Tip Shaping: Forming¶

What it does¶

Happy Hare's standalone filament-tip-forming macro - the default way to get a clean, hair-free tip before an unload, working similarly to PrusaSlicer/SuperSlicer's own tip forming. See Feature: Tip Forming and Purging for the concept, the alternative methods (toolhead cutting, slicer-controlled), and the full step-by-step tuning workflow using MMU_TEST_FORM_TIP - this page doesn't repeat that, just the menuconfig view of the variables it tunes.

Where it's applied¶

_MMU_FORM_TIP, defined in mmu_form_tip.cfg. Active whenever form_tip_macro: _MMU_FORM_TIP in mmu.cfg (the default) - runs through five steps in order: ramming, nozzle separation, cooling moves, an optional skinnydip pass, then parking the result for eject/inspection or the next unload step.

The Macro Variables screen is always visible regardless of whether tip forming or toolhead cutting is selected. Tip Shaping: Toolhead Cutting's screen only appears once a toolhead cutter is enabled.

Happy Hare zeroes pressure advance for the duration of the macro call, so the ramming/cooling moves aren't distorted by it, then automatically restores whatever value was active beforehand once tip forming completes - nothing to configure or restore by hand.

Selecting filament-movement forming¶

Open menuconfig's Tip Forming / Cutting ---> screen, then open Select standalone tip shaping option and choose Tip shaping using filament movement. This writes form_tip_macro: _MMU_FORM_TIP to mmu.cfg.

menuconfig Tip Forming and Cutting screen with filament-movement tip shaping selected

The other settings on this screen control when and how forming runs:

Setting	Purpose
Have servo cutter at MMU?	Enables the separate MMU-mounted cutter. That cutter is additive and does not replace this tip-shaping selection.
Happy Hare controlled in-print tip forming/cutting	Leave enabled to run `_MMU_FORM_TIP` during prints and disable the slicer's own tip forming. Disable it when the slicer will form the tip; menuconfig then exposes Slicer tip park pos.
Extruder tip forming current	Percentage of normal extruder current to use while forming. `100` disables the boost; increase it only as needed, up to `150`.

Configuration¶

menuconfig: Tip forming (_MMU_FORM_TIP) screen, showing the ramming, nozzle separation, cooling, skinnydip, and parking steps

_MMU_FORM_TIP_VARS in mmu_macro_vars.cfg, reachable from menuconfig's Macro Variables → Tip forming (_MMU_FORM_TIP) screen shown above, grouped by the same five steps the tuning workflow walks through. Full variable table: Macro Variables: Tip forming.

Hotend starting points¶

cooling_tube_position/cooling_tube_length are toolhead-specific - tuning from scratch is slow, so start from your hotend's known geometry rather than the shipped default:

Hotend	`cooling_tube_position`	`cooling_tube_length`
DragonST	`35` mm	`15` mm
DragonHF	`30` mm	`10` mm
Mosquito	`30` mm	`20` mm
Revo	`35` mm	`10` mm
RapidoHF	`27` mm	`10` mm