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Greetings,
I had an idea for a third arm to add to the Morgan which could be calibrated with springs to give better stability to the print head by reducing the effects of inertia and dropping of the print head height at far reaches.
As print speed is increased and head weight increased (if you do dual-extruders) I think a third arm could help.Although I have the arm coming from the opposing side, I guess this arm could be mounted from behind the existing arms too.
I am curious to see what people’s thoughts on this idea are.
This third arm should be pretty cheap to do.
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Before beginning my build I had some similar ideas plus some ideas about changing the PVC pipe supports but I don’t believe any changes are warranted. The design is deceiving if you just go by the pictures!
The 2 psi arms are VERY rigid and I don’t think anything much could be gained by a third arm. I was pretty amazed at how rigid the structure actually is \o/
Just my 2 cents…
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Just from watching the videos I was also surprised, as the pictures didn’t really show off the stability that is already there.
I have been thinking about things that could be done to the arms themselves to make them more stable but I’ve not come up with anything interesting besides adding a third arm to smooth out fast motions and stabilise at long ranges.
One of my biggest concerns is the head not being level on the Y axis. (Y? Straight out from the drive shaft, I mean). The further the arms extend out the more they act like a lever that the print head can pull down on.
The concerns I had about inertia carrying the head too far can be (and probably are) addressed in software by simply telling it to slow down before the destination! So I guess I shouldn’t worry about this.
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The Y level “problem” is not a problem since I changed the firmware to deal with that. You level your bed to be 90 degrees to the smooth rod and drive shaft, and run the calibration. Works a charm. The z axis keeps tracking the head, making for very nicely sqaured prints.
The arms are stable to the point of me thinking that I might be able to lighten them more. No problems there.
The only area that really needs work is the Z drive itself. I have a problem on one of my machines where the stepper motor heats up too much, causing some skipping. I will let you know what I find.
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