Multi-Disciplinary Senior Design ConferenceKate Gleason College of Engineering
Rochester Institute of TechnologyRochester, New York 14623
P10711 - WEGMAN’S MEAT TUMBLER PROCESS IMPROVEMENT
Eric Albanese Industrial EngineeringOkechikere Ekeada Industrial Engineering
Jeremy Gray Industrial EngineeringTheresa Ambrose Mechanical Engineering
Jesse Wykstra Mechanical Engineering
ABSTRACT
In February 2009, Wegmans Food Markets opened up their new Culinary Innovation Center. This center produces a majority of their own meat and sauce products. In particular, the meat marinating process has had several issues come up since the start of the plant.
The team observed the entire process and noticed several significant ergonomic, safety, and layout issues. The process was analyzed with ergonomic assessments, value stream maps, and employee surveys. Specifically, the team focused on modifying existing material handling devices to reduce ergonomic issues, reorganized the layout, and performed kaizens to eliminate several of the existing issues. The results of each proposal are outlined in detail below.
NOMENCLATURE
CIC – Culinary Innovation CenterMeat Tumbler – A large “cement mixer”-like machine where meat cutlets along with marinade is combined. The body spins for a period of time to coat the cutlets.Multivac – the vacuum sealer.Dump table – A large cart used to transport approximately 400lbs of marinated meats from the meat tumbler to the vacuum sealing station.Kaizen – refers to activities that continually improve functions and processes, and involves all employees and supervisors.VEMAG Vat – A small square bin on wheels used to transport fresh cutlets to the column dumper to then be loaded into the meat tumblers.
Column Dumper – A large elevator type machine that lifts the VEMAG vats and dumps the contents into the meat tumbler.
INTRODUCTION
The Wegmans CIC moved to a new building in February 2009. The new facility houses the same processes as the old building, but includes new equipment and improved machines.
The Meat Marinade is a process where chicken, beef, and pork cutlets are covered with sauces and packaged for the local stores. The cutlets are stored in VEMAG vats then loaded into a large meat tumbler using a “column dumper” machine, along with different types of sauce. The meat tumbler then spins the cutlets for a set amount of time, marinating them with the flavors. Once completed the cutlets are unloaded into “dump tables”, each holding approximately 400lbs of meat, and then pushed to the vacuum sealer machine. The cutlets are then individually loaded into sealable packs. The Meat Marinade room also includes a chicken-flattening process, where the culets are flattened and then folded and stuffed into either chicken cordon blue or 4 cheese balls.
In the past year since the process has started up, there have already been several ergonomic injuries. There have been 3 “lost time” injuries involving pushing the carts, along with 2 injuries related to dump table use and operation. Wegmans has also expressed a desire to add another meat process in the room and with the current setup and layout, the little amount of free space makes it prohibitive to add.
Everything done in the Meat Marinade room is very reliant on physical labor, but it is unknown if the
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existing material handling devices are the best tools for the new machines. In order to help correct some of the ergonomic injuries, Wegmans in-house ergonomic assessment will be done on moving the column dumper, pushing VEMAG vats, pushing dump tables, loading the vacuum sealing machine, and cleaning dump tables. Kaizens will be performed to eliminate the excessive clutter and unused material handling devices currently in the room. A new, smaller conveyor for the flattening process will be tried out and modified to fit the production and space needs of the new room.
DESIGN PROCESS
Wegmans initially had two primary concerns that became the main focus of the group. The first was the large amount of injuries from poor ergonomic and safety conditions. Wegmans places a high value on their employees and were willing to do whatever to make sure they are comfortable.
Secondly, Wegmans is planning on adding a specialty burger line in the same room in summer 2010. The current state of the room barely provides enough room for the current processes, let alone adding future processes.
In order to ensure that these needs are met, the team came up with different metrics to track, as shown in Figure 1. Wegmans uses its own ergonomic assessment system developed in house. The three ergonomics-focused project proposals all used this metric to track success. Ideally, all ergonomic risk ratings (related to safety accidents) should be “Low”; along with all risk values (related to long term ergonomic issues) should be under 24.
The space related project proposals will be measured by square feet of open space. Both the existing material handling devices and conveyor have large footprints, taking up physical space and blocking off areas of space that cannot be used.
Before any solutions could be generated, the entire process needed to be studied in depth. The Meat Tumbling process takes place 5 days a week over just one shift. The work on the process is very variable, depending on holidays, seasons, and weather. The chicken flattening process takes place as needed, generally 1-2 times per week based on orders from stores.
In order to better understand how the process is run, a value stream map was created to visualize the flow of information and material throughout the room. This map can be seen in Figure 2.
FIGURE 1
Once the team had a grasp of how the room was run, extensive studies were done on the primary concerns of the workers. A list of customer needs was generated, and then categorized in an “ishikawa” diagram. This diagram takes all of the needs and problems and groups them to help find some of the underlying issues that exist. This diagram is shown as Figure 3.
FIGURE 2
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FIGURE 3
CURRENT STATE AND SPECIFICATIONS
In order to properly track progress and ensure improvement, we had to develop metrics for all of our changes. The two primary items tracked was the ergonomic assessment rating and the square feet of space taken by process.
The ergonomic assessment rating was developed in-house by Wegmans by their own expert, Paul Hickey. This assessment takes the effort level, time per effort, efforts per minute, task duration, number of affected employees, as well as the number of past recordable injures, and rolls them up into a single quantifiable value. Ideally, a value of 24 and under would be an ideal ergonomic task. The rating also provides a primary risk rating, which serves as an indicator of the risk of a one-time safety accident.
To track space saved with layout improvements, an overall square feet covered metric was used. This metric not only includes the physical footprint of the items, but also space lost by the positioning of the item. The goal of free space of the entire project is 260 square feet.
The costs for this project are also justified. The ergonomic issues have cost Wegmans $9,607 in claims alone. There are also hidden costs of the injuries, such as the additional costs of training new employees to fill in for the lost time and decreased morale. Additionally, the cost of the conveyor and kaizen projects are easily accounted on the alternative: expanding the marinade room. This option would cost over $100,000 and not a viable option.
PROJECTS
In order to better manage changes and improvements, the issues were grouped into 5 different projects. The ergonomic projects centered on 3 different material
handling devices: the VEMAG vats, the dump tables, and the column dumper. The layout and space related concerns were grouped into two projects: Kaizens of the dumptables and VEMAG vats along with conveyor
replacement.
PROPOSAL 1: VEMAG VAT MODIFICATION
This sub part of the Senior Design project addressed concerns with the shorter VEMAG tumbler vats. The vats get loaded into the VEMAG machine, the column dumpers, and a hydraulic lift for cleaning purposes. These “short” vats are 27 inches tall from the floor. There are no convenient handles or places to grip the vat. This caused ergonomic concern. In order to move a vat, workers had to bend over quite far and remained bent over while walking across the meat marinade room. This bending causes strain on the back, shoulders, and arms. In order to minimize strains, the Team brainstormed a few ideas for some type of handle. Some of the options included a telescoping handle (similar to those on luggage), a spring-loaded handle (like a tension rod), a stationary handle with no moving parts, and a folding design.
After analyzing pros and cons such as cost, ease of manufacture, and ability to solve the ergonomics problem, the stationary design was chosen. Further research and design led to a handle with two vertical rods attached to the vat itself, bent at the top away from the vat, and connected together with a cross beam, much like a shopping cart. The cross beam was designed to extend farther than where it attached to the two supports, allowing space for employees’ hands to securely grip. Final drawing is shown below.
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Stainless steel is required for food processing applications. Maximum stress and force analyses helped determine optimum dimensions for each piece. Observing the VEMAG vats on the floor and in the different machines for which they are used, helped constrain dimensions. Parts for a test model were ordered, including rubber grips that fit the ends of the crossbeam. One VEMAG vat was taken from the CIC and the test model was constructed in RIT’s Mechanical Engineering machine shop. The pieces of the handles were cut and then welded together. The entire handle and all weld spots were polished. The final design did not include the rubber grips that had been ordered; the type of rubber was not suitable for an environment with raw food and strict cleaning requirements. Test model was then delivered back to the CIC for testing purposes. At this time, the modified vat is in the process of being sent back to Wegmans CIC for testing.
PROPOSAL 2: DUMP TABLE MODIFICATIONThere are numerous ergonomic problems involved with transporting and unloading the dump tables. The dump tables are hard to push and maneuver around when they are fully loaded with meat. Only two of the four casters on the dump table swivel, making it very hard to push the dump table sideways into the Multivac station. The employees have also complained about the difficulty in unloading the dump tables at the Multivac station. As the dump table is unloaded, the employees have to bend over farther to scoop the meat up from the bottom of the dump table. This places an enormous amount of repetitive strain on the employees’ backs. The employees unloading the dump tables also have to twist their bodies and pull the meat from the far end of the dump table towards the unloading end, which is closest to the Multivac. This action adds to the difficulty of the unloading task.
Once the dump table is completely unloaded, it has to be cleaned and sanitized before using it for another meat species or marinade flavor. The cleaning process is very difficult because the drains in the bottom of the dump table are not adequate, and clog very easily. This results in the employee having to manually flip the dump table over to clean it. The dump tables are very heavy and awkward to lift, which means only the larger and stronger employees can perform the cleaning process. These are all severe ergonomic issues that have lead to injuries and complaints from the Wegmans employees.A formal design selection process was used to improve the overall dump table design. The main goal was to concentrate on improving the ergonomics involved with pushing, unloading, and cleaning the dump tables.
In order to improve the process of pushing the dump tables around the floor, larger swivel casters will be used. The casters on the dump tables are currently 5 inches in diameter and only two of the casters are capable of swiveling. By adding 6-inch casters, the dump tables will be easier to push. The new casters will all be capable of swiveling 360 degrees. The ability for all four casters to swivel will make it easier for the employees to push the carts sideways, which they have to do when the dump table is being aligned at the Multivac station.
To simplify the unloading process, a spring loaded grate design was created. The design consists of four stainless steel compression springs. Two heavy springs will be placed at the far end of the dump table and two lighter springs will be placed at the unloading end of the dump table. These springs will support pieces of stainless steel tubing, which will push against a 1-inch thick piece of UHMW plastic. When the meat is unloaded from the marinating tumblers into the dump table, it will sit on top of the UHMW plastic material. As more and more weight is dumped into the dump table, the springs will compress. At the Multivac station, the springs will be fully compressed 8 inches. When the employees begin to unload the dump table, the springs will begin to extend due to the decrease in weight on the UHMW plastic. The heavier springs in the back of the dump table will extend at a faster rate than the lighter springs in the front of the dump table. This will tend to accumulate the meat at the unloading end of the dump table to eliminate the need for the employee to twist and bend so far while unloading the dump table.
The cleaning process will be improved by installing a new type of drainage system. A drain bucket was designed for the existing dump table. The drain bucket will sit flush with the bottom of the dump table. The drain bucket will be made from perforated stainless steel sheet metal to allow for easy drainage. A fixed handle on the drain bucket will allow the employees to easily remove the drain bucket during the cleaning process. When the drain bucket is removed, the empty
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4-inch x 8-inch rectangular opening will provide for fast/easy drainage of the dump table during the cleaning process. This will eliminate the need for the employees to lift and flip over the dump tables, significantly improving ergonomics.
Once all of the parts were received, the spring loaded grate mechanism was fabricated in the RIT mechanical engineering machine shop on an existing dump table. Unfortunately, the new casters and perforated sheet metal needed for the drain bucket were not received in time to begin the fabrication. A detailed design/build procedure has been supplied to Wegmans so that they can easily finish these two parts of the retrofitted dump table. The dump table has been returned to the Wegmans CIC for testing purposes.
PROPOSAL 3: COLUMN DUMPER MODIFICATIONThe column dumper is a material handling device that lifts VEMAG vats full of food product up and over a chute that dumps the food product into the meat tumbler. Currently, the column dumper is mostly used by employees of relatively greater strength because it requires a great amount of force to move and maneuver. Typically, the column dumper only travels a few feet or is pivoted into position. Workers load the dumper with the VEMAG vat. The VEMAG vat is secured by having one worker lift a chain while the other pushes the vat into the dumper. They then swivel the dumper into position, raise and dump the vat, and finally swivel the device out of the way. Since this activity is not highly repeated throughout the day, the ergonomic risks can be interpreted as not of greatest concern. However, on particularly busy days, this activity can be very taxing on the body. The major ergonomic concerns are the force it takes to push the VEMAG vat into the column dumper (as well as the strain involved with bending over), and the force it takes to move the column dumper. The efficiency concern involves using two workers to secure the VEMAG vat.
For this proposal, three solutions were initially proposed. The first involved changing the way the column dumper moves (i.e. different casters, motorized wheels, etc). The second solution involved adding a better grip or handle to the column dumper. This may give the worker a better hold of the device, which could make the task easier. After further evaluation, this solution was eliminated due to the fact
that the modification costs would outweigh the benefits. Finally, the third solution involved redesigning the column dumper so that it would only take one person to implement the secondary safety mechanism (the chain). All of these solutions were evaluated and decided with an option selection chart shown in Figure 4.
FIGURE 4
After much design analysis, changing the type of caster was the best solution. Constraints in place by the nature of the food industry and the regulations they abide by include all metal must be stainless steel, wheels must withstand chemicals used in wash down environments, bearings must work in wet environments and must be easy to maintain, and the caster must withstand over 2,000 pounds. Factors for improving the ergonomic aspects of casters include wheel diameter, bearing type, wheel material, and long lead. Because of the design of the column dumper, the wheel diameter is restricted to 4”. The wheel diameter could have been expanded with modification to the column dumper itself. However, the high risk of damaging the dumper rendered this procedure too risky. A stainless steel precision sealed bearing was chosen because it does not need maintenance while providing very little resistance. Polyolefin was chosen as the wheel material because it was available in a solid extrusion, which prevents liquids and chemicals from destroying the wheel. It was also a good balance between hardness and softness. A hard wheel rolls easier while a soft wheel prevents damaging of the tile
floor and provides grip in a wet environment. Because of the other constraints, a standard long lead was all that was available. The longer the lead the easier the caster swivels. The option selection criteria can be shown in Figure 5.
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FIGURE 5Designing the new secondary safety mechanism for securing the VEMAG vat had to be done with the first proposal (modifying the VEMAG vat) in mind. This was due to the concern that the handle might get in the way when the worker is trying to wrap the chain around it. Because many of the projects were falling behind schedule, we designed a solution that lets the worker secure the VEMAG vat from the top instead of around the front, which eliminated the concern of the handle getting in the way. The downside to this design is that pieces would have to be welded to each VEMAG vat, which could call for many parts (depending on how many vats are in use) and could be very labor intensive. Wegmans sent a counterproposal that kept much of the original design, but added a place to temporarily hold the chain so that it would require only one person to do the task. After reviewing this design, Wegmans decided that the design was a bit short sighted because of the handle on the VEMAG vat, and decided to go back to the drawing board.
Many issues arose when it came to the caster part of the proposal. Procurement issues put the project behind schedule several times. A specific type of caster was selected to be ordered for this project. However, Wegmans decided to go with a similar caster from a more preferred vendor. It could not be determined how similar the ordered caster was to the recommended caster because a specifications/materials sheet was not provided. Proper testing was impaired by miscommunications within Wegmans. A test of how much force it takes to maneuver the Column Dumper was to be conducted on two column dumpers using a force gauge. One dumper was to have the original casters installed and another dumper was to have the newly ordered casters installed. However, the new casters were installed on all of the column dumpers, thereby preventing a proper test. It is still our intention to sort this issue out and conduct a proper test in the final weeks of MSD. Documentation, recommendations, and a test plan have been submitted to Wegmans so that they may complete and repeat this project.
PROPOSAL 4: KAIZENSThis part of the Senior Design project addresses the concerns of space utilization in the marinating room of the Wegmans Culinary Innovation Center. At the
initial tour of the process flow, the team accounted for the number of VEMAG vats on the floor and the number of dump tables in queue waiting to be loaded into the Multivac machine.
For the VEMAG vats, the team counted up to 27 vats on the floor. Not all the vats were necessarily in use all the time in part because of frequent switching to different species. This is a cautionary action to avoid cross-contamination. Another reason is that sometimes the vats are not used for intended purposes, like to move product from point A to B. For example, vats could be used to store the parts of one of the machines taken apart at the end of the day.
For the dump tables, there is on average, 14 dump tables in queue in front of the Multivac station. The team noticed that there is no communication between the tumbler station and the Multivac station. For example, when the tumbler station starts marinating, they just keep producing without any signal to stop from the Multivac station. This is because on average it takes 10 minutes for the dump tables to be loaded, compared to 40 minute lead time for the tumbler station. As a result of this, the tumbler station keeps producing without any signals just to keep pace with the Multivac station.
All the above described situations, with both the VEMAG vats and the dump tables take up space that is much needed at the marinating room. This is why Kaizen is critical in this process. Kaizen is a set of activities that would enable the team discover ways to reduce the amount of VEMAG vats and dump tables used on average on the floor of the marinating room. The team scheduled 4 Kaizens, 2 Kaizens for both the VEMAG vats and the dumptables.
PROPOSAL 5: CONVEYOR REPLACEMENTThe chicken flattening process involves taking chicken cutlets, and running them through a pressing machine to flatten them. After the chicken goes through the tool, it comes out on a 26 foot long conveyor. Once on the conveyor,
there are workstations on both sides for up to 10 employees to stand. The most common products produced on this are chicken cordon blue and 4 cheese chicken, where the flatted chicken breast is coated
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with a sauce, covered with cheese, and rolled into a ball. Wegmans also does process regular flattened chicken. Both of these jobs are considered “side jobs” by the marinade room staff, where there is generally 2-3 workers dedicated to the task during the day with others helping during idle time on the regular meat tumbler process. In our initial observations, we noticed that not only was the process done infrequently, but the conveyor itself was not turned on. It was used more like a table than its intended purpose. The employees stated that the conveyor was only really practical for just the flattened chicken, and difficult given the varying levels of workforce available.
Figure 6 shows the different solution options with the conveyor. With the conveyor being located in the middle area of the room, there is space between it and the wall that is considered “dead space”, where the usefulness is lost because of the positioning. Different concepts were generated based on reducing this footprint from 224 square feet to 110 square feet. This space target, along with the kaizen operations, will clear enough room for the new burger operation.
FIGURE 6
The option of replacing the conveyor with stainless steel tables worked the best; however Wegmans preferred that a conveyor system remain in place. The final solution ended up importing a smaller 18 ft conveyor from a different Wegmans facility to replace the current 26 ft one. Once the shorter conveyor was deemed appropriate for use, a layout re-optimization would then be performed to further look for improvements and possibly implement some of the conveyor options to further reduce the footprint. Figure 7 below shows the new conveyor installed in the marinade room.
Figure 7
RESULTS AND DISCUSSION
Kaizen Results: Our targets were to achieve a 40% reduction of Multivac queue and a 28 % reduction in vat utilization. After different kaizen events, Multivac queue was reduced on average from 14 to 6, a 57% decrease. The VEMAG vats were reduced on average from 18 to 12, a 33% decrease on the marinating floor. The key to this success is the implementation of a 3-batch de-boxing limit at the batch opening station. We measured success by how less cluttered the room became and how clear the workers saw the improvements.
VEMAG Results: The addition of a “shopping cart” style handle to the VEMAG vat brought the ergonomic risk rating from a 3 down to a 1. There wasn’t a very large risk associated with this particular project, however there had been three separate injuries reported that related to bending over in order to push these short vats. The same amount of force is needed to get the vats moving because the load of meat is still the same, but the position of the “pusher’s” body prevents further injuries. Initial feedback from team members and machine shop staff was very positive.
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Column Dumper Results: The overall goal of the Column Dumper Project was to make it easier on the workers the maneuver the device all the while using as few resources (workers) as possible. Studying this process and proposing this project called the issues to the attention of Wegmans. Even though these projects are not yet complete, adequate documentation has been submitted to Wegmans so that they may complete it. Although there are no force gauge assessments, Wegmans informed us that the casters they are using were a success on a similar project, and we expect the same results for this one. Wegmans is confident that they can complete the secondary securing mechanism project also. The concept is fairly simple, and we expect success with this project eventually also.
Dump Table Results: The overall goal of the dump table project was to improve the ergonomics involved with unloading, maneuvering, and cleaning the dump table. The implementation of a spring loaded grate to the dump table will reduce the amount of bending/twisting required to unload the dump table at the multivac station. Once the new swivel casters are added to the retrofitted dump table, the overall maneuverability will be greatly increased. After Wegmans builds and installs the new drain bucket design, the cleaning process will be greatly simplified. All of these new dump table features will have to go through a rigorous testing procedure, which will be provided to Wegmans so that they can perform the test.
Conveyor Results: The target of the conveyor replacement project was to reduce both the physical footprint along with open space blocked off by the conveyor positioning from 576 square feet to 273 square feet. By replacing the existing conveyor with a smaller one along with repositioning some workstations the overall footprint was reduced to 270 square feet. Because Wegmans already owned the conveyor, the cost of the project was simply the transportation and installation of the equipment.
CONCLUSIONS AND RECOMMENDATIONS
For the kaizen, process limits downstream help with controlling inventory upstream. What we could have done differently is to try and balance the line and establish a flow system instead of the adopted pull system. We recommend for the CIC to conduct kaizens with the target of balancing the line. We also would encourage the CIC to develop a standard Operating Procedure to document the improvements achieved.
With respect to the VEMAG vat project, the only recommendation is to put a handle on the vats that are remaining in the marinade room after the Kaizens have determined the exact number needed. Modifying all of the vats might negate the effects of the Kaizen and cause the room to re-clutter. It is also highly recommended to polish away the weld marks on the vat and the handle to make it more aesthetically pleasing.
With respect to the Column Dumper Project, we recommend that Wegmans uses the provided documents to complete the project. Because they have already purchased some casters, they should be tested to determine how much they improved the ergonomics. If the results are unsatisfactory, they should purchase the previously recommended casters and test them. If the results are still unsatisfactory, they should modify the column dumper to allow the installation of wheels with a larger diameter. We recommend a 6” wheel at least. Materials Transportation Company, the manufacture of the column dumper, informed us that a company made these modifications, which returned satisfactory results.
There are several future recommendations for the dump tables. The UHMW sheet used for the spring loaded grate is very heavy and could be slimmed down a little to make it easier to remove from the dump table. The drain bucket will have to be installed in order for the new design to work to its fullest potential. When the new swivel casters are added to all four of the corners of the dump table, another set of fixed casters could be mounted to the middle of the dump table. The fixed casters in the middle of the dump table would have approximately an inch larger diameter than the swivel casters. The entire dump table would then be able to pivot around on the larger fixed casters, greatly improving the overall maneuverability.
Regarding the conveyor, the idea of replacing it with moveable tables should be revisited at a later point. The flattener machine is still necessary, but the chicken pieces are manually moved from station to station. The work could be accomplished in a similar manner with custom tables and workstations that would be mounted against the wall.
REFERENCES
Beer, Ferdinand Pierre; Elliot R. Eisenberg; and E. Russell Johnston. Vector Mechanics for Engineers: Statics. 8th ed. Boston: McGraw-Hill Higher Education, 2007. Print.
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Wickens, Christopher D., John D. Lee, Yili Liu, and Sallie Gordon-Becker. Introduction to Human Factors Engineering. 2nd ed. Prentice Hall, 2003. Print.
Budynas, Richard, and Keith Nisbett. Shigley's Mechanical Enginerring Design. 8th ed. McGraw-Hill, 2006. Print.
Owen Kline - Caster City, (2010, February 9). Caster Consultation. (J. Gray, Interviewer)
ACKNOWLEDGMENTS
We would like to thank Professor John Kaemmerlen for all of his help, guidance, and advice throughout the
project. We would also like to thank all of our contacts at Wegmans, including but not limited to Chris Issacson, Scott Young, Paul Hickey, Wyatt Newbould and Mike Benschop, as well as all the employees in the meat marinade room.
