McMeshmixer Master: Open Source Prototyping

It was a recent revelation to me that McMaster Carr - supplier of over half a million industrial bits and pieces, of massive yellow catalogue fame, and secret weapon of inventor, maker, and craftsman - now offers many of its products as downloadable 3d models. What an incredible resource! Engineers and designers now have access to over 100,000 models of highly refined mechanical components. Everything from nuts and bolts, to casters and couplings.

On the other end of the spectrum, tools such as 123d catch allow us to sample the world around us, capturing organic forms and sharing them in the 123d Gallery. (currently totaling over 250, 000 models). What new potential do these developments unlock for artist, engineers, and designers? It is easy to imagine a creative process of digitally assembling prototypes out of these vast catalogues of parts - creating an endless variety of hybrids comprised of geometry ranging from loose, captured organic forms to highly refined mechanical components without having to model anything from scratch.

Meshmixer is a tool expertly suited to bringing these resources together for the express purpose of 3d printing and prototyping. It is the key to bringing these worlds together and unlocking new ways of designing and producing prototypes.

This project aims to explore the use of Meshmixer as a tool to quickly and intuitively combine loose organic forms, be it captured or sculpted, with ready-made, off-the-shelf hardware and precise mechanical detailing. Im hoping to produce a new breed of Hybrid prototypes that exploit these catalogues of models - an expedient creative process of assembling >>> printing >>>assembling.

Here goes nothing!

Step 1: The Prototype: Bunny Task Lamp

I began with the ubiquitous Meshmixer Bunny which comes preloaded with your installation of Meshmixer. It's a good example of the class of organic form that results from a process of capturing or sculpting.

The Bunny will be employed, along with a selection of 3d Mcmaster components, in the design of a prototype task lamp. Why a task lamp? The task lamp provides the challenge of integrating a range of mechanical details, as well as electrical components. Also, why not?

Im going to explore 2 ideas of hybridization:

1. INTEGRAL - To combine the 3d McMaster digital models with an organic form and 3d print them as one Meshmixed part with integral mechanical details.

2. INLAYED - To Boolean precise pockets out of the 3d printed parts so that the 'analog' McMaster hardware can be inlayed during assembly of the prototype.

What could go wrong? These mechanical details will require the use of a high definition printer (FDM machines just wont cut it) so this is also an experiment in reconciling the tolerance of such a printer with the tolerances of the McMaster hardware, particularly at the scale of a 1/4"-20 thread...

Step 2: Download, Convert, and Import Parts

Those familiar with the glory of Mcmaster Carr know how easy it is to become lost in its seemingly endless range of parts and possibilities. This is how I began the process of designing the lamp - looking for inspiration. Searching for interesting ways to use banal items and looking for shapes that could compliment that of the bunny.

If you are specifically looking for parts with 3d models click the following link:

http://www.mcmaster.com/help/drawingsandmodels.asp

...and scroll down to 'Products with technical drawings and 3-D models'

Once you have zeroed on on a product's catalogue page you will see a green CAD icon alerting you to the availability of the 3d model. The process of downloading the model is quite simple. On the product details page select the file type from the dropdown menu in the upper right and click 'save'. I've had the best results with .STEP files.

Now we have a hiccup in the process...

Meshmixer can only import polymesh files (ply, amf, stl, obj) while Mcmaster does not offer a mesh format. The workaround is as simple as importing the Mcmaster file into a 3d modeling program such as 3ds MAX or inventor, and exporting as .stl. All you need is a 3d program that can import .STEP and export .stl. Also, a quick google search finds you 1 or 2 free stl conversion services, although Ive never used those. Wouldn't it be great if someday Meshmixer could import/convert non-polymesh file formats?!

Once you have everything in as an stl you are ready to simply import them into Meshmixer as parts.

Step 3: Repurposing the Bunny

The first step i took in modeling the prototype involved using the tools within Meshmixer to mutate the bunny - throwing into question its 'bunnyness' and repurposing its forms towards the utility of the task lamp.

The process was as follows:

1. Selecting and removing the head from the body

2. Mirroring the body and rotating the mirror plane in 2 axis so that it became 2 'chests' and one rear 'haunch'

3. Mirroring the head and rotating the mirror plane along one axis

4. 'Boolean Difference' with spheres from the face and rear of the body. The crater in the face will be home to a switch, and the rear will receive a metal ball to weigh the lamp down.

Step 4: Meshmixing Mechanical Details

I have imported my selection of Mcmaster parts and can begin to integrate and inlay them into the bunny.

1. 'Boolean Difference' the tube that will house an LED light strip, from the ears. This is comprised of a 3/4" OD clear acrylic tube around a 1/2" white acrylic half-round that will plug into the head and receive the LED strip.

2. The head and 2 halves of the body will be reconnected via a screw detail. I used a 3/4"-10 thread nut and bolt - the nut I integrated into the bottom of the head, and the bolt into the body.

3. Next was to begin the process of splitting the body. Spliting and hollowing the mass of the body will make it much easier and economical to 3d print. I hollowed it out to a 1/8" thickness

4. Then preformed a 'Plane Cut' and proceeded to work with just one half. Since it will be symmetrical, I'll just mirror it at the end to save time.

5. The steel ball will actually be a metal float with a threaded connection. I integrated a 1/4"-20 bolt into the crater to receive the float.

6. Finally, I 'Meshmixed' a leg onto the body from the stock selection of legs that come standard with Meshmixer. I selected and deleted the foot portion of the leg - this is where I will inlay a metal threaded sleeve which will connect to a lever handle serving as a foot.

Step 5: 3d Print Prep

Next is the process of preparing the inlays and splitting/combining the parts for printing.

1. I used 'Add Tube', a great tool, to make a 1/4" inch DIA void in the new leg to match the OD of the threaded metal sleeve to be inlayed.

2-4. I used 'Add Tube' again to make a series of holes for the wiring of the switch, LEDs, and power.

5. Now that all of the form making is done I mirrored the body

6-7. I used 'Plane Cut' > 'Slice' to split the threaded neck and base in half, then combined them with their respective halves of the body.

8. Here are the final 3 parts, ready for printing and (hopefully) smooth assembly

Step 6: Assemble!

COMING SOON!

This is the exciting and most satisfying part! But HD 3d printing is not cheap. Took a while to find an affordable solution and the files are out to print. Check back soon for final assembly!