Monday, 20 October 2008
Process Control in Loom shed
It consists of two parts:
1. Increasing machine productivity
2. Improving quality or reducing defects
Control of the productivity can be done with
1. controlling nominal loom speed close to currently set standards.
2. Ensuring that loss of speed through belt slippage is minimum
3. Control of loss of loom efficiency by minimising:
a. Loom stoppage rate through correct maintenance
b. Control of down time of loom through corrective action on the basis of data collected by snap reading.
3. Factors effecting Loom efficiency
Various factors that affect the loom shed efficency are
2. Human ( Related to weaver skill and work methods)
Relating the three factors
The technical and human (weaver related) factors have a very basic relationship with loom efficiency. The relationship is
P = NEX
= NE at
or E = P/ Nat
Where P= operative efficiency
N= number of machines per operative
E= Machine efficiency
X= Service factor, and it is equal to the average time taken to clear the stops in unit running time of a machine and equals at.
a= average no of stops per unit running time of a machine
t= average time to clear a stop including walking time
Thus if during an hour, the operator spends on an average 30 minutes in clearing stops, 15 min in ancillary durites like bringing raw materials etc and 15 min on rest and relaxation then
operative efficiency = (30 x 100)/60 = 50%
Work load = (30+15)x100/60 = 75%
Thus to maximise loom efficiency
- The stoppage rate should be low
- the weaver should be trained so that he takes the minimum possible time for clearing a stop.
- the operative efficiency should not fall below the optimum level
- loom allocation should be optimum