Forming and sequencing batches
Based on the FF heuristic (Cap=10) Batch processing time Formed batches
Jobs in the batch M1 M2 M3 B1 J2 J1 J7 23 24 19 B2 J9 J3 J6 J10 17 21 23 B3 J5 9 17 9 B4 J4 J8 25 11 13 Step 5: Computing Makespan.
It is well known that excessive variation in the uncured elasticity of mixed batches
can and does lead to downstream quality problems such as dimensional stability problems with extrusion, non-fills in injection molding and physical property variations with continuous vulcanization, to name a few.
In the series of eight experiments, 75% of the batches
were not able to reproduce the reference energy curve, and therefore the rotor speed was kept high (100 rpm), developing an excess of heat through the shear and finally reaching the temperature limit (175[degrees]C) before the batch was well mixed.
As figure 6 indicates, some batches
can have TC50 times shorter or longer than nominal.
Now, instead of just re-running the current aborted batch test, the lab tech had to rerun all of the batches
on that sheet.
For years, blender makers totaled gravimetric weights over 20 to 30 or more batches
and averaged them.
The system ensures correct ingredient addition to batches
, inventory management, tracking and configurations.
Typically, the accuracy of batch blenders is given as a percent accuracy over a large number of batches
- sometimes 10 or more.
The pre-blended batches
were not absolutely homogeneous as they came out of the preblender, and transporting the batches
from the blender to the filling station caused segregation, and as a result, there was no way to assure the correctness of the proportions of the materials that were fed into the bags.