done with stepper motors and geared belts, which allow each of Walter’s joints to be driven by a motor that’s one joint further upstream than would be the case if it were designed with servos. [Jochen] even went so far as to expose the belt in some places to show off the gearing. Walter is worth checking out.

Even if you’ll never build such a fancy robot arm, you should read through the docs just to appreciate all of the thought and work that went into this very refined and simple-from-the-outside design. If you’d like to start out on the simple side of the spectrum, check out these robot arms made of office supplies or a desk lamp. Once you’re ready for your second arm project this short list, some of which [Jochen] mention in his writeup, should get you up and grasping. And do check out his balancing bot, Paul.

DIY Syringe Pump Saves Big Bucks For Hacker’s Lab

February 26, 2017 by Dan Maloney 55 Comments

If you had a choice between going to your boss and asking for funds for a new piece of gear, would you rather ask for $3000 to buy off-the-shelf, or $200 for the parts to build the same thing yourself? Any self-respecting hacker knows the answer, and when presented with an opportunity to equip his lab with a new DIY syringe pump for $200, [Dr. D-Flo] rose to the challenge.

The first stop for [Dr. D-Flo] was, naturally, Hackaday.io, which is where he found [Naroom]’s syringe pump project. It was a good match for his budget and his specs, but he needed to modify some of the 3D printed parts a little to fit the larger syringes he intended to use. The base is aluminum extrusion, the drive train is a stepper motor spinning threaded rod and a captive nut in the plunger holders, and an Arduino and motor shield control everything. The drive train will obviously suffer from a fair amount of backlash, but this pump isn’t meant for precise dispensing so it shouldn’t matter. We’d worry a little more about the robustness of the printed parts over time and their compatibility with common lab solvents, but overall this was a great build that [Dr. D-Flo] intends to use in a 3D food printer. We look forward to seeing that one.

It’s getting so that that you can build almost anything for the lab these days, from peristaltic pumps to centrifuges. It has to be hard to concentrate on your science when there’s so much gear to make.

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This 3D Printed Microscope Bends For 50nm Precision

February 17, 2017 by Michael Uttmark 20 Comments

Exploiting the flexibility of plastic, a group of researchers has created a 3D printable microscope with sub-micron accuracy. By bending the supports of the microscope stage, they can manipulate a sample with surprising precision. Coupled with commonly available M3 bolts and stepper motors with gear reduction, they have reported a precision of up to 50nm in translational movement. We’ve seen functionality derived from flexibility before but not at this scale. And while it’s not a scanning electron microscope, 50nm is the size of a small virus (no, not that kind of virus).

OpenFlexure has a viewing area of 8x8x4mm, which is impressive when the supports only flex 6°. But, if 256 mm³ isn’t enough for you, fret not: the designs are all Open Source and are modeled in OpenSCAD just begging for modification. With only one file for printing, no support material, a wonderful assembly guide and a focus on PLA and ABS, OpenFlexure is clearly designed for ease of manufacturing. Optics are equally interesting. Using a Raspberry Pi Camera Module with the lens reversed, they achieve a resolution where one pixel corresponds to 120nm.

The group hopes that their microscopes will reach low-resource parts of the world, and it seem that the design has already started to spread. If you’d like to make one for yourself, you can find all the necessary files up on GitHub.

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