[Arm-netbook] SPI-based LCDs, 3D printing, RISC-V

[Adam Van Ymeren]

On April 27, 2017 9:23:40 AM EDT, Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
>On Thu, Apr 27, 2017 at 1:00 PM, Christian Kellermann
><ckeen at pestilenz.org> wrote:
>
>> As the current issue is time in producing them I would also scratch
>> the printed parts order myself, maybe in exchange for a discount on
>> future designs done by Luke and print them myself. People with access
>> to a maker lab could consider doing the same...
>>
>> I am not capable to promise good quality printing for 3rd parties as
>I
>> have been starting getting into this for a rather short while now...
>
> well, a 200x200 basic reprap will do the job, with a 0.4mm nozzle and
>a layer height of between 0.15 and 0.2mm is absolutely fine.  it's not
>hugely difficult.  i've just ordered this ($140!!) 3D printer from a
>taobao seller, it's arriving in a couple of days:
>
> https://world.taobao.com/item/526287577504.htm

Here's a thought, if you're okay running a fleet of printers, what if we crowd funded a fleet of 3d printers, whereby people pay for printers, you do a bulk order of printers, use them to print the parts and then distribute the printers to backers.  Sort of like a promotional thing, you can receive one of the printers that was used to make your laptop.

>
>now, at $140 i am quite happy to get up to 10 of those (if the first
>one checks out fine) - it looks *really* sturdy: 20x20 aluminium
>box-section: my only concern about rigidity being that it uses
>L-brackets which go *into* the frame rather than triangle-corners
>which are bolted outside and lock the box-section absolutely solid.
>but, we'll see what happens.
>
> also it looks like it has a clone of the E3Dv6 hot-end (which is
>really good), it has trapezoidal z-axis lead screws with proper brass
>nuts, borosilicate glass plate (to be confirmed).
>
> the one thing i have told the guy (and he's happy to give a RMB 70
>discount): i do NOT want the f*****-s***-for-brains RAMPS 1.4
>controller.  if you're familiar with 3D printing for f***'s sake STAY
>AWAY from ANYTHING that uses the brain-dead "Polulu" driver "modules".
>RAMPS, RUMBA, Lerdge, Megatronics - just don't f*****g well do it.
>
> the reason is really really simple: those QFN ICs are designed
>SPECIFICALLY, as outlined CLEARLY IN THE DATASHEET, for the heat to be
>dissipated THROUGH THE PCB.  there is a ceramic insulator on the TOP
>OF THE CHIP which ACTIVELY PREVENTS HEAT DISSIPATING THROUGH THE TOP.
>if you put a heat sink on top of the chip it does... nothing.
>
> now, when the first reprap was created, in order to save time and
>development cost they bought some PROTOTYPING boards with the stepper
>drivers pre-mounted, which came with SPECIFIC instructions "under no
>circumstances use these in production".
>
> so what happens?
>
> well, they (a) burn out (b) overheat (c) stop working for a couple of
>seconds at a time in the middle of a print...
>
> ... you get the general idea.
>
>so anyway i ordered a Melzi 2.0 from here:
>
>https://www.aliexpress.com/store/group/Melzi-board/1757194_500507171.html
>
>and it turns out that on the reprap wiki there's a mod to them which
>allows for the connection of a BT UART.  it would have been handy if
>those pins had been brought out on a header but hey, what's wrong with
>a bit of soldering.
>
>if you don't want to do soldering then you can just put the Melzi 2.0
>into "auto-load" mode, drop a file in a FAT32 filesystem on a MicroSD
>card and power it up.
>
>i like the Melzi 2.  it's simple, relatively low-cost compared to some
>of the other options, no-nonsense and straightforward.
>
>l.
>
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