Documenting the Mk 2.1

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you may want to come up with a different name other than the Mk 2.1.
the 2.1 has a connotation of being only an incremental change that is
compatible with the previous version. if its not compatible with the
controller board, then its definitely not a v2. its fine that you're
using the mk2 as a stepping stone, but we dont want people getting
confused because they thought yours was going to work with their
machine.

On 2/25/07, Forrest Higgs wrote:
>
> I've made a start on documenting the Mk 2.1 that I have operating. For
> those interested, you can look at what I've done so far here.
>
> [3dreplicators.com]
>
> I know that there is a lot more that I'm going to have to photograph and
> talk about before the full technology layout is adequately described.
>
> I don't quite know where this will fit, if anywhere, in the RepRap site. It
> isn't metric, it won't work with the RepRap universal board and firmware and
> so on and so forth. All the same, the stuff I've done might be reasonably
> be selectively looted by RepRap for incorporation into your core system
> somewhere down the way. Please, it's open source... don't have any qualms.
> If some part of what I've done works for you, it's yours.
>
> As soon as I can print reliably on Tommelise I expect that I will be
> redesigning the polymer pump especially and the Mk 2 in general to take
> advantage of a few ideas I have on matters like making it easier to load
> with filament, making the pressure on the filament in the pump easier to
> adjust (for handling harder and higher melting temperature filamnents) and
> the like.
>
> When I get to that point and have a design I'm happy with I plan on making a
> dozen or so fully assembled Mk whatevers save for the controller board and
> gear motor and share them out amongst anybody who will seriously use one.
>
>
>
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Quoting Forrest Higgs :

> it won't work with the RepRap universal board and firmware and so on
> and so forth.

Sure it will. All that stuff needs is a heater to drive, a thermistor
to tell it the temperature, and a drive motor to connect to its H
bridge. You've got all those.

Why don't you link it from the main Wiki extruder page as an
alternative design?

Yours

Adrian

[staff.bath.ac.uk]
[reprap.org]
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Quoting Zach Hoeken :

> you may want to come up with a different name other than the Mk 2.1.
> the 2.1 has a connotation of being only an incremental change that is
> compatible with the previous version. if its not compatible with the
> controller board, then its definitely not a v2. its fine that you're
> using the mk2 as a stepping stone, but we dont want people getting
> confused because they thought yours was going to work with their
> machine.

Good point. It's a tree, and we don't want people thinking they're on
the wrong branch. Each divergence needs a new name.

Yours

Adrian

[staff.bath.ac.uk]
[reprap.org]


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***Sure it will. All that stuff needs is a heater to drive, a thermistor

to tell it the temperature, and a drive motor to connect to its H

bridge. You've got all those.***

That's rather what I thought. I don't use a thermistor, but that doesn't mean that somebody couldn't strap one on it if they wanted. About the only substantive change that I saw in your firmware was upgrading it slightly to make use of the software driven very slow pulse PWM (pseudostepping) technique that I use to avoid the stalling that Vik has reported in the Mk 2 at very slow extrusion flow speeds. Pseudostepping lets you get pretty much full gearmotor torque right down at 0 rpm, something that PWM doesn't seem to manage. I haven't looked at your new universal board to see if you are still driving the gearmotor with a power transistor or have shifted over to using a dual Darlington that will let you reverse the direction of the gearmotor. I have a feature that uses that capability to extract the stub end of a length of filament from the extruder barrel while the barrel is still hot.

***Why don't you link it from the main Wiki extruder page as an

alternative design?
***

Done. I put a new section for alternative designs between the download and license sections. Somebody might want to check to see that I haven't done too much violence to the format of that page.

***Good point. It's a tree, and we don't want people thinking they're on
the wrong branch. Each divergence needs a new name.***

Done.




----- Original Message ----

From: Adrian Bowyer

To: developers@reprap.org

Sent: Sunday, February 25, 2007 8:29:15 AM

Subject: Re: Documenting the Mk 2.1



Quoting Forrest Higgs :



> it won't work with the RepRap universal board and firmware and so on

> and so forth.



Sure it will. All that stuff needs is a heater to drive, a thermistor

to tell it the temperature, and a drive motor to connect to its H

bridge. You've got all those.



Why don't you link it from the main Wiki extruder page as an

alternative design?



Yours



Adrian



[staff.bath.ac.uk]

[reprap.org]

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