Tolerance Breakdown

Hi All,

I'm just getting into 3d printing and am curious where the tolerance breakdown lies for XYZ?

As best i understand it +/- 0.015" on XY and +/- 0.004" on Z is about normal, correct?

What percent of that is Backlash, Stepper Resolution, Nozzle Size/Oozing ?
e.g is it 50% backlash, 40% ooze and 10% stepper resolution? (made up numbers)

If you find such numbers, it's usually theoretical resolution of the stepper motor only. No belt allowance, no bending, nothing measured.

RepRap in general isn't exactly scientific. RepRap is about enjoying the technology. Example: instead of working out a procedure to calibrate machines properly, CAD models are made parametric to compensate poor calibration and calibrationg contests are run. Scientific methods are developed only slowly and in small steps.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Traumflug Wrote:
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> If you find such numbers, it's usually theoretical
> resolution of the stepper motor only. No belt
> allowance, no bending, nothing measured.
>
> RepRap in general isn't exactly scientific. RepRap
> is about enjoying the technology. Example: instead
> of working out a procedure to calibrate machines
> properly, CAD models are made parametric to
> compensate poor calibration and calibrationg
> contests are run. Scientific methods are developed
> only slowly and in small steps.

^^this

The major error in terms of x/y positioning is going to be slop and dodgy belts, not precision of the steppers. But even still, the weirdness of melting plastic and squidging it out of a nozzle is by far the biggest uncertainty. It'd be difficult to quote specific numbers.

Understandable, however without knowing where the biggest problem lies makes it difficult to know where the low hanging fruit is. If noone has already done this i will prepare an estimate of breakdowns. printer wont be ready till dec though, so it may take some time.