MOULDING

Fibres, Fabrics, Foams, Moulds A fibre can only be moulded if it can be heat set. Moulding a fibre is to stretch it to a new shape take it to a higher temperature for a given time and the fibre will then remain in that new shape even after washing. Natural fibres cannot be heat set. Cotton, viscose, modal cannot be heat set.

Fibres, Fabrics, Foams, Moulds Man made fibres can be heat set to differing degrees. Elastomeric - fully heat set Polyester- fully heat set Nylon- partly heat set Nylon 6.6- better Nylon 6- worse

Fibres, Fabrics, Foams, Moulds Therefore To achieve some degree of setting with fabrics made from fibres that do not heat set we mix them with fibres that will heat set. But We need to have a maximum percentage in the fabric of a fibre that will heat set.

Fibres, Fabrics, Foams, Moulds Guidelines Elastomeric or Polyester Cotton with 12% 60% Nylon with 12% 40% But

Fibres, Fabrics, Foams, Moulds Cotton / Viscose, Modal will yellow at the high temperatures required to set the elastomeric. Viscose & modal will yellow quicker than cotton Therefore Viscose and modal cannot be moulded successfully.

Moulding The fabric is stretched to a pre-determined shape and subjected to heat and pressure for a given time. The pressure, heat and time can be varied according to the fibre combination, the weight of fabric, the degree of stretch and modulus in the fabric and the size of mould being tested.

Moulding Time is not a substitute for temperature.

Moulding The fabric must be taken above the temperature used to set the fabric during the heat setting stage of fabric processing, we must break the previous memory of the fabric dimensions. A typical mould temperature for a Nylon Spandex would be about 195c for 35secs at 4 bar pressure.

Fabrics for moulding To determine whether the fabric is satisfactory for moulding we first select a large size mould and make a plastic hat that fits to the shape of the mould exactly. The fabric is then moulded in the same mould and if we have a good fabric it will fit exactly to the shape of the mould. The fabric movement is then monitored until it is stable, this can take 1 minute or 10 days.

Fabrics for moulding The best fabric construction for moulding is a two way stretch with equal stretch in both length and width direction. The correct degree of stretch depends on the bra size you wish to mould and what function you wish that bra to perform

Fabrics for moulding Not enough stretch and you cannot mould the large sizes. The fabric will not stretch to reach the mould height required. eg, 34B you may mould at anywhere between about 45mm and 55mm but a 40D will require a mould height of about 80mm.

Fabrics for moulding If there is too much stretch so that there is a lot of stretch left in the fabric after moulding the moulded cup will not give enough support, particularly for the large size. The weight of the bust is enough to stretch the fabric. You need stretch but with modulus.

Fabrics for moulding Too much modulus and you require too much power to stretch the fabric and the mould will not retain its height after moulding. We need stretch but with some degree of modulus.

Fabrics for moulding Many fabric constructions can be moulded even if the stretch is not even in length and width but with varying degrees of success. A fabric with high stretch in one direction and little stretch in the other can give pleating around the circumference of the mould at large sizes. The fabric can therefore be moulded for a small size

Fabrics for moulding Polyester is an exception to all these rules because it can be completely heat set, it will therefore mould well even if there is little stretch in the fabric.

Fabrics for moulding If the fabric is of the best fibre combination you may still find that you cannot control it after moulding because the construction has a low stitch density. The fabric will continue to grow after it has been moulded. The construction is too loose.

Fabric Finishes The best fabric finish is one that is stable at high temperatures, moulding temperatures. Most silicone finishes will yellow on moulding and also will flash-off during moulding. The best option is to ask for a fabric without a finish but if you using a tight construction you may find that the fabric will have damage at sewing.

Moulds and Mould Machines Moulds are made in two sections male and female. The male is fitted to the upper section of the machine and the female the lower section. The female mould is stationary and the male descends to fit with the female mould.

Moulds and Mould Machines The first principal is to decide if you wish to use a mould with a hollow female or a mould with a solid female.

Moulds and Mould Machines The moulding technique used for a hollow female is to stretch the fabric round the male mould, The male mould is heated and the heat from the female mould is applied indirectly. There is not any pressure applied to the fabric during moulding.

Moulds and Mould Machines The solid female principal is quite different. Here the fabric is sandwiched between two moulds, the male and the female. Both moulds are heated, the fabric is in contact directly with both moulds and therefore there is a direct heat transfer to the fabric under a given pressure. The two moulds are made to fit together so there is a limit to the variation that can be achieved in mould height from the same mould.

Moulds and Mould Machines The advantage of the hollow female is price and flexibility. A hollow female mould can be used with more than one size of male mould and the choice of mould depth that can be achieved has a greater range. Also the mould is cheaper to make, less metal, less machining time and less accuracy of fit is required between the male and female moulds.

Moulds and Mould Machines The mould shape can be according to your design. The cost of making an alluminium mould is about 2000US$. One bra style will be made in a range of sizes. A small range will include 5 different size moulds to make a range of 8 size garments and a larger range can be as many as 10 different mould sizes to make a range of 17 different size garments. The cost therefore of making your own mould shape for each style would impact heavily on the cost of the garment. That cost being greater per garment for the smaller order quantity.

Moulds and Mould Machines To minimize the cost of the garment we often use available mould shapes. We do two types of fabric moulding for bra’s For a 100% fabric bra, the moulded fabric is creating the shape you desire. To cover a foam pad, the foam pad is the lining and the foam pad is creating the shape of the bra, the fabric is purely covering that shape.

Moulds and Mould Machines Moulds largely fall into three categories Bullet Tear drop Slopper

Moulds and Mould Machines 1)Bullets can be many different shapes, some more pointed than others. An internationally recognized shape would be a simple symmetrical gradual curve.

Moulds and Mould Machines 2) Tear drop moulds have been internationalized by a company in Germany who have exported their products all over the world and now many people use the same terminology. Form, 24,and 25. Form 24 and 25 are asymmetrical tear drop shapes and Form 25 is slightly more pointed than Form 24. The same company do market a bull shape which is called Form 23.

Moulds and Mould Machines 3) Sloppers are asymmetrical bullet type shapes or tear drops without the tear drop.

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