Slicing Settings

Prev: Part 12: Slicing Introduction

This step focuses on the printer, resin, exposure, and motion settings used by PrintFileGenerator. You’ll define a printer and resin profile, then optionally attach component-level defaults like burn-in layers.

Goal: build a minimal, reusable settings profile that matches your printer.

Why settings matter

PyMFCAD components contain reusable geometry and can also represent complete assemblies. PrintFileGenerator uses the component geometry and settings together with the printer and resin profiles to validate component compatibility and generate exposure/motion metadata for a print file.

Printer and light-engine matching

The printer provides one or more light engines that define the available pixel sizes and projection areas. Your printer must have a light engine matching the pixel size used by your component.

Printer and resin libraries

PyMFCAD includes printer and resin libraries with predefined profiles for commonly used hardware and materials. Use a library profile when it matches your setup:

from pymfcad.printer_library import OS1v0
from pymfcad.resin_library import NPS

printer = OS1v0
resin = NPS

The printer library includes HR3v3, HR5, MR1v1, and OS1v0. The resin library includes NPS, AVO, AVO_TPO, and formulations with 1% or 10% crosslinker. Library objects are regular Printer and ResinType objects, so they can be passed directly to PrintFileGenerator or saved and customized like manually created profiles. Define your own profiles when your printer or resin differs from the available library entries.

Step 1 — Define printer and resin inputs

The printer and resin describe the hardware and material used for the print. Below are examples from the resin and printer library (OS1v0 printer and 2% NPS resin). Optionally, you can modify and save each profile to JSON files for reuse.

You can export/import ResinType and Printer objects to JSON using their save() and from_file() methods.

Settings objects (what they are and when to change them)

The following objects divide the print recipe into hardware, material, exposure, and motion information. In practice you only need a small set of profiles; most changes are resin-specific. Component-level defaults can override the general values when needed.

`Printer`

Describes the hardware platform.

Describes the printer’s physical hardware capabilities.
If your printer has multiple light engines, list them all here.
Can be saved/loaded from JSON for repeatability.

`LightEngine`

Describes the optics that define pixel resolution.

name links the light engine to the hardware configuration.
px_size and px_count set the physical resolution.
wavelengths lists the available wavelengths in the projector.
default_exposure_settings lists default settings for each light engine.
grayscale_available lists the availability of grayscale for each light engine
settle_time_ms adds an extra wait before the first exposure after switching to this light engine.
stitched_px_overlay and the offset_limits configure stitching for each light engine.
If the component size does not fit the selected light-engine projection area, slicing will use projection or stitching as appropriate.
If exposure settings use an unlisted light engine or an unavailable wavelength, slicing will fail.

`ResinType`

Metadata used for traceability and consistent settings across experiments.

Tracks monomers, absorbers, initiators, and additives as percentages.
bulk_exposure sets base exposure time (ms) for bulk polymerization.
exposure_offset is an optional offset (ms) before polymerization begins.
Values are saved into the resin JSON and exported with the print file.
Any changes to exposure time are made in multiples of the exposure information contained in the Resin.

`PositionSettings` (in printer definition)

Controls motion behavior between layers (lift, speeds, waits, squeeze).

Think of this as the mechanical side of the print.
Use defaults unless you have a known motion profile to apply.

`ExposureSettings` (in light engine definition)

Controls light exposure behavior per layer (multiplier, power, wavelength).

Use defaults first; adjust only after test prints.
Exposure time is computed as \((bulk\_exposure - exposure\_offset) * multiplier + exposure\_offset\).

Step 2 — Component‑level defaults (optional)

You can attach exposure/position defaults to any component. These override general values for that component (defaults inherited from parent components and printer definition) and can enforce specific settings on its own layers.

If you set use_parent_settings=True in the Component contructor, the component will inherits its setting directly from its parent. Components using this option cannot add their own settings. Use this option for purely geometric components such as pinholes and resevoirs.

Use this when a specific component or assembly needs different motion or exposure than your general defaults.

Step 3 — Burn‑in settings

Burn‑in layers are the first few layers of a print that use longer exposures to improve initial adhesion and stability. They can also help compensate for build‑platform leveling inconsistencies. Use burn‑in when you need stronger early layers (e.g., large flat bases or thin features that tend to detach). Burn‑in values are absolute times in milliseconds, not multipliers of the resin exposure.

The list below applies one exposure time per initial layer, in order.

Example — Prepare the Part 11 device

If you built the full device in Part 11, place the following directly under that code to attach settings, defaults, and burn‑in:

This example mirrors the minimal settings above, but adds resin metadata and explicit defaults so you can reuse the same settings file across prints.