Reviving a destroyed Pint



  • @Lia do you use a shroud on your 3dp? I made one for my old R1 and increased the nozzle diameter to 0.8mm. I made some mounting hardware for a bimini top with nearly 100% infill using PLA and they are really solid! I had also bonded a sheet of PEI to the pre-heated glass build plate. It oozes like crazy but it prints like the blazes with a .5mm layer height. 20 mins per that particular fixture! I use Simplify3D. I'm done bragging...



  • @NotSure Mine sits in my server cupboard which gets a nice ambient temp of around 35c. prevent some first layer warping without a heated bed but needed to get a bigger cooling fan on the hotend to stop some crazy heat creep gumming up the heat break.

    I typically print 0.4mm nozzle, 0.3mm layer height and 20% infill on stuff like this, 10% if I can get away with it and I've not had issues with stuff breaking. That said I do want to try a Hemera hotend so I can dial in retraction since there's a narrow margin between clogs and hairy prints.

    For some bigger stuff I could have done with a bigger nozzle like yours. The poor printer has done 3 day prints before with that pathetic 0.4mm nozzle xD



  • @Lia said in Reviving a destroyed Pint:

    @stinkyface PLA currently still, was considering PETG for the final one but will see if I can get away with PLA at a higher wall thickness and infill density. I'm not sure what sort of heat the ESC is going to put out...

    Yeah the only data points we have are the generic "controller temp", I've seen mine at about 45 deg C here in the tropics, it's getting pretty close to PLA softening temp. PETG only gives a bit more room. FWIW, I'd do what you are planning, trial and error is a slow but effective way to evolve a design.



  • @Lia said in Reviving a destroyed Pint:

    For some bigger stuff I could have done with a bigger nozzle like yours. The poor printer has done 3 day prints before with that pathetic 0.4mm nozzle xD

    I've never tried to print that long before. Before adding the shroud, nozzle and the PEI laminate, I would try batching multiple ABS parts into a single run, and I'd always end up with an awful bird nest of ruined prints by morning. From the look of it, you've certainly dialed in your printer well. Practically zero z-wobble. IMO the best part about a larger nozzle is the increased thermal mass of the bead results in really nice layer adhesion. Increases the shear strength substantially. A 0.8mm nozzle with <=0.3mm layer height makes for really solid parts!



  • @stinkyface 45C is totally near the danger zone for PLA. I've got a plant pot that has deformed just sitting in the sun here in the UK. It was black filament so I was asking for it. Will see if I can get away with it though first and push my luck. Learnt the hard way that assuming failures leads to over-engineering very quickly. Was making an RC sub for 3 years and I bailed near the end from overdoing everything without actually testing my concerns. It sits on the wall to remind me.

    @NotSure I've only ever used PLA so it's been pretty easy to dial it in however every time I swap something out I end up back in tinkering hell xD If I do opt for another printer (maybe an S5 or custom) then a 0.8mm nozzle is certainly on the wishlist. I think I'm ready to get a different machine as I'm getting tired modifying the same system.
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  • @Lia said in Reviving a destroyed Pint:

    @stinkyface It is tempting indeed. I'll certainly try putting the motor on something else for sure just to see what it's like.
    Had this planned out in CAD for another project I think I hinted at in that thread.
    Capture.JPG
    Have yet to actually begin fabrication as it's still just 3d printed test pieces. Shouldn't be hard to try putting the Pint motor on the back and ditch the suspension. Could probably even remove the front steering and rely on the pint tyre to keep the board stable instead.

    Many thanks for all the input so far :)

    Are you in the FB group for the E-caster boards? They would love this.

    I have been thinking about working on one of these, I have some super wide round and soft 9.5" tires I want to try using. I also have an old V1 OW hub I could use for the back with a regular kart hub/tire up front. Same frame would be used to try all these tires out.

    LMK would love to share designs and stuff.



  • @fosterqc Unfortunately not, haven't had a facebook account in a very long time. Say "Hi" to them for me!
    The CAD is based off an existing kickstarter project called Speedboard so credit for the actual concept goes completely to those guys. Pretty cool looking bit of kit but I figured I could maybe do one better with some suspension on the rear and use a hubbed motor rather than a chain drive.

    Here's the last version of what I modelled before I shelved the project for a bit. Will some day return to it but if anyone wants to give it a shot or make some modifications I'd love to see it. Project is made in Sketchup but everything is manifold so I imagine it wouldn't take much to move the parts into another program.



  • Routed out a few mil off the u-profile I got and it fits!.. ugly, but fits.
    IMG_6661.JPG
    Router table was a quick DIY mess made of old desk pieces which make a lovely surface for routing. Had a bit of chatter but that was mostly down to me feeding too fast and not applying consistent pressure... Still did the job mind you.
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    This is only the first pass in which I just remove some material on the inside to fit over the housings and axle mount.
    -Next one is to shave down the internal depth to 10mm since it's about 5.8mm too big.
    --After I'll cut the edges down at around a 53.5 degree angle so they line up with either bumpers.
    ---Lastly I just need to drill all the holes for the bolts and countersink a handful. Since I already modelled the rails I an just print some templates and drill away.

    The edges will still be flat however I can 3D print a curved facade piece to replicate the shape of the Pint then glue it on. I'll finish machining the rails first before doing so, no point making it pretty before knowing it can survive later testing.

    --

    Edit: Okay I got a little impatient and put the axle bolt holes in. Like a glove~
    IMG_6666.JPG
    Even better it holds my weight fine. Can bounce on it (with my foot barely bridging the gap between the rails) and no signs of twisting with the battery in place.



  • @Lia Lol... Is that an oculus rift? Who are you?



  • @NotSure Valve index headset with the old vive wands :)



  • @NotSure it's true, @Lia's last name is Stark.



  • So last week I was attempting to cut the depth of the rails but my Jigsaw blade kept walking so had to buy an aluminium cutting disc for my circular saw.
    Although I made a mess it worked like a charm after setting up a guide for the saw. Excuse the notches on the lower right side of the rail, it's from where the jigsaw walked but after removing the corners it's not that bad.
    IMG_6721.JPG

    With the depth cut to size I made a jig to angle the rails so they could be cut right.
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    Needed to notch out part of the lower rail so it doesn't interfere with the bumpers
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    Like a glove
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    Slapped those on and seem to fit just right, turns out they're pretty strong as is. Still need to make all the mounting holes and cut out where the button and charge port will go.
    Will make a facade to recreate the curved rail edge so it matched the bumpers and holds the lip of the pads.

    https://www.youtube.com/watch?v=hwUeIrMzMrk
    Untitled-1.jpg
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  • @Lia those socks look warm!



  • @NotSure Warm indeed :) Probably going to be a little too warm for them soon (fingers crossed).



  • @Lia -- You are giving that Pint a better life! The process is clear and inspiring to watch!



  • @blkwalnutgrwr Glad it's entertaining to follow along :)
    Hoping to rip around on it soon, the footpad sensor is next on the list and should be the final step if nothing fails.



  • Haven't forgotten about this, just had a few side projects that needed my attention before I set off finishing the Pint.

    One thing I've been working on is a DIY footpad sensor. All the OW's appear to use what's known as an FSR sensor either side of the footpad which when pressure is applied it completes the circuit. I won't bore you with a technical explanation of these however if you want to take a look there are a handful of pages that go over them, fewer explaining how to make a reliable one...

    Why not buy one? Well the largest FSR's I could find had an active area of 45mm x 45mm which is tiny. If you use 2 each side of the pad you still have some very small contact points with them not really being designed for this sort of thing. I needed something more durable. Being unable to find a place that would cheaply make a custom FSR as a one off I opted to just DIY it as is the theme of this Pint rebuild.

    As with most FSR sensors I'll be using metallic traces with a layer of velostat above them separated by a small air gap that keeps them disconnected. Maintaining this air gap is difficult. Failing to do so results in ghosting. Overdoing it and you'll have a pad that might deactivate mid-ride.

    IMG_6839.JPG
    I cut the traces out by hand from a 0.1mm copper sheet. That was fun...not! To stop the traces lifting I'm using 4mm wide double sided tape to attach them to the 3d printed lower plate which is only 0.4mm thick (2x 0.2mm 3d printed layers). Built in is some tiny vertical walls on the upper layer to help prevent the traces ever bending into each other.

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    Using some electrical tape to make sure the ends of the traces never lift and touch the velostat. Then some double sided tape around the edges to attach the spacer that will introduce an air gap. It's 0.3mm thick (single 3d printed layer) which should be enough to prevent it ghosting and require a decent amount of pressure to activate.

    IMG_6843.JPG
    https://www.youtube.com/watch?v=wpG7th3ZrP8
    Untitled-1.jpg

    I won't use the whole single sheet of Velostat in the final so both pads can act completely independent of each other. With a single piece it's possible under some edge cases that both pads regardless of which side is active could stick on.

    Hoping it's reliable enough to last and not kill me while riding. If it's anything else like my other creations it will at least give me a decent injury before I finish it. All my most trusted and favourite creations have done so in the past. I like to think of it like a creator/creation bonding exercise ;)

    --

    Enough with the footpad sensor, wanted to move onto attaching the controller housing to the rails. Needed to use a guide to make the mounting points on the rails for the controller so made a little template to give me guide holes.
    IMG_6849.JPG

    Worked a treat however I don't have M4 bolts that are short enough to not poke out so going to order some.

    IMG_6850.JPG

    Got special plans for the power button. Going to replace it for something a little cooler. Already tested and got the solution almost there but just need to implement it. If it works I won't need to drill a hole in the rail for the power button.



  • @Lia said in Reviving a destroyed Pint:

    I cut the traces out by hand from a 0.1mm copper sheet.

    exacto blade and stencil or snips?



  • @NotSure Tried using an exacto but it dulled too often and began to tear rather than cut.
    Printed off a template, stuck it down then just used a pair of sharp scissors to cut it in the end. Was thin enough to not take a lot of effort.

    Using scissors did introduce twisting in the traces so I had to give them a good flattening for a while with the double sided tape helping keep them flush.


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