Intro to MUSE

Predict How Exposure to Water and Humidity Changes Your Polyamide Parts — Before You Build Them

The hidden variable in every PA design

Polyamides (PA6, PA66 and their glass-fibre grades) are the workhorses of structural plastics — but they all absorb water from the air. A dry part straight from the mould is not the part your customer receives: as it equilibrates with ambient humidity it takes up moisture, swells, and changes dimension and stiffness. A bracket that fit on the assembly line can later bind or gap; a sealing face can lose contact; a press-fit can loosen. The effect is real and measurable — and, crucially, predictable.

MUSE — Moisture Uptake Simulator for Engineering — puts that prediction in the hands of the people who design, mould and integrate PA parts. No lab samples, no weeks in a climate chamber: open a browser, pick a material, describe the climate, and get an answer in seconds.

With MUSE you simulate water diffusion and get meaningful results

At its heart is a fast, physics-based 1-D water-diffusion simulation that answers the three questions every PA engineer asks:
- How much water will my part take up, and how fast?
- How is it distributed through the wall?
- How much will the part grow lengthwise, cross-wise and in thickness?

No matter how complex a part looks, water always enters the same way: it seeps in through the surface and works its way inward, perpendicular to the wall. The wall thickness is therefore the one number that governs how fast moisture penetrates — whether the part is a simple bracket or an intricate connector. MUSE exploits this: describe the wall thickness and the
environment, and you get the full uptake picture in seconds. You provide only what you already know: the material (from a built-in database of Ultramid grades, reinforced and unreinforced, each carrying measured saturation, diffusion and swelling data), the wall thickness, the
exposure (wetted on both sides or one side only), the climate (temperature and relative humidity), the duration, and the starting condition (bone-dry or partly conditioned).

Within seconds you get:

- Moisture profile through the wall — how wet the surface is versus the   still-dry core; the gradient that drives short-term warpage.
- Average moisture versus time — the uptake curve: how long until the part   reaches a target moisture level in your real-world climate.
- Hygroscopic expansion — dimensional growth in three directions (along   flow, across flow, through thickness). For glass-fibre grades these differ strongly, and that anisotropy is exactly what makes parts bow.

Built for real conditioning recipes

Real parts rarely see one steady climate. MUSE chains together multi-stage conditioning cycles — as many environment steps as you need, each with its own humidity, temperature and duration — and handles the cases that trip people up: sealed steps (moisture redistributes from wet skin to dry core without entering or leaving), post-conditioning after a primary soak, and one-sided exposure. Each stage starts from the moisture state the previous one left behind, so the prediction follows the real history of the part.

Who benefits

Design engineers size tolerances against the conditioned part, catching interference on screen instead of on the assembly line. Process and quality engineers plan conditioning steps with confidence. Project engineers and OEMs anticipate how a bought-in component moves in service. Managers get a shared, repeatable tool that replaces tribal knowledge and scattered
spreadsheets. Water uptake is one of the few PA behaviours both certain to happen and easy to predict — MUSE turns that physics into a two-minute answer. Less guesswork, fewer surprises, better parts.

Go back go the MUSE home page.