How do silkworms make silk video

Breeding silkworms is a practice that has been going on in China for approximately 5, years. Since then, the productivity of silkworms has increased nearly ten-fold. The primary reason for this is that silkworms have been genetically selected for maximum silk output and almost little else. The goal of silkworm breeding is to improve the commercial viability of silkworm farming or sericulture and, by proxy, silk production. More specifically, the primary objective has been to improve fecundity - also known as egg-laying capacity.

Other objectives include improving larval health, resilience against disease, and the quantity of cocoon and silk harvest. Healthy larvae produce healthy cocoons. Factors that influence larval health include a higher pupation rate, and fewer dead larvae in the colony.

Additionally, a shorter larval duration lessens the chance of infection, so reducing this time period is also a good thing to aim for. The quantity of cocoon and silk produced are directly correlated with the pupation rate and the larval weight. Healthier larvae have higher pupation rates, which leads to larger cocoon weights, which in turn means a greater silk harvest.

The quality of the silk produced is also influenced by genetic factors. Silkworm cocoons are made of several threads of raw silk spun together. Unspun and laid out end to end, the thread making up a cocoon can be anywhere from to meters 1, to 3, feet long. The silk itself is made of two elements - fiber and sericin. The fiber is very fine, only about 0. The remainder of the thread is made up of sericin, the gum produced by the silkworm which glues the fibres together into a cocoon.

It takes about 2, to 3, cocoons to make a pound of silk 0. The first stage of silk production is egg laying and hatching. Typically, this will occur in a controlled environment like an aluminium box.

The female silk moth will deposit anywhere from to eggs at any one laying, each about the size of a pinhead. The female moth dies almost immediately after laying these eggs, and the male moths don't live much longer afterward either. It is evolution playing a game of cold efficiency, if you choose to see it that way.

They incubate their eggs for a short while - usually no longer than just 10 days - before they hatch into larvae, or caterpillars. At this point, the larvae are only about 0. Once the precious larvae have hatched, the immediate priority is to ensure they are getting the right food, and enough of it. The newly born larvae are placed under a thin layer of gauze and fed immense amounts of chopped mulberry leaves.

Depending on the type of silkworm you have, these can be the leaves of the white, red, or black mulberry tree. During this feeding frenzy, the larvae will shed their skin four times. They eat copious amounts of the mulberry leaves - the best feed if you're after producing the highest-quality silk - usually averaging around 50, times their initial weight in plant material!

This stage of production continues for four to six weeks, during which time the larvae are gorging almost non-stop. There comes a point about 6 weeks after hatching that larvae will begin to molt. This can be distinguished by the fact that at this point, their heads turn darker. After molting, the silkworms enter the instar phase.

In this phase, the silkworms emerge white, naked, and with little horns on their backs. Similar to how they shed their skin in their larval phase, they molt four times in the instar phase. This causes their bodies to become slightly yellow in color, and their skin becomes tighter. At the mature part of this stage, the silkworms measure about 3 inches in length, stop eating, and weigh 10, times more than they did when they were born.

At this point in their lifecycle, the instar starts weaving its cocoon. In order to do this in nature, the silkworm attaches itself to a twig or a shrub. However in a silkworm farm, compartmented frames are used, with each division being occupied by a single silkworm building a single cocoon.

The construction period, also known as pupation, takes anywhere from 3 to 8 days, during which the silk cocoon is spun. Silkworms have a pair of modified salivary glands known as sericteries. They are used to make fibroin, a clear, thick fluid rich in protein, which is pushed through openings adjacent to their mouth-parts called spinnerets.

The thickness of the silk thread is determined by the diameter of the spinneret itself. The thread is produced as a long, continuous string. Secretions harden upon exposure to air. The sericin mentioned earlier is secreted from another pair of glands which bonds the filaments together. Over the pupation period, the silkworm spins its body in a figure-eight shape up to , times in order to construct its cocoon. Each cocoon equates to roughly a kilometer of raw silk.

After its incubation period in the cocoon, the surviving insects release enzymes which bore a hole through the cocoon, allowing the mature silk moth to escape. These enzymes are destructive to the silk, as instead of ending up with a continuous string of silk, you end up with various strands of varying lengths instead, making it much less commercially viable.

In order to prevent this from occurring, the silkworm cocoons are boiled. The heat from boiling kills the silkworms and the water simultaneously makes the cocoons easier to unravel.

The silk is then unbound from the cocoon by softening the sericin gum holding it together. It is then carefully unwound, a process known as reeling the filaments.

The silk yarn is soaked in warm soapy water to remove the last of the sericin gum and give the silk its distinctive softness and shine. At the end of the degumming process, you are left with a creamy white yarn that is soft and ready to be dyed. There is a distinction in the silk industry between pure-dye and weighted silk.

In the pure-dye process, the silk is colored with dye and then finished with any of the following water-soluble substances: glue, sugar, or gelatin. By contrast, in the production of weighted silk, metallic elements are added to the fabric to increase the weight lost in degumming and to add body to the fabric.

We have covered the basic process of rearing silkworms for silk production. If you are thinking about establishing a silkworm farm, the key thing to consider is whether you will be able to access adequate and consistent supplies of mulberry leaves for the larval stages of production. The threads will be soaked together in bundles, inside a pot of hot indigo leaves and water.

This process will occur multiple times over a span of days to ensure proper colour tone and quality. However, these traditional dyeing methods have almost become extinct in the commercial manufacturing of silk. Advances in technology mean that manufacturers instead opt for using various dyes such as acid dyes or reactive dyes. This gives a greater range of choice in colours and shades to be able to serve wider demand.

That being said, the general idea behind the technique remains similar as the silk is immersed in a dye bath to soak up the colour. The silk may be fed into the bath through two cylinders, or fixed to a round jig which is immersed in the bath.

In many cases, this will be one of the last steps of the processes as manufacturers generally now prefer piece-dyeing in an attempt to reduce waste. By holding plain white stock ready to be dyed, it reduces the need to hold too much stock in specific colours that have not been ordered and so may never be used. Here at Biddle Sawyer Silks we hold large quantities of our silks in various colours in order to be able to provide an immediate service with next day delivery on silk we already have in stock.

We also work with clients who provide their own bespoke colour palettes, and are able to match their samples via lap dips. The traditional spinning wheel has always, and will always be an integral part of the silk production process.

Although updated industrial processes are now able to spin silk threads much quicker, it simply mimics the functions of the classic spinning wheel. The process of spinning essentially unwinds the dyed fibres on to a bobbin, so that they lay flat ready for the weaving process. This can be done in many different ways from hand-spinning to ring-spinning and mule spinning. Weaving is the process in which the final piece of silk comes together. There are many different ways in which silk can be woven — satin weave, plain weave and open weave are most common, and the finish of the silk will depend on the type of weave.

Generally, weaving involves interlacing two sets of threads so that they lock around each other and create a strong, uniform piece of fabric. The threads will be woven at right angles to each other, and the two different angles are called a warp and a weft.

The warp will run up and down the fabric, while the weft runs across it. Should a piece of silk require a special pattern or design, it will need to be printed after pre-treatment. This can be done in two different ways: Digital Printing or Screen Printing. Digital silk printing uses a specially designed textile printer, using ink to transfer hand drawn or digitally produced artwork on to fabrics. Screen printing is the traditional, more hands-on method of essentially creating the same outcome — though in some cases, a bolder, more vibrant look may be achieved due to a thicker application of ink.

Read more: Digital Silk Printing — The process explained. In order to be deemed ready for use, silks must be finished. Finishing a piece of silk gives it that highly lustrous sheen that it is so commonly known for, and is the reason that the desired look and feel can be achieved. Silk finishing can be done in many different ways, mainly by applying different chemical treatments which can add a host of valuable properties including fire resistance and crease-proofing. Biddle Sawyer Silks is a leading Manchester and London based silk wholesaler, and the only merchant in the UK with its own state-of-the-art digital printer.

To find out more about working with us or to enquire about our services, please get in touch. Fine quality silks, since How is silk made? A step by step guide. Possibly the most beautiful, delicate and lustrous materials ever created.