Stream of I3V 12" Build Consciousness
I took delivery of my 12" I3V kit yesterday.
Ordinarily, I would share an obsessively detailed log of my experiences with something new.
But not this time... :p
Instead this will be more of a stream of consciousness record of whatever comes to mind during the assembly, tuning, and usage of the printer.
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A little background: I didn't really think too much about getting a 3D printer up until maybe 1.5 months ago. I had told myself that I wasn't going to make the purchase until I really had some other reasons than to just build one. In some sense, it had to earn its keep.
So..., I started a list of items that I wanted/needed that a 3D printer was uniquely suited to provide with the proviso that no printer would be bought until I had at least 10 items on the list.
Heh..., I was a little surprised as to how quickly that list grew. Some items were minor, but nice-to-have, but others were really compelling and aligned well with my other interests, chief among those is pottery..., which seems strangely appropriate.
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So, list in hand, it was time to pick a printer. I'll skip all the details, but I will say that PrintRBot was in the lead for a long time. I liked the mechanical aesthetic of Brook's machines, and was hoping to get a Metal Plus. Unfortunately, I had too many nagging doubts about "issues" with the Plus, and was sorta indirectly steered in the direction of a reprap style kit by comments from someone on the PrintRBot forum.
As I looked into the reprap/open source/kit options, it really became apparent that quite possibly a functionally and practically better choice could be had outside the store-bought options. True, "better" is judged from my specific interests and needs, but there ya are.
Ultimately, my search took me to Makerfarm. What finally sold me was:
- Utility of the finished product.
- Adaptability.
- Support of the reprap community, and this forum in particular.
- Success of others with assembly/tuning.
- Colin. I swear, I don't know how he does the support thing, but he does, and its incredible.
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Some early decisions:
Controller Board: Initially I was gonna go with the RAMPS, but decided on the RUMBA since it seems to position things better when/if comes the time to contemplate a conversion to 24V.
12V vs 24V: I was tempted to build the machine as a 24V system from the start, mainly owing to concerns about heating the 12" bed. Based on comments from Colin, I decided to stick w/ 12V for now and save 24V for another day.
Vinyl Tubing vs Metal Flex Couplers on Z: Decided to stick with the tubing until I've gotten some experience with the machine, on the off chance that the tubing will act as a clutch in the event of an, er, unplanned Z excursion. I would almost be tempted to sacrifice accuracy/reliability early on by lubing the tubing to make sure it slips in the event of "badness". Later, I'd switch to the metal couplings.
Power Supply: I'm a little ashamed that I've decided to go with the cheap option, but mostly for reasons unrelated to "cheap". I got one of the $23 specials off of Amazon..., hopefully it will work out, at least long enough to get things working. What really drove the decision was entirely unrelated to the printer. I needed some obscure spark plugs that no one was stocking..., but they were available as "add-on" items on Amazon. I had kept forgetting about them on earlier orders, and so I figured I'd roll the dice with the cheap power supply, and AT LEAST get the darn spark plugs.
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For now..., that is all!
It's the week END d---it!
Cool. Then the problem wheels are on my list of things to come back to. Thx.
So far things are assembled up to but not including the end-stops. Oh..., I did go ahead and bolt on the power supply and added some nylon spacers between the frame and supply, hopefully to give cooling a bit more of an edge. Also added washers to all the motor mount screws.
Most things went together requiring little or no adjustment afterwards (OK..., ignoring the wheels), and things seem "sound" enough for initial testing without immediately revisiting them.
I've decided that the build is going to move to my sorta working workshop. There, I'll have easy 360deg access to the machine w/o moving stuff around. Optimal wiring routing seems like it's gonna require a bit of creativity and stress-free access to everything will help.
Not sure if I'll be able to make any more progress this weekend, but early in the week things will proceed, including acquisition of the glass.
Also am faced with one of those trivial decisions I'm kinda bad at: which power switch to purchase/use. I'm almost tempted to make a Frankenstein-style scissor switch and bolt it on the side. OK..., just kidding. I think. Yes! OK! I'm kidding.
Have a great weekend!
16 hours and 49 minutes later...
Was looking for something with a little height. I really picked the wrong thing, but it ended up being an interesting experiment anyway.
At the very least, I need to secure the printer to a rigid and stable surface. Still, if this is the worst it does in less than ideal circumstances..., it's not too bad.
https://youtu.be/BAD4ikaqFhE
Will be interesting to see what mods things like this might lead to... ;)
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First trip through FreeCAD...
So I needed a knob for the LCD panel. Who doesn't?
While I was assembling the extruder, I knew what it had to be, and that it might be a good opportunity to begin learning FreeCAD.
On the first go around, I simply doubled the size of the extruder motor pinion, closed up some holes, and put in a 6mm hole.
The print produced something like a 5.715mm hole, and it didn't fit.
Of course, 6mm wouldn't have fit either..., since I didn't measure the shaft particularly carefully. Went back and mic-ed it for real and found it was more like 6.1mm diameter. Adding a 5% allowance seemed like too much, so I kinda split the difference and tried a 3% shrinkage allowance (and added a bevel to the hole to match the shaft). That one fits and is the one in the picture.
Turns out, doubling the size of the part was a bit much. The rotary encoder is not mounted on the PCB in a particularly robust way, and I think this knob gives too much leverage, increasing the possibility of breakage. So..., I'll probably shrink it down to something 1.5x w/ a 6.3mm x 10mm hole.
Was a little disappointed w/ FreeCAD on Linux (Mint 17). The version in the package repo is 0.14, and is flaky as hell. Unusable for my purposes actually. So I'm using the most recent Mac version (0.15) and that seems to be OK, though I'd much rather be using the desktop for this stuff.
Anyways..., here's a vid and a pic...
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retraction test results...
Per Voodoo's comments, I decided to try running some retraction tests.
For context:
- 3mm PLA (tan) filament.
- hexagon HE w/ .4mm nozzle.
- stock MF HE cooling shroud.
- heTemp=225c, hbTemp=70c.
Unfortunately, the final set of photos don't really present very well, so I'll only show some intermediate photos of the first two tests (the 30->20 comparison).
I ran the tests with retraction rates of 30mm-s(per MF slic3r config file for my setup), 20mm-s, and 10mm-s.
The most obvious change in quality came from the 30->20 test (which is what the photos cover). The 20->10 test showed some small improvements, but nowhere near as dramatic.
The article with the equally spaced pylons of all the same height showed the most improvement. With the exception of the base, all the layers are identical, and all segments are relatively close together.
The article with the tall corner pylons behaved much the same way, UNTIL the tall pylons rose above the rest, and whose rendering involved retracts w/ large X/Y moves. I.e., they spent the least amount of time in the downwash of the HE cooling fan. Once the 4 tall pylons, each spaced a significant distance from one another, began to be the only things rendered, things got worse.
Or put another way: the sections that spent the most continuous time under the HE cooling downwash did better than the ones that spent less continuous time in the downwash.
This makes me think that the addition of a part cooling fan might be useful.