[Arm-netbook] first prototype microdesktop casework

[David Niklas]

On Mon, 8 May 2017 06:15:10 +0100
Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> On Mon, May 8, 2017 at 2:07 AM,  <doark at mail.com> wrote:
> > I apologize for DOS'ing the list, I can only get online about once a
> > week.
> >
> > On  Sat, 29 Apr 2017 12:42:29 +0100
> > Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:  
> >>
> >> On Sat, Apr 29, 2017 at 6:08 AM, Luke Kenneth Casson Leighton
> >> <lkcl at lkcl.net> wrote:  
> >> > http://rhombus-tech.net/community_ideas/micro_desktop/news/  
> >>
> >>  ok, ouch, onto the fourth revision of the corner-pieces already, and
> >> some minor changes to the plywood are needed as well.  this really
> >> would have been awkward if someone else did it.
> >>
> >>  the anycubic 3d printer is holding up well.  the higher-quality PLA
> >> from the company i found on aliexpress seems reasonable so far (the
> >> "standard" quality definitely isn't: it literally crumbles under
> >> pressure).  
> > <snip>
> >
> > Luke, (I can call you Luke, since you sign your name that way, right?)
> > PLA stands for Poly-Lactic-Acid and if they are selling you something
> > else you can complain, if not sue for false advertising. That's why we
> > label things, so that we know what they are, right? So one PLA aught
> > to be the same as any other. Aluminum is aluminum, titanium is
> > titanium, why is PLA not PLA?  
> 
>  it's partly down to where the lactic acid comes from: like any
> chemistry you get a different yield and a totally different
> composition depending on the process, the purity and the ingredients.
> 
>  most companies use corn for the raw materials, and they don't process
> (purify) it properly.  the result is that the PLA gives off acrid
> fumes, deforms under pressure, does not adhere properly (to itself...
> which is kinda important) and is generally completely fucking useless
> for well... everything to do with 3D printing.
Is there a way to tell how good a company is with their PLA? Price would
not seem to make a big difference since companies can just charge lots of
moo-la even with a poor product.

<snip>
>  ok, i'd like you to do a test.  take a small piece about 5cm long and
> bend it very very fast, as quickly as you can, making the loop as
> small as you can (8mm or less if you can).
> 
>  good PLA will snap.
> 
>  shit-quality PLA will discolour, going light-coloured.
> 
>  another test - a really really important one - is to make a long
> rectangle (35mm high x 5mm x 10mm would probably do) - the height is
> important - then clamp one end to a desk.  on the other end suspend a
> weight tied with string as close to the end as possible.  make the
> weight... let's say.... 0.5kg or so.  not very much.  now leave it for
> a month.
<snip>

Like this?

      +-+    <--- Rectangle
      | |
+DESK++-+W   <--- Weight
|    |
|    |
|    |


Thanks,
David