Why does support removal force depend on tip diameter?

A support snaps at its narrowest point — the tip where it touches the model. The force needed is the tip's cross-sectional area times the cured resin's tensile strength, so doubling the tip diameter roughly quadruples the force because area grows with the square of diameter.

What tip diameter should I use?

A common balance is 0.3 to 0.5 mm. Smaller tips leave cleaner marks but can snap off the build plate during the peel phase, causing print failures; larger tips hold reliably but leave bigger scars and risk cratering the surface.

What is the notch factor in the calculation?

Support tips are deliberate stress risers designed to fail there. A clean tensile bar would need the full strength times area, but a notched tip breaks earlier, so the tool applies a reduction factor of about 0.6 to reflect real-world break-away force.

Why do my supports fail during printing instead of after?

During printing each layer is peeled off the FEP film, which pulls hard on the contact tips. If the tips are too thin for the model's weight and peel force, they snap mid-print. Increase tip diameter or add more supports to spread the load.

Does resin strength really matter for removal?

Yes. Tough and engineering resins are far stronger when cured, so the same tip diameter needs much more force to remove and leaves worse scars. With strong resins, lean toward smaller, denser tips. Flexible resins barely hold at all and need larger tips.

Support Tip Diameter & Detachment Force Calculator

Choosing resin support tips is a balancing act: too thin and supports snap off the build plate mid-print; too thick and they crater the model when you remove them. This tool estimates the break-away force for a given tip size and resin so you can pick the smallest tip that still holds.

How it works

A support always breaks at its weakest cross-section — the contact tip. The force to snap it is the tip’s area multiplied by the cured resin’s tensile strength.

A = (π / 4) × d²          tip cross-section in mm²
F = σ × A × notch_factor  break force in newtons

d is the tip diameter in millimetres.
σ is the cured resin’s tensile strength in MPa (which equals N/mm²).
The notch factor (~0.6) accounts for the tip being a deliberate stress riser that fails earlier than a clean tensile bar would.

Because force grows with the square of diameter, a 0.6 mm tip is roughly four times harder to remove than a 0.3 mm tip — and leaves a much larger scar.

Tips and notes

Prefer many small-tip supports over a few thick ones: each holds less, but together they resist the peel force without leaving big marks.
Strong resins (tough, engineering, dental) magnify removal force; use smaller tips with them.
If supports snap during printing, raise tip diameter slightly or increase support density rather than over-curing.
After removal, the residual nub can be sanded or kissed with a UV pen and trimmed — smaller tips leave less to clean up.