InstantCAD Promises Faster Iterative Design

The design process for any product is necessarily an iterative one. Often, a prototype is modelled or built, and changes are made to overcome problems and improve the design. This can be a tedious process, and it’s one that MIT’s CSAIL has sought to speed up with InstantCAD.

The basic idea is integrating analysis tools as a plugin within already existing CAD software. A design can be created, and then parametrically modified, while the analysis updates on screen in a near-live fashion. Imagine modelling a spanner, and then dragging sliders to change things like length and width while watching the stress concentrations change in real time. The tool appears to primarily be using some sort of finite element analysis, though the paper also shows examples of analyzing fluid flows as well.

The software is impressive, however there are caveats. Like any computer analysis, serious verification work must be undertaken to ensure its validity. We suspect that there may be issues with more complex geometries that lead to inaccurate simulation. It’s not the sort of tool you’d use for anything that puts life and limb at risk, but we can see it having great uses for designing basic objects when you want to quickly gain an idea of what sort of effect certain parameter changes will have.

The other main disappointment is that while this tool looks great, it doesn’t appear to be publicly available in any form. Whether this is due to universities and complicated IP requirements or the potential for future commercialization is anyone’s guess. Regardless, you can read the conference paper here or check out the video below. Or you could read up on the applications of finite element analysis to 3D printer slicers, too.

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DIY Shortcut Keyboard

Working with CAD programs involves focusing on the task at hand and keyboard shortcuts can be very handy. Most software packages allow the user to customize these shortcuts but eventually, certain complex key combination can become a distraction.

[awende] over at Sparkfun has created a Cherry MX Keyboard which incorporates all of the Autodesk Eagle Shortcuts to a single 4×4 matrix. The project exploits the Arduino Pro Mini’s ability to mimic an HID device over USB thereby enabling the DIY keyboard. Pushbuttons connected to the GPIOs are read by the Arduino and corresponding shortcut key presses are sent to the host machine.

Additional functionality is implemented using two rotary encoders and the Teensy encoder library. The first knob functions as a volume control with the push-button working as a mute button. The encoder is used to control the grid spacing and the embedded button is used to switch between imperial and metric units. The entire code, as well as the schematic, is available on GitHub for your hacking pleasure. It’s a polished project just ready for you to adapt.

The project can be extended to be used with other computer software such as Gimp and the keys may be replaced by capacitive touch sensors making it more sturdy. Bluetooth can be added to make things wireless and you can check out the Double Action Keyboard to extend functionality further. Continue reading “DIY Shortcut Keyboard”

Practical Enclosure Design, Optimized for 3D Printing

[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.

3D-Printed Vise Is a Mechanical Marvel

We often wonder how many people have 3D printers and wind up just printing trinkets off Thingiverse. To get the most out of a printer, you really need to be able to use a CAD package and make your own design. However, just like a schematic editor doesn’t make your electronic designs work, a CAD program won’t ensure you have a successful mechanical part.

[TheGoofy] has a 100% 3D printed vise that looks like it is useful. What’s really interesting, though, is the video (see below) where he explains how printing affects material strength and other design considerations that went into the vise.

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Building a Replica of an Ultraluxury Watch

In the world of late-stage capitalism, unchecked redistribution of wealth to the upper classes has led to the development of so-called ultraluxury watches. Free from any reasonable constraints on material or R&D cost, manufacturers are free to explore the outer limits of the horological art. [Karel] is an aspiring engineer and watch enthusiast, and has a taste for the creations of Urwerk. They decided to see if they could create a replica of the UR202 watch with nothing more than the marketing materials as a guide.

[Karel]’s first job was to create a model of the watch in CAD. For a regular watch this might be simple enough, but the UR202 is no run-of-the-mill timepiece. It features a highly irregular mechanism, full of things like a turbine regulated winding mechanism, telescoping rods instead of minute hands, and tumbling rotors to indicate the hours. The official product sheet bears some of these features out. Through careful analysis of photos and watching videos frame-by-frame, they managed to recreate what they believe to be a functioning mechanical model within their CAD software.

It was then time to try and build the timepiece for real. It was then that [Karel] started hitting some serious stumbling blocks. As a humble engineering student, it’s not often possible to purchase an entire machine shop capable of turning out the tiny, precision parts necessary to make even a basic watch mechanism. Your basic 3D printer squirting hot plastic isn’t going to cut it here. Farming out machining wasn’t an option as the cost would be astronomical. [Karel] instead decided on combining a Miyota movement with a machined aluminum base plate and parts 3D printed using a process known as “Multijet Modelling” which essentially is an inkjet printhead spitting out UV curable polymer.

In the end, [Karel] was able to get just the tumbling hour indicator working. The telescoping minute hand, compressed air turbine winding system, and other features didn’t make it into the build. However, the process of simulating these features within a CAD package, as well as manufacturing a semi-functional replica of the watch, was clearly a powerful learning experience. [Karel] used their passion to pursue a project that ended up giving them a strong grasp of some valuable skills, and that is something that is incredibly rewarding.

We’ve seen others trying to fabricate parts of a wristwatch at home. Keep your horological tips coming in!

[Thanks to Str Alorman for the tip!]

Will Your CAD Software Company Own Your Files, Too?

We’re used to the relationship between the commercial software companies from whom we’ve bought whichever of the programs we use on our computers, and ourselves as end users. We pay them money, and they give us a licence to use the software. We then go away and do our work on it, create our Microsoft Word documents or whatever, and those are our work, to do whatever we want with.

There are plenty of arguments against this arrangement from the world of free software, indeed many of us choose to heed them and run open source alternatives to the paid-for packages or operating systems. But for the majority of individuals and organisations the commercial model is how they consume software. Pay for the product, use it for whatever you want.

What might happen were that commercial model to change? For instance, if the output of your commercial software retained some ownership on the part of the developer, so for example maybe a word processor company could legally prevent you opening a document in anything but their word processor or viewer. It sounds rather unreasonable, and maybe even far-fetched, but there is an interesting case in California’s Ninth Circuit court that could make that a possibility. Continue reading “Will Your CAD Software Company Own Your Files, Too?”

Open-Source Parametric CAD in Your Browser

Until recently, computer-aided design (CAD) software was really only used by engineering companies who could afford to pay thousands of dollars a year per license. The available software, while very powerful, had a very high learning curve and took a lot of training and experience to master. But, with the rise of hobbyist 3D printing, a number of much more simple CAD programs became available.

While these programs certainly helped makers get into 3D modeling, most had serious limitations. Only a few have been truly open-source, and even fewer have been both open-source and parametric. Parametric CAD allows you to create 3D models based on a series of parameters, such as defining a cube by its origin and dimensions. This is in contrast to sculpting style 3D modeling software, which is controlled much more visually. The benefit of parametric modeling is that parameters can be changed later, and the model can be updated on the fly. Features can also be defined mathematically, so that they change in relation to each other.

While still in its infancy, JS.Sketcher is seeking to fill that niche. It is 100% open-source, runs in your browser using only JavaScript, and is fully parametric (with both constraints and editable dimensions). At this time, available features are still pretty limited and simple. You can: extrude/cut, revolve, shell, and do boolean operations with solids. More advanced features aren’t available yet, but hopefully will be added in the future.

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