Needle with eccentric point

Stitching technique

“Invisible” seams(blind seams) can be optimally stitched for a host of different types of material using special blindstitching needles.

Product:

Curved formEcentric point on the outer curve of the needle

Blindstitching needles are characterized by :

Demand	Schmetz blindstitching needles
Exact,punctiform”blindstitching” Of the woven / knitted materials   Greater stability Correct positioning of the needle Reliable guideance of the thread Loop(no skipped stitches)	Eccentric,slim point     Square blade cross-section Flattened shank   Narrow eye.

 

Choosing the right needle size:

Material	Needle Size NM                                      SIZE
Woven fabric Light ( Shirt/blouse material) Medium ( Suit material) Heavy ( Coat material)	60-90 70-100 90-110	8-14 10-16 14-18
Knitwear Fine coarse	60-90	8-14
Densely woven material (microfibers,silk)	60-80	8-12

 

Needles for avoiding specific sewing problems

Materials and stitching techniques with special demands

Optimum seam quality can usually be achieved by choosing the right point form and needle size to match the respective materials andstitching techniques.Some materials and stitching techniques,e.g.:

Materials:

Ø  Elastic material

Ø  Materials with a high man-made fibre content

Ø  Densely woven material,e.g.microfibres

Ø  Insufficient finishing of the material (low atmospheric humidity and extreme differences in temperature)

Stitching technique:

Cross seams

Very high sewing speeds

+/- 5,000 stitches/min

can cause sewing problems despite choosing the right needle.To deal with these sewing problems,schmetz has developed special needles whose use is determined by the sewing problem involved.

Applications:

Ø  Highly elastic materials

Ø  Layers of different materials

Ø  Cross seams

Ø  Elastic threads.

 

Needles for avoiding skipped stitches

Sewing problem

Occurrence of skipped stitches:

A skipped stitch occurs if the needle thread and bobbin thread(s) are not looped.

Effect:

Ø  Reduction of seam strength

Ø  Unravelling of the entire seam with double chain stitching

Ø  Poor seam appearance

Ø  Thread breakage after the skipped stitch in many cases.

 

Cause of skipped  stitches:

Material and stitching

Highly elastic materials:

(e.g.manufacture of brass,bodies,corsetry,bathing suits): Owing to its high elasticity, the material flutters during stitching. This movement causes the loop to be pulled along with the material during the upward stroke of the needle or reduced to such a size that the hook can no longer grip the loop.

Layers of different materials:

(e.g.manufacture of waistbands) The various layers of material flutter under the presser foot.The layers of material not held by the presser foot pull the loop along with them or reduce the size of the loop during the upward stroke of the needle,meaning that the hook can no longer grip the loop.

Cross seams:

(e.g. manufacture of jeans) with this type of stitching,the fluttering is caused by the transitions from thick to thin (thin to thick) layers of material.The layers of material not held by the presser foot again pull the loop along with them or reduce its size to such an extent that the hook can no longer grip the loop.

Needle deflection:

The needle is deflected from its correct piercing path by the structure of the material

 

Thread

Elastic threads:

The high intrinsic elasticity of the thread often prevents optimum loop formation.

Product:

Schmetz needles of SERV 7 design

Demands: Optimum loop formation

Needle stability

Special needles with pronounced scarf(hump between eye and scarf) and reinforced blade.The hump between eye and scarf pushes the loop much further out so that the hook can reliably grasp the loop,regardless of the material and thread properties.

The reinforced blade gives the needle the necessary stability to prevent deflection

 

Needles for avoiding needle and eye smearing

Sewing problem:

Complete needle and eye smearing with low softening points/melting points

Effect:

Ø  Thread breakage

Ø  Skipped stitches

Ø  Untidy seam

Cause

High sewing speed/high friction heat the needle.with materials with a low softening point/melting point,melt residues occur with stick to the needle.

Man made materials

Materials with a high man-made fibre content

Materials with special finishing (e.g.colour,modifications of textile threads or surfing as regards wear and care properties)

Products:

Schmetz Bulkold needles

Demands:

Little or no adhesion of melt residues on the needle.

Special needle with roughened, phosphorated surface & subsequent Teflon coating. Melt residues do not stick to this coating at all,or only much later than on chromium-plated needles for example. The needle remains clean for longer-skipped stitches and thread breakage are avoided.

 

Special Needles for button Sewing

Trouble free button sewing is determined by the following factors:

Ø  Correct machine settings

Ø  Correct needle point/size

Ø  Correct positioning of the button

Ø  Correct sewing thread.

Product:

Needles for button-sewing must meet the most stringent demands.

Demand	Schmetz special needle for button-sewing
No damage to button No needle breakage		Special point STU point
No damage to inserted sewing thread		Special point STU point
No damage to end product No needle breakage		Special point STU point
Centring of the needle in the button holes Is of decisive importance for the quality of the end product		Particularly straight needles

 

Choosing the right needle:

Ø  Type of machine

Ø  Material

Ø  Thickness of sewing thread

Ø  Diameter of button holes

 

Determine the choice of the right needle system and the right needle size,

Choosing the right point form:

Material	Point
Woven Fabric   Knitwear   Fine Medium Coarse	STU     STU SUK SUK

 

Choosing the right needle type:

Machine	Needle type
Button-sewing machine For single-thread chain stitch Double lockstitch	Needle with round shank ; Needles with special point for button sewing.
Button-sewing machine For Imitation handstitching   Needle with two special points and an eye in the middle(central-eye needles).The needles and the measured thread length pass through the entire material during each stitching and form the imitation handstitch	Double point needle

 

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