fabric_form and flat pattern cutting_ designing patterns

© Technical University of Liberec 2009

FABRIC, FORM and FLAT PATTERN CUTTING, DESIGNING PATTERNSBlazena Musilova, FT TU Liberec, Department of Clothing Technology

E-mail: [email protected]

FABRIC, FORM AND FLAT PATTERN FABRIC, FORM AND FLAT PATTERN CUTTING, DESIGNINGCUTTING, DESIGNING PATTERNPATTERNSS

Close fitting garments made from stretch and jersey fabric, these blocks are constructed to be smaller than the body measurements and to the body shape. Some adjustments to the horizontal measurements may have to be made, this should be related to the stretch and relaxation of different fabrics. Most designs in stretch fabric are simple modification of the basic blocks.

The examples in this chapter demonstrate some particular techniques.




Knitted fabric will stretch and mould around the body. Consequently, the amount of ease allowance can be reduced. How much reduction depends on the elasticity of the fabric. The final pattern production may have to be modified for a specific fabric.Weft knitting is more extendable across, in the weft direction warp knitting is firmer. Woven fabric with a blend of elastan (Lycra) can have the ability to stretch in either the warp or weft direction or both.Clothing pressure is a combination of garment, human body and the mechanical interactions between them. True fitting tight - fit sportswear to the body shape can only by achieved by the use of a stretch fabric, which can expand and contract without buckling or wrinkling to accommodate body movement.

Mechanical properties of the fabric




31.6 %

18.6 %

Back part Front part

The Swimsuit final pattern modification

80% PA, 20% EA

F…te

nsile

forc

e[N

/m]

E…tensile strain [%]

80% PA, 20% EA

E…tensile strain [%]F…te

nsile

forc

e[N

/m]

Weft

Warp

stretch

relaxation




Therefore, the mechanical properties of knitted fabrics are defined taking into account the allowed limit of compression influence on human body.

Compression law

Compression(*) Compression law hPa mmHg(**)

Ccl A Light 13-19 10-14 *) The values indicating pressure, whereby reacts garment on hypothetical cylindrical shape of the body part. **

millimetre of mercury 1 mmHg = 1,333 hPa

Fabric - Fibre content (%) Weight[g m-2] F [N] Compression

[hPa] E [%]

PL 67%, PL Coolmax 27%,Lycra 6% 187 2,17 18,56 22,17

PL Coolmax fresh 63 %,PL 33 %,Lycra 4% 102 2,13 16,06 32,29

PL Coolmax 57%,PL micro 37%,Lycra 6% 251 2,16 18,8 24,31

PL Coolmax 60%, PL micro 40% 208 2,16 18,83 20,5

PA Supplex 92%, Lycra 8% 268 2,1 16,24 35,06

CO 90%, Lycra 10% 210 2,15 17,89 25,76

CO 90%, Lycra 10% 271 2,14 18,95 18,13

F…te

nsile

forc

e[N

]

E…tensile strain [%]




1

3

4-5

31-2

cd

0.05 hg+1.5

0.05

hg

+30.

5 lli

-0.1

lli=

x0.

5x

0.25 hg 0.25 hg 0.1 hg

y y

2 2

11

0.5 cg 0.5 cg

0.5 ag 0.5 ag

llo

6-8

The resultant value application in the construction procedure

of tight - fit sportswearBy means of the percentage valueof currently selected knitted fabric elongation the block pattern construction shape of a designed tight -fit sportswear e.g. pair of trousers etc. can determined. Value of elongation within the range 18-35% is applied to body dimension modification as construction input parameters.

Body dimension

[cm]

E [%] Modified girth dimension

[cm] Waist girth (wg) 97 24 73.4 Hip girth (hg) 105.6 24 80.3 Calf girth (cg) 40 24 30.4 Ankle girth (ag) 28 24 21.3 Fabric: PL Coolmax 57%, PL micro 37%, Lycra 6%

(llo) – outside leg length, (lli) – Inside leg length(cd) – Body rise (Crutch depth)




Shape of the body parts

Body shape is an important influential factor towards clothing pressure as greater degree of curvature, the greater pressure exerted.

Type of the fabric used

The amount of pressure, which measured in mmHg (millimeter of mercury) has been found on vary in body locations when garments were made of different types of fabrics.

Design and fit of the garment

Garment fit and pressure comfort play an important role in clothing comfort, especially in the case of tight -fit sportswear.

DesignConcept 3D

Foto:www.sport-invest.cz

Input parameters for Sportweare design

There are three factors, which influence the pressure exerted by garments:




Seven extreme body postures causing changes of 18cm, 24cm, 21cm, 22cm, 27 cm, 16cm and 22cm respectively, relative to a neutral position (Lotens, 1989)

Body dimensionsHumans have to function and move unrestricted in clothing systems.




x(s) - Measurement of body at restx(d) - Measurement of body parts

in motionDynamic factor in percentage

Static Dimensions - measurements of the body at rest.Dynamic Dimensions - measurements of body parts in motion.

- Dynamic factor

α

Ergonomics of movement

Human Tools

Environment

INPUT OUTPUT

Sport performance

Ergonomic research is performed by those who study human capabilities in relationship to their sport demands.

Information derived from these studies contributes to the design and evaluation of tasks, products, environments and systems in order to make them compatible with the needs, abilities and limitations of people.




wg

hg

ng

bg

ta

nw

bw

Easy Fitting Blocks for Jersey WearBlock for Tee Shirts

Measurements required to draft The Block 1.5

y/4 0.75

A

B

B´

A´

A´B´=AB +2,5

0.75

2.0

0.2ng+1

ta+1

=x x/2=

y0.

2ng-

2

nw+1

fl=(n

w+t

a)bw+1

0.25 bg+2.5

0.33 A´B´

x/2

sl

0.5 wtg

wtgsl

Cen

tre li

ne fo

ld




r

sleeve

back

blocks

Cycling Jerseys pattern design

50°

dynamic effect =10% of measurement :

Nape to waist

cent

reb a

c kc e

n tr e

fron

t

front

sleeve

10% of nw

-12 % of bw

Armhole

B1

B7

B3

B5

0,84 [rad]

1,08 [rad]

1,22 [rad]

Back

Front

π [rad]

34,38 %

13,38 %

38,84 %

+8 %

-12 %

H3´

H5´




System of ease allowance

The type of fabric has a great influence on the amount of ease allowances pi for:

body movement, expansion comfort.

The dimensional stability of the fabric is an important factor. The more stable the fabric, the greater the ease allowance. This depends on whether it is:

woven, knitted or non-woven.

Constructional abscissaABi(w) = ki * Bi + ai + piABi(w) constructional abscissaki regression coefficientBi body dimensionai absolute termpi allowance

e.g. for woven fabric:Basic formula for front width:fw (front width)= 0.24*wg+(-1,5)+2,5

e.g. for knitted fabric:Basic formula for front width:fw (front width)= = 0.24*wg+(-1,5) -2,5

The system of the ease allowance can be defined as a complex of influences effective in the shape and dimensions constructed clothing. A B

BA

CK

B

OD

ICE

FRO

NT

BO

DIC

E




MEASUREMENT BODY SIZE DRESS SIZE DRESS SIZE SKIRT AND TROUSERS SIZE BLOUSE 12 ´8 - 16 16 - 24 ´8 - 24 ´8 -24

bust girth 88.0 4.0 to 8.0 5.0 to 10.0 - 4.0 to 10.0 waist girth 70.0 4.0 to 5.0 5.0 to 6.0 2.0 to 4.0 4.0 to 10.0 hip girth 96.0 4.0 to 5.0 5.0 to 6.0 4.0 to 6.0 4.0 to 6.0 neck girth 38.0 2.0 to 3.0 3.0 to 4.0 - 2.0 to 4.0 across back width 35.0 2.0 to 4.0 3.0 to 5.0 - 2.0 to 4.0 across front width 32.0 2.0 to 3.0 3.0 to 4.0 - 2.0 to 4.0 upper arm girth 28.0 5.0 to 6.0 6.0 to 8.0 - 4.0 to 8.0 elbow girth 26.0 4.0 to 6.0 6.0 to 8.0 - 3.0 to 8.0 wrist semi-fit 16.0 6.0 to 7.0 6.0 to 8.0 - 6.0 to 8.0 wrist fitted 16.0 3.0 to 4.0 3.0 to 4.0 - 3.0 to 4.0 depth of armhole 21.0 2.0 to 3.0 3.0 to 4.0 - 2.0 to 5.0 thigh girth 57.0 - - 8.0 to 12.0 - knee girth 37.0 - - 9.0 to 15.0 - ankle girth 25.0 - - 8.0 to 12.0 -

Chart: Suggested minimum ease allowance to be added to the body measurements for women´s block patterns in woven fabric (measurements in centimetres). Size range 8 to 16 and 16 to 24

Blouse




Corporate cultureLife style subculturesHistorical contextMilitary research and development

ProtectionAnthropometryErgonomics of movementThermo physiological regulationPsychological considerations

Duration of activitySafty/SurvivalRange of likely sporting conditions

Cut/Fit/ProportionMaterialsColour

Team/club/Co-identity

Commercial/legal concernsCommunicatio Hero/Fan culture

FashionCode of tradition/etiquette

History, Past heroesHuman factors, Product function, New technology

Contact/Non-contact sport

Environmental conditionsSenses, Health/Safety

Measurement of body

Predominant patternsand posture, Agility

Heat dissipation, Heat retention, Workload, Ambient conditionsAppearance/StyleReliabillity/perceptions of reliabillity

Short, Medium, Long

Rules of governing bodies, Protection, IdentificationLocation, Season, Climate,Transportation

Garment construction,Cutting for movement, Sizing

Fibre types, Yarns, Fabric selection

Mood, Safety, Commercial considerations, Environmental impact

Form/Style

Function

Aesthetics

Culture of the sport

Demands of the body

Demands of the sport

Information tree to guide the design research process for performance sportswear designers




Major international sports trade fairs where leading fibre and fabric producers and garment manufacturers promote new developments for the sportswear




Production patterns

Seams, hems and facings are required to complete a garment pattern for production. The pattern technologist has to be aware of all the factors that influence the completion of the patterns, such as:

the end use of the garment, the design, fabric, production methods and cost.

The pattern construction techniques, creating pattern shapes of the:

Shell patternLining patternInterlining pattern




Seam allowancesThe seam allowance is the distance from the stitching line to the perimeter of a cut garment part. The amount of seam allowance can vary greatly according to:

(1) The position of the seam and how much stress it has from body movement, e.g. an armhole and sleeve head (minimum allowance 1 cm).(2) The curvature of the seam influences the seam width, e.g. the curved seam of a panelled bodice requires a narrower seam where convex and concave curves have to be joined together (maximum of 1cm). (3) Enclosed seams require a narrow seam allowance, e.g. the faced neck and armhole (maximum of 0.7 cm). (4) The type of machinery required for stitching

the seam influences the seam allowance widthe.g. a flat felled seam

(1)

Flat Felled Seam

(2)

(3) (2)




(5) The type of fabric often determines the width of the seam allowance and how it is neatened e.g.:- loosely woven fabric - sheer fabric - thick fabric - stretch fabric (6) A wide seam allowance is required for inserting a zip fastener, e.g. skirt placket (1.5 to 3.5cm). Wide seam allowances, known as inlays, are also required where a garment is specifically constructed for altering and letting out (1.5 to 3.5 cm).

Seam for loosely woven fabric

Seam for thick fabric Seam for stretch fabric

Wide seam allowances

Seams for sheer fabric




The type of corners at the intersection of two perimeter lines can be varied according to the method of production, the type of fabric and whether notches are required. The selection and method of changing these types of corners will vary according to the different computer systems. The following examples are a selection of the most often used corner types:

A mitred corner

Mirrored corners are used where a seam is pressed open and the contour of the intersecting perimeter line is continued.Square corners can be used where the seam is pressed in one direction. A mitred corner is clipped off straight and perpendicular to the corner to remove excess fabric. A shaped corner removes more excess fabric by clipping off a double mitred corner.

Mirrored corners Square corners

A shaped corner




Hem allowanceThe shape of the hemline influences the width of the hem allowance. A straight hem lies flat when folded back so the hem can be quite wide. Curved hems do not lie flat when folded back and therefore the hem width has to be reduced. The corners at each end of the hem also have to be considered so that the turned up hem mirrors the intersecting seam.

Straight hem Straight hem with mirrored corners

Circular hem




Facing

A facing neatens the edge of a garment. It can be an extension of a garment part or cut separately. It is generally concealed by turning underneath to the inside of the garment. It can also turn back to be revealed on the face side.

Facing a buttoned openingExtended facing

WS

faci

ng

Facing a buttoned opening Extended facing

B- button diameter

B

ButtonstandC

F

B

B




Easy allowance is required on linings for two reasons.

Cloth garment pieces „spread“ a little when they are cut out. Extra ease allowance is required on linings because lining fabrics do not relax in the same manner. The amount of ease required will vary depending on the cloth used for the garment.

The lining should also be loose enough to prevent the garment being pulled out of shape when the lining is inserted. Particular stress points are the armholes and the centre back.

Note: Some bespoke tailors cut linings from the cloth pieces of the garment, specific ease is then added at the stress points.

Lining the Suit Jacket

fabric_form and flat pattern cutting_ designing patterns

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