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Thread: CNC plans - DIY kit? Thoughts?

  1. #1

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    CNC plans - DIY kit? Thoughts?

    Just an idea, but it would be cool to have airplane plans as whatever code is needed to run various CNC machines. A metal plane might work well. We could get matched holes, and potentially maximize the number of parts from a sheet of metal. Buy the plans, buy the raw materials, take it all to a properly equipped machine shop, and leave with a kit to assemble.

    Your thoughts?

  2. #2

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    Quote Originally Posted by Cap'n Jack View Post
    Just an idea, but it would be cool to have airplane plans as whatever code is needed to run various CNC machines. A metal plane might work well. We could get matched holes, and potentially maximize the number of parts from a sheet of metal. Buy the plans, buy the raw materials, take it all to a properly equipped machine shop, and leave with a kit to assemble.

    Your thoughts?
    That's largely what Vans does, in quantity. They own some of their own CNC equipment and subcontract out some of the work too.

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    Eric Page's Avatar
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    A group of Canadian guys started a project called MakerPlane (Wikipedia link) to do just that, but it seems to have morphed into DIY avionics and a few 3D printed parts. Their website once had info about the aircraft design effort, but that seems to have disappeared. Their forum might contain posts explaining the history...
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    DaleB's Avatar
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    How many places do you think would have a shop equipped (and willing) to handle large sheets of alclad and run precision cutting and punching operations as a one-off? I suspect that number to be very, very small indeed.
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    To be economical, the shop would have to have both a CNC laser and a CNC punch. At this point you are talking about a shop with a couple of million bucks tied up in tools and a minimum shop rate of well past 100$ an hour. Initial setup and proofing is going require considerable amounts of time and resources. Simply the process of correctly nesting the parts to minimize material wastage and efficiently cycle the materials thru the tools will eat up more time. For the cost of setting this up, one could probably buy a full set of standard kits for everything that Van's has available, and still have money left over for engines and props for a couple of them.

  6. #6

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    Quote Originally Posted by DaleB View Post
    How many places do you think would have a shop equipped (and willing) to handle large sheets of alclad and run precision cutting and punching operations as a one-off? I suspect that number to be very, very small indeed.
    There seems to be some, locally. We prototype sheet metal for instruments regularly, but I don't know the process we go through.
    Last edited by Cap'n Jack; 08-04-2021 at 04:01 PM.

  7. #7

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    Quote Originally Posted by CraigCantwell View Post
    To be economical, the shop would have to have both a CNC laser and a CNC punch. At this point you are talking about a shop with a couple of million bucks tied up in tools and a minimum shop rate of well past 100$ an hour. Initial setup and proofing is going require considerable amounts of time and resources. Simply the process of correctly nesting the parts to minimize material wastage and efficiently cycle the materials thru the tools will eat up more time. For the cost of setting this up, one could probably buy a full set of standard kits for everything that Van's has available, and still have money left over for engines and props for a couple of them.
    Yes, that is the sort of shop I was thinking about. Nesting the parts would be part of the plans that are submitted. Using standard sheets, that will be difficult the first time while developing the programs for the machines, and easy thereafter. The cycling through the tools is probably something that can be done, too, as part of the plans a person gets, as I'm assuming, perhaps incorrectly, that there are similarities between the machines used in different shops.

  8. #8

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    Cap: There isn't a shop out there that will let outside files of any type be loaded onto their machines. When a file for a job comes in, it's loaded on an isolated machine and a CAD guy runs a variety of cleanup processes on it. Once it's ready, it's then moved to a CAM processor and then ports to a POST processor, which then generates the G code specific to the machine. It's then run in simulation for a period of time to identify tooling path errors, cut or punch errors and any machine operation errors. When I was doing CAD/CAM work, even a simple machining file took several hours to complete the path from computer to actually loading and cycling through the first part.

    There are contract shops out there that will do the work, but you will pay for significant shop time for the first pass. For everything laid out on a 4'x12' sheet of AL, you are probably looking well north of 5 grand for the punch work and probably at least that for the laser work. Onsey- twosey type work doesn't really interest the guy with millions of dollars worth of machines on the floor, so they aren't going to be quick and you will pay dearly to have the work done.

    I've contacted a few job shops about some small work before and the quotes are crazy high. Last one was some waterjet work.... about 20 minutes of time on the machine, but I would have to buy a complete hour to cover setup time, plus the CAM time of at least another hour. Let's say I could buy all new drills and rotobroaches for every hole on the parts, do it my self and have less money involved.

  9. #9

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    I did the majority of my project with CNC. I bought a 6040 CNC router when I started the ribs. I had a local place CNC cut a plexiglass jig as my router wasn't big enough. The local place was happy to do the plexiglass jig. I know another place that will CNC laser cut 4x12 sheets of aluminum no problem. I'm not sure why the holes need to be punched.

    I did all the small plexiglass parts and all the wood rib parts. For sure my ribs were accurate because of the CNC. Putting the rib jig together was just a matter of assembling the parts in the pre drilled holes.

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    I also had all the metal parts CNC laser cut locally. My CNC router can't cut 4130 steel. All of the stuff I outsourced was from the DXF files I supplied. They did the conversion to gcode and optimized the parts on the material I supplied. The cost was a few $ per part. Money well spent.

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    I recently learned how to cut Aluminum with my CNC router.

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    The parts I did myself were converted to from dxf to gcode with some software I purchased (~$150). For sure adding a CNC router to your inventory of tools adds another level of skills needed to complete a project whether it's DIY or outsourced. For me, the $2G I spent on the CNC router and learning to use it was time and money well spent.

    As mentioned most of the kits are already done with CNC. I think it's a good idea to start sharing CNC code for plans built projects. Sky's the limit when you put your mind to it.

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  10. #10

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    Quote Originally Posted by CraigCantwell View Post
    Cap: There isn't a shop out there that will let outside files of any type be loaded onto their machines. When a file for a job comes in, it's loaded on an isolated machine and a CAD guy runs a variety of cleanup processes on it. Once it's ready, it's then moved to a CAM processor and then ports to a POST processor, which then generates the G code specific to the machine. It's then run in simulation for a period of time to identify tooling path errors, cut or punch errors and any machine operation errors. When I was doing CAD/CAM work, even a simple machining file took several hours to complete the path from computer to actually loading and cycling through the first part.

    There are contract shops out there that will do the work, but you will pay for significant shop time for the first pass. For everything laid out on a 4'x12' sheet of AL, you are probably looking well north of 5 grand for the punch work and probably at least that for the laser work. Onsey- twosey type work doesn't really interest the guy with millions of dollars worth of machines on the floor, so they aren't going to be quick and you will pay dearly to have the work done.

    I've contacted a few job shops about some small work before and the quotes are crazy high. Last one was some waterjet work.... about 20 minutes of time on the machine, but I would have to buy a complete hour to cover setup time, plus the CAM time of at least another hour. Let's say I could buy all new drills and rotobroaches for every hole on the parts, do it my self and have less money involved.
    So there's no way to get (eventually) a file that could be sent to any shop and run? I'm not talking about a guy like me, who knows very little, creating a solidworks file that needs to be cleaned up. I thinking someone like, for example, Vans, who already has good files made by professionals. I buy plans that include good, usable CNC files. I'm not understanding, maybe the machines are so different?

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