After the MBD history and successes at Gulfstream, a subsidiary of General Dynamics, we learned about the MBD experiences at Gulfstream in software and hardware and in ensuring data integrity. Great design and engineering ideas must go through manufacturing to reach fruition and become physical products. As Dan Ganser, product lifecycle management (PLM) staff scientist with Gulfstream, shared, “The most exciting part of the model-based definition [MBD]project is to watch people run with what we created. Everybody downstream loves it.” Let’s look into how Gulfstream empowers the downstream manufacturing process.
First, as we learned previously, Gulfstream equipped its entire shop floor with CATIA V5 software, workstations and dual monitors. This allows the shop floor workforce to bring up the models and query necessary information in real time without having to wait for others. The 3D models reduce ambiguity in interpretation and avoid time delays.
Second, Gulfstream uses model-based electrical harness design as shown in Figure 1.
Figure 1. A model-based electrical harness design. (Image courtesy of Gulfstream.)
This allows separate electrical analysis to ensure that the critical signals are routed as designed. The team can trace any electrical signals throughout the airplane. Then, the harnesses are merged with the 3D models as shown in Figure 2.
Figure 2. An electrical harness system integrated with the airplane’s 3D model. (Image courtesy of Gulfstream.)
Next, Gulfstream extensively applies numerical controlled (NC) machining and precision manufacturing. Because of the 3D MBD data and precision manufacturing, the produced components are of much higher quality than before, which speeds up assembly time. For example, Jeff Kreide, vice president of Business Solutions with Gulfstream, pointed out that the barrel joining assembly used to take five people three and one-half days to complete. Now the components can be well aligned and assembled in just 15 minutes as shown in Figure 3.
Figure 3. The barrel joining assembly time was reduced from three and one-half days to only 15 minutes. (Image courtesy of Gulfstream.)
Here is another example of faster assembly. Airplanes use a large quantity of fasteners such as rivets. Many different types of fasteners must be installed accurately at a wide range of locations according to a variety of torque specifications and instructions. What’s even more complex is that the installation surfaces are often curved, especially at the entrance doors. Previously, 2D flat drawings had challenges to define the exact fastener locations on curved faces. The shop floor used to draw the fastener maps on nylon pieces and wrap the pieces around the doors to convey work instructions or run quality checks. Now the fastener maps that were previously made on nylon pieces have been digitized as shown in Figure 4.
Figure 4. A fastener map projected onto the curved surface of a door. (Image courtesy of Gulfstream.)
Using a software application, ProjectWorks, along with multiple high-resolution laser projectors, Gulfstream projects the fastener map directly onto the airplane’s body. Of course, the projectors coordinate with each other in order to bend and reshape the image to make sure that all the fasteners are correctly located on the curved surface. With the digital model projection, you can modify the model or instructions in real time and they will be instantly updated and mapped correctly onto the airplane, without having to wait for the redrawn physical nylon pieces anymore. One tip here is that rather than using actual protrusions, Gulfstream only models the fasteners as points and vectors with attributes such as types, tooling and pre-drill information. This can prevent the model heaviness from being loaded onto computers.
Similarly, in 2016, Gulfstream expanded the use of digital laser-projection into painting as shown in Figures 5 and 6.
Figure 5. A technician adjusting and projecting a painting plan onto a Gulfstream G650 airplane. (Image courtesy of Gulfstream.)
Figure 6. A painting plan is projected onto a Gulfstream G650 airplane. (Image courtesy of Gulfstream.)
Traditionally, the painting plan was laid out on 2D drawings. Besides the problem of there being different interpretations to different eyes with flat drawings, the more complex the curved surfaces are, the greater the possibility is for the actual painting to deviate from the drawing. Then when it comes to painting preparation, the step of taping an exterior surface alone could take a crew of technicians eight to 12 hours.
Now with the 3D laser projection, the time to prepare an aircraft for painting has been cut in half. Furthermore, the easier and real-time digital modification allows more design options and greater owner participation.
Last but not least, training is vital to the success of the MBD implementation. For example, Gulfstream uses colors rather than product and manufacturing information (PMI) to indicate certain key characteristics. However, designers use colors differently for a wide range of use cases such as surface roughness or tolerancing methods. How would others involved in the process be aware of this? The color usage must be constantly communicated.
To this effect, Ganser shared a story. An assembly line once installed one of the initial mirrors onto the airplane. The mirror fitted perfectly, except that the reflective side was against the wall, so the mirror wasn’t reflective at all. What was the cause? The engineer built the model and added the color yellow on the reflective face. However, the manufacturing team wasn’t sure about the color’s meaning, so they thought the reflective face could be on either side, or that yellow meant the back side. After all, the model looked the same. The miscommunication led to this mirror being scrapped. There are many other similar issues that require ongoing training and communication to address.
Beyond internal teams, the supply chain must go through a major paradigm shift as well. This is one of the areas where Gulfstream underestimated the impact. For example, during the manufacturing process, shop floor team members often modify the models due to manufacturability considerations, such as deleting holes or adding handles. The problem is that many times, the inspection is conducted against the modified NC models rather than the CATIA V5 models. Gulfstream has to keep training suppliers to respect the CATIA V5 models as the documentation master, not 2D drawings or shop floor NC program models.
To mitigate the risk, the company established a rigorous process for suppliers to go through. Suppliers must make sure they understand how Gulfstream documents its models and how to read them. Before a supplier can be delivered a purchase order (PO) or an MBD part, it has to be approved through the Gulfstream qualification process.
There have also been some pleasant surprises. Originally,the implementation team thought it would be difficult to train the shop floor workers to adopt new software and hardware.It turns out that the team underestimated how quickly the technicians could adapt to the MBD process. The workforce is much younger than before. Not only did the workers like the cool technology, but they also grasped the skills needed for their particular jobs much faster than expected.
That’s it for now about the MBD experiences at Gulfstream. We discussed the practices to empower the downstream manufacturing process such as software and hardware tools for technicians, model-based software applications and training. To learn more about how SOLIDWORKS MBD can help you with your MBD implementations, please visit its product page.
About the Author
Oboe Wu is a SOLIDWORKS MBD product manager with 20 years of experience in engineering and software. He is an advocate of model-based enterprise and smart manufacturing.