This engineer claims 100 grams direct extruder. I want one

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realthor
@Olaf: I don't find the moving bed being an obstacle for a flying extruder.

Right, my argument aimed in the opposite direction. The x-axis is now lighter due to the flying extruder, but the moving bed is still heavy and therefor slow.

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o_lampe

Quote
realthor
@Olaf: I don't find the moving bed being an obstacle for a flying extruder.

Right, my argument aimed in the opposite direction. The x-axis is now lighter due to the flying extruder, but the moving bed is still heavy and therefor slow.

Should the bed be properly built and calibrated, the only direction it foes is downwards once every layer, so not much movement there.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Turns out the Micron's not as big as I thought, looks like a smaller version of the Bulldog,
it's not a nema17 but an 11 (86mm), still looks a little lop sided though, it would only fit on my X if spindle was in line with the Y
this article says it's a 1:13 ratio, the closest motor equiv' I can find is £33 14:1 (13 + 212/289)
[www.ebay.co.uk]

thought this listing states 1:19 ratio
[www.ebay.co.uk]

on it's own here for £28

A bulldog at £35 wouldnt fit so need a custom block, unless an 11-17 step-up adapter could be made, seems to use same principle, bearing & hobbed drive, nothing fancy like a rotary encoder.

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Srek

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realthor
I have noticed threaded rod on your Z or am I mistaking?

Yes, it's M8 threaded rod. The machine is planned as a real RepRap with very basic parts that are easy and cheap to source. The mechanical design is nearly finished, i am in the process of going over all printed parts for optimization and some smaller adjustments. Once that is done a second prototype will be built and tested. After that the final BOM is compiled.
I still have a big problem with the firmware. while in theory Marlin supports Dual X carriage that part is effectively not working currently.

@Srek: Hey Marl, going back a bit to your blog, I was wondering about the silicone sleeve for the heater block / nozzle. I see that it is about 1mm thick on each side.
Have you played with other silicones to check performance of the heat-block? Would thicker walls result in better temp protection (even cooler temp on the outer surface?)

What silicone brand did you use?

Thanks.

Edited 2 time(s). Last edit at 02/07/2016 04:53PM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

I got the silicone from here
[www.trollfactory.de]
I doubt that thicker silicone will make much of a difference before it becomes unusable. There aren't that many different types that can resist these temperatures, so i only tried this one.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I just found these nema 8 steppers, would be great if they could be made to work as the direct feeder, just not sure they can,

[www.ebay.co.uk]

[www.ebay.co.uk]

[www.ebay.co.uk]

[www.ebay.co.uk]

Edited 2 time(s). Last edit at 02/07/2016 05:51PM by MechaBits.

Quote
Srek
I got the silicone from here
[www.trollfactory.de]
I doubt that thicker silicone will make much of a difference before it becomes unusable. There aren't that many different types that can resist these temperatures, so i only tried this one.

Thanks. My heater-block/ nozzle will get close to plastic parts in the millimeter range (4mm-ish) and I was wondering if there is a good method to protect the parts and also to keep the heat where it's meant to be.
I was looking into Armeco refractory coatings and wondering if there is any tangible solution at this other end of the industry.

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MechaBits
I just found these nema 8 steppers, would be great if they could be made to work as the direct feeder, just not sure they can,

$_1.JPG

[www.ebay.co.uk]

[www.ebay.co.uk]

[www.ebay.co.uk]

[www.ebay.co.uk]

@MechaBits: Nema8 is kind of small. Not sure if that can be used, my uneducated guess would be to take the 19:1 and reduce microstepping.

Edited 1 time(s). Last edit at 02/08/2016 06:08AM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

My latest extruder design has the fan duct only 2-3 mm from the silicone covered heater block. The duct is ABS and becomes a bit soft during printing. I want to try to make it from PC to see if that helps, but effectively it already works.

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

I've noticed this on the new ultimaker at the local library:



It seems to be a teflon sleeve on the nozzle but again it looks like the nozzle itself
It might not be teflon at all but what else?

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Chances are it is Teflon. It is a good idea for preventing filament residue to accumlate on the Nozzle

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[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

Seems this thread is drifting a bit off topic. Is there any more information about this 100g extruder that started the conversation?

I just wanted to spark the discussion about something we can achieve. That 100g is a DC motor with encoder just like the Stratasys one the Digital Dentists has shown. So far the motor Marl has shown is looking as good as we can get: nema14 and direct extruder style at 240g if i remmember correctly.

Personally I'm researching a flying extruder for cartesian printers if you want more drifting-off

Edited 1 time(s). Last edit at 02/08/2016 09:25AM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

If you want small, geared motors, there's plenty available. Here's one: [www.goldmine-elec-products.com]

Edited 1 time(s). Last edit at 02/08/2016 09:48AM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Quote
the_digital_dentist
If you want small, geared motors, there's plenty available. Here's one: [www.goldmine-elec-products.com]

But for a DC motor you need an encoder, then interface that with current software. There is nothing like that in mainstream Marlin or Repetier and you will need a separate board just to read the data from the encoder. At least that's the way one of the few such courageous builds I know about does it.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

Yeah Srek I did think too small, had read that nema14 was the ideal over the 11 which the micron uses.
But still way over the 100g target.

Quote
realthor
But for a DC motor you need an encoder, then interface that with current software. There is nothing like that in mainstream Marlin or Repetier and you will need a separate board just to read the data from the encoder. At least that's the way one of the few such courageous builds I know about does it.

That's what you have to do if you want a 100g extruder. That's what the guy in the video claims to have done, though we haven't seen any evidence of it actually printing yet.

How do the 3D printing pens feed filament? That's gotta be a pretty light weight mechanism...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

A pen has no need to match extrusion rate with linear motion, so it can use a more or less uncontrolled extruder, provided the rate is reasonably consistent. Making a closed loop extruder match the rate and acceleration profiles for a printer sounds hard. I guess if you connect to a standard dir & step interface, the input side of the controller keeps tab of the current requested position, and the output side does it's best to get there and you hope that the latency is within acceptable limits. Would be a fun microcontroller project.

Edited 1 time(s). Last edit at 02/08/2016 11:54AM by JamesK.

Printer Pen Teardown [youtu.be]
Cheap n nasty

... I've disassembled one of the smaller types - [forums.reprap.org]

The motor is pretty small, but the gears and assembly so crappy, that one of the two pens I've bought for testing wrecked after maybe 2 hours of occasional use

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

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realthor

Quote
MechaBits
I just found these nema 8 steppers, would be great if they could be made to work as the direct feeder, just not sure they can,

@MechaBits: Nema8 is kind of small. Not sure if that can be used, my uneducated guess would be to take the 19:1 and reduce microstepping.

Assuming that the extruder motor can manage with less drive power (and I'm not sure that's true, given the regularity of clogging and jamming problems)...
a) There's also NEMA11 & NEMA14, or
b) Why not stick to NEMA17 but get a shorter length (e.g. 17HS2408 or 173401)? It would at least fit the existing extruder designs (same mounts and shaft diameter) as the larger NEMA17s, but reduce the weight by 60-130g.

FRank

Yes I like the pancakes and would like to use something like that, but cant get the planatary gearbox on its own, and I'm not sure the pancake has anymore torque than the 11 or 8

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MechaBits
Yes I like the pancakes and would like to use something like that, but cant get the planatary gearbox on its own, and I'm not sure the pancake has anymore torque than the 11 or 8

I linked in my second post this video from youtube cause I liked the use of the pancake stepper and the DIY-looking gearbox.

I wish I had more information about that particular build. It seems very professional. I believe the guy is an industrial designer or something like this (or they use that printer for work or for design)...can't remmember how I got that impression.

Edited 1 time(s). Last edit at 02/08/2016 06:08PM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

I missed that...the video shows its possible, cool. I had the pancake in use in my preliminary designs, (but they where the sanyo's and they where pricey), so it would be nice to actually include it, so what the hell just bought one, has to be useful for something, but they dont do them in black grrr, or with the quick disconnect block, But then the Micron would be useless to me, and I just found one in Blue which would have matched other parts on the printer...Blue or Black hmm that would be a tricky choice.


Edited 2 time(s). Last edit at 02/08/2016 07:09PM by MechaBits.

hello
why don't use a stepper motor from floppy disque or cd rom http://www.codeproject.com/KB/cs/floppystepper/floppyStepper.jpg

Arh, yes.. Those lovely Nema 17 Sanyo pancakes of only 70 grams. Way too expensive indeed. I was planning on using a less expensive nema17 pancake with a 13/44 gear-reduction (not a heavy planetary, but just two gears, one metal, one plastic). Probable MOD1 or MOD.8 or something like that. I'm currenty working on it, using a MOD1 13t pinion with a 44t gear of an HPI savage.

It's fair easy to make a plate that holds the two gears, while enabling the use/boltpatern for using the standard nema17 extruders. But... Gears, adapter plates.. What would weigh more. A stronger nema17 or the pancake with the needed bits..

Another thing that crossed my mind was to use a servo from an RC car, since they weigh about 50-65 grams,
this one for example.Only catch is that you need to remove the pot and find a way to make the brushless motor turn, add an encoder.. (as well as implement a way that the thing could run from step/dir to be compatible with the nowadays standard).. So that might be too much of a fuzz, the NEMA 17 pancake with gear reduction seems like the best suitable way to go. Or not..

Edited 1 time(s). Last edit at 02/15/2016 10:46AM by to3dornottobe.

How about this: [www.youtube.com]
from : [www.ebay.com]

$8 (for two motors and two drivers which we don't really need) from the US, or buy direct from China for about $3 if you don't mind waiting.

Edited 2 time(s). Last edit at 02/15/2016 05:30PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I have some of those for making toys with. Not sure I would put one in a printer though. You can modify them to bipolar and get a bit of a performance boost, but you can't get away from the cheap & cheerful nature of the things. I also got one of these to play with [www.ebay.ca]

It looks like a small step up from the others, but the 12v requirement makes them a bit more tricky for integrating into a printer.

Maybe we need the old propelling pencil mechanism bringing upto date, not much good for retractions though without making additional gubbins. I initially thought thats what the spring in the Ultimaker was for, some kind of additional retraction.
I know it doesnt seem like it can be done using this mechanism, but ya never know, as materials develop who knows what delivery system will be used.



Mechanisms

There are 3 common types of mechanical pencil mechanism, and several less common ones.

twist action: the lead is affixed to a carrier which rides in a spiral slot and a straight slot; by twisting one or the other, the carrier is advanced. Skillcraft, Paper*Mate, and Cross have all used this for larger sizes; with graphite. This type is gravity-independent. Typically used for 0.9mm and 1.1mm leads; 0.7mm leads are a bit fragile, but are available.

Leadholders, commonly called Drafting Pencils, have a friction mouth that holds a fairly thick lead (often 2mm). The mouth is simple: a ring sporting 3 to 5 jaws as a single piece, thicker towards the ends of the jaws, pulled back into a tube by a spring. The lead is advanced by pushing the jaws forward with a button, and letting the lead fall forward. This is gravity dependent. Note that this type usually has no nib.

jaw-pushed lead. A set of jaws is held, much like the leadholder above, but is configured so that the jaws don't open until past a significant part of the stroke by a floating collet, but past a certain point, the collet is blocked, and the jaws then open from their own springiness. On retraction the collet moves back with the jaws, but again, is more limited in range of motion, and the jaws retract back into the collet. This is the most common mecahnism. Typically, additional leads are in a magazine, which gravity feeds a new lead when the first is advanced far enough; this makes it gravity dependent, as the typical lead is short - 3 to 5 cm.

friction and wheel — a friction nib holds the lead in place; a small wheel in the pencil body advances the lead. Not suitable for smaller leads, the lack of jaws often allows the lead to slip, and advancing the lead can be a problem. Very rare. Gravity-independent.

Friction manual advance - a sliding component retracts alongside the lead, and when pushed down and forward, pushes the lead forward as well. Some versions have one-way teeth. A friction nib is typical. Prone to lead slippage. Gravity independent. Requires larger leads (1.5 to 2.5mm)

magazine of nibs with non-advancing lead — the shaft is also the magazine, holding 15 to 30 short (1cm) nibs with 5-6mm of lead. When the lead nib is worn down sufficiently, it is pulled out and fed through the back of the shaft, advancing the other nibs forward. Gravity-independent. Fairly durable (1.5 to 2mm leads are used), but failure mode results in 20 to 40 small items loose.



Dont worry, I wont be damaged & broken if someone tells me it cant be done...

Edited 2 time(s). Last edit at 02/16/2016 01:42AM by MechaBits.

why not the cheaper round nema14. 2 versions

14HR08-0654S 12 Ncm 100gram
14HR05-0504S 7 Ncm 50gram

also not cheap. I am design a dual ( wade's ) extruder with this total width 64mm ( need also new x carrier )
It would be nice if it works with the smaller one. But the bigger one fits.



Edited 1 time(s). Last edit at 02/16/2016 05:03AM by amigob.

That looks nice!