If you've ordered from Big Blue Saw recently, you may have noticed that our logo is stamped on many of the boxes we ship. What you may not have realized is that the stamp that created this logo was itself created using Big Blue Saw's laser cutting.

Here is the laser cutting and engraving the 2 by 4 inch stamp from a sheet of red EVA foam. The stamp measures 2 inches by 4 inches. Our laser has a special setting for cutting stamps so that it leaves a "shoulder" to support the lettering and logo.

I also cut an identically sized piece of white acetal plastic on which to mount the foam.

The plsat

After assembling the hardware, the foam was attached using hot glue.

Finally, here's our resulting image made using blue ink.

I created Big Blue Saw based on the idea that inexpensive, customized manufactured parts should be more widely and more easily available to everyone. So I'm happy to announce today there is a new way to access Big Blue Saw's services.

I was recently contacted by the founders of a startup who wanted to add Big Blue Saw quoting to their website. (Watch the blog for details of the arrangement.) To do this, they needed a way to access Big Blue Saw's online quoting information. My solution was to create an easy to use web based API which gives them pricing and other data they can embed in their website.

Now the same API is available to everyone. Where and how it's useful will depend entirely on our users. Here are some suggested applications that make good use of the API:

• A "Get Quote" button on a CAD drawing package that lets you instantly receive a price for the part you're designing.
• A software package that helps waterjet shops quickly estimate quotes.
• A price comparison website which allows customers to easily get competing quotes for custom parts, like Google Shopping does for consumer goods.
• A website that lets you customize parts like, say, gears, electronic enclosures, or licence plate frames and gives you an instant quote for the price.

Continue reading for the technical details of how it works.

Getting started is often the hardest part of creating a design for a custom part. I often have customers come to me looking for a particular mechanical part that they just want tweaked a little bit. I often tell them that their best bet is to find a CAD file that's similar to what they need, and make the changes that they require. My two favorite resources for CAD files for mechanical parts are McMaster-Carr and SDP/SI. In this article, I will show you how to use these incredible free resources to jump start your project.

SDP/SI

SDI/SI is one of my favorite sources for parts for my robots. They sell a variety of mechanical drive components including bearings, gears, pulleys, and the like. Their online catalog also lets you download CAD files in a variety of formats for almost everything that they sell. From their home page, you can click the "BUY ONLINE" tab to get to their online store where the CAD drawings are located.

For example, let's suppose we want find the CAD drawing of a gear. Their online shop has an expandable list of items that they have for sale. First we can click on "Gears" to see the different types of gear.

Then under "Spur Gears", we can select "Metal".

On the right hand pane, a list of all the metal spur gears will appear. We can click on the part number to show the details of that item.

The product details will appear in a new window. There's a link that says "AutoCAD Drawing", but this link didn't work for me. However, I was able to get the drawing via the "3D CAD Models" link.

SDP/SI wants you to register before they will let you download any CAD files. You can use your existing SDP/SI login or click the "Click here" link to create a new account. The new user registration page (not shown) is easy to fill out and doesn't require you to jump through any hoops like a confirmation e-mail before allowing you access to the CAD models.

After you register, clicking the "3D CAD Models" link will now show you a download page like the one shown below. Before you download, you need to set the file format in the drop down list, as well as any dynamic attributes for the part.

For most of my CAD work involving waterjet or laser cutting, a simple 2D DXF file is quite sufficient to model my final parts. This is one of the formats that SDP/SI can provide.

SDP/SI can provide a simplified drawings using the "Dynamic Attributes" feature. This may help with rendering performance in your CAD tool. In this case, I want to get a model of the whole gear, so I enter 8 teeth for the "# of Teeth to Display on CAD Model".

After clicking the "Download 3D Model" button, the web page will indicate that the CAD model is being generated. When it is done, you will see a link that lets you download the CAD drawing. When you click the link, your web browser will begin downloading a ZIP archive file containing the CAD drawing.

Here's what the downloaded file looks like in QCad.

McMaster-Carr

Mc-Master-Carr is legendary among makers. They carry nearly half a million products of every sort, including nuts and bolts, raw materials, hydraulic components, cleaning supplies, and tools, just to name a few things. If you haven't seen their website yet, take a look.

Their website does a good job helping you sort through the giant variety of stuff that they sell, but getting to a particular part might mean selecting 5 or 6 different parameters. For instance, for machine screws, you have to choose the material, head type, thread size, length, and so on. I'll spare you all of that and just choose a particular screw with McMaster-Carr part number 91241A083. To get to this part on the McMaster-Carr website, just enter the part number in the search box on the home page and click "Find".

This will bring up the product detail page for the part, a type of socket head cap screw. You will notice that this page has a link on the left-hand side for a "Technical Drawing". (Note: this link will not be present if McMaster-Carr doesn't have a CAD drawing for the item).

Clicking on the "Technical Drawing" link brings up a measured drawing in your browser. This is nice, but not quite a useful as a CAD file. You can click the "DOWNLOAD" link at the top of the page to select a CAD format file to download.

In this case, I want a 2D DXF file, so I will select that and click the "SAVE" button. This starts the download process.

Here is the drawing from McMaster-Carr as shown in QCad.

In this podcast, Big Blue Saw interviews Clay Benning of the Alliance Theatre in Atlanta, Georgia. Clay is a sound designer and recently worked with Big Blue Saw to build a portable sound console. In this interview he talks about his background and the experience of working with Big Blue Saw.

Listen to the MP3.

Clay says:

I was very pleased with the say everything came out. I think the anodizing... worked very well and really gives it a nice look to it. I was very happy with the waterjet cutting... I've seen the pre-manufactured ones that you can get from the manufacturer and I think [the custom waterjet brackets] hold up just as well.

I will be competing at Robot Battles on Monday, September 6, 2010 (Labor Day). The event will be held at Dragon*Con in the Hyatt hotel in downtown Atlanta, GA.

This is my robot for the event. It is called "Big Blue Saw Presents Jaws".

The custom parts on Jaws are made using Big Blue Saw's laser cutting, laser engraving, and waterjet cutting services. This includes the frame, the aluminum weapon gears, the gearbox, and the weapon forks.

Video of the machine in action.

Update (2010-09-01): I've fixed a bug based upon a report from commenter blackfox. Download the new version of Big Blue Saw's DXF Export For Inkscape Here.

After the last article on using Inkscape, I received some feedback in the comments section that let me know that DXF export wasn't available for all versions of Inkscape. After a little research, I came across a the free third party Inkscape extensions for DXF export Better DXF Export and Better Better DXF Export.

But I found that these two solutions lacked a few important features:

• There was a Python version incompatibility that caused the export to crash on Linux.
• They only supported metric output as the measurement units.
• When converting curves to line segments, the line segments were quite large, giving the curves a rough appearance.
• Color output was unsupported.
• They would produce layer names which were incompatible with many CAD packages.

With these problems in mind, I made a few modifications to Better Better DXF Output to create Big Blue Saw's DXF Export For Inkscape. It features everything from its predecessor, plus the following features:

• It has been tested on Fedora Linux, as well as Windows Vista.
• The units are now output as inches by default.
• It creates finer line segments, which is important for achieving the highest accuracy possible.
• The lines in the output file will be given the closest matching color in the DXF color palette.
• Spaces in layer names will be replaced with the underscore character.

To install:

1. Close down Inkscape.
2. Download the ZIP file containing Big Blue Saw's DXF Export For Inkscape.
3. Unpack the ZIP file into your Inkscape extensions directory: typically C:\Program Files\Inkscape\share\extensions on Windows or /usr/share/inkscape/extensions on Linux. (Mac users, help me out here.) You will need to overwrite the file simpletransformations.py with the version included in the ZIP archive.
4. Restart Inkscape.

To use after you've installed Blue Saw's DXF Export For Inkscape:

1. Create your drawing as normal.
2. Ungroup all items by selecting everything (Ctrl-A or Edit | Select All from the menu) and then ungrouping repeatedly (Shift-Ctrl-G or Object | Ungroup) until all groups are broken apart.
3. Convert all objects to paths. You can do this items by selecting everything (Ctrl-A or Edit | Select All from the menu) and then pressing Shift-Ctrl-C or choosing Path | Object to Path from the menu.
4. Choose File | Save As from the menu. In the dialog box that appears, choose "Big Blue Saw DXF Output" and click the Save button.

   

One more thing, for those reading this far. Most of the time when I, personally, want to get a DXF from a file loaded in Inkscape, I save it as an EPS, and convert to DXF using the pstoedit package. This preserves splines and curves, which is nice, but requires the use of a command-line tool, which isn't for everyone.

Download Big Blue Saw's DXF Export For Inkscape Here