M6 Version of MakerBeam

A small experiment in 3d printing something like “MakerBeam”, an aluminium extrusion based construction technique, itself derived from 80/20 extrusion (which, by the way, is silly expensive here in New Zealand).

I have lots of sizes of M6 hex head bolts so I scaled it up a bit to fit the heads of those bolts, rather than special headed bolts or special nuts. There’s an M6 thread down the hole in the centre.

The four diagonal slits in the design are an attempt to be tricky. They’re only 0.1mm wide so they should get melted together when printed. However, they trigger the slicer software to add a full set of perimeters around them, greatly strengthening the weakest point of the shape. Not sure how well it will work, but worth a try. I could achieve the same effect by fiddling with the slicer and defining extra volumes to print with higher infill or solid, but I’d rather define it in the model, not the slicer.

In the slicer (I use “Slic3r”) preview window, you can see how diagonal slits have added a lot of extra strength.

Cosplay Experiment (3D Print + Cloth Mache) Spiral Horn

Papier mache (and the related “cloth mache”) techniques has some excellent features. It’s extremely cheap, and can make strong and light weight objects. However – at least when I do it – it can end up rather lumpy and irregular.

I love 3D printing, but making large structures with a normal printer gets expensive fast, and also takes a long time. The longest print I’ve done took 16 hours, but some people routinely print 50 to 100 hour prints. The shapes should be exactly what you planned (except when something goes wrong) but laying down all those layers takes time.

I’m not the first person to think of combining these two techniques. I got the idea from 3d-print-and-papier-mache and I’m sure others have done it as well.

I was playing around with “vase mode” on my printer the other day. This is a special way of 3d printing where, rather than laying down a series of layers, the printer lays down molten filament in one continuous SPIRAL layer. The resulting object has to be hollow, with thin walls only one layer thick. However, since the extruder doesn’t stop and start but just keeps looping around while slowly rising, the results tend to be very smooth and are surprisingly strong for their weight. It’s also much faster as only the outside skin is being printed

I drew up this horn shape in Fusion 360. (For those interested, it’s a loft between two circles, with a coil edge as the guide rail).

Here it is printing. It came out very nicely, with lovely smooth curves that felt very nice to the touch.

My first attempt wasn’t so good. In vase mode, each line of filament must partially overlap the one below, since there’s no interior. If it moves too far horizontally from the previous layer, it ends up splodging in mid-air. I need to do some more experimenting to find the shallowest angles I can print.

I cut some strips of cloth from the rag pile, and wrapped my 3d printed “horn”. I worked in a spiral pattern from the bottom, dipping the cloth in heavily diluted white pva glue (probably 50/50 water to glue). It took a couple of tries but was surprisingly easy.

The very wet mix took a long time to dry. I left it sitting for a couple of days. Since the armature was 3d printed, I didn’t need to worry about it getting damaged or mouldy.

I need to do a bit of trimming and sculpting at the ends, where the cloth ended, but only minor stuff.

Here it is on the turntable, ready for painting. My turntable is built from a car wheel bearing, with a cordless drill motor for rotation. Using spray paint, this gives me a much more even coating.

This is after a very quick paint job. I just grabbed the first couple of cans that came to hand (which happened to be blue and gold). However, it does look a lot nicer than the plain white.

It looks, and is, pretty rough. I’m sure I’ll do more experimenting with this, though. One big advantage of this technique is that I can simply mirror image the model, and hence the 3d print. Compared to trying to make two parts look the same by hand, that should be a big improvement.

Storage for Boot (Trunk) of Toyota Caldina

The boot of our family car is usually full of ‘stuff’. Jackets and blankets in case of a breakdown, tow rope, leather gloves, etc. These tend to get shoved to and fro to make room but flop around and spread out. This annoyed me more than usual the other day, when I had to clear everything out to get access to the floor.

I didn’t take a photo of the mess in the boot, but this is the sort of junk that was in there, hurled over into the back seat.

Looking at the boot, there’s an area just behind the back seat where things could be stored vertically if there was a suitable container.

I took some measurements and used Fusion 360 to work out the angles. I could have drawn up a cad diagram of the unit but it was just as easy to lay it out on paper.

This is what I came up with. It’s a simple box with two partitions. One side is angled to match the slope of the back of the back seat. The other is dropped down a bit to make access easier. Cardboard was the material of choice for this. (The rendering above was done after the fact, while experimenting with Fusion 360’s new sheet metal workspace, which can also be used for cardboard boxes).

I found a suitable chunk of cardboard from our huge collection in the shed and we marked out the main shape and cut it out. Folded up and held with clamps, it looked pretty reasonable, and fitted firmly into the space I’d planned.

When I put it down on the floor, it was immediately inspected.

The weak point will probably be the back (front as you look at it) wall. It’s already got two layers of cardboard over much of it, so I filled in the gap, then covered it with another complete layer. Probably overkill, but cardboard is cheap and light. We slathered it with pva glue and weighted the sandwich of layers down with exercise weights and wood.

I flipped it the next morning, and glued the angled face. The partitions were added with more pva and some tricky clamping. I added a rim of clear tape just for looks

This is what it looks like in place for a test fit. I mucked up the measurements slightly and had to cut a notch for the handle which releases the sunshade fitting. A lot easier to change in cardboard than something harder.

And this is what it looks like full of stuff. It absorbs a heap of bits and pieces and still leaves most of the boot clear.