Janet Seeger, Stock Replenishment Coordinator for BUSYMart, is accustomed to the pressures of her job, given that she oversees the hectic replenishment process for restocking the shelves after a busy day of sales at BUSYMart. However, the stress of recent criticisms of her teams’ efficiency is new to her. Janet has long assured her managers that her team would be capable of meeting the increased volumes that would come with the heavy Fall shopping season, but she has found that the capacity of her crew may not be enough to meet the peak volumes. Given that her manager is unwilling to increase the crew size, Janet is looking for more effective ways to use the existing capacity of her team. She has thus enlisted your help – she would like for you to apply your understanding of constraint management by way of the Theory of Constraints to save her crew from the menacing frowns of the Divisional VP. The Stock Replenishment Process Overview The stock replenishment process at BUSYMart is performed in the hours that the store is closed, from 11:00 pm to 7:00 am, and is the process whereby shelves of stock are replenished using inventory that is shipped from a nearby Distribution Center earlier in the evening. Each weekend evening, eight semitruck trailers full of stock arrive at BUSYMart. These trailers must be unloaded, and the unloaded stock must be verified/counted, recorded in the computer system as received, and put out onto the store shelves and arranged in a manner presentable to the customer. There are two truck docks at BUSYMart, thus allowing for two teams to operate concurrently with each unloading one trailer at a time at one of the docks (i.e. two trailers are being unloaded at any given time - one at each door). When a trailer is emptied, it is quickly replaced by another such that each team will unload four trailers through the night. The two teams each consist of two “unloaders” and one “stocker”; there is also one “scanner” that works both docks and two “facers” that work throughout the store (i.e., the scanner and the facers aren’t assigned to a specific team). Janet has attempted to measure the throughput capacity of each of the functions; however, she has noticed a high degree of variation in this. Volumes will be given in cases and assume that a trailer averages 250 cases. 1. Unloading Two teams of two “unloaders” each work at separate docks unloading cases of stock from trailers and carefully moving it into a staging area where it will wait to be verified/scanned (see step two) and then moved into the store (see step three). A rough diagram, drawn by Janet, has been provided. The unloading is a physically-demanding step, and may involve unloading individual cases by hand or palletized cases using specialized equipment. When the product is in the trailer in individual cases (rather than palletized), the unloaders will have to put the cases onto pallets during unloading. This will result in a pallet consisting of many different types of cases, so the unloaders will have to be careful that all case labels are visible for the scanning step (next). The staging area is quite small, and at times the unloaders find that they do not have any room for more cases or pallets from the trailer, at which time they will either take a break and wait for more room in the staging area to open up, or just pile product up (which can complicate things for the scanners). Observations over a week show that unloaders can unload an average of between 125 and 175 cases per hour. Note, though, that unloading must be complete by 5:00 am to leave time for putaway and to allow the unloaders time to clean out and inspect the empty trailers for the next trip. 2. Scanning A person (we will call them a “scanner”) checks stock that has been unloaded and placed in the staging area, to make sure that it is what was ordered from the distribution center and is of the correct quantity of cases; the scanner then updates the automated inventory system by way of scanning the bar codes on the cases with a hand-held scanner and confirming the quantity received. The scanning is an important job, since data integrity of the inventory system is very important, and thus must be done by one specifically-trained person who works both doors. The scanner typically moves back and forth – they will go to one of the docks and scan all cases that have been unloaded, and then will move to the other dock and do the same, and then continue to move back and forth. When they move from one dock to another, they generally can remember what has been scanned already and what hasn’t, but on occasion they scan the same thing twice (in which case the software will alert them that the product was already received). On some occasions, the scanner will not have scanned an item before a stocker (see step three) attempts to move it to the merchandise area in the store. In these cases, the scanner will usually see the stocker doing this and will stop them, or in the worst case the scanner will have to go out into the store area to confirm receipt of items that they did not scan before they were moved by a stocker. The scanner averages 300 cases/hour, although Janet noticed that it ranged between 200 and 400 during the week of observation. 3. Putaway The Putaway function requires “stockers” to take cases of stock (that have been scanned, hopefully) from the staging area and move them to the required location in the merchandise area of the store (i.e. where the customers shop). There are two stockers, each assigned to one dock for the night. Stockers leave the cases, unopened, on the floor beside their shelf location in the store. Stockers generally drive a forklift around the store with a pallet that may have different cases of different product on it, and leave individual cases where needed. The Putaway job, like the Unloading job, is one of the more physical of the process. On occasion, stockers will be required to help set up an end-of-aisle display when large quantities of product are involved. They will know that they need to do this either by the large quantity of product received or by being told by the “facers” (see step four). When stockers return to the staging area, they usually try to retrieve pallets from near the dock doors first, since that is where the unloaders need space the most; however, often it is the merchandise that is staged further from the dock that has been scanned already, so the putaway workers can be frustrated by conflicting orders from unloaders and the scanner. Each stocker can put away an average of 200 cases per hour, although sometimes as few as 150 if they spend a lot of time on an end-of-aisle display. 4. Facing and Display Stock that is put onto the shelves is organized by two “facers” who make sure that the stock is displayed in an attractive manner, labels are facing outward to the customer, and proper price labels are in place. This job requires some skill, and is somewhat of an art. In general, the “facers” receive a list at the start of the night that indicates which merchandise was ordered from the Distribution Center. They then move around the store finding the unopened cases, as they are put out by the stockers, and put the stock on the shelf and make the displays attractive. In some instances, the facers will not find items they expect in an aisle because (a) they weren’t shipped from the distribution center (out of stock) or (b) they haven’t been brought into the store by the stockers yet. In these cases, the facers look for a different product on their list and come back to look for the missing product later. The two facers each average 130 cases per hour (low of 95, high of 160). Please analyze this process, in light of the Theory of Constraints, and make suggestions for Ms. Seeger for ways in which the throughput can be maximized (preferably without requiring additional labour or expensive equipment, and without compromising accuracy in the work or care to avoid damage).
Please analyze this process, in light of the Theory of Constraints, and make suggestions for Ms. Seeger for ways in which the throughput can be maximized (preferably without requiring additional labour or expensive equipment, and without compromising accuracy in the work or care to avoid damage).
As per the case study we have the following details:
Stocking time(stock replenishment process): 11.00 pm to 7.00 am
Total Trailers:8
Total cases in each trailer:250
2 docks for unloading trailers which are functional at same time.
Total people working on the floor:
Team 1: 2 unloaders and 1 stocker
Team 2 : 2 unloaders and 1 stocker
1 scanner and 2 facers work for both the teams
Unloading should be complete by 5.00 am
Average cases taken out by each team of unloaders( 125 to 175)/ hour ( janet's observation)
Average number of cases scanned by scanner: 300/hour( janet's observation 200 to 400/hour)
Cases put away by each stocker: ( 150 to 200)/ hour
average speed of each facer: 130 cases/hour(95 to 160)/ hour janet's observation
Solution:
total number of cases in 8 trailers: 250 *8 = 2000 cases
Unloading has to end before 5.00 am
so the total number of hours the unloaders have to empty the trailers is= 6 hours
Average speed at which each team of unloaders has to work is: 2000/6*2 = 167 cases per hour
If the scanner has to finish his work with the same speed as unloaders and give enough time for stockers to take the cases till facers, the average speed at which scanner should finish the work by 5.00 am would be = 2000/ 6 = 334 cases/hour
To finish the stocking by 5.00 am each stocker has to stock: 2000/6*2 = 167 cases per hour
total time the facers have to finish their work: 8 hours
Average speed at which each facer should work: 2000/ 8*2 = 125 cases/hour
Challenges being faced by the team: the potential reasons for delay of work, or extra time spent or unwanted breaks.
1. improper coordination between scanner and stockers
2. unavailable unloading space for unloaders.
3. additional time taken by stockers.
4. Scanner has to overlook both the unloading spots and in case some items are missed for scanning and taken away by stockers than scanner needs additional time to figure out.
From the data we have :
SOLUTION:
Instead of using two unloading positions, use only one unloading dock.
in this way communication will be better and scanner wont miss out on any cases, moreover wouldn't have to spend additional time moving back and forth to the 2 docks.
The stockers have a higher speed of stocking as compared to unloaders, so there will never be an issue of space, if only one dock is used and both the stockers are working at the same location. Hence this would avoid unnecessary breaks taken by unloaders.
Moreover even if the stockers take additional time in this case, there would be no communication gap and hence scanner won't have to spend double time.
Hence, i would conclude by suggesting Ms. Seeger to use only one dock instead of 2 and just trying to focus on above mentioned averages which are below the maximum each person can do, therefore easily attainable.
Janet Seeger, Stock Replenishment Coordinator for BUSYMart, is accustomed to the pressures of her job, given...