1 Topic by pcm81

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Topic: Extruder+Hot End Optins

So, I am planning to build my own 3d printer with 2 extruders. I am trying to decide between 2x Pico hot ends, which will need additional extruders vs this combination.

http://www.ebay.com/itm/DUAL-HEAD-ALL-M … 1396100624

What do you all think? I've never heard of this company before, but pictures sure look nice...
I want to be able to print to 300C+ so not sure what temp range the above linked hot end can deliver. Pico should be able to go to 500C with thermistor upgrade. Now limited by thermistor to 300C.

I am planning to be running all this off RUMBA board; unless someone can suggest higher quality options. This is intended to be quality build, not a cheap build.

Thanks ahead.

2 Reply by johnforeman

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Re: Extruder+Hot End Optins

i've always wondered how you slice a model to use more than one color.  what software is used and does the model have to be designed using different solids to represent the different colors?
as for the extruder, it looks nice. seems pricey but all things considered, i guess it's on par for what your buying.

3 Reply by COASTER19

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Re: Extruder+Hot End Optins

Well the Pico looks good to me, but one concern with two direct drive extruders would be weight, which lowers your max printing speed.  It looks like they've done their best to keep it down on the pico, but if it were me, I'd go with two E3D bowden style extruders and have the stepper motors located on the back or off to the side of the printer.  Something like this would probably work: http://www.thingiverse.com/thing:157817

4 Reply by adrian (edited by adrian 2014-02-15 17:04:37)

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Re: Extruder+Hot End Optins

as noted, weight would be my concern - otherwise all fine. The already overdriven X-axis motor will not cope and the y will be pushing it if we are talking the solidoodle anyway...

johnforeman wrote:

i've always wondered how you slice a model to use more than one color.  what software is used and does the model have to be designed using different solids to represent the different colors?

http://manual.slic3r.org/MultipleExtruders.html

Specifically the end part about AFM and multimaterial.

5 Reply by pcm81

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Re: Extruder+Hot End Optins

My build will not be an SD mod. I am planning to get good stepper motors and the RUMBA controller. I was thinking of 58in-oz steppers like this one:

There are many motor options, ranging from 58in-oz to 200+in-oz

58 http://www.amazon.com/Stepper-Motor-oz- … pper+motor
125 http://www.amazon.com/Stepper-Motor-125 … s_indust_6
257 http://www.amazon.com/NEMA-257oz-Steppe … s_indust_8

So as long as the controller can drive them, this is why i am leaning towards Rumba,  weight of the head should not be an issue.

Indirect drive sounds interesting, I have not thought of doing that, but i am wondering if there would be any issues with feed rate control?

6 Reply by adrian (edited by adrian 2014-02-16 01:03:32)

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Re: Extruder+Hot End Optins

Ok - just bear in mind there is a lot more to motor selection than just torque.. Rotor Inertia, resistance, size, etc..
Maybe spend some time researching what is in a motor, and how to best choose a motor for 3D printing... as there is a bit to it and its not just 'big numbers = good'..

Also - word to the wise - you need to expand your search beyond Amazon... several of those motors are marked up hugely and are just 'sell through' from sparkfun..

E.g, the 125oz-in, is *really* sold from Sparkfun.. Amazon wants $27.95 + $7.93 shipping. Sprkfun wants $23.
Sparkfun will also ship free on order of $60 or more.. so buy 3 motors, get them shipped free for $69.. the same motors from Sparkfun bought via your Amazon link would be $107.64
https://www.sparkfun.com/products/10847

The 58oz-in.. is really a 68oz-in, and it costs $16.95 at Sparkfun, or $22.94 via Amazon.
https://www.sparkfun.com/products/10846

These aren't 'similar' motors - if you follow back the Amazon goods you'll see they are the exact same sparkfun ones sourced from sparkfun often via another retailer.....

Bottom line - Amazon is not the place to search for stepper motors - and its not just about numbers for holding torque... smile

Re 'indirect drive' - Its referred to as Bowden Drive/Setup/Extrusion, and its very very common. Might want to do a bit of research in that area too.

7 Reply by pcm81

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Re: Extruder+Hot End Optins

adrian wrote:

Ok - just bear in mind there is a lot more to motor selection than just torque.. Rotor Inertia, resistance, size, etc..
Maybe spend some time researching what is in a motor, and how to best choose a motor for 3D printing... as there is a bit to it and its not just 'big numbers = good'..

Also - word to the wise - you need to expand your search beyond Amazon... several of those motors are marked up hugely and are just 'sell through' from sparkfun..

E.g, the 125oz-in, is *really* sold from Sparkfun.. Amazon wants $27.95 + $7.93 shipping. Sprkfun wants $23.
Sparkfun will also ship free on order of $60 or more.. so buy 3 motors, get them shipped free for $69.. the same motors from Sparkfun bought via your Amazon link would be $107.64
https://www.sparkfun.com/products/10847

The 58oz-in.. is really a 68oz-in, and it costs $16.95 at Sparkfun, or $22.94 via Amazon.
https://www.sparkfun.com/products/10846

These aren't 'similar' motors - if you follow back the Amazon goods you'll see they are the exact same sparkfun ones sourced from sparkfun often via another retailer.....

Bottom line - Amazon is not the place to search for stepper motors - and its not just about numbers for holding torque... smile

Re 'indirect drive' - Its referred to as Bowden Drive/Setup/Extrusion, and its very very common. Might want to do a bit of research in that area too.

Thanks for the insight. I have Amazon Prime, which is why i start there; i get free 2d shipping on most things, but i hear what you are saying about buying direct from sparkfun.

I realize that there is more than big numbers = good; impedance, current draw etc are all important factors; which is why i started another thread asking for "best controller for home-brew" to be able to accept as wide of the range of the motors as possible.

8 Reply by Hazer

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Re: Extruder+Hot End Optins

Another thing about motors:

The first motor you speced has an Amp rating of 1.7Amps. Without proper cooling, the A4988 drivers will not handle that well. The second motor is 2 Amps. That is the maximum rating for the DRV8825 drivers. We wont even bother talking about the 3Amp motor.

You should also know that when dealing with motors, speed can become a concern too. Higher-torque motors are often slower. You can determine their speed using this calculator:

http://www.daycounter.com/Calculators/S … ator.phtml

The speed rating isbased upon voltage, amperage, and the inductance of the motor. As long as the calculator shows the motor is capabe of at least 1 revolution/second, you should be fine (most motors rated under 2 amps are good). If it is not (mtor that has high voltage or high inductance rating) will be slow, and while the top speed is theoretically capable, you will see in real life that the acceleration is very poor resulting in skipped steps even when you have the amperage maxed out.

So, for the two motors you have shown the speed should be good enough for most axis except for a geared extruder (wades) setup. Its then just a matter of having to get DRV8825 drivers.

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9 Reply by pcm81

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Re: Extruder+Hot End Optins

Hazer wrote:

Another thing about motors:

The first motor you speced has an Amp rating of 1.7Amps. Without proper cooling, the A4988 drivers will not handle that well. The second motor is 2 Amps. That is the maximum rating for the DRV8825 drivers. We wont even bother talking about the 3Amp motor.

You should also know that when dealing with motors, speed can become a concern too. Higher-torque motors are often slower. You can determine their speed using this calculator:

http://www.daycounter.com/Calculators/S … ator.phtml

The speed rating isbased upon voltage, amperage, and the inductance of the motor. As long as the calculator shows the motor is capabe of at least 1 revolution/second, you should be fine (most motors rated under 2 amps are good). If it is not (mtor that has high voltage or high inductance rating) will be slow, and while the top speed is theoretically capable, you will see in real life that the acceleration is very poor resulting in skipped steps even when you have the amperage maxed out.

So, for the two motors you have shown the speed should be good enough for most axis except for a geared extruder (wades) setup. Its then just a matter of having to get DRV8825 drivers.

Thanks for info. I know that Rumba and most, if not all, other controllers cant support motors beyond 2A. Speed vs torque is important balance; however with higher gear ratio, i should be, in theory, able to convert torque to speed to ballance the two out.
Good point about inductance, vs acceleration. That i did not think about.

P.S. My main computer is a water cooled beast, pulling 1.2KW at the wall; so i have no objections to adding a fan or two to the printer controller assembly. This build is still just a theoretical design and my parts budget is $1,000. So, i am open to, and appreciate any and all suggestions.