Tablet Press Monitoring System

Key Features:

  • Production Speed @ 5,000 tablets per minute

  • Measurement and decision speed: 12msec per tablet

  • Counts total number of accepted and rejected tablets

  • Multiple turret selection of different sizes and shapes and detection of minor variations in object formulation

  • Statistical Analysis of force data

  • Low False Rejection Ratio

  • 100% Quality Control

  • 21CFR Part11 Validation Compliance

Tablet Press Settings Optimized by Instrumentation:

Tablet Hardness is directly proportional to Thickness & Hydraulic/Spring Pressure. In some cases, excess pressure can make the tablets brittle and hardness can go down. Thus, the behavioral pattern can be ascertained for the longer life of machine and better product for the customer eventually.

Load Cells are fitted in on Compression Roller Bearings & at Ejection Point. Newton's Third Law is applied in this system. When the upper punch & lower punch comes between upper pressure roll & lower pressure roll, granules are compressed. The compression force generated on the granules also causes Reaction Force towards the Pressure Rolls. This Reaction force is being measured by Load Cells. Load Cells signals acquired by a data input card are scaled with real world units and are compared with the set limits. If the actual value not falls under set limits, system starts indexing that particular object and the same will rejected at desired location using high speed Air solenoid. All statistical data and Set point limits are communicated with SCADA through TCP/IP at regular interval for history and further downward analysis.

System Flow:

The functionality of the Tablet Press System can be divided into 2 main tasks:

High Speed Data Acquisition & Monitoring High Speed data acquisition & monitoring of average peak value of Load Cells at every revolution Main Compression, Pre Compression, Ejection Force, Punch Tightness Top and Punch Tightness Bottom Load Cells data are acquired on each encoder pulse edge which is related to physical angle of turret in resolution of 0.1 degree. So actual number of data points are equal to number of encoder pulses per revolution. Once filtering and offset is applied, data analysis is carried out. Per revolution average peak for each Load Cell and standard deviation for Main Compression force is calculated from analyzed data. Row value, average peak value and standard deviation are sent to SCADA continuously.

Rejection of Tablet if Main Compression Peak Value is out of Set Limits on Every Punch On the Punch Signal, set limits are checked with peak value of Main Compression Load Cell and accordingly bad tablets are rejected after indexing. Air Solenoid for rejection becomes on after wait time and pulse is generated based on Solenoid on time. Reject counter indicates total count of rejected tablets. Counter Reset command from SCADA resets the reject counter. Reject punch shows actual punch number from which tablet is rejected. This helps to identify if tablet is rejected from the same punch repeatedly.

The last revolution total peaks data of Main Compression Force are sent to SCADA on request.

Real time simultaneous loops running parallel are required to meet measurement and control action simultaneously. At the same time, real time connectivity on TCP/IP for further SCADA integration is required. Optimized level of programming provides a complete solution to the customer fulfilling all the requirements & functionality.


An Instrumented Tablet Press gives correct & precise data on Main Compression Force, Pre Compression Force & Ejection Force. This data when plotted on chart helps a pharmacist to understand the peculiar behaviors of a Tablet more precisely and arrive at conclusions like what should be the Tablet Press settings, formulation, etc. 
One can measure the impact of variation in the Tablet Weight by depth of fill adjustment in the Tablet Press, Tablet Thickness by adjusting the main compression (Gap between Upper Punch Tip & Lower Punch Tip) and Tablet Hardness / Thickness by adjusting hydraulic pressure / spring pressure.

Thus, Tablet Press Monitoring can be successfully utilized in Quality Control, Formulation Development and Formulation Analysis.

Himanshu Bhavsar