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Some design points

November 14, 2014

I lied, next is design. From baby rattles to skyscrapers, you have to have a plan. For a lot of stuff, a sketch on a piece of paper is fine, but other things, especially things that need to be documented, and things that utilize more complex manufacturing, like CNC machines, plans will be good. For things like 3D printers, you pretty much have to use a CAD program of some sort, because you need a 3D model file for the printer to actually turn into a physical object.

There are three basic kinds of programs to look at here, artistic 3D modeling, CAD 3D and 2D modeling. 2D is just drawings, which is find for a lot of stuff, and also puts out the “vector” files things like laser cutters use. They’re the most prolific of the free software, and reasonably powerful. 3D is harder to find, and software that approaches the Solidworks level of easy to use even harder. There’s a reason you pay for professional software. I’ll not spend much time on specific software, you’ll have to find one that works well for you, and/or you can find training for it. Artistic modeling is of limited use, since it’s for sculpting, not machine parts. Blender is a pretty good program, but except for a relatively recent mod that you have to install separate and learn to use, it’s hard to get things to precise dimensions, for say a bolt hole. Solidworks on the other hand will have a wizard where you just tell it where the hole is, what bold you’re using, and it’ll figure out the rest.

3D design is of three basic kinds, and we can define it with three programs—Autocad, Solidworks, and Rhino. Autocad, and a lot of 2D systems, use a command based system—each line or feature is defined by a command line type code, which tells the software where to draw lines. It gets even more complicated when you go to 3D, since a bit of behind-the-scenes work is used to defined a solid, and you don’t really have a solid until it’s saved in an appropriate format. Solidworks goes 3D from the start, and you run from sketches that are extruded into solids, and the solids modified. Solidworks and it’s little brother Geomagic design, which uses a similar GUI and interface, are also designed to work with assemblies of multiple parts, with Solidworks having native support for extensive simulation and testing before putting something into reality. Rhino is different, it’s default system having template solids, which are then sized, arranged, and “boolean” functions are used to add or subtract from the object. It’s a little awkward when learning Solidworks to begin with.

I’ll not mess much more with all that, a good google search will find most of the programs, and show you how they work. You’ll need something though, and some of the lower end but still paid for programs will prove their worth in slightly better interface and ability. Geomagic is a good example of this, more or less replicating the UI of the $4,000 Solidworks, but for less than $500 for the basic version. Sketchup, google’s free one, is similar, with the sketch-and-extrude system, but lacks many qualities of the other software, like a history system and it’s not “parametric” where dimensions are more thoroughly connected to features, allowing easy modification of a design. More advanced versions of some software will have special stuff, for example Solidworks and the higher levels of Geomagic have “weldment” and sheet metal tools that let you work directly with structural members and sheet metal, automatically calculating angles and fillets and bend angles and stuff like that.

The other important things are books. Drafting is well standardized, and this allows easy discussion of matters between disparate people. A lot of standards are in the Machinery’s Handbook, and others are published as drafting references. Good idea to get something you can use to tell what you’re saying to someone, and what someone else is telling you.


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  1. Boon Vickerson is out there permalink

    Planning or planning for unknowns? Or contingencies?
    I’m not a good planning kind of guy. Better at preparing for contingencies. Such as stocking my blacksmith shop with a variety of materials in order to fabricate basic tools and devices. Junk and scrap metals are an excellent source of metals. One junked half ton pickup is a smorgasbord of alloys in handy shapes and dimensions.
    I’m attempting to get into foundry work. This is a great way to use scrap metals, aluminum alloys, like cylinder heads, the typical alloys are usually 356 or 354. Super strong with the highest strength heat resistance going. Cast iron engine blocks and crankshafts, good stuff, nodular iron, bordering on steel qualities. There are some very fine tool steels in driveline components. There is copper wiring, plastics, electronics, selenoids, alternators, diodes, pumps, actuators, gear motors, pulleys, belts, hoses, rack and pinions, etc. Don’t some near vehicles have linear actuators for windows, antennas and such? Vehicles are just loaded with 1st rate materials.
    How does one repurpose composites/plastics, use them for additive machining?
    How about window glass? Heater blower motors? Air conditioning units, make refrigeration for food and medicine. Build water turbines or over shot/undershot water wheels to run alternators. Batteries? You have sulphuric acid, battery plates, various leads, make new deep cycle batteries, construction explosives from the acid, bullets, solder, roof flashing, pewter alloys. You get transmissions and transfer cases to make things with. Driveshafts for power transfers.
    Leaf springs are generally formed out of 1095 carbon alloy. Makes excellent forged cutting tools, knives, axes, swords etc. And it comes in a useful shape and dimension. Coil springs are perfect round stock tool steel, torsion bars are made from alloy with high shock resistance. Charcoal is simple to make in 55 gal drums, it is a top notch fuel for forging, heat treating, and foundry/smelting. No sulfur to soften steel, no need to make coke. Burns quicker than coal volume for volume, but wood is everywhere, and you can take off the gas to run a gasifier fueled Gen set or other engines. Might even use it to run a gas torch of sorts or lighting.
    Can you use the fuel mapping part of a vehicle ECU to control a machine tool? Throttle bodies have throttle position switches. How handy are they? Can you use them on an axis setup, XYZ? Use a separate ECU for each axis, take your signal that would run injectors, and control a motor on an axis? I’m no electronic guy, but it seems like vehicle electronics are robust and fairly basic. That has a quality all its own in my practical perspective. Need a high vacuum to form plastic? Run a turbo off your exhaust, or a roots blower from a equipment diesel, just normally aspirate the engine and use the cold side of your turbo for vacuum. A 15lbs of boost turbo should make 21 inches of vacuum for vacuum forming.
    Poop hits the fan, lot of vehicles be laying around.

    • Was it really that unclear? If you’re designing and making something, whether it’s a baby rattle or an engine, you design and plan for the job, even if it’s just mentally. For a knife, you might just think a bit before starting to beat on metal, for a 3D printed baby rattle you have to build out the design in cyberspace to send to the printer. A sketch might be enough to design a simple mechanism, but I’ve seen some pretty sophisticated assemblies in Solidworks that are basically the whole factory, planned out virtually. Planning and designing become more and more important the more complicated the item you’re making, and the methods you’re using to make them. It also helps to standardize the designs, to make communicating with others easier.

      • Boon Vickerson is out there permalink

        My apologies, I think I is my ignorance of the higher orders of planning your talking about I missed. But then, maybe I did understand you, and was trying to share with you a method of planning for fabrication of things you can’t know what ahead of time. Like a junk vehicle. A lot of resources which can be used in a myriad of ways.It seems like planning for the unknowns from my perspective.
        But nonetheless I see where you are coming from now.

  2. FrozenPatriot permalink

    Self taught Solidworks guy here. I finally talked my employer into a copy of Solidworks for several projects on which I’m working. During discussions with the sales reps, I learned that I can use the license at home on weekends/evenings — with OR without the network license server. If you work somewhere that uses Solidworks, even if you don’t have access at work, ask to use a seat during off hours. Tell them you’re working in your off time to be a better employee (which you are), and then draw for FREEFOR while learning a new tool.

    • You get an off site locense for every license you have, as long as they don’t think you’re abusing it. You still need the license though.

      One of the reasoslns I’ve been looking at geomagic(used to be alibre) is the similarity with Solidworks without the wallet punching price tag. Looking at doing design work professionally though, so also looking at biting the bullet on solid works.

    • sonofasmith permalink

      Hi could you elaborate on how you are able to use solid works at home under your employers license? My job has solidworks too and I am unable to use it on the job as drafting isn’t in my routine at work, but I’d love to learn it on my own time and it would benefit the company and me both. Thanks

  3. sonofasmith permalink

    I am just starting out on my path toward becoming a machinist. I’ve worked in residential maintenance, have some carpentry schooling under my belt and am currently going to trade school and working part time as a mechanic at a factory. Up until recently I didn’t realize that machining is what I really want to do. I’ve fallen in love with the phrase “see that part right there its bad. Lets go back to the shop and make one.” My father was a gunsmith and i enheritted his machine shop and what seems like a billion tools, half of which I don’t know what they are for yet.
    Now my point for commenting here is to ask your advice for a beginner to point me in the direction you would go if you had to start over again. As far as books, web sites, software to begin learning cad at home without going broke etc. Thanks in advance for your time and input.

    • First thing is what you already have, figure out what you want to do. Took me ten years to figure that out properly.

      Find the old guys that don’t mind you bugging them too much with questions, and bug them. To add to that, I spent too much time in a shop that wasn’t really teaching me as much as they could have. Since you’re learning, they may try to pay you a bit less, which is fine as long as you’re learning. If you’re not learning much, start complaining, and then start looking.

      I learned a lot more in a job shop than the production shop. Job shops, mostly in the oil fields, do a lot of one-off work, it was rare for us to get more than a dozen pieces in an order. This means tearing down a setup, building up another one, and repeating perhaps a dozen times a day. Anyone can sit and watch a machine run, the hard part is in the setup, sometimes as much of an art as science. If there’s a job shop that will take you with your school schedule, that’s the place to learn.

      Also look at related fields. A lot of production work is automated, robotics and process control will go well with machining, and it wouldn’t hurt to finish your carpentry on the side. Since electricity is involved, take a few classes in that if you can, as well as drafting and design.

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