The value of the quality

Silk

Processing cycles

The cycle can be broken down into two phases: preparation operations and reeling operations.

    The preliminary operations are:
  • removing the fluff: the cocoons are separated from the “fluff”;
  • selection: it separates the flawed cocoons besides dividing them into different categories that must be as homogeneous as possible in terms of colour, quality and grain for the next processing cycle. The best cocoons are the “royal” ones;
  • sifting: this divides the cocoons according to size, letting them go through specific adjustable sieves so as to obtain the various counts.

Analysing reeling, there is a first phase called “soaking”, where the cocoons are sent through into other tanks with heated water. Soaking softens the first layers of the cocoon's silk sheath so that the work of the brush, searching for the yarn lead-in, is not prolonged which would produce far more waste and reduce the yield. After soaking, the cocoons are transferred to a container where they are ready for the thread to be extracted.

Searching for the end of the filament is called "brushing" and is done with a large brush. In the next phase it is fixed to a reel which turns continuously to form hanks. This is the true reeling operation: the yarn twists, rubbing against itself and on the neighbouring yarn which squeezes out up to 70% of the water content. This makes the yarn more compact and improves the regularity of its section, reaching a higher final tension.

Once the yarn has been reeled into a hank it is then dried simply by the circulation of air at 35°. Rewinding is the next operation, its purpose being to remove everything from the yarn that contrasts with its cleanliness. Another phase of the processing cycle is doubling which consists of coupling a number of yarns coming from the same number of bobbins to form a single yarn.

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Twisting then follows which, besides given the yarn greater strength, is useful to prevent the silk getting tangled in the next operation called degumming which eliminates the silk gum that joins the two silk filaments.

By twisting, spirals are formed that keep the two filaments joined that make up each single thread of silk. Twisting affects the shininess of the threads, decreasing as the number of spirals increases such to give a dull effect. Being able to vary the shininess of the silk thread with the number of twists is used to advantage in weaving to achieve certain optical effects in the fabrics.

Raw silk reaches twisting in the shape of a hank. By undergoing different treatments different yarns are obtained that will be used to make items such as foulards, shirts, ties and even wedding dresses. The first processing phase is a bath of natural substances which are the secret ingredients of each company, to make the yarn softer and easier to work with. The hank is then sent to the winding department where the yarn is wound onto a bobbin and then loaded on the twisting frame.

Steaming and winding then follow where the yarn goes from the bicone to the package. The next making-up stage is handled by cutting edge machinery that, by means of the clearer function, purifies the yarn removing any imperfections. The length, antistatic treatment and precision cross winding facilitate and prepare the yarn for the next dyeing and weaving operations.