InsightsStated limits
Which plastics can these sorters not handle?
Direct answer
Pellets and soft film. Mayson's plastic flake platforms are not designed for pellet sorting, and film, bags and very light flexible plastics cannot be sorted because air-jet ejection cannot reliably control their trajectory. The limit is mechanical rather than a recognition limit — a camera sees film perfectly well.
What a chute-fed sorter needs from the material
In a chute-fed machine, material slides down and passes the inspection point in free fall. A decision is made in flight, and a timed pulse of compressed air removes the rejected piece a few milliseconds later. The whole sequence assumes the piece travels predictably between the moment it is seen and the moment it is hit.
That assumption, not the camera, is what sets the boundary. Recognition is rarely the part that fails.
Pellets and film
| Material form | Status | Why |
|---|---|---|
| Rigid flakes, sheets and fragments | Suitable | Travel predictably and can be presented consistently |
| Whole bottles | Suitable, different platform | Handled by MAS-B / MAS-B Pro before shredding |
| Plastic pellets | Not these platforms | Mayson's plastic flake sorting machines are not designed for pellet sorting |
| Film, bags and soft flexible plastics | Not these platforms | Air-jet ejection cannot reliably control the trajectory of a light flexible piece |
It is worth being explicit about the film case, because it is counter-intuitive. A camera has no difficulty seeing a plastic bag. The machine fails at the ejection step, where a light flexible piece does not go where the air pulse sends it.
Black material: a different kind of limit
Black and carbon-black plastics are a recognition limit rather than a handling one. They travel fine; they simply absorb near-infrared light, so NIR cannot identify their polymer type.
The consequence is different too. Pellets and film are out entirely, while black material can still be removed — as a visible color reject, before the polymer decision runs on what remains.
What to do when your stream is on the wrong side of a limit
For pellets and film, these platforms are not the answer and no configuration changes that. Saying so early is more useful than a qualified maybe.
For everything near a boundary — an unusually fine flake, a stream with a heavy black fraction, material with a lot of dust or moisture — the honest answer is that the boundary moves with the real material. Particle size, thickness, presentation and contaminant rate all shift it, which is why a representative sample settles it and a specification sheet does not.
Where this stops applying
- Mayson's plastic flake sorting machines are not designed for pellet sorting.
- Film, plastic bags, soft films and very light flexible plastics are not suitable, because air-jet ejection cannot reliably control their trajectory.
- NIR cannot reliably identify black or carbon-black plastics, though color sorting can still remove them.
- This page is about the plastic platforms. The food, glass and metal series serve their own material categories with their own limits.
- Anything near a boundary is decided on a representative sample of the real production stream.
Common follow-ups
Can you sort plastic pellets?
Not with these machines. Mayson's plastic flake sorting platforms are not designed for pellet sorting, so pellets are a boundary rather than an application.
Why can film and plastic bags not be sorted?
Because ejection, not recognition, fails. Air-jet ejection cannot reliably control the trajectory of a light flexible piece, so the reject does not go where it is sent even when it was correctly identified.
Is the limit on film a camera problem?
No. A camera sees film perfectly well. The limit is mechanical, which is why a better sensor does not change the answer.
Is black plastic also excluded?
Not in the same way. Black material handles fine and can be removed as a visible color reject; what it cannot do is return a NIR signal, so its polymer type cannot be identified.
What material forms do these platforms suit?
Rigid flakes, sheets and fragments that can be presented consistently, on MAS-C, MAS-P, MAS-P Pro, MAS-PC and MAS-PC Pro; and whole bottles on MAS-B or MAS-B Pro.