Proposal #1 – Time and Process Standardization
Phase I (MSDII Weeks 1 through Week 5)
Run the K-rolls at a speed equal to, or less than, the speed of the oven at all times. Improvements in line balancing and product flow will be realized.
Phase II (MSDII Week 3 through Week 8)
Standardize the way in which trays are loaded and unloaded from the racks. Decrease the amount of time the door to the Proof Box is left open. All racks will hold a maximum of 36 trays; cover the top unused rack shelves. Introduce visual aids to help standardize the Proof Box area. Standardization, variability elimination, and product flow are lean principles that will be implemented.
Phase III (Time Permitting)
Investigate temperature and humidity within Proof Box. Standardize temperature and humidity.
Visible Problems
- Oven is working at maximum capacity
- Queuing before and after Proof Box
- Inconsistent bake times and proof times
- Each Oven operator has their own rack
- Rack loading/unloading variability
- No standard procedure or formal flow process to follow
Data
Running 2 K-rolls:
-Speed of 100 rolls/min, rack loading is 3.56 sec/tray = 2:25 minutes
-Speed of 80 rolls/min, rack loading is 5.25 sec/tray = 3:30 minutes
-180 rolls/min, 10,800 rolls/hour
-2 racks loaded at K-roll every 2:30
Oven:
-Load/Unload speed: 1 set of 6 trays every 15 seconds (8min bake times)
-8,640 rolls/hour
-2 racks loaded into Oven every 3:20
-Capacity: 6 trays loaded from 2 racks every 15 seconds, 3 per worker
-Each oven operator has their own rack
Proof Box:
-Ideal proof time is 50 minutes.
-Observed times ranged between 55 minutes and 75 minutes (10% and 50% overages, respectively)
-Capacity: 49 racks
QC:
-Normal operation – 5 trays per oven cycle, 15 seconds per cycle = 20 trays per minute
-Rushed operation – 6 trays per oven cycle, 13 seconds per cycle = 28 trays per minute
-It is assumed that the top trays on a rack yield the most dry spots
Analysis
The rate that the oven can produce is less than that of the K-roll by 2,160 rolls/hour. The result of this is product back up in the Proof Box, causing added queue time after K-roll and before the oven. Additional proof/queue time increases the dry spot defect percentage.
- Standardized rack loading/unloading procedure already established – needs to be followed.
- Using only one rack at the Oven will reduce waiting time outside of the Proof Box.
- Multiples of 6 trays on a rack will ensure correct batch sizes.
- Mark each rack with a time when entering the Proof Box.
- Re-number each door to the Proof Box.
- Proof Box door will only be opened when necessary and not left open for longer than needed.
Phase II Options
Top Rack Cover:-Empty tray
-Rack cover attachment
-Plastic/paper cover / Time Stamp:
-Colored stickers
-A fixed timer on each rack / Visual Aids:
-Sticker/Magnets on doors
-Signs reminding to close doors
Impact of Proposal Implementation
Defect Reduction- 40% estimated reduction in defects
- No waiting queues outside of Oven
- Proof Box time standardization
- Recycled pans will have more time to cool
- Standardized work throughout Proof Box
- Energy savings due to improved Proof Box door procedures
- Slower work pace will decrease elevated worker stress levels
- Mindset of standardized work will be developed for future improvements
Risks
- Little/no employee buy in
- Large scale schedule modification
- Lack of long term consistency and commitment
- Workers may not agree with process changes and standardization
- Visual aids distract workers
- Timers ignored/not used
Financial Justification
Expenses:Minimal to none
- Low cost associated with longer k-roll operations, visual aids, timers
- Down stream workers will have no change in work quantity or time
Savings: Substantial
- Improved resource allocation
- Schedule standardization
- Increased product through put
- Absolute decrease in defect percentage from (10%-12%) to (6%-7.2%)
K-roll and Oven Flow Capacity
K-roll:
K-roll 1:100 rolls/min = 6000 rolls/hr
K-roll 2:80 rolls/min = 4800 rolls/hr
Both:6000 + 4800 = 10800 rolls/hr
Oven:
6 trays of rolls at 8 min bake times (15 second cycles)
Oven:36 rolls/15s = 2.4 rolls/s = 8640 rolls/hr
Proposal #2 – Defect Sorting Efficiency Improvement
Improve defect sorting accuracy in the Quality Control (QC) area. Create a visual aid of the different types of defects. Generate a training manual to show new employees, and to reference to for all QC workers.
Visible Problems
- Inconsistency in defect sorting
- No standardization or formalized training in detecting defects
Analysis
Phase I – Visual Aid
- The visual aid will consist of a flipbook with pictures of “barely passing” defects as well as “barely failing” defects.
- Priority will be given to the roll types with the highest throughput.
Phase II – Training Manual
- The training manual will consist of detailed instructions on how to categorize/detect defects, and it will also contain pictures similar to those from the visual aids flipbook. This book will be shown to new employees as well as those who are temporarily placed in QC.
Impact of Proposal Implementation
Defect Reduction
- Type I errors reduced (throwing away acceptable rolls)
- Type II errors reduced (letting defects through to the customer)
Additional Benefits
- Greatly tighten quality control (QC)
- Reduction in sorting ambiguity
- Sorting becomes a less stressful task for QC personnel
- Higher quality product
Risks
- Workers may not utilize visual aids
- Visual aids may distract/slow-down workers
Financial Justification
Expenses
- Visual Aids on the QC Line ≈ $300
- Paper, high-quality photo printing, laminating, stands, binding, etc.
- Training Manual ≈ $200
- Paper, high-quality photo printing, binding, etc.
Savings
- Improve defect sorting efficiency
- Overall defect reduction
- Increase in throughput
- Estimated breakeven in about 8 months
Figure 1: Page from Defect Flipbook
Figure 2: One Defect Type from Page of Defect Flipbook