Categories
3D Printing Cloud Projects

3D Printing a Replacement Door Handle

How I created a new handle for my fridge/freezer by 3D printing a new one.

This handle is used to open the freezer door in a combined fridge/freezer. The current handle has been hanging on by a thread for a while and been through 2 repairs previously, but now it’s no longer viable.

3D Printing - the broken part

At first I thought it would be easy enough to get a replacement handle, so contacted the manufacturer of the fridge/freezer.

Good Morning,

Thank you for your email.

The part you require is discontinued without replacement.

Sorry for any inconvenience caused.

“For help with your home appliance trust ******** Customer Service. Service you can depend on.”

Inconvenient? Yes it’s a bit difficult to open the freezer when it doesn’t have a handle – but at least I can, just about, open the fridge without the handle.

DSCN3833

Seems a shame, though, to have to replace the whole fridge freezer for want of a handle.

It is possible to locate an equivalent handle (genuine part) but, unfortunately, only in white.

whitehandle

It looks like I need to make my own handle. Is it possible to use 3D Printing to print a new handle ?

Design

First thing to do is to create a 3D model of the handle.

I have used a number of different 3D CAD Modelling programs in the past but for this job I’ll be using Onshape a full-cloud, online 3D CAD system used from a web-browser.

It is straightforward to create a fairly close representation of the required handle and I completed work on the design/model in about an hour. I didn’t come across any particular difficulties with the modelling or any problems using Onshape during this process.

modelhandle

I also did a couple of quick renders using OneRender https://www.onerender.com , an online rendering application which works with Onshape.

11430-rendered-60447_gi

11430-rendered-60449_gi

Looks OK to me.

3D Printing

In order to generate a file suitable for 3D printing, simply export the model from Onshape in STL format. Then either use your own printer or, as in my case, upload the STL file to your favourite online 3D Printing service.

I haven’t used an online service in the past so I’m going to try i.materialise

It’s simple to register and upload your model.

Here it is

order

Not sure what the best material is to use for this application, but thought I’d try Polyamide which appears to have similar strength properties to ABS (but perhaps a bit more flexible). The manufacturing process for this material uses Laser Sintering.

Laser sintering is used to build your design with this material. The models are printed layer by layer by a laser that draws thin lines in the powder, which melts and bonds it together in order to form a thin layer of the model. After a layer is printed, a new layer of fresh powder is spread over the surface by a roller. The printer has a print chamber that is heated to just below the melting point of the powder; the laser beam adds the extra energy to melt the powder, forming a solid model. After a print job is finished, the result is a big block of heated powder with the printed models contained inside.

Also chose a polished and dyed black finish.

iMaterialise also provides an Analysis option which checks whether your model can be printed and highlights any potential problem areas.

Looks good to go

analysis

so submitted the order.

It’s probably taken less time creating the part and sending it off for printing than trying to find the exact equivalent original (genuine) part.

If my 3D printed model does not prove to be “fit for purpose”, at the very least it should establish whether the 3D model (design) is good enough.

The only problem now is having to wait 2 weeks before I can get my hands on the new 3D printed handle ….

…. 2 weeks later

I received the following parcel today, what could it be ?

DSCN3835

Nicely protected and here it is – looks promising.

DSCN3837

The new handle can be compared to the original. The actual modelling is a good match to the original design, but of course, the surface finish of the new one doesn’t (exactly) match the gloss finish of the original.

DSCN3845

5 minutes later it is fitted in place – and fits perfectly, of course. I would make a couple of minor (design) modifications if I was to do it again. The countersinks for the the screws are on the wrong side ! (my fault) but otherwise it seems OK. Also, I would do a stress analysis of the design before having it printed. (various simulation packages are available to use with Onshape via their App Store).

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Aesthetically speaking, it looks good and actually the matt finish is growing on me. (The wife hasn’t seen it yet though). I can always paint it with acrylic, or something similar, to get a glossier finish.

DSCN3847

Time will tell how it stands up to use. I’ve noted a bit of flexing of the handle when the door is opened and perhaps it should be a little bit more rigid/stronger (different material?) although I did notice some flexing in the original handle too.

All in all a successful exercise so far – the handle is about to enter Beta Testing.

While I can understand why manufacturers may be reluctant to make technical information (design details) available for their spare parts, is there any reason why they couldn’t offer a 3D printing service for the parts that they discontinue ? Even if they were to outsource the production to a 3rd party it seems to me like a valuable additional revenue stream and they would really be able to claim that they were offering a Service you can depend on

Categories
Software

OpenSCAD

openSCADlogo

OpenSCAD is a free, open-source, application for creating 3D CAD models and is available for Linux, MS Windows and Apple OS X. There’s also an online (cloud) version available that runs from within a WebGL enabled web-browser.

It introduces a different approach to creating 3D models as it’s not an interactive 3D modeller in the sense of being able to manipulate the model directly from a graphics window, rather it interprets instructions that describes the model and then renders the result.

A simple user interface is provided and includes a text editor, graphics and console windows.

A textual language is used to define geometric primitives and describes how they are modified and manipulated to create 3D models. Essentially, you are provided with a 3D CAD modelling programming language. The language is easy to understand and can be used by anyone – no specialist knowledge is required.

For example, create a cube with the command

cube(10);

Or create a variety of primitives using the following


// cube 
cube(10);

// box
translate([0,-15, 0]) { 
    cube([20,10,10]);
}

// sphere    
translate([-20,0, 0]) {
    sphere(10);
}

//cylinder
translate([20,5, 0]) {
    cylinder(h=10, r=5);
}

openSCAD Figure 1

OpenSCAD provides two types of 3D modelling, Constructive Solid Geometry (CSG) or the extrusion of 2D primitives into 3D.

Here’s a CSG example

openSCAD Figure 2

Here’s an example showing the extrusion of a profile

openSCAD Figure 3

There are lots of youtube videos showing how to use OpenSCAD for example

(original link at https://youtu.be/XNghpq9sKRc )

Models can be exported in various formats including STl, DXF, SVG and CSG. It is also possible for users to distribute CAD models as OpenSCAD (human-readable text) documents

Details about OpenSCAD can be found at

http://www.openscad.org/

It can be downloaded from

http://www.openscad.org/downloads.html

and documentation can be found at

http://en.wikibooks.org/wiki/OpenSCAD_User_Manual

Here’s a quick cheat sheet

OpenSCAD cheatsheet

The source code can be obtained either from the download area on the website, or directly from github

https://github.com/openscad/openscad

If you don’t want to download and install the program on your machine, there is also a version available which runs in a web browser that supports WebGL.

OpenScad openJSCAD

OpenJSCAD can be used directly from

http://OpenJSCAD.org/

Summary

OpenSCAD provides a powerful and unique tool for programmers and other users wishing to create 3D solid models. It can be used on your local machine either as an installed program or used directly via a version available on the web. With the ability to output models as STL files, it can be used to easily produce models the can be used for 3D printing. Although lacking in some features found in other CAD systems it nevertheless provides a useful tool in your 3D modelling toolkit and it will be interesting to see where it goes in the future.

Categories
News Research

Printed Optics

Interesting research from Disney Research,

http://www.disneyresearch.com/

explores using 3D printing with custom optical elements for interactive devices.

This embeds sensing, display and illumination features into the body of a device using Light Pipes printed with optically clear material.

(original link at: http://www.youtube.com/watch?v=eTeXTbXA6-Y).

Read more about the project and some potential uses at

http://www.disneyresearch.com/research/projects/hci_printedoptics_drp.htm

or read the research paper Printed Optics: 3D Printing of Embedded Optical Elements for interactive Devices at

http://www.disneyresearch.com/research/projects/PrintedOptics/printedoptics-paper.pdf

Other Useful Links:

Light Pipes: http://en.wikipedia.org/wiki/Light_tube

LED light Pipes: http://www.toby.co.uk/content/catalogue/series.aspx?category=87