Batching Automation in Manufacturing Plants

Introduction:
This blog talks about automation in Industries which are into Batch based Manufacturing. It focuses on the supervisory software needed above the control system for improvising on production efficiency and consistency in product quality. We tried to put our knowledge in simple terms for better understanding by readers.

The intended audience is manufacturers, automation system providers, engineering consultants and that every person who is interested in knowing and understanding batch management systems as part of automation solutions in manufacturing industry.

Basics In Manufacturing:

Manufacturing any product or finished good is the process in which raw materials are processed and converted to desired product. Basically any manufacturing industry needs Raw Materials, Money, Manpower, Product understanding and Process know-how. Raw materials can be naturally found or one industry's finished good can act as raw material for another industry. 

There are 2 types of processes in manufacturing. Either Continuous or Batch based. Continuous process as the name says is continuous production with continuous output form. Batch process produces finished goods in batches, in lots. We always see Batch no along with Manufacturing date, expiry date on the packing box or wrapper of many of the products we use in our daily life. The batch no and manufacturing date represents the unique identification of that manufactured product. It is very much useful for tracking particular item manufactured in case of any issue or for better future enhancements in the product by the manufacturer. Batches are nothing but various lots with unique identification.

Evolution to Automation Solutions In Manufacturing

The evolution in manufacturing is from manual manufacturing to each machine or individual plant section specific automation to semi-automation of complete manufacturing plant to full automation. It doesn't only stop here but it's still in evolution mode with add-ons like smart manufacturing with feather touch operations, IoT, Enhanced reporting, Data storage on cloud, Data analytics on your smart handsets or tablets and so on. The evolution never stops in human world and it will never.

When we say evolution in batching manufacturing, it goes more or less like this. There is lot of information available in the shop floor. The most important is keeping track on in-stock/available/utilized/scrapped raw materials, finished goods. Also, the data of in-process parameters tested during manufacturing is also needed. The additional information about plant elements like valves, pumps usage, details of sequential operations carried etc. is also required for improving plant efficiency. Initially all this data was collected from various areas by operator or man-at-site and entered in registers or notebooks. Then this data started getting fed in Excel or similar data entry Softwares. Then the operators used to enter manually in local excel files or registers and parallely in ERP system of the organization. Now a days mostly the real time data is not manually fed in the system but it is part of automation control system itself. Control System reads actual data from various plant elements via different instruments.  It stores in some database which can be proprietary or open. Many organizations have opted for batch management systems along with Control system which help in improvising quality of the product by bringing in at par ‘Consistency’ element in the production. I will explain in detail about Batch Management System in the later part of this blog. As compared to older manufacturers, today’s industrialist do know the importance of the data and its analysis. There are various ways data is stored on intranet or cloud server and then analyzed by providing various reports, dashboards, MIS reports showing Key Performance Indicators for improvising the process as well as quality of product. Also, the term IoT (Internet of Things) is wandering in everyone's mind making them think to have the info of their plant or production handy. For example on mobiles, tablets or smart devices. 

Layers of Automation Systems

There are mainly 3 layers of the Automation system for manufacturing plants.

The 1st level is Field level which comprises of hardware in the plant. It includes all plant elements like valves, pumps, motors etc. Also includes Instruments like temperature transmitters, pressure transmitters, level transmitters, stirrers, twin shaft dispensers etc. The equipments like reactors, blenders, Raw Material Storage tanks, various other supplementary or utility equipments like chillers, cold brine utility, hot water utility etc., packing machines etc. are also part of this level.

The 2nd level is Control System which can be either PLC-SCADA based or DCS. The controller from such system is connected hardwired with all the above mentioned plant elements, field devices and equipments. This controller acts as the brain of the control system. The Human Machine Interface (HMI) is provided to get feel of the whole plant in the form of graphical display. Such graphical screens can be segregated as per geographical locations. The screens display section wise equipments and plant elements. The more detailed screens can be designed as per individual unit for ease of operator who already has know-how of the shop floor. These HMIs do interact with the controller; the brain and provides a platter to the operator to monitor and control the whole plant operations with best possible ease of operation. These HMIs can be PC based, Touch screen displays, Smart devices, web browsers or any such devices from which the user can monitor and control the activities of the Manufacturing. The location of the control panel having controller along with hardwired connections to the plant Inputs/Outputs will be in the control room or field which can be finalized during detailed engineering. The location of HMIs can be finalized based on user comfort to operate them. Mostly PC based HMIs are provided in Dust free, air-conditioned control rooms. Touch screen HMIs can be in the field itself for faster and immediate operations comfort to the operator. And some HMIs can be handy in the form of smart devices or web browsers etc.

The 3rd level comprises of all the supervisory systems which are above the control system in the automation system hierarchy. The supervisory systems can be add-on softwares like Batch Management System, Databases for data storage, data analyzing systems, KPI/MES reporting systems and many other which act as essential supplements to the control system to help improve and enhance the Manufacturing. 

Batch Management System (BMS)

'Batch Management System' (BMS) as the name says is used in Batching processes. Basic aim of BMS is to have quality consistency in every batch and provide batch wise information. In control system, we have the data but element/tag/time based and not batch based. Recipe management is one of the key features of BMS.

ISA S88 is the worldwide Standard for Batch Management System by ISA (International Society of Automation). The BMS product should be developed based on this standard. The BMS should comply with ISA S88 standard. The minute details are provided in this ISA standard for every aspect of BMS to be incorporated.

We shall try to write in simplified manner.

There are 2 main important segments of BMS. 
1. Recipe Management
2. Batch Execution and Batch wise Data Management and Analysis

1. Recipe Management

Recipe is the process in which raw materials are processed and various operations are carried out to produce desired product or finished good. Meaning of Recipe in process industry is same like the meaning of recipe we use to cook any food item.

Raw materials are mixed in right quantity at different stages of recipe and also processed by various operations like heating, cooling, maintaining at one temperature, applying pressure/vacuum, stirring with desired speed(RPM), passing hot/cold water, chilled brine etc. at required stages of recipe. The output is the desired manufactured product which is then packed in necessary styles like bottles, packets, bags, pouches, cans etc.

As I had mentioned, the product should be of same quality every time it is manufactured. How can we achieve this consistency? It can be achieved only if every time we use same quality raw materials in exact same sequence of processes in exact similar fashion in every batch while manufacturing.

Information about field elements, equipments, storage tanks, list of Raw Materials, List of Products, List of Quality and in-process parameters is required. There should be a facility to enter and store this data in BMS. After storing this master data, various recipes can be defined as per variations in products range. For each product, there has to be one specific Sequence of Operations or Processes (SOP) to be carried out. This sequence is configured in Recipe Management module of BMS. While configuring the SOP, at every stage or step, the detailed operations of field elements to be used and operated are also defined for automating SOP. The desired values for process parameters, RM quantities for each stage/operation are defined in Recipe. Such combination of SOP and parameters, RM quantities definition is marked with unique identification called as Recipe name. This recipe with unique name is saved in BMS database with its version and status if released for production or not. The recipes which are marked as Released for Production can only be used while executing batches during manufacturing. Such predefined recipes are called as Master recipes.

2. Batch Execution and Batch wise Data Management and Analysis

• Batch Planner / Scheduler

Now, as per product requirement in market, the production is planned for a week or a month. This production plan comprises of batch schedules along with Recipe to be used with its specific version mentioned. Batch schedules include unique batch no, batch size to be produced and expected manufacturing date/time during that week or month. The master recipe when used and assigned to specific batch, it is called as Control Recipe. Ideally, the control recipe should be exact replica of master recipe so that there will be definite consistency in product. However, there can be minor changes due to environmental factors or change in RM due to supplier change or any such reason. The planner or supervisor can do such changes in the control recipe for that particular batch keeping master recipe unaltered.

• Batch Execution

As per scheduled date and time, the batches are executed using such generated control recipe in BMS. Each stage is either manually or automatically carried out with the ease of batch information readily available on the HMI screen. Manual interventions needed stages are genuinely carried out by the operators due to the threat of the real time data of each stage is getting logged in the BMS which will keep management aware of the actual facts on the shop floor. Values of the the process parameters are auto cut off as required at necessary stage of SOP and actual data is logged in BMS. Anytime during batch execution, the supervisor can monitor the online batch progress using BMS. Every stage wise and operation wise actual data like operation/stage start time, end time, RM quantity used, values of process parameters like temp etc, values of quality parameters recorded during lab testing or in-process checks is recorded in BMS.

• Batch Data Analysis and Reporting

Thus, the desired / to be executed data from control recipe and actual executed data from batch both are available in BMS. This data can then be used for analysis for studying and improvising the way product is manufactured. It is also useful for verifying any batch's information in case of any fault or issue in manufactured product. The manually filled in batch log sheets are no longer needed. The batch log sheets or reports are auto generated in BMS. There are many Key Process Indicators (KPIs) of each manufacturing company which are needed to be served as platter to the management for efficiency enhancements. The KPIs can be Batchwise RM consumptions during month or desired period, Overall Equipment Effectiveness (OEE), Yield, Batch Cycle Time (BCT), Equipment Utilization etc.

The batch wise available data is calculated or logically worked to portray tabular or graphical reports showing all KPIs. These reports can be locally available on HMIs at shop floor, web based reports remotely available for management, on smart devices like mobile handsets, tablets. 

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