Using Markforged Simulation to Enhance Efficiency in Engine Development: PUNCH Torino case study

Published on : 7 September, 2023

The Customer

PUNCH Torino is a well-known research and development center in Europe, specializing in internal combustion engines and propulsion systems. It all started in 2005 when it spun off from the Fiat-GM powertrain joint venture in Torino, Italy after GM sold its share. Under GM's ownership, the center grew from 80 employees to over 700, hailing from 12 different countries. Then, in 2020, it was bought by Belgium's PUNCH Group.

Since then, PUNCH Torino has been providing its services not only to GM but also to an expanding list of companies and startups. They work on various technological projects, covering areas like gasoline, diesel, and hydrogen engines, generator sets, gearboxes, additive manufacturing, and collaboration software.

The Challenge

At PUNCH Torino, they work on developing and testing new parts for existing engine designs. They also build prototype engines for their clients. During this process, engineers have the crucial task of installing a timing chain that connects the engine's crankshaft to two camshafts. These camshafts have lobes along their length, and when they turn, these lobes open and close the valves in each cylinder. This action allows the right amount of fuel and air to enter and exit the engine at precisely the right moments.

When tightening the timing chain sprocket, it's crucial to keep the camshafts completely still in a precise position. This ensures that the engine's timing system remains perfectly synchronized when the engine runs. If the camshafts aren't securely held in place, it can lead to the valves opening and closing at the wrong times, potentially causing harm or even ruining the engine.

Engineers at PUNCH Torino came up with a smart solution to keep the camshafts from moving during this process. They designed special fork-shaped camshaft locking tools using a material called Onyx, reinforced with fibers. These tools have to withstand a torque of up to 120 Newton meters and ensure that the camshafts don't turn while they're being tightened. Now, these camshaft locking tools are crafted using a Markforged X7 3D printer, using a combination of Onyx and carbon fiber reinforcement. It's estimated that each of these tools takes about 18 hours to print.

If one of these locking tools fails while they're tightening the camshafts, it can cause the camshaft to move because of the torque. When this happens, the team has to undo or take off the timing chain, put the camshafts back in the right position, and then do the tightening again. If they have to wait for a new locking tool to be printed, it could delay the construction of a new engine by a day or even longer, potentially causing some problems with their schedule.

In the process of designing engines, engineers often need to make small changes to various engine parts, especially in the early stages of development. This means that the team has to adjust the design of the camshaft locking tools and create new ones each time they make a change. Sometimes, the engineering team is testing multiple camshaft designs simultaneously, and each design requires a slightly different tool design to work with it.

Before, making these camshaft locking tools was a tough process that required a lot of trial runs. They didn't have a good way to be sure if a tool would be strong and sturdy enough to handle the torque. Plus, they couldn't easily tell if changing the design of the tool might make it weaker. Also, because the FEA (Finite Element Analysis) analysis they used wasn't meant for 3D-printed stuff, they had to make a bunch of guesses and rough estimates to create tools that worked well for their needs.

“Simulation has enabled us to eliminate a lot of trial and error in the design of our camshaft locking tools. It has helped us cut our development time by more than 50 percent.”

– Valerio Ametrano, Senior Pre-Production Engineer, PUNCH Torino S.p.A.

The Solution

PUNCH Torino managed to make substantial savings by using the Simulation tool from Markforged. Valerio Ametrano recalls that when they had to adapt to a new camshaft design, it often meant printing and testing as many as eight different jig designs before they found the right one. Changes in the camshaft's shape or measurements, like its lobes, length, or diameter, might require tweaking the fork shape to hold it in place. However, these adjustments sometimes didn't fit the camshaft's curvature and led to it turning too much. So, the team had to print many tool versions until they got it just right.

“Simulation frees up our team members’ time to focus on other priorities and the X7 to print parts for other projects.”

– Valerio Ametrano, Senior Pre-Production Engineer, PUNCH Torino S.p.A.

However, when they started using Simulation for Markforged, they managed to reduce the average number of tool design tests from eight to just three. Ametrano explains that it took some trial and error initially to learn how to use this new simulation tool effectively, particularly in terms of understanding things like force, deformation, and boundary conditions for the locking tool. However, now that they have a handle on this data, they can typically model and print a standard locking tool in a single go.

According to Ametrano, Simulation for Markforged not only saves the team around 18 hours for each jig but also the time they used to spend on modifying component designs, which is now managed within the program. Additionally, it frees up a significant amount of printer time that was previously tied up making multiple versions of camshaft locking tools.

Ametrano follows a structured process using Simulation to evaluate components and optimize print parameters along with the placement of carbon fibers. He often experiments with different arrangements of manually placed fibers, assessing factors like estimated deflection and safety. With Simulation, he can quickly assess how different fiber configurations impact the part's performance, allowing him to swiftly identify the most effective arrangement for printing.

In the early stages of engine development, engineers frequently make adjustments to camshaft designs. If these changes are minor, the team tweaks the design of the camshaft locking tool, ensuring it still meets the necessary strength criteria by using Simulation for Markforged. However, if there are significant modifications to the camshaft designs, they need to redesign the locking tool and rerun the simulation based on the new design.

When it comes to engine assembly, the PUNCH Torino team must gather a large number of components and tools in one place to assemble multiple engines within a tight timeframe, often assembling eight to ten of them. The Markforged simulation ensures that the camshaft locking tools are properly configured and ready for use when needed. Ametrano stresses the importance of having tools set up correctly because an improperly configured tool can fail under pressure, potentially causing delays in engine construction, sometimes for a day or more.

“The Simulation tool is very affordable and easy to use compared to finite element analysis tools for testing and validating of tooling designs directly on operations.”

– Valerio Ametrano, Senior Pre-Production Engineer, PUNCH Torino S.p.A.

The Future

Aside from their work on designing and prototyping engines for various global OEM automakers, PUNCH Torino also offers its 3D printing knowledge to various industrial and technology clients. Recognizing the potential benefits, the team is considering using Simulation from Markforged to enhance the efficiency of their part design and building processes. They see this tool as a powerful and cost-effective solution that could significantly save time and enable them to provide superior parts to their clients.

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