Re: [CAD_CAM_EDM_DRO] reprap build started

Hi Jon,

It certainly sounds like it wouldn't be too hard to accommodate an
extruder with normal Gcode! The 'E' axis is just another stepper motor
(or even a servo), with the appropriate scaling.

The RepRat does use Z, it moves it up each layer (step size).

I just heard about pull-back, that sounds like it might possibly be
accomplished with some sort of back-lash comp algorithm (?).

I can just see a compact little stepper-driven extruder that mounts
where the current Sherline spindle mounts!

Alan KM6VV

On 10/11/2011 6:25 PM, Jon Elson wrote:
> Alan wrote:
>> Kevin, Mike,
>>
>> What's the basic relationship of feeding stock to the travel in X&Y?
>>
>> Sounds like it would be a direct relationship. So one could calculate a
>> "feed distance" for the stock, and assign it to another axis to drive the
>> extruder (scaled, of course)...
>>
>> Seems like if the X axis needed to move 5" to lay down the filament, then 5"
>> of stock (or some scale of that) would need to be extruded at the same time.
>> Just like a "coordinated move"! Has someone already thought of that?
>>
>> I could see a little program that took normal Gcode, and generated the
>> "pseudo axis" for the coordinated move.
>>
> Since the filament fabricator has no Z axis, just a layer step size, one
> could assign the
> extruder drive to another axis, like Z (or U). Then, the G-code could
> be written to
> always move Z scaled by the sqrt(x*2 + Y*2) movement. This would give
> an acceleration
> ramp on the extruder that matches the acceleration of the X-Y table.
> The only thing this
> lacks is the pull-back each time the extruder needs to stop. That could
> also be written
> into the code.
>
> So, this could ALL be done in G-code, although it might end up being a
> LOT of lines.
>
> Jon
>