Haze, streaks or white marks on transparent polycarbonate or acrylic parts often come from the release agent film transferring onto the part, or from too much release. The usual fix is a light coat of a clear, non-staining non-silicone release such as Micron 1110 Non Silicon Mould Release Agent, in the grade matched to your resin. Micron's page says grades are available for polycarbonate and acrylic, so confirm the grade before you order.
Why it happens
Clear parts show every defect, so a release film that would be invisible on a black ABS housing can show up as a cloud on a lens. Common causes:
- Release film transferring to the part. Some of the film moves from the mould onto the moulded surface.
- Too much release. A heavy coat leaves more material to transfer, and it can pool in corners and fine detail.
- A release that does not suit the resin. Polycarbonate and acrylic (PMMA) are sensitive, and a release chosen for another plastic may mark them.
You will usually see cloudiness or streaks on clear parts, or visible residue on optical and display surfaces.
How to fix it
- Use a release described as clear and non-staining. Micron 1110 Non Silicon Mould Release Agent forms what its page calls a "crystal clear" anti-stick layer and lists "Non-staining" among its properties.
- Match the grade to your resin. The 1110 page says grades are available for polycarbonate, acrylic, nylon, PP, HDPE and ABS. Do not assume the standard 550 ml can is the right grade for your resin. Tell Micron your material and ask which grade you are buying.
- Apply lightly. Use a thin, even coat and avoid heavy application on optical surfaces.
- Clean the mould if residue has built up. If old release or grease is on the tool, clean it before switching release so you start from a clean surface.
The 1110 page has no step-by-step directions. Follow the instructions on the can and the TDS.
A simple way to test: mould a short run with the new release on a cleaned tool, inspect the parts under the same light your QC uses, and only then switch the line.
What to avoid
- Avoid heavy application on optical parts. More release does not mean better release on clear parts; it usually means more haze.
- Do not assume the standard 550 ml is the right resin grade. Confirm the grade with Micron first.
- Do not treat haze from the release agent and haze from the process as the same problem. Moisture in the resin, wrong melt temperature or a dull mould polish can also cloud clear parts.
- Keep the can label and SDS to hand; this is a pressurised aerosol.
When to ask an expert
Hand off to Micron's technical team if:
- the parts are optical or medical clear parts, where any residue matters;
- haze persists after cleaning the mould and switching to a light coat of the right grade;
- you are not sure which resin grade of 1110 you need.
If the haze persists with no release agent at all on a clean, polished tool, the cause is in the material or the process. Talk to your resin supplier or process engineer.
FAQ
Why are my transparent parts cloudy only near the edges?
Release can pool in corners, edges and fine detail when the coat is heavy. Apply lighter and check whether the haze follows where the release collects.
Is non-silicone release better for clear parts?
The 1110 non-silicone release is described as crystal clear and non-staining, and Micron lists grades for polycarbonate and acrylic. Which grade you need depends on your resin, so ask Micron before ordering.
Can I clean the haze off finished parts?
That depends on the resin and the residue. Polycarbonate and acrylic can be damaged by some solvents, so test on a scrap part and ask your resin supplier. Preventing the transfer is easier than cleaning it off.
Does the 550 ml can work for polycarbonate?
The page lists grades per resin but the store sells one 550 ml SKU. Confirm with Micron which grade it is before using it on polycarbonate or acrylic.
See the product: Micron 1110 Non Silicon Mould Release Agent. More moulding problems and fixes: moulding hub.