[Arm-netbook] Existential 3D Printing Moments

Thu Jul 20 23:07:26 BST 2017

Any status update on the 3D printing issues?

On 05/19/2017 07:03 AM, Luke Kenneth Casson Leighton wrote:
> ---
> crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
> 
> 
> On Fri, May 19, 2017 at 5:08 AM, Neil Jansen <njansen1 at gmail.com> wrote:
> 
>>>  and now you can use a 24v heater you can spend another extra $5 on an
>>> E3Dv6 volcano clone, now you can get *another* 20% increase in speed
>>> for only a 2.5% increase in budget.
>>
>> As you can see from the pics, we ran on the cheapest 12V power supplies that
>> we could find.  Before that I tested 24V, it wasn't worth the cost.  Again,
>> brickwall economics here.  We went cheap.  The 12V power supplies were
>> purchased in bulk and were maybe $14 USD each?
> 
>  yeh meanwell's my favourite and there's no difference between 12 and
> 24v prices.
> 
>> The 3D printed mounts and
>> the little PCB's were practically free and it would turn the supply on and
>> off between jobs whereas our 24V bricks were on all the time.  The ONLY
>> thing that we splurged on at the time was the E3D nozzles and that was more
>> of a crapshoot.  I would have done better to cheap out on those as well, I
>> could have printed more reliably with the cheaper J-Heads.
> 
>  i wonder what was going on as the only time i've had problems with an
> E3Dv6 is when the fan on the heatsink wasn't running.  that was bad.
> heat travelled up the tube and melted the filament *above* the hotend
> entry point.  all bets were off at that point.
> 
>> Don't bother minimizing extrusion if you do end up redesigning (gah!).  It's
>> cheap as dirt nowadays if you're buying the generic stuff.  If you want
>> rigid, well there you go.
> 
>  i do - and i know how it's achieved.  i've had an excellent 3D visual
> manipulation ability for like... 35 years.
> 
>> I have a junk box full of Melzi's, they were horrible, but it was all
>> manufacturing defects from a crappy Chinese company.  The Chinese version
>> took some artistic leeway that the original (British IIRC?) designer
>> probably never intended.
> 
>  aiyaaa...
> 
>> I've used both as I've said.  Mine never stalled out.  I used cheap-as-dirt
>> A4998's.  Of course, I was running them < 100mm/sec and they were happy
>> there.
> 
>  yehyeh.
> 
>>>  i just... i can't bring myself to spend backers' money on stuff that
>>> i know is crud, neil.
>>
>> You're starting to sound like a German engineer now :)  They're not crud if
>> you use them within the constraints that I outlined.  No need to turn your
>> nose at them.  What I'm trying to get at is that you've got this huge point
>> of diminishing returns, you can place yourself on either side of it.
> 
>  i will stop when the speed/$ improvement is parity.  anything that
> gives a 1:1 ratio (or less, obviously) is not worth it and is "out"...
> *unless* an improvement can in turn have a cascade effect of allowing
> *another* improvement that *does* increase the speed/$ ratio.
> 
>>>  sso i've been spending some time tracking down board designs and so
>>> on.  Arduino Due: https://world.taobao.com/item/539393961702.htm RMB
>>> 75 so that's around $12.
>>
>> Dang those Due's are getting cheaper, back in my day those were a pretty
>> penny.
> 
>  yehyeh - my favourite's the STM32F072 as it has a built-in crystal (a
> not very good one) but then the PLL can phase-lock to the USB bus from
> whatever it's connected to, compensating for crystal inaccuracies.
> price? $1.70.  STM32F072-NUCLEO board? $10 on digikey.
> 
>  mad.  absolutely mad.
> 
>>>  and TRAMS uses TMC2100s, where their Reference Design has full PCB
>>> and schematics available: if i'm doing 10+ i can just send that to
>>> mike and he can make them.  TRAMS is *real* basic.  4 steppers, 2
>>> beefy power MOSFETs (extruder, printbed), 2 smaller ones for fans.
>>
>> <3 TMC2100's.  Our PnP was going to use TMC2130's. Great German drivers.
>> However #1 they're hard as shit to import into China, which sucked for us at
>> the time.  You can get damn near anything in China but this was one of those
>> parts that just isn't really something that they use.  It was, to this day,
>> the only part that I could not find on Taobao.  We may have smuggled our
>> samples in from Hong Kong.
> 
>  dang.
> 
>  well.. https://world.tmall.com/item/551108503978.htm?spm=a312a.7700714.0.0.3zdhiQ
>  RMB 23.  about $4.
> 
>  so that looks prooobably like it's sorted...
> 
>>  #2 they're only really necessary if you want to
>> squeeze performance out of your stepper motors.  For our farm we never did
>> that, we didn't need to.
> 
>  $200 for a 50-100mm/sec printer with low-cost steppers...
>  $300 for a 200-250mm/sec printer with only-slightly-higher-cost steppers...
> 
>  a 2x or greater speed improvement for only a 1.5x cost... that's an
> opportunity i can't ignore
> 
> 
>>
>>>  MGN9C rails so that the problems associated with rods go away.
>>> triple lead screws (i might consider quadruple) on the printbed, NO
>>> CANTILEVERING.
>>
>> You're a madman.  You sure like to over-engineer things, don't you? :)
> 
>  no, i simply like to properly and comprehensively assess all six
> degrees of freedom, which i am honestly constantly amazed that 3d
> printer designers don't do, and i like to properly and i do _mean_
> properly research what the best mechanical options are.  but... that's
> taken me about... 2-3 years to do (!)
> 
> 
>>>  well, here's the thing: i actually quite like trying out things that
>>> other people aren't doing.  but also taking calculated risks.
>>
>> Sounds like you've already got your mind made up.
> 
>  i've got an _approach_ (an assessment criteria) where my mind's made
> up, but nothing else.  the one thing that i might add is "risk".  as
> in it would *really* piss me off to have a chain of improvements that,
> at the end of the design process, there's something i missed which
> made the whole exercise totally frickin useless.
> 
>  i had that happen once before.  not a huge fan of it happening again :)
> 
>>  I'm not here to tell you
>> what to do.  I'm just sharing my experience and what worked for me.
> 
>  appreciated.
> 
>>  Like
>> many technical problems, it's all about the approach.  There are as many
>> different approaches as there are engineers and business men.  You know what
>> is ultimately best for your situation.  If it were me in your shoes though
>> .. well, I'd never put myself in that position again, haha.  Nope, one and
>> done, thank you very much.
> 
>  :)
> 
>> Any of my future products I make will be CNC
>> machined, laser cut, or injection molded, and then outsourced.  As long as
>> it's a durable product, it's not really any worse than the energy expended
>> to setup a printer farm.
> 
>  yehh we're not quite at the medium-volume phase yet, i don't want
> 10,000 people dropping by the forum expecting "user support" on "how
> to compile and patch linux kernel drivers"
> 
> 
>>
>> ...annd from your previous-previous email, I forgot to reply to this little
>> bit:
>>
>>>   love it.  well let's get you on the list for a pre-production prototype
>>> ok?
>>
>> Yea, hook a brother up.  The pre-production is the A20
> 
>  yes.
> 
>> or is it the older
>> one?  Are there any basic breakout boards or dev boards for it to plug into?
> 
>  yeah i have a breakout board PCB done (one component - the PCMCIA
> socket) and am also planning to get early devs a microdesktop as well.
> 
>> If you need an address or anything like that just let me know.
> 
>  later.  i just need numbers initially.
> 
> l.
> 
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