Bronze shrink factor

#1

Hello,

i’m trying to build a watch case in bronze, i want some support from you about your accuracy factor 5%(±0.15mm minimum). Do I have to apply a scale factor to my model or is something that you apply before printing the wax? If yes how much?

On my model I have holes of ø0.75 mm diameter, which is your minimum diameter with this process?

Thanks in advance

#2

Hello,

We use the file as delivered to us and make no corrections whatsoever. It’s not that simple that we could advise you to increase or decrease the dimensions of a part to get exactly what you want.

The only thing I can say is that the average accuracy is ± 2% (around ± 0.1 mm), but a part is considered as a good print when the minimum accuracy ± 5% (including finish and geometry variables) with a lower limit of ±0.15 mm.

We measure these tolerances on the outer dimensions of the entire part. So it’s also impossible to make a statement on the minimum diameter of the holes.

Kind regards Lizy

#3

Hello,

many thanks for your kind answer. I have another pratical question just to understand: if I have the nominal external diameter of ø30 mm, after casting and polishing it will be 30±0.6mm (2%) or 30±0.1mm?

Thanks

Luca

#4

Hello Luca, with outer dimensions of 30 mm, a bronze part would be considered as a good part if the outer dimensions are between 29,85 and 30,15 mm. Kind regards Lizy

#5

Ok perfect!

Thanks

Luca