Textiles - Processes and Manufacture

For marking and measuring:

• Flexible measuring tapes - to accurately follow curved surfaces.
• Tailor's chalk - transfer marking onto your fabric that you can remove later, e.g. when you're marking out the pattern.
• Pattern master - help you draw paper patterns. Use the curve edge to mark out smooth curves and the parallel lines to mark out extra width for seam allowance.

For cutting:

• Paper scissors - to cut out patterns.
• Fabric shears - to cut out fabric. These have long, very sharp blades that cut through fabric more easily and neatly.
• Embroidery scissors - for more delicate jobs, e.g. snipping threads or clipping curved seams. They have short, sharp blades.
• Pinking shears - to cut fabric with a zig-zag edge which helps prevent the fabric from fraying.
• Craft knives - to cut stencils. They give more detailed and accurate results than scissors.
• Seam rippers - to unpick seams. Less chance of cutting the fabric.

For sewing:

• Pins - to hold the fabric together before stitching with a sewing machine. They help keep fingers away from the needle when you feed fabric through.
• Needles - for hand stitches. Use a needle that is the right size for the thickness of the fabric and the thread you are using.

For pressing:

• Dry irons - use heat and pressure to press creases out of the fabric and flatten seams.
• Steam irons - more effective. They use water and steam as well as heat and pressure.
• Irons can be used to apply designs from transfers onto fabrics.

• Machinery speeds up each stage of manufacture and makes some processes automatic.
• As long as the operators are well trained, machines can improve safety in the workplace, be more cost effective and make quality consistent.
• Machines to transport materials, monitor and inspect production and package finished products assist the workforce and speed production.

Overlockers

• Overlockers are used to finish edges and to stop them from fraying. 
• They do this by enclosing the edge, or edges in a thread casing.
• An overlocker works by using several top threads, but no bobbin.
• It also has a blade to trim the fabric edge before it's enclosed.
• They can be used just to finish seam edges, or to sew, trim and neaten all in one go.
• They can be used for side seams in stretchy clothes like T-shirts.

• CAM machines can stitch designs that are already programmed into the machine. 

One-off production

• An exclusive textile product is made to meet an individual client's specification.
• The product is high quality - it's made by one person or a small team, either by hand or skilled machinists.
• The product takes a long time to make, and the high labour and material costs (as materials aren't bought in bulk) make it expensive.

Batch production

• Is used to make a specific number of identical products.
• Machines can be altered for each batch. This means that the manufacturer can react to specific orders, and a variety of styles can be made.
• Production costs are less than in one-off production. 

Mass production

• Used to make a large quantity of identical products. It makes products that are in continual demand. It is the cheapest system as materials can be bought in bulk.

Mass production is carried out using production lines and sub-assemblies:

Production lines

• As a product is made, it passes through a series of stations.
• At each station a worker or machine operator does a particular job. Then they pass the product to the next station, and repeat their job on an identical product.
• Large numbers of products are made quickly.
• Workers may work on the production line in shifts so that it runs continuously.

Sub-assembly

• A sub-assembly is a separate line of manufacture that can feed into the main production line. 
• Sub-assembly runs at the same time as the main production line, speeding up the overall process.
• It means specialist machinery and specially trained machinists can be used for certain stages, which means there are fewer faults.

Economies of scale:

• The cost of an item gets lower the more of them you produce - this is called economy of scale.
• Materials and components can be bought in bulk which allows manufacturers to negotiate discounts.
• Because each worker carries out a specific task on the production line, semi-skilled or unskilled labour can be used, reducing wages and training costs. Workers repeating the same job over and over again become quick and efficient at it.
• The high cost of machines is spread out over the large number of products that they churn out.
• High-volume production is often done using computer-controlled machines. Using CAD/CAM makes production more efficient, so it reduces manufacturing costs.

Just In Time stock control

• The manufacturer gets the materials and components delivered regularly in small amounts when they're needed, and uses them as soon as they're delivered.
• It saves costs of storing materials.
• It avoids money being wasted through stock going out of date, or unsold finished products piling up.
• However, materials and components must be delivered on time and fault free - there's no time to return poor quality materials or wait for late deliveries.

• It is a good idea to work in a 3D way to explore possible ideas for trying out shaping the product and creating design features - this is called modelling.
• Some designers choose to model in paper - a paper model is inexpensive and can easily be cut to size and manipulated.
• Garment designers use a manikin when testing the model.
• An existing pattern can be altered by hand to make it fit new design ideas and then a toile (a model of a garment often made from inexpensive cotton calico) can be made up from the modified patttern.
• A pattern can also be made through disassembly of an existing product.
• Fashion designers may decide to make their own pattern by modelling with calico fabric on  a manikin - this is known as moulage.
• Designers make samples, toiles or prototypes to test techniques and method of making and to look at costing implications.
• Models try on prototype garments so that the designer can make further adjustments to the pattern to ensure that the fit is correct.

Plain (flat) seam

• Take two pieces of fabric and put the right sides together.
• Pin the fabric together along the seam line, leaving an allowance of 1.5cm.
• Stitch about 1.5cm in from the edge of the fabric.
• Strengthen the seam by reversing over it for a few centimetres.
• Finish the seam edges to stop them fraying.
• Press the seam as stitched and then press it open so it lies flat.

French seam

• Used for fine or sheer fabrics, or fabrics which are likely to fray.
• Place the wrong sides of the fabric together. 
• Pin the fabric close to the seam line. Stitch 5mm to the right of the seam. Press as stitched.
• Trim the seam allowance to 3mm.
• Press the seam open and turn the right sides of the fabric together.
• Fold on the stitch line and press.
• Stitch along the seam line and press as stitched.

Flat fell seam

• This gives strength and decoration to a product.
• With the wrong sides of the fabric together, pin along the seam line and press the seam open.
• Then press both seam edges over to one side.
• Trim the underseam allowance to half its width.
• Turn the upper seam allowance edge evenly over the trimmed edge and pin into place.
• Top stitch along the turned-over edge, removing the pins, and press as stitched.

Overlocked seam

• Strong and quick
• Good for stretchy clothes

Neatening seams

• Pinking - pinking shears are used to cut a zigzag edge along a woven fabric edge. This helps to stop the threads from unravelling.
• Overlocking - an overlocker is used to encase the edges of a fabric. This is an inexpensive way to neaten the seam.
• Hems - hems are used to finish raw edges of a product. The fabric is folded over and stitched.
• Bias binding - when it is essential to cover the fabric edge, bias binding can be folded in half and stitched along both edges of the flat seam. 

Darts

• These are used to fit a garment more closely to the body, e.g. at the waist or bust.
• Fold the dart, right sides together matcing small perforations and stitch tapering to a point at a single perforation.
• Press dart to one side.

Tucks and pleats

• Tucks and pleats are folds in the fabric that can be either pressed or stitched.
• They can be used to control the fullness of fabric, e.g. make a skirt tighter at the waist and fuller over the hips. They can also be used to attach larger pieces of fabric to smaller pieces, e.g. joining sleeves.

Gathering

• Fabric width can be reduced by gathering to give a wavy shaping.
• A couple of rows of stitching are pulled to form small tucks

How to make a simple patch pocket

• Iron the fusible facing to the wrong side of the outer pocket.
• Fold the pocket over so the right sides are together and pin into place.
• Stitch the pocket, leaving an opening for turning it right side out in the centre of the bottom edge.
• Backstitch ends of stitching.
• Trim the corners.
• Pull the pocket through the opening, turning right side out and press.
• Pin and tack the pocket on to the garment. 
• Start to stitch (1cm) from the top right hand corner and backstitch just into garment fabric to reinforce.
• Stitch close to the pocket edge on 3 sides, finishing securely.

Making buttonholes

• A special automatic buttonholing foot is needed for the sewing machine. 
• When cutting open the buttonhole, use a pin and seam ripper to give an accurate result.

The manufacturing specification describes the stages of manufacture and materials needed in order to make the product. It includes:

• product name, description, reference number and date
• working drawing or photo of product
• fabric and component details and samples
• specific tools needed
• pattern lay plan
• instructions for making
• quality control check points
• tolerance levels
• packaging requirements

Tolerance levels

Tolerance levels are given to ensure that when products are made in quantity they conform to a specified range of variance allowed on each process. They might be given for size of a product, seam allowance or for the placement of components.

Quality control checks take place at three main critical control points during the manufacture of a product.

1. Raw materials check - Raw materials are checked to make sure that the right order had been delivered from the supplier, and that the materials are in good condition and meet the product specification.

2. Prototype testing - A final prototype product will be manufactured to check that the manufacturing specification is exactly right. This prototype will also be compared to the design specification to check that all the design criteria have been met. Any problems identified when making the prototype will need to be solved, and the manufacturing specification modified.

3. Production sampling - The manufacturing specification will specify several points in the production process where quality should be checked. At these points, a sample product is taken and checked to make sure it matches the product specification. If there is a fault then modifications need to be made.

You can use CAD to:

• Produce mood boards
• Draw and annotate your initial and final design ideas
• Design logos, stencils, fabric prints and transfers. The design can then be manipulated on screen and used to produce 'virtual reality samples'
• Model your design in 3D
• Communicate with your client
• Draw the pattern pieces for your design and work out how best to lay them out (the pattern lay plan) to minimise waste
• Calculate how to change a pattern to make different sizes of a garment (pattern grading)

CAD/CAM is used a lot in industry:

• Computer-aided manufacture (CAM) is the process of manufacturing products with the help of computers.
• CAM is usually linked with CAD. A product is designed using CAD, then information from the CAD software is used to manufacture the product using CAM.

CAM is used in:

• Pattern design, grading and pattern making
• Pattern lay plans are worked out in the most efficient way to reduce wastage
• Digital printing onto fabric
• Computer controlled weaving looms
• Individual seamless knitted garments 
• Automatic spreading of fabric and cutting out
• Sewing machines can be programmed to perform tasks such as making buttonholes and attaching pockets
• LAbelling

Advantages of CAD/CAM:

Design development:

• Different designs can be quickly and cheaply modelled and compared on-screen.
• Changes to a design can be made quickly and easily.
• Designs can be sent quickly across the world via email.
• Computers can be used to work out the best way to arrange pattern pieces on the fabric, so that waste is minimised.

Manufacture:

• CAM machines speed up production processes - processes can be done automatically, much faster than people could do them manually.
• Machines controlled by computer are more accurate then if they were controlled by people. Computers can monitor quality too. Consistent, higher quality products and less wastage.
• CAM machines don't need people to control them so they cut labour costs.
• Workers aren't directly using dangerous machinery so it's safer for them.
• Computers can be used to control stock levels, saving time, labour and storage space.
• Computerised machines can transport materials around factories, saving time and labour.

Disadvantages of CAD/CAM:

• The initial cost of software and hardware is high.
• Workers need training in how to use CAD/CAM and this can be expensive.
• Viruses, corrupt files and power cuts can destroy work.