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

[Hrvoje Lasic]

On 27 April 2017 at 15:23, 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
>
> 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.
>


this 3d printer looks ok, can you update on quality when available?
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