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***Dan*** · 05-12-2015, 08:11 PM,

I came up with a novel way to tension the upper pulley (at least in my mind) Smile

Basically this(rendering attached) would sit on top of the linear shafts and hold the pulley (on a free wheeling shaft) then 2 M3's would be used to thread down on top of the linear shafts to lift the whole assembly up.

Might look a little goofy since the shafts would have to protrude past the upper most layer

**ABearden** · 05-12-2015, 09:15 PM,

How do we attach the top platforms if the top-most plate is drilled completely through for the guide rods?

**ABearden** · 05-13-2015, 11:46 AM,

Just had a thought, you could flatten that bracket and add two divots in the top plate for the M3 bolts to set in. You would need a 3rd point for it to sit in though.

**ABearden** · 05-27-2015, 10:04 PM,

Quick update for stats, because I can:

Estimated runtime for the printed parts is close to 150 hours and 1.4 kg of filament if I use my preferred settings of 0.1 mm layers and 40% infill. If I go with a "rough" print (0.25 mm layers and 20% infill), it's still nearly 40 hours and 0.9 kg with each spacer and carriage taking about 2.5 hours each. Assuming zero problems, that is. Guess I start tomorrow!

***n8cutler*** · 05-28-2015, 09:00 PM,

(05-27-2015, 10:04 PM)ABearden Wrote: Quick update for stats, because I can:

Estimated runtime for the printed parts is close to 150 hours and 1.4 kg of filament if I use my preferred settings of 0.1 mm layers and 40% infill. If I go with a "rough" print (0.25 mm layers and 20% infill), it's still nearly 40 hours and 0.9 kg with each spacer and carriage taking about 2.5 hours each. Assuming zero problems, that is. Guess I start tomorrow!

Awesome! Are you still targeting to have it complete for the open house?

**ABearden** · 05-29-2015, 12:06 AM,

That's the plan, but it won't be in pretty blue/white for the rough run. It'll be down to the wire, but I think we can make it.

**ABearden** · 05-31-2015, 12:02 PM,

Did a test-fit run of the first quarter inch or so of the frame brackets and the carriage. Nice job Dan!

At 103% (accounting for ABS shrinkage) the bearings are a perfect press fit into the carriage. The frame-to-guide fitment is more like an interference fit, so I might oversize those slightly to 104%. Probably going to need a vice/press/hammer to push everything together. Only thing I need to change is the "return" passage for the belt is too small to let the belt move freely, so I'll open that up for the final prints.

**ABearden** · 06-04-2015, 11:53 PM,

More fighting with the project today. Got another frame bracket printed after two complete tear downs the 3D printer's carriage due to yesterday's near meltdown. Still printing alright, but the head temperature seems to vary +/-5 C which I don't think is physically possible so I'm guessing the temp sensor is starting to go. 5 of 12 brackets done though and should be able to complete those easily. If my machine stops, the Leapfrog machine can do it too and I had it all-but-running on Wednesday.

Also started laying out the machining plan for the plates Dan has so excellently provided. Looking like 35 to 40 minutes a plate based on the gcode generated by CamBam (so much nicer to manually set the execution plan instead of letting the computer pick some wild, random, and slow paths). Not too shabby and that should be easy to knock out this weekend. Should look really good in the plywood Dan picked up! Check out the execution plan and simulation in OpenSCAM though, 26" wide x 23" tall:

***Dan*** · 06-06-2015, 03:11 PM,

Looking Good!

Please let me know if you need me to do anything?

I was able to print in PLA on the leapfrog machine (you can look at TOOLBOXNW facebook) I tried ABS several times but had a lot of problems, I think the bed was not hot enough. I had read online that it should be 100c but the highest I could get was 87c and that was after several hours of it warming up. it still did not stick to the bed correctly so perhaps you can show me what I need to do to fix that.

Just let me know what I can do to help

**ABearden** · 06-06-2015, 05:22 PM,

Sweet! If you can do PLA, that at least means the mechanicals were close enough and the extruders were good to go.

I normally do PLA between 180 and 205C, bed at 70C. Rarely have problems with adhesion to the glass as long as I print a good brim, the first layer height is set right, and I wipe off all of the finger oils with a solvent.

ABS I normally print at 225 to 235C and 100C for the bed. It won't stick to bare glass though. I use hairspray and it works well. You can also use certain gluesticks or "ABS juice" which is acetone with ABS dissolved into it (or a small amount of acetone on the glass, then rub it around with a failed print of ABS). Makes cleanup a little more involved than blue tape, but that's ABS for you.

The Leapfrog bed doesn't seem to be insulated enough to manage that well. We may need to adhere some cork to the bottom to help hold in the heat. Fully enclosing the printer would help too (though the top might be hard given how the Bowdens are setup). We may have to modify the bed power setup with a relay and run higher voltage through it to get it to heat properly. Once I have all the printing and machining done, I'll probably do some extra-curricular building during the day.

As for the build, the only thing I don't have yet is the dxf for the feet. If you want to try printing the tensioners or the carriages I haven't started on them yet. I don't have enough blue to do the carriages in the same color as the brackets (though, we have more blue with the leapfrogs). Trying to decide between red or lime ABS. With the light color of the ply, the red/white/blue would look pretty good in my opinion, but so would lime/white/blue or just blue/white. So far, I've got 8/12 brackets printed; took a little while between tuning for these prints and the meltdown recovery. Once I have all the printing and machining done, I'll probably do some extra-curricular building during the day.

Spent all day getting things setup for the frame plates. Given that's some dense plywood, I had to slow things way down from my original estimate. Running at only 15ipm and only 0.05" deep per layer. Takes a little over an hour per plate. Making me really wish for a fullsize mill. One corner of the test plate was a little chewed up from testing problems, but it looks nice overall. Now that I've got it dialed in, the rest of the plates should come out awesome because that is the best machining plywood I've ever worked with so far.

Okay, dinner break over, back to building.