Automated Under-Fluid Assembly of Hydraulic Engine Mounts

Automated Under-Fluid Assembly To Guarantee Quality And Decrease Cycle Time

Many different bits and pieces make up automobiles, but they all have one thing in common: Their makers must ensure their products are of consistently high quality.

When that consistency is in jeopardy, suppliers run the risk of losing their place in the competitive automotive supply chain.

In 2002, our customer—a major North American automotive supplier—realized it needed to rethink how it mass produced hydraulic engine mounts. They turned to Arnold Machine, hoping our expertise in automated assembly systems could help address the problem.

CHALLENGE: Inconsistent Cycle Times And Too Much Scrap

Prior to integrating the Arnold-built system, our customer relied on a manual assembly and filling process. This setup was prone to some inconsistencies.

For one thing, the customer could not guarantee that each engine mount would be assembled the same way every time. Such is the nature of having people—who are not perfect—on the job.

For another, the consistent and correct filling of the mounts with fluid also could not be guaranteed. The mounts are specified to be totally full without any air pockets. But they’re only tested after being sealed closed. By that point, rework is impossible. Mounts that failed the test had to be rejected.

Add to these issues the fact that human workers cannot do repetitive tasks at the same pace from the beginning to the end of their shifts. Cycle times were unpredictable and too many mounts had to be rejected because they were assembled incorrectly, were not totally full or both.

SOLUTION: Automated Under-Fluid Assembly To Guarantee Quality And Decrease Cycle Time

Arnold had successfully delivered many automation solutions to this customer in the past. That existing relationship led the customer to call on us again. Our task was to develop a system that eliminated inconsistency and improved the cycle time of the assembly and filling process.

Our idea was to assemble the components robotically inside a tank of fluid. Here’s how it works:

• A robot retrieves parts and plunges them into a tank of fluid. Previously, a person was responsible for this and their cycle times were inconsistent.
• Jets inside the fluid tank send the fluid into the part cavities and force all air out. Previously, the human operators would be responsible for removing the air from cavities.
• The robot then assembles the mount while keeping it submerged in fluid. The machine then seals the part while it is still submerged before the robot unloads it. Previously, a single person was responsible for assembling and sealing the mounts. This took too long.
• The system features many moving parts, but operators are protected from the system’s motion. Previously, operators were exposed to moving parts and their risk of injury was higher.
• The robot carrying out these tasks was a FANUC LR Mate series system. LR Mate models are highly customizable, with ranges from 550 mm to 919 mm on a five- or six-axis format depending on process requirements.

The LR Mate models are also compact and lightweight, making them perfect for the small footprint of the machine we built. Because of that, no facility or workflow modifications needed to be made in our customer’s plant to accommodate this automated system.