This software aim is to limit the production waste and to better satisfy customer requests.
Our specific experience is focused on fabric cut optimisation, but the software is suitable for all the products that need to be fractioned from a big roll into smaller rolls.
Often this happens at the end of the production line, in order to obtain products that, by size and quality, can be sold to final customers.
There are a lot of aspects to take into account in this operation, that ranges from economical to commercial aspects.
In the typical situation the process starts from a certain amount of finished or semi finished material, of which all the quality features that can affect the fabric cut are known; in other words, by mean of visual inspection by human operators or by automatic camera-based systems, all the defects of the fabric are detected together with their size and position, as well as other fabric characteristics ( shade of color, width etc… ).
The optimisation software will consider all the quality features of the fabric and the constraints imposed by following processes ( in the case of semi finished products ) or by the final customers.
Just to make an example we can refer to the textile industry, where the fabric that arrives at the end of the production process is tipically winded onto big rolls or plied into trolleys, and is necessary to roll it into smaller rolls that are accepted by final customers.
The constraints can be divided into two main groups:
Dimensionals :
Tipically each final customer defines a minimum and maximum size of the rolls he can accept; if the roll is made up of more pieces sewn together, normally each piece must have a minimum size
Qualitative:
This kind of constraints are more in number and they typically vary a lot between one customer and the other even on the same article.
In order to check the quality of fabrics the first thing is to evaluate their defect; as a first classification, defect may be divided into “acceptable” and “to be cut away”.
The faults “to be cut away” are those not tolerated inside a roll to be sold, so they will be classified as scrap during the optimization step; it also may happen that a fault that is acceptable for one customer isn’t acceptable for another one.
The “acceptable” faults are so only within a certain range, there is always a limit to the number of defects in a given lenght of fabric; if the different gravity of the various faults is to be taken into accont, then instead of the number of defects their “demerit points” are considered.
There are other aspects to consider, like the fault concentration; for example, the quality rule may say that “10 faults are accepted in a roll 100 mt long” but if all of those 10 faults are inside a piece of fabric 5 mt long then it will be very difficult for any customer to accept those 5 mt, even if the rest of the roll is a 95 mt perfect fabric.
The position of the fault inside the roll can also be very important; it happens often that some defect of the “acceptable” kind is not accepted at the begin and/or end of a roll ( for example: no fault accepted in the first and last 2 mt of each roll) or in other particular positions.
The horizontal position of the defect ( distance from the fabric edge ) can be another aspect to consider, typically a fault that is near the selvedge is less disturbing that one that is in the middle of the fabric.
After all these considerations, it is clear that decision on where to cut the fabric isn’t so easy to take, and that sometimes it is really impossible for an human operator to take the best decision; that is where Optimon – Fabric cut optimisation software, comes into play.
The advantages that this software tool offers are measurable in terms of production yield, the amount of first quality fabric will increase reducing the quantities of second quality and scrap.
Another advantage is the possibility to check the results of a big roll fragmentation in advance, not after the operation is already performed physically; this way it is possible to take different actions, like reworking the fabric or try to see what happens if the fabric is assigned to a different customer that has different requests.
The whole process focuses a lot the attention on the control of the production’s defectivity and on the real problems that it causes; in fact after running an optimization it become evident which faults are causing loss of first quality production and which other have the tendency to stay within customer’s tolerance.
