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3D modeling 3d printing

A curved 3d printed lithophane in OpenSCAD

How can I wrap a flat surface around a cylinder in OpenSCAD. This was a question I asked myself. OpenSCAD doesn’t provide a ready made method so we need to write our own. Luckily we don’t have to invent the wheel here, others have done that already. Justin Lin has written a very handy tutorial on his website Openhome.cc how to wrap a text around a cylinder.  In this project I took it a step further and wrapped a png image over part of a cylinder resulting in a curved image.

3D printed curved lithophane

It seemed like fun to combine this technique of wrapping with the 3D print of a lithophane. A lithophane is an engraved image on translucent material. Many 3D printers have already produced lithophanes sometimes with stunning results. For this experiment I’ll use white PLA because it  has excellent translucent properties.

Now first let me explain the basics on how to wrap a 2D image around a cylinder. First we create a circle out of triangles. These triangles are then extruded to segments to form a cylinder.  Next all segments of the cylinder are lined up in a row and the image is place on the far side but just within the limits of the segments. When we intersect the image with every individual segment and return the segments to their original position in the cylinder, a curved image emerges (see images below).

If you want to know more please watch my video below. In this video the OpenSCAD script is explained and demonstrated. Also is shown how to import the stl file in Cura and what settings are used.

Here you can download with an example file of a curved lithophane:

If you want to use your own png file change the surface command in the OpenSCAD file to include your own png file. Make sure to also change the height and width according to the imported png image in px. Prerender and render can take some time so it’s recommended to use a fast PC. And the larger the png the longer it takes.

A circle created out of triangles
The extruded triangles form a cylinder
The segments are lined up in a row
Image placed on the far side of the triangles
The triangles returned to their original positions
The image intersected with the triangles and returned to their original position.
Categories
3D modeling 3d printing open source programming

Peddle wheel boat (3D printed)

I found an example on Thingiverse, a rubber band powered boat with two peddle wheels, but it has two problems. First of all the author only provides .stl files and second the design is a bit flawed. I therefore decided to design the boat from scratch with the 3d CAD program OpenSCAD. With OpenSCAD I’m not only able to edit my models quickly, I’m also able to share the OpenSCAD script allowing other to use and change it. Links to the downloadable files can be found here: https://my.hidrive.com/share/pyilt3itb8

Assembled Paddle Wheel Boat.

The Paddle Wheel Boat that I created consists of four parts: the boat, the shaft and two peddles. The main change of the boat that I designed is the position of the shaft. It’s been shifted to the middle of the boat providing more balance. I also enforced the attachment point of the rubber band to the boat making it impossible to break it.

The redesigned Paddle Wheel Boat with shifted position of the shaft and enforced attachment point for the rubber band.

I also increased the size of the paddles enabling the boat to move faster. The shape of the paddles are rounded instead of square improving the dynamics of the paddles through the water. A problem with the old design is that the rubber band has to be fixed to the shaft with some tape. Not a very elegant solution. I added a square hole to the design of the shaft. The rubber band can be inserted through the hole and fixed to the shaft. No tape needed.

Simple square hole in the shaft. The rubber band fits right through the hole making it easy to fix it to the shaft.

Changes to the models are easily made. The OpenSCAD script is simple and the result of a change can be reviewed immediately by pressing F5. E.g to move the shaft to the back of the boat can be achieved by just one simple change in the script.

Just four parts, the boat, shaft and two peddles, are needed to make the boat. If you don’t want to make changes to the design just download the provided .stl files and open them in your favourite slicer. After printing the Peddle wheel boat can be assembled and tested. Have fun.

All printed parts plus the rubber band.
Categories
3D modeling 3d printing open source programming

OpenSCAD parametric hook

Writing a script for a simple hook in OpenSCAD is easy but I wanted to do something more and make a parametric hook. With parametric I mean that a user can easily adjust the script by changing some variables to make your own hook.

To make it even easier the script makes use of the Customizer of OpenSCAD. This means that users don’t have to tinker with the code but can adjust the values of the variables with a easy to use panel on the right side of the GUI of OpenSCAD called the Customizer. (If you don’t see the Customizer in OpenSCAD go to the menu bar and click on Windows and then Customizer).

Screenshot of the script with the Customizer on the right side.
Smaller hook with chamfer
Larger hook with fillet

Aside from changing the dimensions I also added the possibility to add a fillet or a chamfer to the hook. And I added the option to change the radius of the hook and the diameter of the screw holes.

If you’re interested here is an explanation of some parts of the code. The fillet of the cube shaped parts of the hook is created with the fillet module. Within this module I simply intersect a cylinder with radius r1 and a cube of the desired length l.

module fillet(l,r1) {
    intersection() {
        cube([l,l,l]);
        cylinder(h=l, r=r1, $fn=50);
    }
}

In the module roundedCube the thus created fillet pieces are positioned in a such a way that the hull command shapes them to the desired filleted cube.

module roundedCube(l,w,h,r1) {
    d = 2 * r1;
    translate([r1,r1,0])
    hull() {
        rotate([0,0,180]) fillet(l,r1);
        translate([0,w-d,0]) rotate([0,0,90]) fillet(l,r1);
        translate([h-d,0,0]) rotate([0,0,270]) fillet(l,r1);
        translate([h-d,w-d,0]) rotate([0,0,0]) fillet(l,r1);
    }
}

I published the OpenSCAD script (.scad) and some example hooks (.stl) on Prusaprinters. You can download it here:

https://www.printables.com/model/91734-parametric-hook-with-source-file

EDIT: V1.1 of the OpenSCAD file (.scad) has the option to add a countersunk to the screw holes.

Categories
3D modeling 3d printing open source

My videos remastered on PeerTube

I wrote earlier about my move from YouTube versus PeerTube. My new videos will appear on both platforms but I’m also remastering my old Solvespace videos. These videos were all 720p which isn’t ideal for a tutorial. Having most of the material of the videos available I’m recreating them in 1080p. When I’m done I’ll only upload these HD videos to PeerTube. The videos take a lot of time to create and I’m currently very busy so the videos appear irregularly but whenever I have time I’ll make them.

The latest video that I remastered is about the Geneva Drive. A wonderful project to design and 3d print. I redid part of the screen recording because either the original was gone or wasn’t good enough. For this video I used the latest version of OpenShot (v2.5.0) but I’m unfortunately still having issues with this video editor. For the next video I’ll return to Shotcut which is currently my favourite free and open source editor. Here is a link to the video if you want to see it on PeerTube.

When I tried to embed a PeerTube video here I found that the WordPress embed block is not suitable for this purpose. Apparently PeerTube is not (yet) whitelisted by WordPress. Also it appears that iframe tags, my other option, are blocked by WordPress because of security reasons. That’s a bummer.

Categories
3D modeling 3d printing

The BQ Hephestos2 (3D printer), nine months later

Introduction

It’s been nine months since I received and assembled my BQ Hephestos 2 printer and I think it’s time to share some of the experiences that I had with it. For those who don’t know the Hephesthos 2 it’s a 3D-printer that is based on the Prusa i3 design with a thick steel frame and almost all metal parts. It’s not cheap but it’s a well designed, high quality 3D-printer with a large printbed. It does have it’s shortcomings but more of that later.

Categories
3D modeling 3d printing

Using Filaflex to improve my cooler

Introduction

A week ago I finished my audio cooler. Although I was happy with the result improvements could be made (as is always the case). Most important I didn’t particularly like the console on the side of the coolers lid. This was a 3d printed part of PLA that I glued to cooler with a superglue. This was far from ideal because of the space left between the printed console and the cooler . Another improvement could be made by the way that the speaker was fitted to the lid of the cooler. The speaker was directly attached to cooler with four screws again leaving some space between the two. I already had some FilaFlex filament but hadn’t used it yet. Because of the elastic and flexible properties of Filaflex I figured that I could both fix the issues with the console and the speaker.

Left the cooler with improved speaker and console and right "old cooler" with printed part of PLA filament.
Left the cooler with improved speaker and console and right “old cooler” with printed part of PLA filament.

Categories
3D modeling 3d printing amplifier electronics

Making a tiny audio system for our cooler (part 2)

Introduction

A couple of weeks ago I started to make a tiny audio system for our cooler. In my previous blogpost I described all the audio components that I chose for this project. I wanted the components to be small since I didn’t want to waste too much space in the cooler. With the audio components in hand I could design other parts for the audio system. I needed an enclosure for most of the audio components and a simple console to operate the audio. The parts were 3d printed with my Hephestos 2.

The complete audio system in the lid of the cooler. Most components are placed in the 3d printed enclosure.
The complete audio system in the lid of the cooler. Most components are placed in the 3d printed enclosure.
Categories
3d printing

Assembling a Hephestos 2 printer

Introduction

While making my projects like the Darth Vader chest box 2.0 I use the local fablab a lot, especially the laser cutter and the 3D printer. It was a bit boring to wait for the 3D print to finish (laser cutting is typically much faster) with not much else to do at the fablab. I therefore decided to buy my own 3D printer. I choose for the BQ Hephestos 2, a sturdy Prusa i3 all metal printer that comes in a kit.