How do Cotton Harvesting Machines Work?

One of the most amazing things about cotton harvesting is how much it has changed in the past century. Since cotton harvesting is no longer done by hand (something that was the case until the turn of the 20th century), specialized cotton harvesting machines are used to separate the cotton fibers from the mature bolls. The machines used can be divided into a few different types for each stage of cotton preparation: namely, there are cotton pickers, cotton strippers, boll buggies, and finally module builders.

Cotton Pickers and Cotton Strippers

There are a few different types of cotton harvesting machines, with two general methods of removal of the fibers. 

A cotton picker removes the seed cotton from the burr by means of high-speed rotating spindles which extract the cotton from the open burrs of the plants which then wrap around moistened spindles. The spindles are then cleaned off by a specialized machine, known as a doffer, to extract the cotton that has been removed. This method is the cleanest method for extracting cotton, but it’s not the only one. 

In some cases, cotton strippers are used instead of cotton pickers, most commonly after the green vegetation has been killed off by frost. Cotton strippers use a roller method with bats and brushes which push the open bolls onto a conveyor belt, along with leaves and stems. In this case, the material has to be cleaned off by special devices at the cotton gin. 

In both cases, air is used to lift the seed cotton (which, by itself, is quite light) into a storage basket, to be transferred to a boll buggy. However, in the case of the cotton picker, the moist spindles are what hold the cotton in place. After the cotton is transferred to the boll buggy, the cotton picker or stripper is ready for more harvesting.  

Boll Buggies and Module Builders

Boll buggies are used to transport cotton to module builders once the harvesting is complete. Boll buggies come in a number of designs, and are designed to keep the harvesting machines effective by collecting what is being harvested, leaving the continued operation of the harvesting machines more efficient. 

A boll buggy has both the ability to collect cotton from the harvester as well as to carry the entire weight needed to be compacted on its side. Module builders are large machines that operate in a similar fashion to trash compactors. After the buggies load the cotton, the module builder then crushes the fibers to compact them into a cube. 

Module builders, first designed in 1972, are designed to carry loads of cotton weighing up to 10 tons. The history behind the module builder is itself surprising: after almost 100 years of mechanized cotton picking, the problem of cotton storage remained, as the dried material was prone to loose storage, making the dried cotton a cause of fires and losses for farmers, who had been storing the cotton in trailers up to that point. This virtually disappeared with the advent of the module builder.

After the cotton is compacted, the module builders take the cotton to a textile mill for processing or to a purification manufacturer. Cotton module builders presented a quantum leap in cotton transport, making even larger-scale cotton fiber production possible. A cotton module builder is up to 30 feet long and 12 feet wide! In some cases boll buggies themselves have built in compactors to make it even easier to collect and transport the extracted cotton, or to make for compact transport to the module builder.   

The Cotton Harvesting Process Today   

Cotton harvesting has undergone massive changes in the past 100 years thanks to the rise of technology. As cotton pickers and strippers were not in widespread use until the 1940’s, the first major quantum leap in the centuries-old practice of cotton harvesting is less than a century old, before which cotton had historically been harvested by hand. 

Just two generations ago, the problem of storage and fire which had plagued the cotton industry for hundreds of years ended with the advent of the module builder. Modern technology in the cotton industry, which started in the United States and is now used all over the world, has changed the world we live in, and these large, bulky machines are responsible for changing everything from the price to the accessibility of all the uses we make of cotton today, whether clothing or even the humble cotton swab. 

All of it started with a plant, and today, machines do all the work of bringing cotton from the field to the production facility.