Posted May 18, 20222 yr I thought I wouldn't have time to participate, but looks like I got some free time on my hands now that there's still couple of weeks left before the contest deadline. So I wanted to participate, and to build something that's a sort of unusual, but easy enough to make in the short time that's left. 3D-printing is all the rage now, and even buildings can be printed. There are many kinds of machinery for that, but to fit the contest rules I chose a type that moves on tracks and extends a printer arm for spraying the concrete in place. Something along these lines: I'm not going to attempt replicating the machine pictured above, but something similar with the same basic functionality. Here's what I've built so far: I intend to add at least outriggers and a knob for rotating the turntable. Not sure what else I can fit in, we'll see.
May 18, 20222 yr The gearing to move the rack seems over complicated. A 1L worm does the job plus driven from the fixed end using two 2L axle connectors and a12T DBG gear
May 18, 20222 yr Author 3 hours ago, doug72 said: The gearing to move the rack seems over complicated. A 1L worm does the job plus driven from the fixed end using two 2L axle connectors and a12T DBG gear Yeah, but worm gear requires so much of knob-turning that I prefer something that's faster to operate. But I will think about it. 13 minutes ago, Jundis said: Is it the chassis of the 42121, just turned upside down? :D Not exactly, just the tracks. They are mainly placeholders to stabilize the thing as I needed quickly something to keep the arm upright and to give a feeling of size and I happened to have assembled 42121 at and so I just took the tracks from it. I will make better ones if I have time.
May 25, 20222 yr Author I'm almost finished, only some little touches remain. The final size is 7488 cubic studs (L: 27, H 18, W 16 studs). I struggled a lot with the outriggers as I wanted to have one in each corner, positioned at an angle, and to operate them simultaneously with only one knob. I also wanted to make them self-locking by geometry, which forced half-stud offsets, complicating matters further. I'm not sure I'm satisfied with the result as it feels somewhat like a kludge, but it works and doesn't look too bad. The arm was quite a straightforward build, though the geometry required some fiddling before I got it right. I also wanted to use a pneumatic hose to simulate the tubing through which concrete is pumped to the tip, and to make a infinitely rotatable joint inside the turntable so that the external hose could be attached to the chassis. The arm would be even better if there were more articulated joints, but I'm not sure the scale permits such complexity, and remaining time definitely doesn't. There's also a weight brick acting as a counterweight. The colour scheme (red, along with LBG/black) was forced by the boom housing, which I only own in red (ok, I do have them in yellow and blue too, but those currently assembled in Zeux and Tow Truck). The tracks are slightly modified tracks from 42121. As there's not much time left, I didn't want to risk unfinished entry by attempting to fix what's not broken. Some photos follow:
May 25, 20222 yr This has come out great! And I love the outriggers - they look solid and efficient. The only thing I might change - and it's just personal chromatic taste 'cause I'm not too keen on red&yellow - is to replace the two yellow half-bushes with one DBG 1x3 half-beam. Overall, beautifully designed and executed.
May 26, 20222 yr Author Thanks a lot everyone! I'll maybe do some touching up and then get the final photos for the entry. 18 hours ago, suffocation said: This has come out great! And I love the outriggers - they look solid and efficient. The only thing I might change - and it's just personal chromatic taste 'cause I'm not too keen on red&yellow - is to replace the two yellow half-bushes with one DBG 1x3 half-beam. Overall, beautifully designed and executed. I thought of that, but I decided to use yellow bushes as a colour of "warning" which pops out from the background, fitting nicely to a construction machine.
May 27, 20222 yr On BBC news today is an item about 3D printing schools in Africa. see this link https://www.bbc.co.uk/news/av/technology-61588608
May 27, 20222 yr Author 16 minutes ago, doug72 said: On BBC news today is an item about 3D printing schools in Africa. see this link https://www.bbc.co.uk/news/av/technology-61588608 Nice! Very different kind of machine there though.
May 28, 20222 yr Completely overlooked this one, what a cool machine! The outriggers driven by one wormgear are a genius idea :D
May 29, 20222 yr Author 23 hours ago, Jundis said: Completely overlooked this one, what a cool machine! The outriggers driven by one wormgear are a genius idea :D 2 minutes ago, Jurss said: That rear outriggers mechanism is genious. Thanks! The outriggers came out surprisingly nicely. The only problem is that due to the wormgear they are slightly out of phase, so they don't move identically together, but it's not a big enough difference to matter really.
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