Cams And Pushrods Improve 3D-Printed Compressed Air Engine

April 27, 2018 by Dan Maloney 12 Comments

Some folks just can’t leave well enough alone, and that often ends up being a good thing. Such is the case with this 3D-printed compressed air engine, which just keeps getting better.

The design has changed a lot since we first covered [Tom Stanton]’s attempts at reviving the powerplant from the glory days of the Air Hogs line of toys, which he subsequently built a plane around. The engine was simple, with a ball valve that admitted air into the cylinder when a spring mounted to the top of the piston popped it out of the way. That spring has always bothered [Tom], though, compelling him to go back to the drawing board. He wanted to replace the ball valve with one actuated by a cam and pushrod. This would increase the complexity of the engine quite a bit, but with the benefit of eliminating the fail point of the spring. With a few iterations in the design, he was able to relocate the ball valve, add a cam to the crankshaft, and use a pushrod to open the valve. The new design works much better than the previous version, sounding more like a lawnmower than a 3D-printed engine should. Check out the design process and some tests in the video below.

And speaking of lawnmowers that run on compressed air…

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A Mechanical Laser Show With 3D-Printed Cams And Gears

June 15, 2017 by Dan Maloney 22 Comments

Everyone knows how to make a POV laser display — low-mass, first-surface mirrors for the X- and Y-axes mounted on galvanometers driven rapidly to trace out the pattern. [Evan Stanford] found a simpler way, though: a completely mechanical laser show from 3D-printed parts.

The first 10 seconds of the video below completely explains how [Evan] accomplished this build. A pair of custom cams wiggles the laser pointer through the correct sequences of coordinates to trace the desired pattern out when cranked by hand through a 1:5 ratio gear train. But what’s simple in concept is a bit more complicated to reduce to practice, as [Evan] amply demonstrates by walking us through the math he used to transfer display shapes to cam profiles. If you can’t follow the math, no worries — [Evan] has included all the profiles in his Thingiverse collection, and being a ~~hand model~~ software guy by nature, he’s thoughtfully developed a program to automate the creation of cam profiles for new shapes. It’s all pretty slick.

Looking for more laser POV goodness? Perhaps a nice game of laser Asteroids would suit you.

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Plasma Cutter Jig Notches Tubing Quickly And Cleanly

February 23, 2017 by Dan Maloney 14 Comments

It may be [MakeItExtreme]’s most ambitious build to date. There are a lot of moving parts to this plasma cutter tubing notcher, but it ought to make a fine addition to the shop and open up a lot of fabrication possibilities.

We have to admit to a certain initial bafflement when watching the video below for the first time. We can usually see where [MakeItExtreme]’s builds are going right from the first pieces of stock that get cut, but the large tube with the pressed-in bearing had us scratching our heads. The plan soon became clear — a motorized horizontal rotary table with a hollow quill for the plasma torch leads. There’s a jig for holding the torch itself that can move in and out relative to the table. Cams made of tube sections can be bolted to a fixed platen; a cam follower rides on the cams and moves the torch in and out as the table rotates. This makes the cuts needed to properly fit tubes together — known as fish mouth cuts or saddle cuts. The cams can be removed for straight cuts, and the custom pipe vise can be adjusted to make miter cuts.

All in all a sturdy and versatile build that ought to enable tons of new projects, especially when teamed up with [MakeIt Extreme]’s recent roll bender.

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‘LinuxCNC-Features’ Is The Garage-Fab’s Missing CAM Tool

December 25, 2015 by Sonya Vasquez 15 Comments

It takes a long toolchain to take the garage-machinist-to-be through all the hoops needed to start cranking out parts. From the choice of CAD software to the CAM tools that turn 3D models into gcode, to the gcode interpretters that chew up this source code and spit out step and direction pulses to turn the cranks of a cnc mill, there’s a multitude of open-and-closed source tools to choose from and even an opportunity to develop some of our own. That’s exactly what [Nick] and the folks over on the cnc-club forums did; they’ve written their own CAM tool that enables the end user to design a procedure of cuts and toolpaths that can export to gcode compatible with LinuxCNC.

Their tool, dubbed “LinuxCNC-features”, embeds a LinuxCNC-compatible graphical gcode programming interface directly into the LinuxCNC native user interface. Creating a part is a matter of defining a list of sequential cuts along programmable toolpaths. These sequential cuts are treatments like drilled holes, square pockets, bolt holes, and lines. The native embedding enables the machinist to preview each of the 3D toolpaths in LinuxCNC’s live view, giving him-or-her a quick-and-dirty check to make sure that their gcode performs as expected before running it. [Nick] has a couple of videos to get you up-and running on either your mill or lathe.

LinuxCNC-features has been out in the wild for almost two years now, but if you’re looking to get started cranking out parts in the garage, look no further for a CAM tool that can quickly generate gcode for simple projects. In case you’re not familiar with LinuxCNC, it’s one of the most mature open-source gcode interpreters designed to turn your PC into a CNC controller, and it’s the brains behind some outstanding DIY CNC machines like this plasma cutter.

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Hacklet 31 – Software Tools

January 23, 2015 by Brian Benchoff 20 Comments

For every computer error, there are two human errors, and one of them is blaming the computer. Whenever a human blames a computer for something, there are two tools, and one of them is the computer.

Not all of your nifty tools need to be fancy robots, CNC machines, or nifty Robertson screwdrivers; a computer is equally capable of being a fantastic tool, provided it has the right software. For this week’s Hacklet, we’re going through some of the best software tools on hackaday.io.

[Alan] was inspired to build a software tool for making sewing patterns. Sewing patterns are usually designed for the ‘average’ person, but if you’re making custom wearables, you should end up with a piece of clothing that fits perfectly.

The first project [Alan] is using this tool for is a fleece cap that fits the contour of his head. He captured a 3D mesh of his head, imported the mesh into Blender, and unwrapped the resulting mesh. The two halves of the hat were then plotted with a Silhouette Cameo, cut out of fleece, and sewn together. The result is a beanie that fits perfectly around [Alan]’s head. It’s an extremely cool and novel application of 3D modeling, and if you ever need to wrap a 3D object with a 2D material, this is the project you want to check out.

And you thought the autorouter in Eagle was bad.

[Anderson] built a tool called Pyrite that will take a schematic and build a layout in three-dimensional space. He calls them Volumetric Circuits, and it’s basically the point-to-point wiring found in old radios and amplifiers taken to the next level. We featured this project before, and there haven’t been many updates since then. Maybe giving [Anderson]’s project a few skulls will help motivate him to get back to the project.

Not satisfied with the existing free and open source CAM programs, [Snegovick] started work on his own.

[Snegovick] calls his project BCAM, and it’s exactly what you need to mill holes in PCBs, cut gears with a CNC router, engrave plastic, and anything else a 2.5 axis CNC machine can do. The project is written in Python, and yes, the source is available. Supported operations include drilling, path following, offset path following, and pocketing.

Write enough microcontroller projects, and you’ll eventually come up with your own library of common code that does one thing and one thing well. If you’re smart, you’ll reuse that code in future projects. [ericwazhung] is cutting through the hard part of developing all this code and released some things that are useful in a whole lot of projects.

Included in the commonCode library are the usual ‘heartbeat LED’, non-blocking input, a standard interface for AVR timers, bitmaps of text characters, DC motor control, and a whole bunch more. Extremely useful in any event.

That’s it for this round of the Hacklet, bringing you the best hackaday.io has to offer.

Retrotechtacular: Fire Control Computers In Navy Ships

October 28, 2014 by Kristina Panos 29 Comments

Here is a two-part Navy training film from 1953 that describes the inner workings of mechanical fire control computers. It covers seven mechanisms: shafts, gears, cams, differentials, component solvers, integrators, and multipliers, and does so in the well-executed fashion typical of the era.

Fire control systems depend on many factors that occur simultaneously, not the least of which are own ship’s speed and course, distance to a target, bearing, the target’s speed and course if not stationary, initial shell velocity, and wind speed and direction.

The mechanisms are introduced with a rack and pinion demonstration in two dimensions. Principally speaking, a shaft carries a value based on revolutions. From this, a system can be geared at different ratios.

Cams take this idea further, transferring a regular motion such as rotation to an irregular motion. They do so using a working surface as input and a follower as output. We are shown how cams change rotary motion to linear motion. While the simplest example is limited to a single revolution, additional revolutions can be obtained by extending the working surface. This is usually done with a ball in a groove.

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Software Advice For Anyone Thinking About A CNC Router

December 23, 2013 by Jeremy Cook 128 Comments

Excellent results can come from a small CNC router, but don’t forget the software!

CNC tools, whatever their flavor, can greatly enhance your “making” or DIY ability. My current tool of choice is a CNC router. Being familiar with a manual milling machine, the concept seemed similar, and the price of these is quite reasonable when compared to some other tools. As described in this post, my machine is a Zen Toolworks model, but there are certainly other options to visit like this Probotix V90 model noted recently in this post.

Although any number of CNC router models look great in videos and pictures, rest assured that even the best machines require some patience to get one running satisfactorily. Setting up the machine can be a challenge, as well as figuring out what your machine is capable of, but one thing that might slip peoples’ minds is the software involved. Read on to find out ~~all you need to know~~ the basics of what goes on behind the scenes to “magically” produce interesting parts. Continue reading “Software Advice For Anyone Thinking About A CNC Router” →