USE CASE
Reducing bottlenecks at Balancer stations
Objectives
- Identify issues affecting residual unbalance
- Increase accuracy at balancer stations to prevent bottlenecks
Challenge
Bottlenecks and inefficiencies often occur at balancer stations due to a lack of understanding of the data, and human error introduced in the process.
Key Results
Alerts set up when potential issues arise at balancer station
Reduced bottlenecks at the balancer station
Background
A balancer station is usually situated within the production line, where rotating components such as axles, fans, driveshafts, and turbos are balanced before being integrated into the final assembled part.
Components are balanced to avoid downstream problems related to vibrations, wear and tear, reduced efficiency, and potential safety concerns. ISO specification 1940-2 defines the acceptable residual unbalance for components spinning at certain RPMs. Since this is a worldwide and commonly used standard, accuracy is critical. A customer may even specify tighter requirements than the ISO standards dictate to improve customer comfort.
Due to the complexity and problem-solving this process requires, balancing stations are primarily run by human operators and are not routinely automated. A number of possible inefficiencies and errors can be introduced at this station. LinePulse offers a variety of functions that can help solve station-specific problems, reducing bottlenecks and scrap.
Capability metrics studies to track upstream problems
To balance a part, it must be run through the station at least twice. The first time to assess the amount and location of the residual unbalance, and the second to measure if the applied correction successfully met the spec. The range of initial unbalance measured from each part’s initial pass through the station will tend to be within a certain range, but this initial range often has no defined limits—only the final pass does.
Controlling the incoming residual unbalance can help in several ways:
- It can be an early sign that an upstream process has begun to break down. If all parts are balanced after this station, then evidence of an upstream problem can be hidden.
- It can reduce the amount of variation in the correction needed to balance each part, simplifying the rework task.
- It can reduce the amount of correction required, saving costs and time.
The Capability Metrics module in LinePulse can be used to explore the history of the initial residual unbalance that is measured the first time a part reaches this station. Through this study, the normal limits of the initial residual unbalance can be determined. With this information, it is possible to determine fixed control limits on this signal and automatically alert team members when the process deviates from the norm.
If these limits are exceeded, it may indicate a potential upstream problem in the process that is resulting in a less-balanced part to meet the station, and LinePulse will issue an alert for an engineer to investigate.
Monitoring final residual unbalance to determine process errors
The balancing process is highly manual and subject to human error. Should a balance not be corrected accurately at this station, it can cause any number of issues downstream. For example, improperly balanced components could lead to damage or premature wear on test machines, or lead to early life failures in operation and potential warranty actions by your customers. No one remembers a vehicle with a smooth-running turbocharger, but everyone will remember the one that blew up. And not in a positive light.
By monitoring the final residual unbalance with LinePulse, errors in this station’s operation can be uncovered. If the process begins to deviate from the norm, it could indicate a lack of skill or training with newly hired operators. LinePulse also allows for signal associations to be evaluated and understood. Users could look to see how much a signal impacts other signals and tighten/loosen limits to improve downstream throughput and increase line yields.
Results
Many vehicle components contain rotating parts that must be balanced to ISO specifications. Challenges often arise at the in-process verification step when a part is tested for balance.
LinePulse contains several modules that can assist in the optimization of balancer stations and prevent bottlenecks and problems related to it. By leveraging capability metrics and single-variate anomaly detection, quality teams can maintain a high degree of accuracy at these stations, while improving overall efficiency.