More hang angle possible solution

I'm designing a bunny figurine but I realize that the ears are more horizontal than the Makerbot rabbit. Then I thought, if the ears are long on the x axis what if I tilted the machine? If the ears walls are at a 70 degree angle and the max angle is 45 so then I tilt the printer 25 degrees before printing, would it work?

One problem could be the stepper motor would struggle lifting the extruder causing deformations. That could be resolved by putting a counter weight that hangs from the belt pulley that goes down when the extruder goes up.

The other problem might be printing with the nozzle angular to gravity.

Wondering if it has been tried?

Gravity is not the problem. Repraps can print upside down with no real change in performance. The problem is the limited contact between the new filament and the existing object.

Andrew Smith Wrote:
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> Gravity is not the problem. Repraps can print
> upside down with no real change in performance.
> The problem is the limited contact between the new
> filament and the existing object.

If the contact is zero then it will fall onto the plate unless it is tilted then it will fall onto the model or am I missing something?

I think your 25 degrees would be worth a try - if you're using 40N*cm NEMA 17s then the steppers should have plenty of grunt to spare,
( Of course, you;ll have to watch out for overhang angles on the "downside" which may have been negligible before taking on the Pisa Profile )

As far as contact goes, well, normal bridging is by definition no contact at all.

What I have found is that the "level-of-smoosh" is a critical factor... ( just for printing on the level)

For that first layer to stick properly and give you a stable base for the rest of the print, I find I need the Z-home needs a little less than layer height clearance from extruder top to the bed.
I print onto blue 2090 tape, cold bed, and as long as I have that first layer level right, no slippage, I have to chisel the objects off. ( 0.4 mm layers, a little less than 0.3mm Z-home clearance, using my highly accurate(?) folded-piece-of-paper thickness guage)

The relevance to your topic is that even on an angle, if that first layer gets smeared onto the bed without any chance of falling anywhere, then subsequent layers should print as normal...

Very interested to hear how you experiment goes ...

( These opinions totally hypothetical, this person holds the equivalent of reprap kindergarten diploma, YMMV, hot when heated, do not run with scissors )

ps Someone really needs to do a utube vid of a reprap printing upside down !

The filament doesn't fall onto the model. It has to be pressed onto it so that it is squashed and sticks. You can't do that if there is nothing underneath.

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[www.hydraraptor.blogspot.com]

I've found that lowering your layer height makes it easier to print overhangs because the distance each loop has to stick out beyond the one beneath it is reduced. Try your print at 0.1 or 0.05mm layer height; I bet it'll come out okay.

nb99 Wrote:

> As far as contact goes, well, normal bridging is
> by definition no contact at all.
>

Bridges have contact at both ends, which makes it possible to stretch the filament over the gap. Overhang doesn't make that possible, you have limited contact along the whole length of the filament but no solid anchor point. At some point, its going to stop working.

> ps Someone really needs to do a utube vid of a
> reprap printing upside down !

[www.youtube.com]

Pointedstick Wrote:
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> I've found that lowering your layer height makes
> it easier to print overhangs because the distance
> each loop has to stick out beyond the one beneath
> it is reduced. Try your print at 0.1 or 0.05mm
> layer height; I bet it'll come out okay.

That makes sense to me.

I'm in the modelling stage right now but I wanted to make sure my 3D models would be capable of being printed in the first place.

Thanks everyone

Hehe - comment from the upside-down youtub vid

"That's exactly how we in New Zealand do it "

I knew I was missing something down here ....