Tuesday, July 19, 2011


Textile and garments process control technology is not as specific as vision technology; process control encompasses all textile manufacturing sectors. The process controllers relevant to textile manufacturing are basic information-electronic systems that, installed on the textile and garments machine, control certain fundamental parameters relating to the production process carried out on the machine itself. Essentially, they can be broken down into 4 categories according to the technology of the controller involved, which is itself dependent upon the type of process being controlled.

1.Cycle programmers: These process control system are present on many dyeing machines and they are based on the general principle of activating outputs according to inputs of the process. But their actual functioning is more specific. Those control system are pre-programmed to manage a sequential cycle of operations automatically. This facilitates programming, because the only thing that has to be done is determine the sequence of the steps in the cycle and the conditions required for the passage from one step to the next (the reaching of a certain temperature, the expiry of a set time, the arrival of a go-ahead signal, etc.). There exist two types of cycle programmer: one based on a microprocessor whose hardware and software remains the property of the supplier, and one based on a PC- or PLC-formatted architecture, which offers all the advantages of standard hardware and flexible software of automated process control.

2. PC-driven Programmable Logical Controllers (PLCs): these systems of process control are equipped to receive logical information (from switch or pushbutton contacts, limit switches, photocells, any kind of ON/OFF sensor) and to activate logical outputs (electric drives, relay contacts, etc). A controller checks continuously the status of inputs (openings/closures, presence/absence of electrical current), and according to the configuration of the inputs, activates its own outputs (activated/deactivated, ON/OFF, command presence/absence). The logical correlation between input status and the output status consequently imposed is determined when programming the system. Thus, the PLC can be regarded as a completely general purpose tool, capable of carrying out, when duly programmed by the user for proper process control, the most diverse functions. In practice, PLCs are used to resolve all those problems relating to automation and sequence management that used to be resolved using electrical systems and relay logics for process control. They feature on practically all the systems used for automated process control, in textile finishing, for operations such as washing, mercerization, dyeing, drying, calendaring, raising, pad-batching and steaming.

3. Numerical Controls of process control:
these control system are electronic systems, specifically designed to control the positioning of a number of moving organs (e.g., robot axes). Using special languages, they programmed the sequences of the positions of the various axes, each of which is controlled through measurement of the position of the organ. This measurement is carried out by high precision transducers (encoders, resolvers, optical rulers), which transmit to the numerical control a number (hence the name of the system) which represents that position.

4. Special programmers:
This automated process control system is developed specifically to carry out dedicated functions of textile process. These programmers are designed with and for the machine, in such a way that input and output signals and processing capacity are kept to the absolute minimum. In order to reduce costs, size and maintenance of production, they are often engineered in the form of single electronic cards. The four systems of process control described above are can be integrated with one another, and are often used together.

Benefit of automated process control
 -Better process quality
 -Reduction of errors
 -Greater production flexibility
 -Rationalization of the cycle according to scientific criteria
 -Rapid personnel training
 -Greater familiarity with production characteristics
 -Scope for integration with other company information systems
 -Repeatability of procedures
 -End quality no longer dependent upon the skill and experience of staff

Limitation of automated process control

 -Need for organizational changes
 -Difficulty personalizing the system to specific requirements
 -Difficulty interfacing with different IT products
 -Need for assistance and maintenance

You should read RELATED POST for automated process control system
Wish you good luck..................

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