2.7- accuracy in design and manufacture Flashcards
(30 cards)
why is a high level of accuracy needed?
to ensure the final products are constructed according to the agreed standard and perform well
what is tolerance?
The acceptable variation in the size or part of a product, usually given as an upper and lower limit. for example, between 5mm and 15mm and are written into the manufacturing specification
what is usually the lower and upper limit in a tolerance?
5mm to 15mm and this is written into the manufacturing specification
what do tolerance levels determine?
the accuracy of construction but will vary depending on the required performance of a product
why is setting very fine tolerances for textiles less important?
Because it can be very difficult to achieve an exactly accurate tolerance level
what fabrics are the hardest to work with to keep within a tolerance level?
knitted fabrics and fluid fabrics which have a lot of give and change shape/distort slightly during cutting and handling processes such as sewing.
when are finer tolerances set?
bespoke and made to measure garments as a high level of precision is essential for the final fit to ensure it fits the customer perfectly
what is the difference between low and fine tolerance levels?
Low tolerance allows for a wide range of variations in dimensions and is used in garments where high precision is not critical, such as rough construction, large assemblies or cost sensitive projects
fine tolerance allows little deviation from the specified measurement and is used in garments where precision is critical.
what are the advantages of fine tolerance?
-ensures high accuracy of a product and that it fits the customer or intended size precisely (this is essential for one-off production)
what are the disadvantages of fine tolerances?
higher cost and more difficult to produce
what are low tolerances used for?
cutting and construction of sections that must fit together successfully, for example on waistbands or skirts
what products can have low tolerances?
Products where precise sizing is less important, for example soft furnishings such as cushions and curtains are constructed to quite high tolerances.
what are pattern layouts used for?
working out how to calculate the amount of fabric required, and to take into account the most efficient way of cutting out the pattern pieces
what will commercial patterns include?
commercial pattern will include pattern layouts for different fabric widths and to accommodate one-way designs and fabric with a nap
if you are making your own pattern templates?
that you have included seam and hem allowances or allowed for them on the pattern layout.
what is the typically size/width of seam allowances?
15 mm (1.5cm)
the typical seam allowance in garments is 1.5cm, what is the exception to this?
in commercial and large scale production will be slightly less to allow for more economical use of fabric/materials
what is the benefit of using a cutting table?
a large table or flat surface will help you cut out the pattern pieces more accurately, and you will be able to try out different arrangements to achieve the most economical fit.
what are alternative’s to tailors chalk?
Tailor’s tracing paper and a tracing wheel, but this can leave marks on both sides of the fabric, which are more difficult to remove
what are tailor’s tacks?
a temporary stitch used to mark out seam lines, dart positions or balance marks. Double thread is used and the stitches are easily removed.
in commercial manufacture, quality control checks are conducted- what are these and why are they used?
quality control checks are conducted at different stages of production to make sure the product matches the agreed standards
where can quality control checkpoints be written into?
The manufacturing specification to ensure a logical sequence in the manufacturing process
what are examples of reasons for adjustments on finished products?
-faulty equipment that needs to be fixed
-machinists not producing the desired quality of work requiring further training
what is a datum point?
a fixed reference point on a fabric or garment used for measurement, alignment or desired placement. It plays a key role in pattern making, cutting and quality control
