Comment on [Advice wanted!] Things to consider when printing parts for a self-watering planter?
cyberwolfie@lemmy.ml 1 week agoThanks!
This is pretty darn ambitious for a starter project. I say this as someone who is trying to get some fancy new 3D printable tomato cages going before the plants get tall and dangerous and I’ve been doing this for a while.
Yeah, I realize it is ambitious, but my inexperience is perhaps making me think this will be doable from the get-go when it’s really not? We’ll see… I have a limited time before it no longer makes much sense to pursue this this year, so at some point I will need to cut my losses if I haven’t gotten anywhere.
So you really probably want to de-complicate this, either by only making planters that are sized for the printer or finding a existing planter that’s the right size but not self-watering and designing just the self-watering part. You’ll probably learn a lot about the right way to do one this year and then next year you can attack the next generation of the planters.
The design itself will be quite uncomplicated: a bottom container which will hold the water, and then some plates that will hold the soil, supported by the cups that will be submersed into the water that will be packed with soil and perforated to allow absorption. I was planning on lining these plates with some soil fabric so I could keep them loose, only with holes cut out for the cups. The reservoir will be filled through a PVC-pipe that leads from the top and down to the reservoir. I will then build this in with wooden panels (loose, as I otherwise would be unable to get the whole thing inside the shelf where these will go).
One of my big problems last year was finding anything of the right dimensions already existing. They will need to fit inside the shelf.
The problem with printing in pieces is that you are going to have to make sure that the joints are strong enough for the weight of the soil. This is why using a ready-made outer container might help. In the same way, what you really want is something finger-ish or jigsaw-ish so that the pieces align themselves more easily and interlock.
The soil container will have a quite broad base compared to the height. The plates that will hold up the soil will be supported by these cups as described above, and I can make these cups as broad as I need. Are PLA or PETG not particularly strong?
How do people achieve these interlocking patterns - standard tools in the software, plugins or do you do this manually?
You will probably want a fatter nozzle, otherwise this is going to take forever to print.
Oh, good point I didn’t think about, and adding this to be research list. I guess it is delivered with a 0.6mm nozzle.
PETG seems to have worked fairly well for me for outdoor stuff? Coating or paint or whatnot is handy. You might want to look at the epoxy family? If you can print on the balcony, you might consider ASA which is totally fine for outdoor use with no paint.
Cheers! Two suggestions for PETG, so I should probably order some filament already! And adding epoxy to my research list, thanks :) Printing on the balcony will unfortunately not be an option for now.
FreeCAD is a bit of a learning curve? The thing that FreeCAD would make easier is a parametric model, where you say that you want a 400 x 400 x 300 planter. Except that if you are really serious about making large self-watering planters that are parametric, you are going to end up wanting to write code to make it all happen, which either means the Python in FreeCAD, the Python in Blender, or maybe just use OpenSCAD.
I will need to look into parametric modelling it seems. Python I am very familiar with, so making use of that in modelling would in any case be a good skill to acquire. My instinct was just to add a mesh in Blender and resize to my desired dimensions and that would be good enough. My tolerance for the outer parts here is quite high, but for the joints I would want higher precision. OpenSCAD I have not heard about, so I will check out that.
The dimensions of the planter would be 120x40x40 cm ish (based on eyesight from where I am sitting).
One avenue, which is also too big of an ask for this season, is making a multi-part model to cast the large pieces in concrete.
Oh, interesting - that is far from anything I’ve considered. But yeah, not quite something I would be ready to tackle for this season.
Another avenue would be to just design around the outside being wood and the 3D printed parts being brackets and jigs and connectors and the self-watering bits.
It is not that far from what I am going for actually, but the self-watering parts is basically a water reservoir, so it would need to be a water-tight container. Had I only been able to find boxes of proper dimensions where I live, I would not even consider trying to 3D-print this. But they are either too tall, too deep or not long enough.
wirehead@lemmy.world 1 week ago
Yeah, see if you know Python, then OpenSCAD is not a hard jump? One of the reasons why I really like OpenSCAD is that libraries like BOSL2 have parametric joiners and snaps and stuff. And you could totally write modifiers for FreeCAD or Blender to do it, sure, but it’s a lot less trouble to get it done with OpenSCAD. This way your end-result would let you input the size of the bed and it would figure out how many sections it needs, etc.
Lesee… 120x40x40cm is a lot of plastic to print, even with a single printer running all day all night.
What I’d suggest is that you make the wooden outside for the 120x40x40cm shelf and make 20cm x 20cm x 40cm units. At which point you can make bigger multi-part modules. It might actually make sense to keep the cups separate because you could adjust the holes and stuff based on the plant’s needs. Whereas the reservoir section is going to be happiest as a single tub. But the important part is that if you are a few modules short, just add a spacer for this season. And it gives you more time to experiment on the tub and allows you to swap that out mid-season.
cyberwolfie@lemmy.ml 1 week ago
Oh, that could be a much better solution. How would you design the reservoir filling system in that case? It would be difficult accessing the rear reservoirs directly, but I could maybe make something with cheap PVC-pipes. Ideally I would fill it from only one point, and I eventually plan to have some sensors measuring the water level in the reservoir(s)
wirehead@lemmy.world 1 week ago
You can always mock some stuff up and try it out in PrusaSlicer to see how long it thinks it’ll take?
Wall thickness potentially depends on the size of the object? I guess 2mm would the the starting point, fill one with soil, see how sturdy it feels. Complexity for 3D printing is “free”, kinda. A lot of the best container designs incorporate ribs to strengthen them without using up too much material. Given that the joins are the weak part, you’d potentially want that a lot thicker.
You also want to look at “vase mode”. Some of the fastest printing objects you can get on a 3D printer are where you design around the constraints of vase mode and then you can use a fat nozzle with thick layers to print really fast.
You can always print plumbing instead of using PVC pipes? I’ve definitely seen self-watering pots such that they just have a pipe incorporated into the design such that it just sticks up along the corner. So, worse case, each module has a watering port. If you want to get fancy, you could make a manifold such that a single pipe sticks up in the middle and fills 4 reservoirs, although the fancier the plumbing the more likely you are to have one of them get dried out faster unless your filling routine tops them off.