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Textiles: Manufacturing techniques - EduqasVisual checks and tolerance

In the textile and clothing industry fabrics are dyed, printed and finished before being cut, assembled and shaped by machine operators. For the garments to fit, accuracy in construction is important.

Part of Design and TechnologyIn-depth technical principles

Visual checks and tolerance

The best way to ensure the quality of a finished product is to visually check the accuracy and quality of what has been made. These are called checks.

Quality control checks might be carried out:

  • before manufacture to ensure fabric has no faults or misprints
  • during manufacture to ensure seams are sewn straight, stitching is even in length and neat
  • after manufacture to ensure components are sewn on straight and sewing is strong

Although quality control checks can increase waste, with faulty products being thrown away, if a factory develops a reputation for being reliably high in quality, money is saved in the long term through products being reordered.

In a manufacturing , quality control checks are placed as decisions in diamonds to show where a step would need repeating if there was a mistake:

A flowchart for quality control processes within textile production. Once the pattern has been cut out, is it accurate? One the side seams have been sewn, is the stitching straight?

Preparation

The following factors need to be considered before garment assembly commences and form part of a factory鈥檚 procedures, intended to ensure that a manufactured product meets the specified requirements of the client or customer:

  • stitch length
  • stitch type
  • stitch tension
  • pressure foot type
  • thread type

Accuracy

in textiles is the amount of acceptable variation from the specified measurement from which you can cut out pattern pieces, add or sew seams.

is the amount of material between the edge of the fabric and the seam, and it is tested to check it meets the tolerance stated in the . In home sewing, seam allowance is generally 1.5 cm, whereas in industry, to save on fabrics, the seam allowance is often 1.0 cm. The is always minimal - otherwise the product won鈥檛 fit together.

Some seams become bulky once sewn, eg points of collars, and they need to be trimmed so that once and pressed they will sit flat. Trimming of seam allowance is also necessary on curved seams.