Paste Manufacture – Throughput Increase


This multinational pharmaceutical and healthcare company manufactures a wide range of OTC medicines and healthcare products. For the production of pastes a number of batch mixers are used alongside a highly automated continuous mixer which was designed to produce 4000 kg/hr of paste. Paste, once produced, is stored in bulk tanks. The plant runs seven days per week and feeds a number of high speed packing lines each running at up to 500 units per minute.


The mixing plant was specified and designed to run continuously at 4000 kgs/hr, but when first installed it was initially run at considerably less than this throughput. The volume requirements from the continuous mixer had grown significantly. However, as the throughput settings were turned up it was found that the number of short stops increased and these prevented the plant from reaching the originally specified throughput level. The result, typically the plant was set to run at only 3,200kg/hr. In the three months prior to the Lauras BID workshop the overall output averaged only 2200 kgs/hr with an OEE of less than 50%. The stoppages were found to be due to the powder-feed systems being unable to keep within the tolerances specified. Eight to ten stoppages per hour were the norm, with a manual reset of the plant being required on each occasion. If the operator, due to other duties or being at break, was not immediately available to carry out the reset, the plant could be left at a standstill for up to 20 minutes.  



A team was put together including experienced plant operators, technicians and area management to work on these problems. A number of Problem, Cause Solution (PCS) exercises were carried out to find the root causes for the large number of stoppages associated with the powder feed systems.
Root causes determined included: control system settings not optimized, feed systems unable to run at the desired maximum speed, bulk density variations and line blockages caused by valve timings not being optimally set.


Following this workshop the OEE of the continuous plant increased by 38%. Based on the following year’s planned volumes the required running hours dropped by over 2000 hours.
The plant ran continuously at 4000 kg/hr and the number of stoppage alarms dropped from an average of eight to ten per hour down to below two.