On 27 April 2017 at 15:23, Luke Kenneth Casson Leighton lkcl@lkcl.net wrote:
On Thu, Apr 27, 2017 at 1:00 PM, Christian Kellermann ckeen@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?