Conveyance, as the name implies, has to do with wasteful transportation, storage or handling of work in process (WIP). Think about all of those single item trips you make to your local grocery store and you’ll start understanding the waste of conveyance very quickly.
Another useful analogue for explaining the waste of conveyance is found (once again) in the food service industry.
We have a restaurant chain in our area that features the one price, all you can eat, multiple station buffet concept. I’m sure you’ve seen these places. You move through a little maze of chrome fences designed to regulate the unending tide of humanity flowing toward the cashier station and ultimately to the real goal, unlimited food.
You pay in advance and then you are given a set of flatware and a rather small plate. After that, you are directed into the serving area or as I like to call it, Hog Heaven. Gourmands of the world probably fantasize about this place.
There are numerous colorful kiosks, each featuring a different type of food.
You will have a pancake, omelet and waffle bar. There will be steak, prime rib and roast beef counters. There is a pasta bar with spaghetti, ravioli, rigatoni several types of pizza. Our Hog Heaven features separate stations for fried chicken, hamburgers, baked potatoes, assorted salads, vegetables (not too many vegetables!!) and of course, dessert. . . . Lot’s of desserts.
Just driving by this place makes me reach for my Lipitor.
However, the real action is not so much the food, but rather the patrons. Believe me, these folks fully understand the waste of conveyance. Their little plates are stacked high with food. Apparently, the goal is to limit the number of calorie wasting trips through the serving area by piling as much food as is possible onto the little plate.
You will see plates with a nice bed of pancakes supporting a porterhouse steak, which serves as a foundation for several slices of pizza held in place by a mountain of mashed potatoes containing a crater of tomato soup. Lying on top of the potato mountain will be a slice of apple pie and a side of baby-back ribs. Finally, a glorious crown of chocolate ice cream, whipped crème and maraschino cherries top everything off. Any empty areas between the various courses of the meal are filled with Jell-O salad, which serves as a kind of cement to hold the towering structure together.
The patron will head for the nearest available table comfortable in the knowledge that further energy depleting trips will not be necessary because the 5,000 calorie self serve banquet crowded on the single little plate will satisfy even the most massive appetite.
Contrast this model of caloric efficiency with the traditional restaurant concept.
After more waiting, a waiter brings them water and provides them with menus. Then . . . more waiting. The waiter returns and takes their order.
A few minutes later, salads appear; again brought by the waiter. After a few minutes, the salads are finished the waiter removes the salad plates, soon replacing them with soup bowls. Another trip is spent removing the soup bowls and then bringing in the entre. This repeated through all the courses of the meal. Plates and food are moved multiple times from the food preparation area to the eating area and back.
Some folks probably find it difficult to get full with all the waiting between courses. Also, consider the multiple trips between the food preparation area and the table. It certainly isn’t the model of efficiency found at Hog Heaven.
Unnecessary conveyance in the manufacturing process may not be as obvious but the result is the same. The unnecessary transportation of work in process, people and/or machines involved in the manufacturing process or of parts and supplies can add up to a devastatingly large hidden cost.
With supply chains extending to all corners of the planet, conveyance is an unpleasant fact making it doubly important to make sure that any conveyance is indeed necessary. Keep in mind that conveyance can be wasteful over miles or inches, it’s not just the distance, it’s the movement itself. It can be wasteful over days or seconds.
It’s the human involvement in the unnecessary movement and the time wasted moving, removing and moving yet again. Even the smallest movement multiplied over hundreds of production cycles will add up to a huge number.
Once identified, eliminating unnecessary conveyance can be as simple as redesigning the workspace or layout of the shop floor. It may mean relocating production facilities to a location in better proximity to suppliers or distribution channels.
It can also be very complex involving re-sequencing several production processes to reduce the movement requirements of WIP. Perhaps embracing a cell based process versus the tradition linear production flow.