Thursday, January 21, 2010
Low Hanging Fruit - 3
Part 3 in a series
The hierarchies of manufacturing we've been discussing reflecting the different levels of "control" and "flexibility" one has from design to manufacturing have both temporal and organizational spans. We were discussing the need to clearly identify the quality and quantity of information that passes through the interfaces between the levels because a natural result of information crossing interfaces it the potential for noise and inaccuracy. It is like the game we played as kids trying to whisper a phrase around a circle of other friends - the phrase coming out at the end was usually quite different than the one we started with!
This time we'll discuss the interaction between the four temporal and spatial levels described in the last two postings. A figure in the last post showed these four levels, from product design through process design and planning (manufacturing plan) to parameter selection and process optimization to post manufacturing operations (finishing, etc.) The flexibility to make decisions decreases as we move "lower" in the levels.
This makes sense. On the factory floor we are no longer able to change the product or component design, material or other features. We may not, at level 3, be able to do much about the suite of machines we intend to use to produce the part. We most likely can adjust some of the operating parameters or, at level 4, do some finishing or alteration to overcome a problem. The difference is somewhat like experiencing building and outfitting a house - from the architect-design stage to arranging the furniture in the finished house.
In the first posting we listed a number of "spatial" levels of manufacturing (from device to enterprise) and the levels discussed above are temporal levels - relating to different times. We can represent the interaction between these four temporal and spatial levels as in the figure below (and this is another one you'll probably have to click on to see clearly). The smaller arrows represent flow of information from one decision to another.
The figure represents, at differing spatial levels, the equivalent to the four temporal levels from above, the interactions and some of the details. This figure is from a paper submitted to the 2010 CIRP Life Cycle Engineering Conference in Heifei China later this spring (see http://lce2010.hfut.edu.cn/) and co-authored with C. Reich-Weiser and A. Vijayaraghavan.
As we move up and to the right in the figure we suffer a loss of decision making capability as all earlier decisions earlier in the product design cycle, or lower in the supply chain, effect the ability to make decisions at higher levels. So, at the enterprise spatial level, level 3 (logistics adjustments here) decisions are restricted to adjustments in supplier locations or distribution strategy rather than substantial changes. Similarly, at the machine design spatial level (equivalent to enterprise design but closer to the product), level 3 (machine manufacturing adjustments here) decisions are limited to such things as adjusting consumables or tooling.
How you address what is happening at any location within this matrix depends on what information you have about the process or system represented there, what your understanding is of what this information says about what's going on, what ability you have respond to this understanding, if needed (or leave it alone if it is performing correctly), what "levers and buttons" you have at your disposal to make a response and, finally, what means you have to determine if your response had any impact and, if so, how much.
So, back to our low hanging fruit. It seems obvious that the lowest hanging fruit is found at the lowest branches of the tree. So, in this representation, the low hangers are at the lowest level of flexibility. Changing the design or material of a product is not going to be low fruit. Changing machine operation to produce that item using less consumables (or less damaging consumables) or energy (change operation) may be. In a metal cutting operation, changing tooling to increase machining efficiency is relatively straightforward. Adjusting tool path and cutting conditions, if on a computer controlled machine tool, is a bit more complicated but also reasonable. These are also low level fruit.
And, referring to the information you have and your understanding of it discussion above, choice of the appropriate methodology for conceptualizing and measuring environmental impacts is important.
We will pick up on this discussion next time. I need to keep this edition a bit shorter as I am still traveling in Europe at my conference.
And we'll also talk a bit about "smart grids" next time and what their impact might be on manufacturing. If you are not familiar with what smart grids are, your assignment is to google it and find out!