January 12, 2024
Expanding your options: A case study of process innovation
Hartzell Propeller’s expander was on its last leg. If it died before they found a replacement, manufacturing services manager Brian Hicks was going to have a problem on his hands.
For around 15 years, the machine had molded carbon fiber propeller blades for various aircraft — a delicate and finicky process more like an art than a science.
“This was a machine that we implemented and produced with some help years and years ago,” Brian said. “So, to try to replace it identically? We were afraid… We don't want to worry about our old dinosaur dying and putting us in a bad spot.”
At the time, we were already working with Brian and his team to supply the expander’s tooling. So, he brought us a blade and asked if we could replicate his “old dinosaur.”
Not only did we build Hartzell Propeller a new expander, but we also transformed the art of processing propeller blades into a science. Here’s the story.
The “old dinosaur”: A special machine ready for retirement
For as crucial as the expander was to Hartzell Propeller’s manufacturing processes, it wasn’t originally designed for that purpose. In 2006, Brian had worked with a different supplier to convert a hydraulic IO sizer to the ER machine.
This ER machine, also called an expand/reduce machine or just an expander, pushes a mandrel through segmented fingers to expand a component with a diameter of up to 80 millimeters. In Hartzell Propeller’s case, the manual machine expands a metal component inside the hub of a resin propeller blade to the correct shape. Often, this required the operator to manually rotate the blade and run the process again.
But this wasn’t the only hassle of working with the old expander. To prevent carbon contamination from the hydraulic oil, the machine also had to be kept in a different room from the rest of the equipment.
The goal: A reliable, programmable machine for an expensive process
Brian and Hartzell Propellers were looking for a few specific things with their new expander:
Reduced operator influence
Their whole propeller manufacturing line hinged on this machine functioning properly. Expander downtime would down all production lines.
Additionally, because resins and other composite materials are so expensive, they needed a process that resulted in low or no scrap. The more accurate the machine, the less waste there would be.
And their current, manual machine relied heavily on the operator and produced inconsistent blades. Reducing the operator’s responsibility and increasing part consistency would improve Hartzell Propeller’s manufacturing process.
With these parameters in mind, our engineering team took a clean sheet of paper and got started.
Eliminating carbon contamination with an electric machine
Composite materials — like the resin in Hartzell Propeller’s blades — react poorly to oils and other contaminants. This makes processing components with traditional hydraulic machines difficult.
If hydraulic oil from the machine gets into the resin, it prevents the materials from bonding properly, creating flaws. And when flaws like that happen, it means the operators must rework, or even scrap, a blade. Not only does this slow production down, but it also wastes time and material.
Brian’s team had to take special precautions to keep both the blades and facility’s layup room clean. Some of these precautions added steps to the manufacturing process. Literally. Operators had to walk out of the room to operate the machine.
“We struggle with carbon contamination,” Brian said. “We actually had to have the expander outside of the room with just the nose sticking in because of contamination to the machine and also to the room.”
To combat that, we recommended an electric machine. Not only did this eliminate carbon contamination by removing hydraulic oil from the process, but it also lowered the facility’s noise levels and operating costs.
Traditional hydraulic machines are always drawing power, even when they’re sitting idle. In contrast, Brian’s new electric expander gives him power on demand, meaning the machine doesn’t generate heat, noise or unnecessary energy costs when it’s not in use. To accomplish this, the machine uses precision roller screws with electric actuators in place of a traditional hydraulic power pack and cylinder.
“You hardly hear it run, where my old one sounds like a tractor running,” Brian said. “So, it's quiet, no contaminants… it doesn’t get into the boards, it doesn’t get into the working parts, the working systems of it. That was extremely helpful.”
Eliminating carbon contaminants would reduce Hartzell’s scrap rate. And switching to an electric machine provided opportunity for process innovation, which would reduce the operators’ influence and result in more consistent parts.
Reducing operator influence with a digital program for each component
Working with composite materials, like resin, requires a balance that can be difficult to master. Using too much force too quickly can damage the blade, while not using enough force won’t expand the blade.
Before working with us, maintaining that balance relied heavily on the operator’s skills. And while Brian wanted to change that, he was hesitant about recreating this manual process mechanically.
“We were apprehensive in changing the way that we typically do things,” Brian said. “The operators that do my layup are not really machinists. They’re more of artsmen, if you will, because the process that we do is more, in my mind, an art than a production atmosphere.”
But if Brian wanted this process to be quicker and more consistent, it needed to become less of an art and more of a science. So we gave the Hartzell Propeller team more control over their machine. This started with process controls for force and velocity and expanded to include profiles and programs for each component.
"iES is out to do exactly what their name is. You know, innovative."
Now, instead of creating a fresh program for each component, an operator can simply pull up a pre-saved program, press a button and produce parts quickly and accurately. Not only does this set up take less than a minute, but it also removes human error from the process.
The future: A process and equipment fit for scale
The electric expander was exactly what Brian and his team needed — a process that turned their art into a repeatable science. As Hartzell Propeller moves to a larger facility with the capability for a higher throughput, having an expander that can maintain consistency will improve the team’s efficiency and limit the possibility of downtime.
“Our business is just phenomenal, so I'm looking at tripling my layup room,” Brian said. “That means I’ve got to triple my equipment as well. So, we're looking at least another expander, if not more.”
As Hartzell Propeller expands, our team continues to work with Brian to improve the electric expander’s design. Our new goal is to reduce the operator’s influence even more by adding in a part-locating fixture that will load parts into the machine the exact same way, every time.
“iES is out to do exactly what their name is. You know, innovative,” Brian said. “They were a spot-on crew. I feel like Hartzell Propeller and iES? We’re partners now.”
Want a partner to improve the process controls in your production? Get in touch with our team to learn how we can help. We’ll get back to you within 24 hours.