[Arm-netbook] Existential 3D Printing Moments

Fri Jul 21 04:38:36 BST 2017

http://forums.reprap.org/read.php?177,767087,778191#msg-778191
---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Thu, Jul 20, 2017 at 11:07 PM, Vincent <ml.eoma68 at eml.cc> wrote:
> 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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