标签: Draw2CNC

As you may recall from my previous column on this topic (see Creating flaming flanges ), I'm on a quest to create some fabulous flanges that will hold strips of Adafruit's NeoPixels around the necks of the giant vacuum tubes sitting on top of my Inamorata Prognostication Engine (phew -- try saying that sentence ten times quickly!).     Quite a few folks commented on my previous column offering suggestions. Based on these, my chum Steve Manley whipped up the following 3D drawing and suggested I try using 3D printing techniques.     As fate would have it, I recently had a lot of success with 3D printing regarding the base-plate and face-plate for my clock, so the idea of 3D printing my flanges and then painting them to look metallic was definitely a contender.   On the other hand, I was recently introduced to something called Draw2CNC, which is an online CNC prototyping service that can fabricate my fabulous flanges out of aluminum.   So I contacted Bill Parodi, the founder of Draw2CNC and explained what I was trying to do. One of the issues from my end is that some of my vacuum tubes have glass/metal protuberances sticking out the bottom of their necks, so my flanges have to come in two parts -- a bit like a donut cut vertically into two halves.   Meanwhile, the fact that the 3D Draw2CNC drawing package is intimately linked to the fabrication process -- thereby ensuring you can’t draw something you can’t fabricate -- does impose its own limitations. This resulted in the fact that we had to create my flanges as two rings -- a bit like a donut cut horizontally into two slices.   I'm confusing myself now. Let's take a look at some Draw2CNC drawings, and then at the finished proto-flange. (If you wish, you can download the Draw2CNC software for free from Draw2CNC.com , and then click here to download a compressed ZIP file containing the drawings used to create my proto-flange).   The two halves of the main ring   The four connectors     Two "slices" and associated connectors for one half of the ring disassembled (left) and the two "slices" and associated connectors for the other half of the ring assembled (right)     The fully assembled proto-flange   What can I say? The fully-assembled proto-flange shown above is much like yours truly: bright and shiny, as light as a feather, and awesomely good looking. The other guys in my office were effusive in their praise when they saw this little beauty attached to its tube as shown below.         This really does look stupendous in the flesh -- and the style really fits in with the rest of the Inamorata Prognostication Engine. Unfortunately, there's currently a 1/8" gap between the two halves of the flange, but that's why they call it a prototype. And I want to go on the record right here and now stating that this was nothing to do with the fact that we had an idiot measuring the diameter of the tube necks (I resemble that remark).   So, that's where things stand at the moment. The next step is to tweak the design and produce fabulous flaming flanges of desire for all five tubes. Watch this space for further developments...

Yesterday, I posted a blog about an interesting new prototyping service startup. The idea is that you download the free, easy-to-learn-and-use Draw2CNC software; create a 3D drawing of the object you wish to build; pick a material; receive a quote; press the "Go" button, and your newly-machined whatchamacallit arrives in the post shortly thereafter. The thing is that -- while I was writing this article -- I thought to myself: "Hang on a moment; maybe I could use this process to fabricate my fabulous flanges."   "But what are these fanciful flanges of which you speak?" I hear you cry. Well, take a deep breath, settle down in a comfy chair, and I shall expound, explicate, and elucidate (and then I'll tell you about the flanges).   This is part of my Inamorata Prognostication Engine (see also Yummy Scrummy Faceplates and Awesome Startup Sequence ). Mounted on the top of the upper cabinet we find five fabulous vacuum tubes:     These really are robust little rascals -- the largest one stands a tad over 12 inches tall as illustrated below:     These are antique tubes that no longer work, but this isn't a problem because I intend to light them up using tri-colored LEDs in the form of Adafruit's NeoPixel strips. Check out this video showing an early experiment from last year.   All I'm doing in the above video is holding a strip of NeoPixels against the neck of a large tube and then sequencing the LEDs on and off, but the final result is pretty spectacular. In the real world, an optical illusion sometimes makes it appear as though the structures inside the tube are rotating in the opposite direction to the LEDs. Furthermore, the experiment above employed a strip containing only 60 LEDs per meter , but my final implementation will be based on strips boasting a phantasmagorical 144 LEDs per meter .     Now, I could simply use a hot glue gun to stick the NeoPixel strips to the bottom of the tubes as shown in option (a) toward the bottom of the sketch below, but -- let's be honest -- that's not going to happen because it would look pretty drongo. The alternative is to "wrap" each NeoPixel strip in some sort of collar, or flange, as illustrated in option (b).     Until recently, I've been toying with the idea of using a 3D printer to create these flanges, but now I'm thinking machined aluminum à la Draw2CNC might look tantalizingly tasty.   My first thought was of a simple circular flange augmented with a tubular extrusion to accommodate the cable carrying the power (+5V and GND) and data signal as illustrated below. As an aside, I'm planning on using vintage-looking cloth-covered cable -- the sort of thing you used to see on old headphones. I remember finding a supplier for this a few years ago, and I even purchased a few meters at that time, but -- sad to relate -- it's "gone to ground" somewhere in my office and -- try as I might -- I've not been able to track it down (1,000 curses).     The actual cross-section of the flange is shown toward the bottom of the above image. There would be a large channel in the middle to accommodate the NeoPixel strip, and two smaller channels at the top and bottom to accommodate rubber seals (I was thinking of using rubber bands for this purpose).   While I think about it, although the NeoPixel strip is about 2.1mm thick, the main channel in the flange needs to be deeper that this because we'll have to bend the strip between pixels. In the illustration below, 'x' = 1,000mm / 144 = ~6.95mm, which we could use to calculate the theoretical channel depth. In practice, however, we will also have to account for the way in which the material forming the strip bends, so the best way to determine the required channel depth will be to use a "suck it and see" approach (or empirical measurement, if you wish).     Even though the five vacuum tubes have different diameters, I'd like to keep things as consistent as possible -- having the same channel depths for all five flanges, for example -- which means basing the channel depth on the smallest diameter tube because this will demand the largest bending of the strip (my head hurts).   But wait, there's yet another consideration. Consider the following images of the five tubes (the "diameter" values refer to the diameter of the necks where the flanges will be located).   Back row; left-hand side; 2.61" diameter.   Back row; middle; 2.26" diameter.   Back row; right-hand side; 2.48" diameter.   Front row; left-hand side; 2.505" diameter.   Front row; right-hand-side; 2.26" diameter.   I'd originally planned on making simple circular flanges that could simply "slip" over the neck of the tubes. I was also thinking of giving myself say 3/64" (~1mm) clearance on either side -- that is, making the inner diameter of each flange 3/32" (~2mm) larger than the diameter of its tube's neck -- where this extra clearance would be taken up by my rubber seals.   The problem occurs with the tube in the middle of the back row; also the tube on the left-hand side of the front row. As we see from the images above, both of these little scamps have glass/metal protrusions toward the bottom of their necks. This means that we're going to have to split the flanges into two halves as illustrated below (I haven’t shown the three-channel cross-section in order to keep things simple):   Since I have to do this for two of the flanges, I might as well do it for all five for consistency. So, that's where we stand at the moment. Now I'm going to have a play with Draw2CNC to see if it will to bring a smile to my visage or a frown to my phizog. Watch this space for further developments...

A few weeks ago, I had a chat with Bill Parodi, an embedded systems designer and the founder of a recently-launched company called Draw2CNC that will be of interest to anyone who needs to create rapid prototypes.   Ten years ago, Bill founded an avionics company called UAV Navigation . When Bill and his colleagues were making their first inertial units, they discovered great services to prototype the electronic portions of their designs -- like ExpressPCB for the printed circuit boards -- but they couldn’t find anything similar to prototype the mechanical components (enclosures, mounting brackets, etc.). This forced them to use traditional machine shops, which have several shortcomings, including long lead times and multiple iterations on designs to match manufacturing capabilities.   The way this typically works is that you generate your 3D CAD drawings using an expensive and hard-to-use program. You send these drawings to the machine shop; the folks at the machine shop examine the drawings and inform you as to any elements in your design that may cause manufacturing problems; you re-spin your drawings and return them to the machine shop; and so it goes. At the end of the day, the folks at the machine shop are going to bundle all of their service and support costs into the price of your prototype.   Now, although there are some companies that do provide mechanical prototyping services, such as Front Panel Express , these companies tend to work with 2D objects. What Bill required was the ability to quickly and easily prototype 3D mechanical objects.   Based on his experiences, Bill decided to create a solution that would offer the simplest way to draw something and have it machined in a few days. The key features Bill wanted to provide with his solution are that end users should not have to purchase expensive and hard-to-learn-and-use CAD programs, they should not need to iterate their designs to match manufacturing capabilities, and they should not obliged to commit to large orders.   Bill crafted his solution, Draw2CNC , based on his experiences with ExpressPCB. The idea here is that the folks at ExpressPCB provide a free schematic capture and board layout package. This is a stripped-down, no-frills package with limited capabilities, but with the corresponding advantage that it's quick to learn and easy to use. More importantly, this package is 100% integrated with their board manufacturing process, which means that it simply isn’t possibly to create a design that cannot be manufactured. Once you're happy with your design, you press the "Go" button and your boards are manufactured.   Similarly, in the case of Draw2CNC, you start by selecting the type of material you wish to use and the size of the block with which you wish to work. The materials that are currently supported are 6061T6 aluminum (with an optional post-machining alodyne treatment) or Teflon, but Bill is planning on adding additional material options over time.   You then use the free Draw2CNC 3D CAD software to draw arbitrary cuts in five of the block's six sides. The great thing here is that the Draw2CNC software won't let you create a design that cannot be manufactured.   This enclosure for a Raspberry Pi single board computer was created entirely using Draw2CNC, including the enclosure itself (alodyned aluminum), the lid (not shown here), and the port covers (Teflon, also not shown here).   When you are ready to rock-and-roll, Draw2CNC will give you a detailed quote that breaks our material costs and machining costs (based on the complexity of the design). Once you press the "Go" button, the standard manufacturing time is eight working days from order to shipping (an express process is also available).   Personally, I think this is a brilliant concept. There are all sorts of small mechanical parts I wish I could have had fabricated over the years. In fact, now that I come to think about it, I have a current project that could benefit from a little tender loving care by Draw2CNC; watch this space...