Yeah, I know. I haven’t even finished blogging about the build of the 3D printer. I do want to add more about that, but it’s proving very difficult to do more than 24 hours after I did it. I may be doing some re-wiring on it to clean things up soon and that will make it easier to remember the gotchas I ran into. The 3D printer has been working great for me – a few minor issues now and then but is overall really working better than I had expected. So the past week I’ve had it busy working on parts for my next project. I estimate I still have around 35 hours of printing (give or take 10 hours) before I can move onto the next stage of this project but here’s the start of my attempt at building a CNC machine.
The parts for this are printed with more perimeters and more infill than I’ve used before. A few minor issues have been exposed by this and it’s throwing my completion time estimates all out of whack.
These four are printed at 3 perimeters (I usually use 2) and 70% fill. My slicer estimated about 4 hours to print them, which usually means about 5-5:30 hours. It ended up taking 8.
I’m also trying a different filament this time. Hatchbox from Amazon. It’s fairly cheap at $22 but seems fairly good quality so far. The color is much richer than these flash photos make it appear. It’s also more purple than pink in person though it is a fairly pink purple.
Those are “Corner Locks” that hold a piece of 3/4″ conduit to a “Corner Block” The Corner Blocks were only 40% fill and only took about 4 hours each. Usually printing multiple pieces together goes quicker but on these parts it seems to take a lot longer than printing them individually. Here are the four corners mostly assembled (there are still some regular nuts I need to replace with nylocs)
The 3/4″ conduit is currently about $3.70 for 10 feet here. The designer of this setup suggests a 21″ X 21″ x 6″ (500mm X 500mm X 150) size to start which can be done with 2 10′ lengths – but I’m following a slightly modified build plan which will be 36″ x 48″ so I need to pick up one more stick of conduit next time I’m at the store.
Yeah, I know. Conduit?! 3D printed PLA parts?! 36″ x 48″?! Ok, it does sound kind of crazy. And I’m not going to be milling steel, if I want to do aluminum I can spend $9 on another set of tubes to make a smaller more rigid frame. The reason I’m going this big is so I can fit sheets of dollar tree foam board. Even so quite a few people have built these and they seem to be very capable machines and are good at 3D Printing, laser engraving, CNC Milling, plotting, and just about anything else you can do with a 3D motion platform.
The problem was my retraction settings. With this high infill and the crazy shapes of these parts the slicer had it printing chunks of infill in crazy patterns – every time it shifted from one to another it left a “zit”. This was repeatable across multiple prints of the same file – always in the same place.
I’m still not convinced I actually solved this and didn’t just mask it. But changing the slic3r settings so it prints outside perimeters first pretty much eliminated the zits. I made a few other changes but started getting pits instead so it’s a pretty fine line right now. I can’t complain about the current results though.
That’s one of the center pieces that joins the X, Y, and Z together and mounts the tooling. That’s about a 4 hour print and I need two of them. This machine takes about 1.5kg of filament which means two spools so I’m printing half the pieces in purple and ordered black for the other half.
These were the first pieces I printed. Well, the four clips I already showed were actually the 2nd plate of parts. The other 4 small bits were all short <1hr prints so I put them together on one plate. Unfortunately I messed up the infill and had it too low so I'll probably have to reprint all of them.
They, like the corner blocks, suffered from the zits. The center section prints are all clean. But I wouldn’t mind reprinting the pieces with zits at some point. There’s still so much printing to go I’m not in any hurry. I still have to order hardware and electronics for it. The designer sells a kit of parts for $240 which looks like a pretty good value for the money. I’m probably going to do it the hard way though and just order things separately here and there as I go. (He also sells a package of pre-printed printed parts for just under $200 if you don’t have your own printer or don’t want to spent 2-3 weeks of evenings and weekends non-stop printing on the one you do have.)
Here’s where I’m at on the printing after just under a week.
Starting with the black piece and going clockwise we have the two middle joiners in contrasting colors followed by the first “middle end” and “improved middle Z”. The Improved Middle Z is the only piece that needs support to print and like the middle end and middle joiners there will be two of them in contrasting colors. Next are the four “Roller Locks” followed by the first “Foller F” still need 3 more roller F’s and will probably do two of those in black (might redo two of the locks in black to go with them while I’m at it.) Then down in the lower right corner we have the first “SolderLess Mount” – but I’m thinking with the way I plan on wiring it the regular mounts will use less plastic, print faster, and work just fine because I don’t mind soldering. And across the bottom row our friends the Corner Blocks and Corner Locks. Behind those in the middle on the left we have the Z motor mount – but it was printed at only 10% infill and should be 60%, plus I may need a taller version depending on my steppers, so that’s VERY likely to be reprinted. The three little objects were also printed at only 10% infill, The coupler in the lower left is almost solid anyway but it connects the Z axis to it’s motor so I should reprint it. The small round thing to it’s right is the “Z Adjust Knob” that lets you adjust the Z height manually without grabbing the leadscrew (which is hopefully covered in grease.) And finally above that is the “Z Nut Lock” which couples the nuts on the leadscrew to the whole crazy middle section.
Hopefully I can finish the printing this week. But the black filament I ordered is giving me fits, and tonight my printer seems to have had some kind of failure on the arduino board that is it’s brain. So progress may slow for a few days 🙁
If I have to order parts maybe that will give me time to finally post about the wiring and setup on the printer!