Key Elements to Implement and Sustain Lean Reliability

When implementing any lean initiative, there are key elements to successfully implementing and sus- taining the improvement. The elements are the areas that bring true success to the initiative.

Education. Education is so important for person- nel from senior management to floor level personnel to truly understand all aspects of how lean reliabil- ity affects the operation. Everyone in a plant should understand reliability and what it means to the success of the company. Operators and maintenance personnel

need to understand the reality of how equipment fails and learn to manage asset health.

Support from senior management. The easiest and fast- est way to get support from senior management is to develop a business case. The business case must be developed with plant leadership identifying the oppor- tunity based on the business goals of the company. It should include an assessment to determine gaps between the current and future state and identify spe- cific opportunities for improvement, both financial and nonquantifiable. An action plan also should include costs and a return on investment to obtain senior man- agement support. Without executive support, the entire project is a waste of time—it either will not get off the ground, will not succeed, or will not be sustainable. When assessing the organization and setting the plan, ensure employees are involved, so later they feel the ownership and are empowered to make decisions.

Effective change management. Implementing lean reli- ability is all about people. Changing the way people think—the culture of a company—is very difficult. Do not expect to change the culture within the plant overnight. Change happens gradually. With the right practices and tools to support a lean project, it can be implemented one asset at a time and a significant return on investment quickly realized. Remember the Five S and the DMAIC processes, and focus on one asset at a time. This will provide the needed and sus- tainable change.

Technology support. Technology can make a data-

intensive process easier to manage. Ensure the FIGURE 7.7. The DMAIC asset reliability process. (Courtesy of Ivara Corporation.)

Define Improve Control

Align Reliability Strategy with Business Goals Work Identification Continuous Improvements Loop Sustained Maintenace Loop Performance Analysis Follow-Up Work Planning Work Scheduling Work Execution Identify Physical Assets Contributing to Goals Prioritize Assets by Consequence/ Relative Risk Establish Targeted Performance Requirements Measure Analyze

120 The Basics of Maintenance and Reliability

systems chosen can be integrated and work effectively together.

Value stream mapping. This mapping process is

critical to the success of lean. It is used to determine current work processes against a future state elimi- nating non-value-adding elements of the process. In manufacturing, this refers to work flow processes for product output. In reliability, this refers to the work flow processes for reliability output, such as asset criticality assessment, work identification, planning, scheduling, and the like.

Roles and responsibilities. Map the tasks required to manage and execute the asset reliability process to the roles required in the organization and the responsi- bilities of those people associated with equipment reli- ability. The goal is to ensure that improved equipment performance is achieved and sustained. The need is for clearly defined role descriptions with associated responsibilities. Everyone must focus on executing the asset reliability process. Start by analyzing the business process tasks, then identify the duties required for each role to ensure that optimal equipment performance is sustained.

Key performance indicators. KPIs in lean begins with the manufacturing KPIs (quality, throughput, OEE, asset utilization, safety) and all other KPIs must align with them. KPIs should be categorized as leading or lagging. The key lagging (or results) indicators for reli- ability are failures (MTBF is the recognized measure of reliability), downtime attributed to maintenance, and cost. These KPIs demonstrate whether everything is done right or wrong in a lean process. Lagging indica-

tors cannot be managed because they are the results of everything already done. Leading (or process) indicators provide an indication of where problems are occurring before they affect the lagging indicators. Leading indicators are what can be managed. Reli- ability process metrics are identified to drive specific actions in the process.

Many other valuable metrics can be identified for benchmarking, but we focus on the metrics that drive the execution of a successful reliability process and directly measure its impact. As an example, wrench time is a useful metric to benchmark maintenance efficiency, but it tells nothing about how to improve it. However, by acting on process metrics for plan- ning, scheduling, and execution, wrench time can be improved.

7.2.6. Summary

In today’s competitive world, lean reliability is key to a company’s survival. Eliminating non-value-add- ing tasks and continuously improving must be a part of everyone’s daily life. As lean reliability progresses, reactivity begins to vanish and a proactive lean asset reliability becomes the focus. The hidden plant finally is found, where the plant experiences more capacity and asset availability and lower cost than anyone ever imagined.

Do not think this journey is easy or without sacrifices, because it is not. However, once you have traveled this journey, you will never return.

8

Chain Drives*

Chain drives are an important part of a conveyor system. They are used to transmit needed power from the drive unit to a portion of the conveyor system. This chapter will cover:

1. Various types of chains that are used to transmit power in a conveyor system.

2. The advantages and disadvantages of using chain drives.

3. The correct installation procedure for chain drives. 4. How to maintain chain drives.

5. How to calculate speeds and ratios that will enable you to make corrections or adjustments to conveyor speeds.

6. How to determine chain length and sprocket sizes when making speed adjustments.

Chain drives are used to transmit power between a drive unit and a driven unit. For example, if we have a gearbox and a contact roll on a conveyor, we need a way to transmit the power from the gearbox to the roll. This can be done easily and efficiently with a chain drive unit.

Chain drives can consist of one or multiple strand chains, depending on the load that the unit must transmit. The chains need to be matched with the sprocket type, and they must be tight enough to prevent slippage.

Chain is sized by the pitch or the center-to-center distance between the pins. This is done in 1_Ú

8 ′′ incre-

ments, and the pitch number is found on the side bars. Examples of the different chain and sprocket sizes can be seen in Figures 8.1 and 8.2.

Sometimes chains are linked to form two multi- strand chains. The number designation for this chain would have the same pitch number as standard chain, but the pitch would be followed by the number of strands.

*Source: Ricky Smith and Keith Mobley, Industrial Machinery Repair: Best Maintenance Practices Pocket Guide (Boston: ButterworthÐ Heinemann, 2003), pp. 120Ð134.

35

3/8⬘⬘

FIGURE 8.1. Chain size, 3_/ 8′′.

FIGURE 8.2. Chain size, 4_/ 8′′.

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124 Equipment and Processes

8.1. CHAIN SELECTION