Autodesk experts discussed digitalizing and streamlining injection mold tool modification and repair processes with hybrid manufacturing.
In a competitive world of manufacturing, hybrid manufacturing is a growing trend that brings the best of additive manufacturing and subtractive manufacturing together in one machine tool. Digitizing and streamlining processes using that method was the focus of the recent Autodesk University session “Realizing the Circular Economy in Tool Making with Hybrid Manufacturing.”
The session was presented by Desmond Ho, project manager, Autodesk Research; Paul Brincat, senior research manager, Autodesk Materials Lab; Kyle Saleeby, research staff member, Manufacturing Automation and Controls Group at Oak Ridge National Laboratory (ORNL); and Daniel Noviello, senior research manager, Autodesk Research.
During this session, the presenters focused on a project that used hybrid manufacturing to modify and repair injection mold tools. According to Noviello, along the way, the team “wanted to be able to demonstrate the circular economy principles with tool re-use in the injection molding industry as opposed to building brand new tools and re-machining.” This project also presented opportunities to address flexible manufacturing—using the same tool to produce successive versions of a product.
The team looked to the automotive industry for inspiration. It is common to have to mill away damaged areas of a part and insert a prefinished element back in to regain the right geometry. This typically requires welding and machining, which isn’t a cost-effective solution for smaller tools. With cost and waste always top concerns, streamlining the process using hybrid manufacturing allows for a circular economy in which tools are modular, reusable, and can easily and quickly be modified. Hybrid manufacturing allows all of that to happen in one machine, reducing lead times and minimizing the steps involved.
While thinking of ways to demonstrate the benefits of this process, an opportunity presented itself.
“Just days before finishing off our hybrid modify inserts to be ready for the next event, IMTS 2022, we were informed of the Autodesk logo change, which means our original Autodesk logo will not be relevant for any coming events,” Ho said. “We then thought to ourselves, isn’t this the best way to show the benefits of having manufacturing for model modification and repair? So, an immediate update on the CAD model with Fusion 360, followed by additive and subtractive tool path regeneration, prepared us for a really quick turnaround time for physical modification of the insert.”
Once the demonstration component was selected, there was a combined effort with ORNL, Autodesk Materials Lab and Autodesk Research to make the magic happen. ORNL has a manufacturing demonstration facility and has been working with Autodesk for more than two years to further its hybrid manufacturing and other technologies. The Materials Lab served as a molding shop for the project to create the insert and perform molding trials. The next step was creating a Fusion 360 project.
“We had a product designer, tooling designer, injection molding simulation—and all this working in the same environment,” Brincat said. “So straight away, it impacts the design decisions. We reviewed the tooling and injection molding processing issues, so it enabled collaboration rather than sequential design, tool and simulation.”
During the workflow, which everyone on the team was able to see, the team looked at the component’s design to determine possible ways to reuse it. A simulation was run with material shrinkage properties for mold flow. Those results determined if the design needed to be refined. After concluding that the design was suitable, a milling tool path was generated on the insert block to start manufacturing it. A small batch was run to identify any areas of concern. Component design updates were made. Areas to be modified were milled and then material was added into the area.
Thanks to the Fusion injection molding building preview, there was immediate access to the material database, which has more than 11,000 materials with real-life measured properties. Next, processing details were selected, such as injection speeds. The software also predicted part shrinkage, which was 0.7 percent for this design. With a few clicks, all that was left was waiting for the results.
The flexibility of incorporating additive manufacturing allowed the team to more easily handle issues that arose. Due to the gate design of the part and a long tab that frequently broke, they had to look for ways to improve it to eradicate ejection issues. Another issue was that the part would get stuck into the fixed half.
The team took three main steps to redesign the mold. First, tool paths were programmed to prepare the existing geometry’s surface and location. After this revision, tool paths were programmed to remove the engraved text. Finally, a tool path was programmed to machine a small pocket for the material to be deposited.
“One of the benefits of Fusion 360, clearly, is the ability to change rapidly between workspaces and manufacturing operations,” Saleeby said. “This capability became extremely powerful when we needed to switch back between subtractive machining, additive DED and even the redesign changes to make these tool parts. After programming and completing the preparation steps, we heavily leveraged that ability to switch to program a DED feature construction strategy to rebuild both the logo text and the new Autodesk logo.”
After the process of erasing and rebuilding the updated feature, re-machining operations continued and were duplicated on the moving mold insert. During the process, extra care was taken to ensure proper material dilution and adhesion of the new material to the mold surface. Strategic tool path limits were set, and other features were physically masked to avoid weld or slag damage. Monitoring techniques were set into motion to capture, record and analyze the mold repair process.
“We learned a great deal about repairing the existing mold by leveraging the Fusion 360 environment,” Saleeby said. “There were a couple of tool path considerations in terms of giving extra feed height than the roughing operations to bring that preform down to size. We heavily relied on that design workspace to make sketches, boundaries and other geometric features that helped us guide and control the subtractive tool paths. This can also now be done with the new manufacturing model process as well.”
Once the new part was made, the team was able to reflect on the quick resolution and ability to collaborate from different locations. The team members were from four different countries and were in four different time zones, and the physical work was conducted in two labs.
“The unified hybrid manufacturing workflow in Fusion 360 creates opportunity for more makers and manufacturers to reuse their mold tools, and at the same time, enjoy a shorter lead time, reducing waste, and eventually reducing their cost,” Ho said. “It also provides a very good platform for research into new engineering material characterization, which often requires successive changes in model design to achieve the desired results.”
While hybrid manufacturing has proven benefits, like most things, it has its downsides. For some manufacturers, the costs associated with the tools may not fit into their budgets. The model itself also presents challenges. The size, weight and surface determine if it can be repaired or modified, which means load restrictions. If trying to work with a part that is too big, traditional methods will likely still be required.
“We are exploring the possibility to bring down the entry barrier, transferring this know-how onto less costly hybrid machine hardware set up with a single, easy-to-use software application like Fusion 360, which we have already approved the single workflow to cover the whole process,” Ho said. “We are also scaling up the process to cater to bigger and more complex repairs or modifications, and also for manufacturers that have to produce very high-mix and low-volume injection molding components.”
For more information on the latest Autodesk updates, check out Autodesk University Shows Off Big Changes to Fusion 360 Simulation.
