Portable CNC - Leaving the workbench behind

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ScaleBirdsScott

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Came across this just now reading one of the blogs in my daily rotation:

http://www.core77.com/projects/69637/BeamCNC-Works-with-Common-Materials-to-Help-Produce-Grid-Beam-Projects

And thought it might be a neat method to make it easy to feed a chunk of L-angle or square tube into a machine and have it drill a repetitive series of holes for riveting longerons or spar caps or some other such thing.

It's maybe not exactly the most cost-efficient or time-efficient unless one has a project with an obscene amount of such work to do, but maybe if its original purpose - to drill random wood into viable "gridbeam" units as a sort of low-cost 80/20 - is appealing to you, then let this thread serve as one example of how it could be used beyond the original scope.

Could this tool also be useful for profiling or pocketing long boards? Maybe some wooden I-beams? Who knows.

It's another example of the increase in more custom form-factors in CNC, going beyond just a big machine station and expanding into portable tools. I predict in a few years we'll start seeing CNC type motion control tools in more niche roles, potentially even seeing such tools in Home Depot. They already have Ryobi battery powered hot-glue-guns and Milwaukee mini vacuums that use the same battery pack as your impact driver. Why not start adding microcontrollers and tiny stepper motors that can be programmed via a slick Android app?

Also there's the Goliath, which is another case where you will no longer need big tools or a lot of space to cut a 4x8 sheet of plywood down into various rib shapes. This little guy will just drive around like an RC car, happily cutting away where needed. No large table, nothing taking up room, but when a sheet does need to be cut, you can get accurate and detailed results.
 

cluttonfred

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Great stuff! The BeamCNC seems pretty limited in this form but it's not hard to imagine something similar but with the ability to move the cutter sideways as well so it could position the holes anywhere on the front surface of an angle or rectangular tube as well as cut the ends at whatever angle is needed. You could probably also work out how to get it to cut both sides of an angle or all four sides of a rectangular tube if needed. The Goliath looks about perfect for cutting gussets, bulkheads, and panels in plywood or aluminum. Between the two machines, (fictional) Improved BeamCNC and Goliath, you could cut out most of the parts for a tube-and-gusset or all-metal aircraft project, making your own kit at home.
 

ScaleBirdsScott

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And that's just it, I could forsee a few small, specialty type tools where you just stick your Bosh router into the socket, put it on your wood or metal, or feed in a strip of material, and let it go to town. And then it could be practical for an individual to spend a few hundred bucks on such a tool, or maybe it's a local hardware store rental option. Makerspaces could jumpstart it by offering a Goliath to rent for a day or weekend from their tool crib and use it to make custom parts all in a big batch. I am pretty sure if you planned ahead and had the files, one could cut all the sheet parts for something like a Hummelbird in a weekend with such a tool, along with all the forming blanks from MDF.
 

Jay Kempf

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Once you put yourself through all these mental exercises you end up back at a nice CNC router somewhat large. Replaces all of these tools. $3000 or less gets you in the game. If you don't have space or that sort of scratch then the portable tools make sense. It is easy to rack up $3000 in tools to replace what one router will do. Any wood router can cut thin aluminum sheet, tubing, etc...
 

pictsidhe

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A giant CNC router is a definite maybe for me. My plans for the future involve building several structures from raw trees. To help do so, I'm going to build myself a sawmill. It'll use 30-40' angle iron rails set into the floor so they can stay there when I'm not running a saw mill in my workshop. Those rails could feasibly take a CNC carriage whizzing back and forth instead of a sawmill. I'll likely spread the rails a bit wider than I would for just a sawmill. A 6' or 8' x 30' CNC would make some of you turn green with envy! I've considered the probable lack of rail straightness and think that calibrating the thing with a laser should produce very good results.
 

etard

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Has anybody designed a CNC router that would clamp onto a standard 4' x 8' sheet of plywood? I'm picturing 2 long 8' pieces with some sort of corner holding mechanism and a bridge connecting the long sides, like a gantry. You could break the whole thing down into maybe the size of an ez up for storage.

Also, the idea of the little car that drives around on the sheet cutting your shape is interesting. If you could only add a grid system with ink or laser onto the face of the plywood (could be as easy as adding an ink roller with grid at the end of production line) so the little car could constantly check it's position and adjust if needed, does not seem like it would add too much to production costs. That plywood could also be useful for manual use as well, no?
 

poormansairforce

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Has anybody designed a CNC router that would clamp onto a standard 4' x 8' sheet of plywood? I'm picturing 2 long 8' pieces with some sort of corner holding mechanism and a bridge connecting the long sides, like a gantry. You could break the whole thing down into maybe the size of an ez up for storage.

Also, the idea of the little car that drives around on the sheet cutting your shape is interesting. If you could only add a grid system with ink or laser onto the face of the plywood (could be as easy as adding an ink roller with grid at the end of production line) so the little car could constantly check it's position and adjust if needed, does not seem like it would add too much to production costs. That plywood could also be useful for manual use as well, no?
https://www.kickstarter.com/projects/1830738289/maslow-cnc-a-500-open-source-4-by-8-foot-cnc-machi
 

FritzW

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The Carvewright machine would fit into the category of non-standard form factor CNC machines. To a limited extent it can take the place of a table saw, jointer, planer and CNC machine. It'll handle material 5" tall, 14" wide and unlimited length (within reason).

787_std_1478035600.jpg

They're one of the few "new CNC gadgets"that have made it all the way from "theoretically cool" to "real life practical". The table saw, jointer and planer functions are pretty clunky but the CNC function works pretty good.
 

proppastie

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looked into this one...accuracy is about down to 1 mm and getting better with up grades. My plotter is good to .01 in. I bought a used 2 hp router and router table on Craigs list and a am planning a "cheap shaper tool" by pasting the plotted part onto plywood or aluminum and doing it by hand. Others have said it should work as long as I use the router for say less than 1/4" cut, pre-cut with a jig saw. The plan is for accurate contour boards for better accuracy in constructing the LE wing nose ribs, and constructing an accurate assembly fixture for the wing. For a one off I am not convinced the trouble of CNC is worth it, considering the time and trouble and learning curve. They are really nice tools though. Now if you are planning on selling parts or completed aircraft then probably is well worth it.
 

pictsidhe

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I'd been pondering something like the Maslow before finding the link to it. I've had a good look at it now, including spreadsheeting the tension at 1' intervals and inaccuracies from chain stretch. I didn't get as far as the catenary sag as the stretch needed fixing and the tension is too variable IMHO. The X error from stretch is pretty small, but the Y error from stretch varies by over 3mm. I'll mull it on a long drive in a few days then see what a spreadsheet thinks of any tensioning idea I have. stretch and sag can be calculated if the head isn't moving too violently, so could be corrected for. Chain wear would be a lot harder to calibrate out and bothers me, given the amount of error a new chain gives from stretch. a 20mm wide 5M HTD or GT2 belt would have similar stiffness to the #25 chain but wouldn't wear. Just getting the motors further out and up would be a big help, if your workshop allows it. With the motors up high, they shouldn't be too intrusive if you hook the chains up out of the way too when it's not in use.
 

proppastie

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I see same platform, with X-Y movement on rods with bushings. The sled idea is great, the slanted foot print is also great. Wish I could find some off the shelf "cook book"/ hardware/software. The potential is there for a very accurate and in-expensive machine. Youtube has lots of DIY CNC. but I am sort of busy with my current project and do not want a diversion.
 

ScaleBirdsScott

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Vigilant1

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My plotter is good to .01 in. I bought a used 2 hp router and router table on Craigs list and a am planning a "cheap shaper tool" by pasting the plotted part onto plywood or aluminum and doing it by hand. Others have said it should work as long as I use the router for say less than 1/4" cut, pre-cut with a jig saw. The plan is for accurate contour boards for better accuracy in constructing the LE wing nose ribs, and constructing an accurate assembly fixture for the wing. For a one off I am not convinced the trouble of CNC is worth it, considering the time and trouble and learning curve. They are really nice tools though. Now if you are planning on selling parts or completed aircraft then probably is well worth it.
Using a manual router to cut up to a pasted-on pattern can work well, but if the desired accuracy is high (e.g. the width of a pencil line) then I think it might be difficult. You'll need a very bright light in the router, a steady hand, a lot of patience, and probably a back brace by the time you are done. When trying to do something similar, I usually ended up stopping short of the line and using a belt sander to go the rest of the way, which isn't much fun if doing a lot of linear feet.

I love tools, but I don't know if a CNC router setup is one I'd buy. It seems like the kind of high-cost, infrequent-use item that is way better to rent when needed (go to a makerspace, or to a shop and give them the data file and instructions). Of course, if I owned one I'm sure I'd find a lot of fun uses for it.
 

FritzW

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Santa Claus (my wife) authorized me getting an Origin last Christmas but I decided to wait, at least, a year. I think the 'concept' is completely valid but the 'real life' hardware and software are still maturing too fast to *jump in now.

*I learned my lesson when I bought my first CarveWright machine before they we're ready.

>>>random thoughts<<<

I just watched the "pros and cons" video on SBS's link. I disagree with a lot of what the guy said (feeds and speeds calculations being an issue, etc.) but he did say his opinion was biased.

Comparing an Origin to a Gantry style CNC machine is like comparing a table saw to band saw. They can "kinda" do the same thing but they're different tools with different missions.

We've talked about "thumb drive and pile of wood" airplanes before, I think there could be an " 'Origin' and pile of wood (or aluminum)" airplane just as easy. ...design the airplane to match the tool, just like Bud Evans designed the VP-1 for a drillpress and jigsaw.
 

proppastie

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Using a manual router to cut up to a pasted-on pattern can work well, but if the desired accuracy is high (e.g. the width of a pencil line) then I think it might be difficult. You'll need a very bright light in the router, a steady hand, a lot of patience, and probably a back brace by the time you are done. When trying to do something similar, I usually ended up stopping short of the line and using a belt sander to go the rest of the way, which isn't much fun if doing a lot of linear feet.

I love tools, but I don't know if a CNC router setup is one I'd buy. It seems like the kind of high-cost, infrequent-use item that is way better to rent when needed (go to a makerspace, or to a shop and give them the data file and instructions). Of course, if I owned one I'm sure I'd find a lot of fun uses for it.
I never made the contour boards...ended up using finishing nails in soft pine for the rib jigs....plotted paper rubber cemented to the pine...see build log. The router base/table ended up a high table for my small drill press. I am sort of disappointed because I was looking forward to playing with the router...I never had one.

It remains to be seen if the nose ribs will be close enough....the rivets will be covered with an extra layer of fabric then the whole LE and wing is fabric covered......Compatible Fibefill for the Polyfiber is an option. The other LE finished on the tail feathers had only two nose ribs one at each end.

Right now I am in the "finish this monster" mode,... so playing with new toys is not happening.
 
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