An IPhone Case Study

December 15, 2024 by Bryan Cockfield 14 Comments

Way back in 2008, Apple unveiled the first unibody Macbook with a chassis milled out of a single block of aluminum. Before that, essentially all laptops, including those from Apple, were flimsy plastic screwed together haphazardly on various frames. The unibody construction, on the other hand, finally showed that it was possible to make laptops that were both lightweight and sturdy. Apple eventually began producing iPhones with this same design style, and with the right tools and a very accurate set of calipers it’s possible to not only piece together the required hardware to build an iPhone from the ground up but also build a custom chassis for it entirely out of metal as well.

The first part of the project that [Scotty] from [Strange Parts] needed to tackle was actually getting measurements of the internals. Calipers were not getting the entire job done so he used a flatbed scanner to take an image of the case, then milled off a layer and repeated the scan. From there he could start testing out his design. After an uncountable number of prototypes, going back to the CAD model and then back to the mill, he eventually settles into a design but not before breaking an iPhone’s worth of bits along the way. Particularly difficult are the recessed areas inside the phone, but eventually he’s able to get those hollowed out, all the screw holes tapped, and then all the parts needed to get a working iPhone set up inside this case.

[Scotty] has garnered some fame not just for his incredible skills at the precision mill, but by demonstrating in incredible detail how smartphones can be user-serviceable or even built from scratch. They certainly require more finesse than assembling an ATX desktop and can require some more specialized tools, but in the end they’re computers like any other. For the most part.

Continue reading “An IPhone Case Study” →

Optical illusion gingerbread house from an odd perspective

An Engineer’s Perspective On Baking Gingerbread Houses

December 10, 2024 by Heidi Ulrich 5 Comments

If you’ve ever wanted to merge the worlds of holiday cheer and clever geometry, [Kris Wilk]’s gingerbread house hack is your ultimate inspiration. Shared in a mesmerising video, [Wilk] showcases his 2024 entry for his neighborhood’s gingerbread house contest. Designed in FreeCAD and baked to perfection, this is no ordinary holiday treat. His pièce de résistance was a brilliant trompe l’oeil effect, visible only from one carefully calculated angle. Skip to the last twenty seconds of the video to wrap your head around how it actually looks.

[Wilk] used FreeCAD’s hidden true perspective projection function—a rarity in CAD software. This feature allowed him to calculate the perfect forced perspective, essential for crafting the optical illusion. The supporting structures were printed on a Prusa MK4, while the gingerbread itself was baked at home. Precision photography captured the final reveal, adding a professional touch to this homemade masterpiece. [Wilk]’s meticulous process highlights how accessible tools and a sprinkle of curiosity can push creative boundaries.

For those itching to experiment with optical illusions, this bakery battle is only the beginning. Why not build a similar one inside out? Or construct a gingerbread man in the same way? Fire up the oven, bend your mind, and challenge your CAD skills!

Continue reading “An Engineer’s Perspective On Baking Gingerbread Houses” →

Zero To Custom MacroPad In 37 Easy Steps

October 21, 2024 by Dave Rowntree 5 Comments

[Jeremy Weatherford] clearly has a knack for explaining projects well enough for easy reproduction but goes way further than most and has created a four-part YouTube series detailing every step from project inception to the final assembly, covering all aspects of 3D modelling and PCB design for a custom MacroPad design. Many tools are introduced along the way, all of which help reduce complexity and, by extension, the scope for errors. As every beginner hacker knows, early successes breed confidence and make for better and more ambitious projects.

Part 1 covers the project motivation and scope and introduces a keyboard layout editor tool. This tool allows one to take a layout idea and generate a JSON file, which is then used to drive keyboard tools. XYZ to produce a usable KiCAD project. The tool only generates a PCB project and an associated netlist file. No schematic is created; you don’t need one for a simple layout.

Part 2 is a walkthrough of the design process in KiCAD, culminating in ordering the PCB from JLCPCB and assembling the surface-mount parts. This particular design uses a controller based on the Sea-Picro RP2040 module, but there are many options if you have other preferences. [Jeremy] shows what’s possible with the selected suppliers, but you need not follow this step precisely if you have other ideas or want to use someone local.

Part 3 covers exporting the mechanical aspects of the PCB out of KiCAD and into a 3D CAD program, specifically OnShape. [Jeremy] covers some crucial details, such as how to read the mechanical drawing of the keys to work out where to place the top plate. It’s very easy to plough straight in at this stage and make a design which cannot be assembled! The plan is to use a simple laser-cut box with a bottom plate with mounting holes lining up with those on the PCB. A Top plate is created by taking the outline of the PCB and adding a little margin. An array of rectangular cutouts are designed for the keys to protrude, lining up perfectly with where the keys would be when mounted on the PCB below. The sides of the case are formed from laser-cut sections that lock into each other and the laser-cut base—using the laser joint feature-script addon tool from the OnShape community channel. A second feature script addon is used to auto-layout the laser-cut components onto a single sheet. A CAM application called Kiri Moto is used to export for laser cutting and is available on the OnShape store.

Continue reading “Zero To Custom MacroPad In 37 Easy Steps” →

CADmium Moves CAD To The Browser

May 23, 2024 by Bryan Cockfield 43 Comments

For plenty of computer users, the operating system of choice is largely a middleman on the way to the browser, which hosts the tools that are most important. There are even entire operating systems with little more than browser support, under the assumption that everything will be done in the browser eventually. We may be one step closer to that type of utopia as well with this software tool called CADmium which runs exclusively in a browser.

As the name implies, this is a computer-aided design (CAD) package which looks to build everything one would need for designing project models in a traditional CAD program like AutoCAD or FreeCAD, but without the burden of needing to carry local files around on a specific computer. [Matt], one of the creators of this ambitious project, lays out the basic structure of a CAD program from the constraint solver, boundary representation (in this case, a modern one built in Rust), the history tracker, and various other underpinnings of a program like this. The group hopes to standardize around JSON files as well, making it easy to make changes to designs on the fly in whatever browser the user happens to have on hand.

While this project is extremely early in the design stage, it looks like they have a fairly solid framework going to get this developed. That said, they are looking for some more help getting it off the ground. If you’ve ever wanted something like this in the browser, or maybe if you’ve ever contributed to the FreeCAD project and have some experience, this might be worth taking a look at.

Throw FreeCAD Some Curves

August 12, 2023 by Al Williams 43 Comments

[Mango Jelly] got a question from someone trying to model a phone box with a complex curved roof. We have to admit that when we saw it, we knew it would be hard to model well. Naturally, there are several ways it could be one, but [Mango Jelly] used the curves workbench in FreeCAD to produce a wireframe of the shape, and you can see how that works in the video below.

The curve bench didn’t sound familiar to us, and that’s because it is an add-on workbench. He starts with a sketch of a curve, constrained to be symmetrical. Then the draft workbench allowed a rotation to convert the curve into a nice skeleton of the curved roof.

The curves workbench can create a Gordon surface over that skeleton. You can extrude that into a solid object. There are still some details to add, though, and you’ll see how each part of the roof takes shape.

Watching videos like this reminds us that we use a small fraction of what FreeCAD can do. You’ll probably pick up at least one tip from this video. If you need a quick basic tutorial, try the one from [NovaSpirit]. Or, try a longer one.

Continue reading “Throw FreeCAD Some Curves” →

Enhance Your Enclosures With A Shadow Line

August 7, 2023 by Donald Papp 15 Comments

Some design techniques and concepts from the injection molding world apply very nicely to 3D printing, despite them being fundamentally different processes. [Teaching Tech] demonstrates designing shadow lines into 3D printed parts whose surfaces are intended to mate up to one another.

This is a feature mainly seen in enclosures, and you’ve definitely seen it in all kinds of off-the-shelf products. Essentially, one half of the part has a slight “underbite” of a rim, and the other half has a slight “overbite”, with a bit of a standoff between the two. When placed together, the combination helps parts self-locate to one another, as well as providing a consistent appearance around the mating surfaces.

Why is this necessary? When a plastic part is made — such as an enclosure in two halves — the resulting surfaces are never truly flat. Without post-processing, the two not-quite-flat surfaces result in an inconsistent line with a varying gap between them.

By designing in a shadow line, the two parts will not only self-locate to each other for assembly, but will appear as a much more consistent fit. There will be a clear line between the two parts, but no actual visible gaps between them. Watch the whole thing explained in the video, embedded below.

This isn’t the only time design techniques from the world of injection molding have migrated to 3D printing. Crush ribs have been adapted to the world of 3D printed parts and are a tried-and-true solution to the problem of reliably obtaining a tight fit between plastic parts and hardware inserts.

Continue reading “Enhance Your Enclosures With A Shadow Line” →

Splitting 3D Prints Into Parts Can Add Strength

July 28, 2023 by Donald Papp 5 Comments

One of the great things about 3D printers is their ability to make a single part all at once. Separating a part into multiple pieces is usually done to split up objects that are too big to fit on the 3D printer’s print bed. But [Peter] at Markforged (manufacturers of high-end 3D printers) has a video explaining another reason: multi-part prints can benefit from improved strength.

This part can be easily printed as a single piece, but it can be made nearly twice as strong when printed as two, and combined.

The idea is this: filament-based 3D printers generally create parts that are strongest along their X-Y axis (relative to their manufacture) and weakest in the Z direction. [Peter] proposes splitting a part into pieces with this in mind. Not because the part is inconveniently large or has tricky geometry, but so the individual pieces can be printed in orientations that provide the best mechanical strength.

This is demonstrated with the simple part shown here. The usual way to print this part would be flat on a print bed, but by splitting the parts into two and printing each in their optimal orientation, the combined part withstands nearly twice as much force before failing.

[Peter]’s examples use Markforged’s own filaments, but gives advice on more common polymers as well and the same principles apply. This idea is one worth keeping in mind the next time one is seeking to optimize strength. because of how simple it is.

We’ve seen a variety of methods to toughen up or ruggedize prints in the past, but they’re usually more complex (or at least messier.) Examples include embedding braided steel cable, embedding fiberglass mesh, applying electroplating to a printed structure, and plain old embedding some bolts and washers to buffer load-bearing areas.

Continue reading “Splitting 3D Prints Into Parts Can Add Strength” →