EWI – Lightening in a Document
First, I’d like to thank Grant Vokey, Gerard Ipskamp, and Jean-Luc Delcuvellerie for their contributions in the LinkedIn Manufacturing Execution Systems Group discussions. I find these group discussions to be a rich and thoughtful source for all things MES.
Electronic Work Instructions, what are they? Good question… you may not like the answer. The only way to answer this is to understand, at a high level, what they could be, and at the ground level, how they are implemented in different packages.
First, it helps to understand where they’ve come from. Standard Operating Procedures, SOPs, have been part of the manufacturing environment since production managers could write down instructions. Typically you’ll find these kind of instructions on the production floor on a laminated sheet (or sheets) hanging at an operation or bound in a humongous book in the quality office for every product and procedure. They’re a big step in the right direction. Getting your people to know what the right process is, and following that process is huge. So… problem solved? Not really. So, thinking that through… what happens when I have a change to the document? Let’s say R&D has improved the operational procedure for a handful of products. How does the change happen? New documents are printed and distributed to the right locations. When do you change over? How do you coordinate the release of the document with when you want that new procedure put in place? And this is really the simplest case. Let’s consider what else might be in that SOP. If we include setup instructions, quality inspection instructions, or production data collection instructions in the SOP, this document becomes a living document. Each area of information may be managed differently, by different groups. In addition, the information for each may or may not be related. How do you coordinate this disparate data? How do you make sure the right data is updated in the document at the right time and appears at the operator when it’s supposed to?
Managing this kind of information in a pure text document is both difficult and ineffective. This has driven the need for Electronic Work Instructions, EWI. So… what could EWI be? Since there isn’t a definition in Wikipedia, I’ll make one up. It could be an electronic document that contains embedded data fields that can be managed and distributed either automatically or according to some scheduling criteria. I would add that there are some ancillary functions that actually make this manageable and useful:
- Document Versioning – An important feature, especially useful in a flexible production environment, or where rapid product changes occur.
- Review and Approval – The ability to create/modify a document and route it for review and approval.
- Data Integration – The ability to add or update data fields in the document based on an external data source (e.g. Control Limits for a given product and operation).
- Distribution Management – The ability to schedule document distribution or initiate distribution based on business rules (such as release coordination with new products).
- Hierarchy – The ability to structure a master document with related sub-documents. For instance a master document for Product A may contain sub sections for production, quality, safety, sanitation, etc. Each of these sub sections may be divided into smaller divisions based on operations for instance.
- Security – The ability to control who may read, create, or modify documents.
- Electronic Signatures – Having the ability to record sign-off on a document is incredibly useful. This is usually the cornerstone of becoming CFR 21 part 11 compliant, providing auditable records that can be easily retrieved and reported.
Once we’ve created a document and know how to publish it when we need to, we also need to be able to control access to it. Actually, we’d like to coordinate document access with production processes, so that the right document (or sub-section, or sub-section item) is made available based on production conditions. What conditions?
- Operations – Displaying the right document item based on the production operation
- Product – ditto for the product, usually in combination with Operations.
- Quality Status – Showing the right quality procedure based on sampling results and showing the procedure for further testing/evaluation. Things like Hazard Analysis and Critical Control Points, HACCP, Corrective and Preventative Actions, CAPA, and Material Review Board, MRB fall into this category.
- Setup or Changeover – Displaying the right document for machine/unit setup based on a product change.
- Sanitation or CIP – Displaying the right document for sanitation or clean in place operations before or after a production run.
All of the above require extensive coordination. That’s why EWI has become more main stream in MES applications in the last few years. You mean EWI creation and management in MES? Well… Yes and no. Yes, there are packages that have most of the required EWI capabilities in them. What better way to determine current production state than through MES. No argument from me. MES applications typically have an intimate awareness of operations and the production state. The issue is the information embedded in those documents. Much of what should be there comes from Product Life-Cycle Management, PLM, applications, Enterprise Resource Planning, ERP, applications, or Laboratory Information Management System applications. If you create those documents in a MES EWI function, then (if you don’t have some mechanism for automated updates) you have to manage that information in multiple systems. You just don’t want to go there. Better to use the MES EWI as a kind of reference engine, letting it retrieve the appropriate document from another location or system based on production conditions.
So if we only point to the documents we need from MES, where should the documents be created? No simple answers here. ERP’s typically have some capability to create and manage these documents. PLM’s are usually a better place to keep/manage them simply because the majority of the information needed is managed there anyway. PLM’s also usually have the ability to distribute those data elements (like limits, set-points, sample id’s, etc) to other systems. PLM’s aren’t for everyone however. They aren’t cheap and require a resource investment to keep them fed with current and accurate data. However you choose to implement EWI’s (or a combination of EWI and document management) there are some important factors to consider:
- Minimize the management of document data to as few systems as possible – keeping systems synchronized can be painful and unreliable.
- Use the MES EWI system to refer to documents – freeing the MES EWI function from document management functions simplifies the MES configuration and keeps the data in the system of authority.
- Develop alignment between systems – Making sure the ERP operations and the MES operations share common boundaries will ensure that the right document with the right data arrives at the right time.
- Data Integration – Mapping out where and how data is managed before implementing an EWI can significantly reduce data integration requirements and significantly increase data accuracy and timeliness.
EWI can make dramatic improvements in production efficiency and quality. How you choose to implement it really depends on your product mix, production complexity, and to a large part your IT infrastructure.
