Carding Machine

Overview

A carding machine is the heart of spinning preparation. It takes a thick, tangled mat of opened cotton or staple fibre and turns it into a clean, even rope of parallel fibres called a sliver. Along the way it does three jobs at once: it separates the fibre tuft by tuft down to individual fibres, it removes the short fibre, neps and trash that would weaken or spot the yarn, and it lays the surviving fibres roughly parallel and gathers them into one continuous strand. The quality of everything spun afterwards is limited by how well the card does this, which is why carding is often called the operation that "makes or breaks" the yarn.

The machine works fibre against fibre by drawing it between two surfaces clothed in fine metallic teeth moving at very different speeds. Modern high-production cards run a metre-wide cylinder against a slow belt of flats and deliver well over a hundred kilograms an hour, held to a constant sliver weight by an autoleveller.

How it works

Fibre enters at the Feed & Lickerin, where a fluted feed roller grips the lap against a spring plate and presents it to the fast lickerin, whose saw teeth open it into small tufts and throw heavy trash out past the mote knives. The opened fibre transfers to the Main Cylinder & Flats, the carding zone proper: a large wire-clothed cylinder turns close beneath a slow chain of revolving flats, and the two clothed surfaces split the tufts into single fibres, lay them parallel and strip out neps and short fibre into the flat waste.

The cleaned web is lifted off the cylinder by the Doffer & Stripping, a slower roller whose clothing pulls fibre away rather than carrying it past, and a doffer comb peels it off as a wide gossamer web. The Web Condensing & Coiler then funnels that web through a trumpet into a round sliver, presses it in calender rolls and lays it in even coils in a can. All these speeds are set by the Cylinder Drive, a motor and gearbox that step the cylinder, lickerin, doffer and flats to their working ratios.

To hold sliver weight constant, the Autoleveller measures delivered thickness and trims feed speed in real time, while the Waste Suction pulls fly and stripped trash away into a filter. The Card Control sets the speeds, runs the leveller loop and shows production and quality to the operator.