vcp
Well-Known Member
Somewhere in another thread there was mention of printed flyaway launch lugs. I'd mentioned I'd done a flyaway styrene band and split plastic lugs long ago (Astrobee-D), a concept that might be possible to do now with a printed lug. So I finally got around to spending an evening fiddling with it, and here was the result.
This is the view of the .stl file. The band is printed in two parts, so it can be trimmed to fit a tube, and the bands glued together. Note the overlap printed into the right end of the back band. The plate includes a short section of 'C' rail, used to hold the band on the model when not on a rail. This was printed with full supports provided by Simplify3D, which are pretty easy to remove, though the supports could use a bit of adjustment to make the removal easier still. The band could be printed in a single piece, to length for a specific tube, but the tube diameters that could be served would be limited by the build space on the printer. It still is limited to a little over a 4" dia tube on my printer, but I suppose the band could be printed in three or more pieces.
Close view of the printed split lug and it's leading and trailing edge rake. It's occurred to me that the print could be paused after printing the band, and the split lugs printed with Igus iglidur Tribo-Filament, which is intended for bearing surfaces - it's slippery. Assuming that the Igus filament would bond with the band material (it prints at the same temp as ABS, so I'm hoping). A little bit of filleting would strengthen those inside corners.
Here's the printed band. The material is ABS, and the band is two 0.2mm thick layers. This produces a very flexible and remarkably strong band. Notice the printed-in overlap at the joint and the lug 'keeper' in place. (Also notice evidence of over-extrusion; I need to adjust some settings.)
One half of the printed split lug. It could use some clean-up and some printing adjustments.
Fitting the band to the tube, with the keeper in place. The band is not cut to fit or glued at this point.
Marking the band for cutting to size. Note the printed overlap for gluing.
In the process of gluing the bands. I just brushed on acetone, but CA should work.
This is the final fit of the glued band and I'm pretty pleased with the fit. The spreading force isn't too bad, but I believe it could be lessened somewhat by angling the split rails toward each other by a few degrees. Right now, trying to hold the split rails flat together tries to flatten the band; a bit of an angle would approximate the tube curve better.
So that's it. I believe this style of flyaway band, split lug is feasible for printing. Now I need to cleanup and do a better job of parameterizing the OpenSCAD code, and making it so that I can plug in standard launch rail sizes. And, I suppose, someone should try flying one.
Hmmm, perhaps a means of adjusting the band joint, rather than gluing it, so the same band could be used on a variety of tube sizes... Shoot, maybe just glue on some velcro. Other ideas?
This is the view of the .stl file. The band is printed in two parts, so it can be trimmed to fit a tube, and the bands glued together. Note the overlap printed into the right end of the back band. The plate includes a short section of 'C' rail, used to hold the band on the model when not on a rail. This was printed with full supports provided by Simplify3D, which are pretty easy to remove, though the supports could use a bit of adjustment to make the removal easier still. The band could be printed in a single piece, to length for a specific tube, but the tube diameters that could be served would be limited by the build space on the printer. It still is limited to a little over a 4" dia tube on my printer, but I suppose the band could be printed in three or more pieces.
Close view of the printed split lug and it's leading and trailing edge rake. It's occurred to me that the print could be paused after printing the band, and the split lugs printed with Igus iglidur Tribo-Filament, which is intended for bearing surfaces - it's slippery. Assuming that the Igus filament would bond with the band material (it prints at the same temp as ABS, so I'm hoping). A little bit of filleting would strengthen those inside corners.
Here's the printed band. The material is ABS, and the band is two 0.2mm thick layers. This produces a very flexible and remarkably strong band. Notice the printed-in overlap at the joint and the lug 'keeper' in place. (Also notice evidence of over-extrusion; I need to adjust some settings.)
One half of the printed split lug. It could use some clean-up and some printing adjustments.
Fitting the band to the tube, with the keeper in place. The band is not cut to fit or glued at this point.
Marking the band for cutting to size. Note the printed overlap for gluing.
In the process of gluing the bands. I just brushed on acetone, but CA should work.
This is the final fit of the glued band and I'm pretty pleased with the fit. The spreading force isn't too bad, but I believe it could be lessened somewhat by angling the split rails toward each other by a few degrees. Right now, trying to hold the split rails flat together tries to flatten the band; a bit of an angle would approximate the tube curve better.
So that's it. I believe this style of flyaway band, split lug is feasible for printing. Now I need to cleanup and do a better job of parameterizing the OpenSCAD code, and making it so that I can plug in standard launch rail sizes. And, I suppose, someone should try flying one.
Hmmm, perhaps a means of adjusting the band joint, rather than gluing it, so the same band could be used on a variety of tube sizes... Shoot, maybe just glue on some velcro. Other ideas?
