Cantilever printer design based on leftovers

3D Printing
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Fabbed this idler tensioner tonight. I ended up making it a bit bigger so that I could get more M3 screw engagement in the hinge block at the top. I used two M3 screws, one from each side, so that I can adjust the location of the hinge block without removing the screw, and I don’t think I’d have a long enough M3 anyway to use just one. I ended up with 20mm between the arms, far more than I need otherwise but also not a problem, I expect.

Silicone heated bed arrived earlier than previously predicted, so I won’t end up using the old aluminum heat bed as a heater after all. Not sure what I’ll do with it now, though! Maybe an enclosure heater for the corexy printer? I think I’ll still fab the kinematic mount features in small bits of aluminum and attach the to the bed with high-temp RTV as I’d been thinking of using for the heated bed, because that lets me replace them easily if I screw up.

Still remaining:

  • Electronics: still pretty much nothing done, but the new 24V supply arrived to replace the one I am using for the drying oven.
  • Heated bed (120V 500W silicone heater, high-temp RTV, SSR, TCO, cast aluminum plate, kinematic mount fixtures)
  • Y belt clamp for saddle
  • Extruder mount
2 Likes
42

This morning I got the Y belt clamp set up. I had intended to attach the top side of the belt to the middle of the saddle, but then realized that the adjustment screw would be inaccessible. I then discovered that with a clamp piece I had already made (a test piece for the X axis clamp) it was aligned already with the bottom of the saddle, so all I needed was to screw an extension to the bottom of the saddle and fix the belt to that on the bottom side. It will reverse motor direction for Y, which is fine.

DSC_1768
DSC_17682970×3333 1.28 MB

The tensioner worked great. I was able to slide everything around so that everything is square and it runs true. The clamps are wide enough to move to 9mm belt later if this 6mm belt isn’t sufficient.

DSC_1771
DSC_17711482×1611 530 KB

I installed X and Y stops. The Y stops are 9mm openbuilds spacers fixed with M5 screws and drop-in T-nuts that the saddle hits at the travel limits. The X stops are more interesting, M5x30 screws with locknuts screwed on to leave 7mm of travel, then an M5 washer, then a slide-in T-nut screwed into a slot and which the hotend mount hits at the limits of travel.

DSC_1772
DSC_17724149×2934 2.13 MB

I’m so glad I cut the frame a little oversize just in case I hadn’t thought things through well enough. I’d missed something in my calculations and padding Y by 15mm gives me about 2mm extra room for bed travel in Y. That came close to being really annoying.

I am also making some feet, because I realized I needed to hold the frame off the table to run wires under it. I lathed them out of 20mm PE round bar stock; 20mm long, 5.5mm through-hole for M5 bolt, 10mm countersink for M5 bolt head 14mm deep, M5x12 bolt into slide-in T-nut in frame. After a day of drying out my ninjaflex, I will print TPU inserts (“shoes”?) that fit into the 10mm counter-sunk holes as the bottoms of the feet. Without the “shoes,” here they are on the corner. I like the flush frame mount that works from a good square cut!

DSC_1764
DSC_17644065×2718 1.74 MB

I think I’m going to run electronics and try the printer out with wires run through wire loom before I commit to drag chain installation parameters; I’m not 100% on routing yet.

This means that the remaining tasks before first print are

  • Design, fab, and attach an extruder mount.
  • (Re)-design bed mounts; fab, assemble, and mount heated bed
  • Design and fab limit switch mounting blocks and flags; attach them
  • Wire up all the electronics

Before that’s all done, I should have the ninjaflex dried and the “shoes” printed and ready to use.

Here’s what it looks like now:

DSC_1763
DSC_17632981×4307 1.99 MB

4 Likes
43

Okay, now that I see the layout and the surrounding equipment I can make up and LCD mount and control box. I didn’t see the pictures earlier when I saw this latest post. Just to confirm, the base is 2060 extrusion, and you’d like the LCD to the left instead of in front of the front extrusion, and the control box along the left hand side? Also would you like the electronics closer to the z pillar?

2 Likes
44

Yeah, the frame is 2060 extrusion mounted on 20mm feet (which will soon have another 4mm or so of TPU under them, in a few hours after my marathon print of fittings for the enclosure for the corexy printer finishes, which will be the tallest print I’ve ever made).

There weren’t pictures earlier; I am so ashamed of my disaster of a shop, where I am halfway through so many projects that I sometimes can’t find the tool I’m looking for, that I couldn’t bring myself to take pictures of the work I was doing in there. I back-filled pictures last night. :blush:

I finally got far enough in SolidWorks this morning, after hooking up my space mouse to that computer, to find the actual part (rather than an assembly into which it was linked), remove the smaller display, import the model of the TFT35, and start to try to figure out how to re-link constraints to the features of that model. (Got far enough to think that if I could just take a week or so to get past the initial ramp of the learning curve, I’d probably enjoy using SolidWorks enough to get over needing to run Windows to do so.)

Then I looked again at the display I have and discovered that it isn’t the part that was modeled. What I have is the TFT35-E3 V3.0 which, I think, re-packaged up the TFT35 in a form factor that is an exact replacement for the Ender 3 display board. The dimensions are on github but I don’t know of a 3D model for it. They have a 3D PDF but not quite clear to me how useful that would be; Linux support for that seems to be slim pickin’s…

I was thinking of an arrangement that exposes the microsd card and micro-USB slot in the mini-e3, because on-board SD has lowest potential for print artifacts, and the USB port is useful, with the board set vertically for better thermal management. I want to put the 24V power supply remote under the desk to reduce noise from the fan, but make the mains power switch accessible. I need 120VAC to feed the heated bed from the SSR anyway. I like having the screen right out front, easy to get to, and I have plenty of desk space for it.

I’m attaching pictures here roughly mocking up the layout that I have in mind:

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DSC_17844587×2904 2.48 MB

This doesn’t show the mini-e3 board as high as I would make it actually sit in order to have access to the USB port. There is plenty of room between the frame and the bed, so the case can stick up above the frame without a problem. (I just ran out of pieces of foam nearby to prop it up. :slight_smile:)

The AC inlet could be on its side with the C19 receptacle toward the back, instead of oriented vertically. That would probably make more sense than the mockup.

Here’s a top view:

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DSC_17862219×3075 1.42 MB

Thank you! :slight_smile:

2 Likes
45

Nice thing is it looks like there’s a model for the E3 version as well:

https://grabcad.com/library/bigtreetech-tft35-e3-v3-display-1

later on tonight once the kids get to bed or maybe tomorrow I’ll start playing around with some layout ideas.

1 Like
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Thank you so much! Looking forward to seeing this, and hoping it’s useful to more people than just me… :slight_smile:

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Played a round a bit quick to get in the parts. Will start laying them out later. Gotta get back to the family.

Here are the files if you want to do a little solidworks playing as well. It’s a pack and go so all parts are included.

MMaEMf4ox5
MMaEMf4ox5781×481 26.8 KB
efGBnmxiIF
efGBnmxiIF1019×469 62 KB
mUhhBGthHt
mUhhBGthHt846×487 75.9 KB

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I moved things around. Just the SLDASM file, since as far as I know I didn’t modify anything else:

https://drive.google.com/drive/folders/1mEDElnHv0afwhLoRkK-Scboc7oYvcJ01?usp=sharing

I moved the display slightly forward so that it would be possible to get at the SD reader if necessary, and rotated the switch/C19 receptacle and moved it forward.

I’m learning a little bit! :slight_smile:

1 Like
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Great, I’ll begin with your layout as the preliminary positioning, then and start coming up logical dimensions for the offsets. Then an enclosure to go around it that is printable. I’ll try and break it up into logical sections so it can be disassembled and printed without being a big monolithic structure, plus it’ll also make servicing easier.

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Thanks! Just so no surprises, I had to remove the mates for the power socket in order to rotate it, and I didn’t try to put any back, because I know that such things exist but not yet how to set them up. :slight_smile:

I am happy to not have the SSR enclosed, because the more free airflow, the cooler, and thus the longer lifetime; and — it’s less plastic to print!

My expectation is that with the vertical orientation for the control board, passive cooling with cooling slots should be enough, but it might make sense to be able to mount a 40mm fan on the bottom if I’m wrong about that…

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This seemed odd to me, so I just did a quick check. I exported from OpenSCAD to a *.csg file, then opened that in FreeCAD and exported to a *.step file, which I was then able to open in FreeCAD.

So if *.step is acceptable, maybe try exporting from OpenSCAD to *.csg first. A little cumbersome, but if it works…

1 Like
52

Yeah I should have broken all the mate so you could move stuff around I just put them in quick so I could get some basic alignments. If you ever want to do a quick half hour solidworks tutorial over Hangouts or something let me know.

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Ahh, you have a newer version of Solidworks than me. Mind saving out the assembly as an X_T format so I can take some dimensions off it??

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That was indeed what I tried.

Neither FreeCAD 0.18 nor 0.19-20802 can read the CSG file. 0.19 complains that it is corrupt; 0.18 reads it and forms lots of polygons but I don’t see them anywhere and v f doesn’t show anything in the view.

55

Oh. Windows decided this would be a good time to blow away my mouse driver, so as soon as I get a mouse again, I can do that. (Thank you, Microsoft!)

And, of course, rebooting to fix the mouse problem means applying who knows how many windows updates!

It’s uploaded.

That would be even more awesome! I’m going to read through the introductory docs and watch a few more videos to get the general sense so that I can follow along better! :smiling_face:

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It appears I’m using a rather old version of FreeCAD:

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16110 (Git)
Build type: Release
Branch: (HEAD detached at upstream/releases/FreeCAD-0-18)
Hash: f7dccfaa909e5b9da26bf50c4a22ccca9bb10c40
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

However, I suspect your OpenSCAD model is more than a little complex (my test was just a simple cylinder), so it may be exposing a flaw in the exporter. Oh well, never mind.

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Windows tech support: “Have you tried turning it off and on again?” :wink:

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0.18 is latest stable; that’s one of the versions I tested. It’s much more likely that the CSG importer in FreeCAD is getting confused than that the CSG exporter in OpenSCAD is broken. OpenSCAD can read the CSG just fine, which makes sense. It’s just exporting the compiled tree as a limited but strict subset of the OpenSCAD language.

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If I created the x_t file correctly, the layout should look something like this:

Placement-sketch
Placement-sketch1653×860 280 KB

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Doh! I said exporter, but yeah, that’s what I meant. :upside_down_face:

1 Like