由Chris Kudla，高级应用工程师ITT Enidine
减震器和隔振器等能量吸收产品可以帮助保持速度和吞吐量，同时在线保持线性运动过程，减少停机时间。
Within the automation industry, a linear motion system is most aptly characterized as a series of drives and guides that work in harmony to perform a precision motion task. Most linear motion systems rely on a complex array of subsystems to help move objects from point A to point B. Moreover, linear systems often experience a sequence of start and stop impacts and vibrations that can adversely affect an object during its travel time, making the entire operation more susceptible to costly failures and unexpected downtime.
As part of a holistic preventive maintenance plan, plant operators should look to energy absorption products that control kinetic energy and reduce vibration to help keep processes online with less failure.
As advances in technology help provide manufacturers with improved performance feedback, the constant demand for higher speeds, improved cycle times and increased meantime between failures continues to drive the industry forward. By using today’s most advanced motion control and vibration isolation products in linear motion systems, manufacturers will see improved accuracy and production with minimal damage from abrupt starts, stops, turns, precise locating and vibration.
Shock absorption
当考虑在线性运动系统中控制移动的方法时，管理在开始/停止过程后面的动能对维持有效操作非常重要。没有管理这种能量的工程方法，生产线对操作速度有一个限制。超出此限制的运营可能导致设备停机，因为无计计划的维修。例如，随着产品沿着装配线移动，每个止动件有冲击，这可能会导致产品损坏或减少组件本身的寿命。为了添加额外的复杂性，产品也可以在不同点增加或减少，这影响了影响能量的量。
Shock absorbers are used to cushion the impact at each stop. Tuning of the shock absorbers becomes critical in this application, considering the energy variations. Proper sizing and tuning of the shock absorber will result in the lowest transmission of impacting force to an object.
Case Study 1— A major automotive OEM was experiencing excessive shock force on its nearly 1,000-lb assembly pallets as they stopped at each workstation down the line. The major hurdle was that the weight of the pallet almost doubled as it moved through each of the workstations having components assembled, creating a unique impact condition at each stop along the assembly line.
To improve the overall process, providing an ECO OEM series adjustable shock absorber, as seen in Figure 3, helped to manage the shock force within the assembly. To accommodate for the application’s weight variations, the shock absorber used a different setting at each stopping point on the assembly line.
By implementing the new product, the customer was able to reduce the transmitted shock force to the assembly line by an order of magnitude, significantly reducing downtime and improving overall efficiency.
Case Study 2— Vacuum-operated pick-and-place robot systems in tire manufacturing rely on the forces generated through vacuum to lift the tire and move it to the next station during the molding process. When operated slowly, the shock induced at the end of stroke has very little energy, and the system functions properly. However, to increase throughput, the cycle times are reduced, increasing the impact velocity at the end of travel, leading to higher impacting energy. This impact energy can cause the tire to break free from the vacuum, stopping production and potentially damaging the product.
In looking for a way to increase throughput and reduce overall impacting energy, the manufacturer of the production molding equipment implemented ECO and PMXT series shock absorbers, as seen in Figure 2, for stopping the motion at the end of travel (the model and size is dependent on the type of tire). Through simulation of the impact event, the team generated performance curves and data to show that the deceleration and maximum allowable force requirements were being met, leading to a more reliable operation.
Today, tire manufacturers are experiencing faster cycle times without losing control of the product during movement.
Vibration reduction
Failures associated with vibration, such as loose bolts or broken welds, are often related to general fatigue or degradation of the assembly rather than one, abrupt movement.
在线性运动系统中，振动控制产品通过从振动源解耦设备，使振动难以使其进入设备。例如，振动表通常用于在许多制造过程中传递组件和材料，包括线性运动系统。振动的频率导致处理的材料在横跨振动表面上巧妙地反弹并流动。虽然这是一种有效的移动材料和部件在大量生产中的方法，但允许这种运动的相同振动也可以损坏周围设备。通过将振动组件与钢丝绳隔离器隔离，如图1所示，保护周围设备。隔离损坏振动的周围设备可防止螺栓松动，破坏焊接和损坏的电子元件。这减少了停机时间并提高了生产率。
In addition to controlling vibration within a linear system itself, vibration control devices are also used to steady a system’s electronic components (the brains behind the operation), as they are typically expensive to fix or replace and can cause significant downtime if they are damaged.
Take, for example, monitoring cameras used to regulate equipment for operations and security purposes. Many overhead crane manufacturers rely on these cameras to control the entire production process. The motion of the cranes causes vibration, which is not only damaging to the cameras, but also impacts the clarity of the image. Moreover, the cameras are often mounted in difficult-to-reach locations and are exposed to severe environments. To help protect the equipment and stabilize the image, wire rope isolators are often applied to decouple the camera from the vibrations in the crane equipment. The rugged design of the isolators is ideal for severe environments, while keeping them maintenance-free.
Conclusion
When looking for a way to minimize damage and increase meantime between failures in your linear motion application, it is important to consider using energy absorption devices like shock absorbers and vibration isolators to control the kinetic energy of your system. By tuning your solution to match an application’s unique requirements, plant operators will see improvements in operational runtime, efficiency, product life and protection as well as overall profitability. On the manufacturer’s side, it is equally important to arm customers with the right tools and products to fully optimize their system for improved results.
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Filed Under:Linear Motion Tips
