[GTA04] When is the next and more powerful openmoko releasing

Dr. H. Nikolaus Schaller hns at goldelico.com
Fri Oct 22 08:24:10 CEST 2010

Am 22.10.2010 um 02:17 schrieb Al Johnson:

> On Friday 22 October 2010, EdorFaus wrote:
>> On 10/21/2010 07:59 PM, Alfa21 wrote:
>>> you should try 3d print like this:
>> <snip>
>>> made in ABS which is a good plastic and up to 0.01 inches resolution
>> Unfortunately, that's not quite good enough (different units).
>> 0.01 inches = 0.254 mm, which is 2.54 times the required size:
>> On 10/21/2010 07:32 PM, Dr. H. Nikolaus Schaller wrote:
>>> the required precision (0.1 mm, 0.5 mm wall thickness, etc.)
>> 0.1 mm is approximately 0.0039 inches.
>> I have a question, though - is this precision required for making *any*
>> well-working case design (due to the electronics etc.), or is it just
>> for making more of the current case design?
>> If it's the latter, it would be possible to create a new case design
>> that would be easier to get manufactured...
> The electronics don't need much precision in the case design. Cases that clip 
> together firmly and securely do need precision though, and that's true of the 
> current design. An alternative design needing less precision is possible, 
> especially if we accept things being screwed together. 

Generally yes. If we sacrifice quality, ergonomics, and size, we can
find simpler and less expensive case constructions.

One aspect to keep in mind for precision are the push-buttons (AUX and Power).
The buttons [1] are specified for a "Travel 0.3 mm +0.1 –0.2 mm". I.e. if we don't
want that the buttons get stuck we come to this 0.1mm precision. We have
experienced the same with the PCB design where the position of the buttons
must be within these 0.1mm...

The same is with mounting the display. If that is not precise enough, touch operation
will be deteriorated.

So if we reduce precision of the case production process, the buttons become
larger and finally, the phone is more a brick than a handheld phone :)

Personally, I am in favour of high-end high-quality design (like the iPhone)
even if it costs money. But it should never cost freedom and independence...


[1]: http://industrial.panasonic.com/www-data/pdf/ATV0000/ATV0000CE5.pdf

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