Taken form the archives /pw
Conveyors are “non value adding”!?
This is a position taken by the Japanese that has been accepted as truth in the western industry. Very few have regarded the fact that Japanese factories very often do not have much space - the total available space for Japan society is smaller thant the sate of Michigan USA. Very few realise that most of the Japanese thinking is forced by necessity to minimise floor space. This floor space is a fraction of what western industries have available.
The very unique need in Japan have brought many good principles. Very few are new, they are to a large extent inherited from western industry but made more understood by the Japanese.
How is Non Value Adding defined?
- Value Adding
- Things that I as a customer would be willing to pay for. (accept as a part of the price) Ex; defined as anything that change the shape or finction of their product
- Non Value Adding
- Things that I as a customer not necessarily want to pay for but is a part of the business and can therefor not be eliminated. Ex defined as anything that supports Value Adding
- Everything else
What about “non value adding conveyors”?
Depending how value adding is defined, conveyors can be Vale Adding or Non value Adding
Non Value Adding conveyors are a conveyor that does nothing else than move a part from point A to point B which adds little value. Why? It will evidently have parts in queues and will eventually create waiting times rather than reducing waiting times. However it can improve qiaulity and reduce operating expense.
Value Adding conveyors are conveyors configured to increase utilization and thereby reduce the need for machines, reduce inventory, reduce scrap, support production in small batches. reducing the number of machines required is obviosuly soemthing machine suppliers don't like so they tend to argue against conveyors.
Waste conveyors are when the the focus is on sub-optimizing technology rather than focusing on total investment and pay-back.
What’s a conveyor?
“To convey “ means “to transport”. And transporting something from one point to another beeing just transport is by some argued to not add value. So, in some respects the pre-assumption that a conveyor is “non value adding” have it's merrits!
If, so this is valid for all types of “transport devices” including conveyors, gantries, robots on rails, shuttles, AGV’s, etc. but how to produce anything without moving the material from operation to operation?
The sequential transfer line approach was popular for many years, but is today limited to very specific processes. Transfer lines is what often comes to mind when conveyors are discussed. The variety with parallel operations is the one being used most, while only providing limited re-routing functionality
Another trend was the cell approach. This principle is easy to understand and to implement, but does not provide either the pull or re-routing capabilities that Continuos Flow requires. Companies turned away from the cell approach to look for something else, but as it seams to be the “least bad” solution the concept is partly coming back.
Many consultants are also promoting the cell approach, as this solution is something a consultant can propose and yet not have to be responsible for.
To be continued....