Magazine July 2015

Focus on the textile world: from batteries to artificial turf

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Selecting the right needle

For the processing of knitted and woven fabrics

Seams on clothing have to remain intact. That held true when clothing was primarily protective in its function, and still applies today in an era where fashion trends and functionality play a far greater role. As a result, seams have been given new tasks: They not only have to satisfy additional aesthetic requirements; an increasing number of different materials are also being processed today, some of which are very fine and delicate. Hence the demand for many different needles which process material gently. Groz-Beckert offers a wide range of sewing-machine needles – and to find the ones among them that are "right" for the respective application, it is important to be aware of the three most important selection criteria.

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Finding the right needle system

The first step is selection of the right needle system. This is generally determined by the machine used and the sewing operation selected. Here, the technical dimensions of the needle – i.e. the overall needle length, the length of the needle from end of shank to eye, and the shank diameter – all play a decisive role.

Within every needle system there are variants, enabling users to adjust the parameters to suit their specific requirements. The following criteria have to be considered:

  • What is the most appropriate needle size?
  • Which point style is most suitable for the material used?
  • Is using a standard needle sufficient, or is the use of a special application needle (SAN® needle) required?

Selecting the right needle and thread size

For the selection of needle size, the principle applies: The needle should be as thin as possible and as thick as necessary. During the seam test, the needle size to suit the respective material can be identified in three steps:

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Step 1:

Slight pulling and shearing movements expose material damage.

Just an imageRed fabric that shows little holes right beside the seam

Step 2:

If the fabric is damaged, the test continues with the next smaller needle size.

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Step 3:

If no more material damage can be seen, the correct needle thickness has been found.

To obtain an optimum sewing result it is also very important to use the correct thread thickness. The selection should always enable smooth movement in the eye area. If the thread is too thick, problems such as thread breakage or skipped stitches can arise. The correct ratio of needle thickness to thread thickness can however be established by means of a test – as in this diagram:

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If the needle thickness and thread thickness are right, the needle glides smoothly down the thread.

Recommendations for suitable cloth points

In the processing of woven, knitted or felted materials – as opposed to leather – cloth points are used. These displace the material on entry, ensuring that the fabric is not damaged.
The available ball point shapes are RG, FFG, FG and SKL, and the round points offer the variants R and RS (see data sheet "Cloth points"):

Generally, the following recommendations can be made:

Fine knitted fabricsFine woven fabricsRecommended point
  • Fine interlock
  • Multihead embroidery
  • Sewing buttons
  • Multihead embroidery
  • Standard chainstitch
  • For material damage
  • Single- and ribknit
  • Fine and ultra-fine knitwear with elastane
  • Fine to very fine woven fabric
  • In case of material damage
  • Knitwear with higher proportion of elastane
  • Fabrics with openwork structure (tulle)
  • Warp-knitted fabric and corsetry with bare elastane yarns
  • Straight seams
  • Lockstitch
  • Extremely straight seams
  • If prone to stringing in lockstitch seams

To guarantee process safety, it is also imperative that the point is regularly checked and exchanged in good time. Check the needle point by pulling it gently over a fingernail. If scratch marks are visible, the needle has to be replaced.

Special application needles: Yes or no?

Many applications and a variety of materials make very different demands on sewing-machine needles. However, standard needles cannot always meet special requirements. For this reason Groz-Beckert offers a number of special application needles (SAN® needles) for the processing of apparel fabrics. Their geometry has been optimally adapted to the relevant applications, and guarantees even higher process reliability:

  • SAN® 10 / SAN® 10 XS: needles for fine and very fine woven and knitted fabrics
  • SAN® 6: needles for jeans and other heavy materials
  • MR: needles for multidirectional sewing
  • SAN® 1: needles for embroidery with higher stability and titanium nitride coating (GEBEDUR®)

What should be done if application problems arise?

There are numerous causes of sewing problems, and they cannot always be solved merely by using the right needle. Recommendations and possible solutions for typical application problems will be presented in an upcoming edition of this magazine.

Success with the right partner

If you rely on Groz-Beckert as a partner, you can be certain you will always get the right needle. With an extensive and specialized range of products, a variety of point styles, and SAN® needles, tailored to special requirements, Groz-Beckert offers the right product for every application. Should application problems arise nevertheless, the Groz-Beckert experts are available worldwide and will gladly assist you at any time.