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.
Continue reading “Retrotechtacular: Fire Control Computers in Navy Ships”
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”
[Vilem] sent in a tip about a plugin he’s been working on for Blender, called Blender CAM. It allows for exporting directly from Blender to a G-code file. He has been working on it for several months, and releasing regular updates with various tweaks and improvements. While the project isn’t complete, [Vilem] has made some very impressive progress. It currently supports 2D and 3D strategies, various cutter types, simulation of 3D operations, and even automatic bridges.
The image above was made using the plugin, and it shows the level of detail possible. We can’t wait to see the 4 and 5-axis support that he is planning on adding.
A basic tutorial video is embedded after the break. As with anything Blender-related, it isn’t incredibly automatic, but another free tool is definitely a good thing. It looks like [Vilem] is looking for some other developers who could help out. If you have the knowledge, you might consider contributing.
Continue reading “Blender CAM – Open Source CAM Software”
Long ago, before servo motors and linear actuators were common, clever mechanical devices were what engineers used to produce the needed motion for their processes. The CNC-cut Geneva Drive may not be fit for industrial use, but this type of device has been used in everything from film projectors to rotating assembly tables. The constant rotation of the driving wheel is translated into intermittent motion by the [Maltese cross] driven wheel.
The drive and Maltese cross section of this particular drive are made out of MDF with the exception of a putty material that the motor shaft press-fits into. The article claims that this is the only Geneva drive in existence made out of MDF, however, we’d love to see that proven wrong in the comments!
If you’d like to make one of these yourself, CAD and G-code files are given for the hand-cranked version that this Drive is based off of in a separate post. If you’re not familiar with how a drive like this works, or would just like to see everything in action, be sure to check out the video of it after the break! Continue reading “A Little Geneva Drive Made of Wood”
Here is the next installment in our series of Eagle CAD videos. In this video we skip ahead a bit and show off the CAM processor that you use to create the files necessary to have your circuit boards be manufactured. After watching this video, you will know how create a new CAM program, load a circuit board into the CAM processor, tell it where to save your files, and actually use it to create the files.
We’re skipping ahead today because of a screw up on our part. We meant to show the layout portion of the program today but edited the wrong video… We’ll show layout next week. After that, we will show the completed circuit board and solder the parts onto it.
If you are itching for some Eagle CAD layout info, you may be interested in some supplementary videos that we have uploaded to our Youtube channel. In those videos, we show how to use the most important features in the layout portion of the Eagle CAD.
Have you missed the previous videos? Here are some links to them:
Schematic and the beginning of a custom part: [click here]
More custom part stuff: [click here]
Video is after the break:
Continue reading “Video – Eagle CAD’s CAM processor”
PartKAM is a Flash-based CAM production package created by [Jack Qiao]. There are a ton of computer aided manufacturing suites out there, this one is simple and requires nothing more than having your browser open. We played with it for a few moments and found it useful but still a bit buggy. Most notably, it lacks a ‘undo’ option. That being said, you can export as SVG or gCode for use when you just need to hammer out a few parts with that CNC mill you threw together.