[Arm-netbook] 3D printing requirements

[Luke Kenneth Casson Leighton]

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crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Fri, May 19, 2017 at 12:42 AM, Vincent <ml.eoma68 at eml.cc> wrote:
> Hi Luke,
>
> I saw your recent update on crowdsupply. Could you please list the
> specific requirements you need for 3d printing? Otherwise it will be
> difficult to help you out.
>
> Ideally, you can provide us with the following data:
> - maximum print dimension in width X length (e.g., 200x200mm)

 200x200 is enough to print the 260mm-long edge parts *across the
diagonal*.  you get about a 4mm gap all the way round so it *really
does* need a printer that is *genuinely* 200x200.

> - minimum wall thickness (e.g., 1mm)

 yeah it's about 1mm, maybe 1.2mm.  a couple of places are  0.7mm
which cura 15.04 _will_ still do... but only with a 0.4mm nozzle.  a
0.5 will be "optimised out".

> - smallest detail (e.g., 0.3mm)

 0.3mm sounds about right

> Also, having a single component of the casework as a sample print could
> be helpful (meaning: if this prints OK, we would expect that all the
> other components are of equal quality).

 http://hands.com/~lkcl/eoma/kde_tablet/3dcase/  then go to the stl
directory.  i recoomend trying base_back.stl, base_end.stl and
back_base_hinge.stl with orientation *AS-IS*.  do NOT alter their
orientation.

 then try fitting all 3 together.  do NOT add "internal support" to
any except back_base_hinge.stl.  raft is not necessary.  brim *might*
be necessary (try it).

> I value your quality-first approach and do not want to settle for less.

 :)

> We have a couple of decent 3dprinting suppliers in Germany which I did
> use in the past (though, for tiny objects only). I could offer to get
> quotes from them and/or do some negotiating. Also, check their quality
> based on the sample component to print (which I could also send to you).

 appreciated

> Another approach could be to distribute the load: There are many
> hacker/maker spaces around the world. Many of them do have 3d printers
> and offer printing at much cheaper rates. I do have good friends at a
> maker space with an Ultimaker 2+ and most of the time the printer is
> idle. Since they are a registered voluntary association, they are always
> interested in receiving minor donations in return for services.
>
> I could ask them to print a couple of cases?

 see what they say.

> Another idea:
> How about buying 10 Ultimaker+ and selling them via crowdsupply as part
> of the EOMA68 campaign (with a reasonable deduction, due to the reason
> being used)?

 yeahhhh that's $USD 12,000 just on 3D printers.  and on 3D printers
that can only do around 150mm/sec.  see message to neil: we really do
need to be smarter about the selection criteria.

 particularly given that the budget's not going to be enough.   i also
have to get smart about this, hence why i'm looking to do a second
campaign, and this time increase the prices (and volumes) so as to
bring in more cash in order to complete all the pledges, *but* make
designs that use the same PCBs *as the first campaign*, thus reducing
overall the manufacturing cost for *both* campaigns.


> You did address PLA a couple of times. How about the resin option? Any
> specifics? How many people ordered it?

 not many.  i honestly haven't investigated resin fully, yet.  i do
know it'll come out great, but it's lower on the priority list.

l.