1. Accessing data. One of the great challenges when executing a project to gather and report OEE metrics is easy access to manufacturing equipment status. The obstacles may include islands of automation or even equipment that's not automated. Don't expect that all equipment information is available via existing automation systems. Be prepared to install simple data acquisition systems to gather the necessary data to track OEE.
2. Stakeholder input. Lean manufacturing is critical in today's global economy because it helps you drive your output (product efficiency) higher while maintaining low defects and rework, thereby increasing throughput in quality. Before building a lean cell, talk to your operators, quality people, manufacturing engineers and process engineers. Get their input, hold meetings and keep them in the loop throughout the project. They are the main stakeholders who will eventually approve of your cell.
3. Lean management. Lean manufacturing is a powerful concept when employed correctly. The problem is that with Lean, along with other methodologies, one size does not fit all. Managers can get caught up in how great it improved this company or industry, and then try to implement it internally. What they fail to do is penetrate the details of why did it work, what support structure is required and how does that translate to their internal business. Lean is as much about management engagement in daily operations as it is about the methodology.
4. Measure the right things. Nothing is worse than the wrong input. OEE is not always a KPI metric in batch operations. If you speed up the drying process, for example, the OEE goes down, but you will be making more product in a shorter period of time.
5. Visual management. Visual management, including large display screens on the factory floor, are an effective tool for OEE programs, letting both managers and workers easily monitor the metrics of production lines and track KPIs. Displays harness natural human competitiveness. In one experience, once data was displayed it started a race between shifts to drive up OEE. Without any management intervention there was a 20 percent increase in productivity. Among the most useful KPIs to display: count (good or bad), reject ratio, operating speeds, Takt (cycle) time, downtime and OEE (availability multiplied by performance and quality) for determining resource utilization.
6. Increase uptime. Lean manufacturing is a very important factor in a production plant. Just by placing materials at the point of use within the production floor area, you can increase product uptime. This is just one small adjustment that will fine-tune the flow of your product.
7. Too lean? If you operate with vendors that are stationed in areas with a high potential for natural disasters, think carefully about being too lean with your supplies. You'll need to plan for alternative routes and suppliers. Another area that has to be monitored is the amount of time for production to customer need. Sometimes manufacturing is too lean and when there's a sudden demand, the slow ramp to manufacture can cost more money than producing stock.
8. Business support. Make sure the business has adopted and fully understands OEE. This can be a huge change management nightmare if not well-entrenched prior to the project (or as part of the project execution). Lean manufacturing can also be applied to service disciplines, not just product manufacturing, mostly with only minor adaptations. Look to these techniques and principles to streamline your own processes and eliminate waste.
9. Meaningful reports. Data capture is quite easy. Reporting the data in a manner that helps implement change can be challenging. Don't assume a single report is sufficient. Different users need different data. And that data must be presented to each user in a manner that is meaningful.
10. Improvement tool. OEE can be a very valuable tool to identify problems within a process. Ensure that everyone understands what the three elements are that make up OEE: availability, speed and quality, and how to calculate each. Once processes are stabilized, use OEE to drive improvement.
11. Software less important. Software selection plays only a small part in the OEE process, but that is where customers spend the most time upfront. Operator involvement, the quality of the integration partner and the ability of the controls hardware to collect data are what truly make an OEE project successful.
12. Efficiency tool. OEE has to be automated to be successful. The data needs to be driven from machine status, not humans inputting the status. Any manually derived OEE system can be fiddled with to produce the expected 85 percent efficiency rate. Improving systems and automating OEE measurements may bring into question the accuracy of historical OEE data. To avoid internal politics, put an amnesty in place and promote automated data as a new way of measuring OEE. On the other hand, the only reason to use OEE is to help drive an improvement process to increase operational efficiency. If that isn't a widely embraced priority, then save yourself lots of time, money and effort.
13. Improving uptime. OEE can help you identify opportunities to improve your total uptime. First, understand the categories that OEE represents. Next, determine what things you want to track and how specific you want to be. There isn't a set rule as to what that may be. An example may be that under your performance efficiency category, you list specific pieces of equipment in an assembly line to track. By breaking down your categories you will have better opportunities to make improvements. The last hurdle is how to capture the data used to calculate OEE. Keep it simple and train your people in how to capture the data you need, what it is and why it's important.
As described in World Class OEE, the OEE calculation is based on three factors: availability, performance and quality. Here's how each of these factors is calculated:
Availability takes into account Down Time Loss, and is calculated as: Availability = Operating Time / Planned Production Time.
Performance takes into account Speed Loss, and is calculated as: Performance = Ideal Cycle Time / (Operating Time / Total Pieces). Ideal Cycle Time is the minimum cycle time that your process can be expected to achieve in optimal circumstances. It is sometimes called Design Cycle Time, Theoretical Cycle Time or Nameplate Capacity.
Since Run Rate is the reciprocal of Cycle Time, Performance can also be calculated as: Performance = (Total Pieces / Operating Time) / Ideal Run Rate. Performance is capped at 100%, to ensure that if an error is made in specifying the Ideal Cycle Time or Ideal Run Rate, the effect on OEE will be limited.
Quality takes into account Quality Loss, and is calculated as: Quality = Good Pieces / Total Pieces.
OEE takes into account all three OEE Factors, and is calculated as: OEE = Availability x Performance x Quality. It is very important to recognize that improving OEE is not the only objective.
For a detailed discussion on calculating Overall Equipment Effectiveness, go to http://awgo.to/022
Source: Automation World
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