Target Management through Hour by Hour reporting for a Continuous Coating Environment

Transcription

1 Target Management through Hour by Hour reporting for a Continuous Coating Environment 2013 Aimcal Web Coating & Handling Conference Charleston, South Carolina Josh Rauen Tim Buntrock Jeff Hammes

2 Background Today most large manufacturing companies have adopted programs aimed at the elimination of waste. Waste being defined as anything that does not add value to the product from the customer's perspective. Customers are only willing to pay for value added activities, not for their product to wait, get reworked, or moved around the facility. Large gains can be made through tools such as 5S and value stream mapping but what are the next steps once the process has reasonable flow and is organized? How do you measure what is being done every day against the goals that have been set? How do you identify issues, respond quickly to problems as they develop, and minimize the waste caused by routine issues? These can be especially difficult to quantify in a continuous coating environment. Without a visual indicator of real-time performance there will always be time spent trying to figure out where the coating line is in terms of the production schedule. Often people will ask are we on time, will we get everything done before the end of shift, or how many late orders do we have. They will typically have to ask this several times throughout the day. Different answers may be given depending on who is asked if verbal communication is the relied upon method. An Hour by Hour board is a visual metric that clearly lays out expectations for an operation on an hourly basis, and then continuously records how well the expectations are met. Hour by Hour: Summary An Hour by Hour board is a simple concept but can be complex to construct. The first action that needs to take place is goal setting. Managers set goals for each hour, for each day, for each area of production. These goals are posted on the board close to the production area. Preferably the board is in a location where it can be viewed not only by the individuals working in the area but anyone who may pass by. The operators then record output every hour as they work. Everyone, including the person doing the work, can instantly see how well the operation is performing compared to the goal. The managers view the data throughout the day. The review can be with operators and/or on a daily walk with other managers and plant staff. Management interaction is important whether it be responding to issues or highlighting when operators have met or surpassed a goal. Simply having operators record hourly performance can have a significant impact. They will immediately know what is expected of them and how they measured up. They will no longer be able to fill the time of their shift as they now have an hourly obligation to track their progress. Operators will also be more prepared to explain why an event happened since they now will be required to explain why the expectation was not met. Creating the Board: Goal Setting Creating an hour by hour board is simple when working in an assembly line where the goal represents the number of units per hour. Setting hourly goals in coating environment can be more difficult. The goal must be realistic and should be achievable if The operator follows procedures The equipment is functioning properly 1

3 The raw material is of the quality needed to complete the job In a coating environment goal setting can be even more complicated if your setup times are inconsistent. You first need to know what you are capable of to set a realistic goal. You may have to revisit standards later if they don t align with real-world conditions on the equipment. The golden rule is to always do your best to reflect reality. If the goals set by management are not realistic, operators and staff will quickly become frustrated and lose interest. When operators are getting ahead or falling behind it may only be due to false standards and they will quickly lose faith in the process. Creating the Board: Format & Use The figure to the left shows an example of an Hour by Hour used in a coating environment. Keep in mind there is no one correct way to setup the board. In this example the headings are Product, Target vs. Actual Setup Time, Target vs. Actual Yards Ran, space to indicate hourly results, and a cumulative schedule attainment, Comments, and a place to list the Actions taken. If the setup or run time targets are met for a given hour a green indicator is used, if the goal is not reached a red indicator is used. Over the course of a shift if may be useful to use a cumulative indicator in the case where the last hour hit target but overall the coater is behind schedule. It is also useful to list who is responsible for what portions of updating the board at the top. As issues happen they are recorded and can be tackled immediately. If you are not sure if an issue was a one time or infrequent occurrence use a Pareto chart. Allow data to build up and choose to work on the categories that cause the most pain in the process. This approach can be far more effective than firefighting. When implementing an Hour by Hour board be careful to not fall into the perfection trap. As soon as things start to break down don t worry if the board starts to drift from the goals as things change. Adjust the board if something changes, such as the machine goes down or the schedule changes. The idea is to reflect reality on the board and highlight issues and 2

4 successes. Don t waste time arguing over exact yardage counts. The objective Is clear communication so keep it simple. View red hours as opportunities as they highlighting issues that are preventing you from reaching your goals. Hour by Hour: Does and Don ts As we developed this process in our organization we learned a lot about what not to do. Target management through Hour by Hour boards needs commitment. The quickest way to failure is management that does not regularly review and take action from the data on the boards. When management is not engaged, operators will view the board as unimportant. The opposite is also true. If management focuses on the boards and follows up regularly asking questions and giving good feedback operators will take it seriously. It is essential that the data is gathered every hour. If data is held until the end of the shift it is too late to react. Filling out the board at the end of the day does almost nothing to improve productivity. It simply adds an additional clerical duty to the operator. It is the process of getting an hourly grade which is one of the most powerful aspects of the board. Managers following up on hourly results and making sure things are being filled out timely is crucial. Hourly goals don't have to be perfect but they do have to be reasonable. Establishing a goal that operators feel is impossible will undermine the process and make them feel like management is pushing them to work harder which isn t the main objective. On the other hand, a goal that is too loose may allow the operators to fill the time available. The solution is to be honest when setting goals. The manager should admit that the goal is a reference. Therefore, the production goal is not set in stone. It is possible (and desirable) to adjust the goals after monitoring actual output over time. It is critical that after an operator notes an issue on the board that action is taken in timely manner. Whoever takes action on an issue needs to comment on the resolution. This completes the feedback loop to the operator. Then the issue should be populated on the Pareto to assist in future problem solving. We have found it useful to leave the previous shifts hour by hour up for the following shift to see. This facilitates a valuable shift change meeting. Another crucial element to have in place is leader standard work to ensure the expectations of the board are being followed by operators as well as managers. You may need to redefine how you work throughout the day to make an hour by hour work. A written document outlining the team lead or supervisor responsibilities as they relate to the board is key. Data Collection Below is Pareto data that was collected after implementing an hour by hour in our coating facility. The data was collected from the comments and actions sections of the board and grouped together based on several common categories. It is clear where we should concentrate our efforts as machine failures and schedule changes due to R&D and engineering occurred most frequently during the time period measured. This accounted for most of the hours lost. We also began to Pareto data from the board on quality issues as operators commented on what they were struggling with. This operator recorded data in conjunction with downstream quality Pareto data was used for in depth problem solving. Armed with this 3

5 data we were able to implement many improvements to our coater which also resulted in cost savings and a reduction in variability. These improvements will be detailed in the following sections. Figure 2. Pareto data (count in hours) Figure 3. Pareto data (count of occurances) 4

6 Problem Solving A common starting point in adhoc problem solving is to Pareto quality defects of outgoing product. This product based approach is very customer focused as it reflects customer satisfaction; however it does not capture the whole picture. Below is a graph showing quality defects generated from a thermal transfer ribbon manufacturing process. Ribbon Defects Yards/Dollars Yards Dollars 0 WRINKLES STREAKS MISSOUTS/DEWETS MOTTLED GAUGEBANDS Figure 4. Pareto of downstream quality defects Defect Type These defect rates are complaints by downstream operations and although they do highlight problems that most definitely need to be addressed, you will not understand the entire picture unless you consider productivity metrics such as those recorded from an hour by hour board. If we were to analyze the defects from the internal perspective, an entirely different picture materializes: 5

7 Q3 DEFECT TYPES Coat Weight Square Yards DOLLARS COAT WT HEAVY EDGE BANDING UNCOATED BLANK APPEARANCE WRINKLES DEWETS DEFECT RHEOLOGY STREAKS SCRATCHES BLOCKING COAT TO WRONG SIDE Figure 5. Pareto of process quality defects Figures 4 and 5 together show that although our highest defect counts are associated with wrinkles and missouts, the most time spent internally is coat weight control. This quickly prioritizes the work done for process improvement. Wrinkling Further breaking down the downstream quality Pareto data, we identified 2 issues that were addressed to reduce wrinkling; coater alignment and a bowed roller. When these improvements were adopted, all wrinkling defect rates dropped to near zero (occasional failures that can attribute to material would occur). Missouts/Dewets Analyzing the defect data, we found that 90% of the complaints were attributed to a single failure. It was determined that a leaking oil line had contaminated a mix. It was these oil droplets that dewet on the surface causing large missouts in the print. Ignoring this assignable cause incident, the other 10% was attributed to interpretation of a poorly written specification, with most failures being attributed to the test method used by the customer. The customer was printing the thermal transfer ribbon and counting failures that were attributed to a poorly maintained printer system. With clarification of the specification and aligned test methods, these failure rates also dropped to near zero. Having addressed the two highest failure rates experienced by the customer, the team acknowledged that the level of streakiness/banding seen in the product could be improved. This was suspected to be aligned with internal process defects associated with coat weight control, so the team turned their attention towards this weakness in the process as highlighted by the Hour x Hour data 6

8 Coat Weight Control Drastic improvements in coat weight control were achieved through a combination of using more robust gravure cylinders, higher quality doctor blades, and better control through redesign of the enclosed doctor blade. Historically using chrome plated gravure cylinders was the method of choice due to cost. In recent years however, many cylinder suppliers have developed their ceramic gravure engraving processes to achieve superior uniformity and life at a very comparable cost to chrome. The life of these cylinders allowed for adequate ROI. Another source of variation was blade life. By moving to a higher quality steel doctor blade with additional surface treatments designed to improve blade life, we were able to drastically reduce blade wear-in period and hold coat weight more precisely over time. We evaluated 3 blade types and measured coat weight change over time. Blade A B C Description Standard: Low Quality Blue Steel High Quality White Steel High Quality White Steel, with surface treatment Coat Weight Hours Y Blade B Blade C Blade A Figure 6. Doctor Blade Comparison You will notice that Blade C resulted in a wear-in period of less than 30 minutes and was able to hold precise coat weight over multiple hours. In the past, operators would be changing doctor blades at the end of every roll in order to maintain proper coat weights. 7

9 The final step of controlling our coat weight was through proper blade pressure control. The following figure shows an expected coat weight vs. pressure profile. Figure 7. Coat weight vs. blade pressure profile. At low blade pressure, incomplete doctoring and thicker coat weights will be observed. As blade pressure increases, the system will reach maximum doctoring capability where all excess material is being wiped from the gravure cylinder and is generally robust to changes in blade pressure. This is the desired operating region for the doctor blade. Increasing blade pressure further can result in a butter knife effect and coat weight increases again. The blade pressure at which the lowest, even coat weight is achieved will be the point at which slight variations in pressure affect coat weight the least. Using the appropriate blade pressure will reduce the variability in the coat weight when manufacturing materials. Generating these blade pressure curves with the three blade material types, we can see that the shape of these curves is highly dependent on the type and geometry of the blade being analyzed. 8

10 % Ct Wt Change vs Blade Proximity Coat Wt % Change Blade C Blade B Blade A Original Position Distance from Standard Figure 8. Graph of coat weight change vs. blade proximity You will notice that when using the old blade we were not operating in a region that allows for insensitivity to blade pressure. As the blade would wear in, the effective pressure would change. Since we are on a steep part of the curve, the coat weight obviously would change as well. By switching the blade to Type C we experienced a drastic reduction in coat weight change with pressure. A hydraulically loaded doctor blade was purchased which allows very precise control of blade pressure through the use of pressure manifolds. This allows the system to control to a pressure set point as opposed to proximity using clunky manual controls. The result of these changes has been nothing short of amazing. Using end of year metrics, we have determined that the improvements made to Brady s gravure process has reduced defective parts per million from an annualized rate of 2495 DPPM in FY12 to 673 DPPM in FY13 - a 370% improvement!!! 9

11 Conclusion In conclusion an hour by hour board has been a valuable tool to kick off our process improvement efforts on a strong footing. Without the data that was gathered we could have easily gone down the wrong path. In addition, having operators track targets hourly has provided a powerful communication tool while keeping everyone more engaged in the process. Conversations with production staff are more direct and real-time. We spend less time guessing at what happened and more time looking and analyzing the data as its happening. This allows us to identify issues as they happen, predict variances from standards before a job is complete, and respond proactively to steer us back on track. As we continuously evolve our target management systems we ask ourselves the following questions 1. Can we easily determine if we are we winning or losing? 2. Can we illustrate and quantify the opportunity? 3. Can we tell what are we working on? 4. Are questions 1-3 clearly visible? An hour by hour board can answer all four. In addition the improvements that we have realized from the data gathered through this tool has been outstanding, helping us to paint a more complete picture of real-time issues as well as successes. 10