説明
主な学習内容
- Learn how to apply GD&T using the Tolerance Advisor
- Learn how to assess the value of downstream using Model-Based Definition
- Discover the benefits of using Model-Based Definition to create GD&T
- Learn how to get started with 3D Annotation
スピーカー
- Melanie ThiloMelanie Thilo has worked for more than 10 years as a mechanical design engineer and project manager for different companies and industries. Since 2018 she is a Technical Specialist in presales for design and manufacturing at Autodesk.
MELANIE THILO: Imagine the following scenario, a designer defines the function of a component, the machinist knows what to pay attention to during production to make it part work, and the quality engineers know how to inspect the component.
In this session, you will learn why it is important that everyone has the same understanding of what finished parts should look like and how to use this method, this model based definition in Inventor. Geometric dimensioning and tolerancing is an excellent tool to describe the function of a component.
Hi. My name is Melanie Thilo. As a child, I loved looking over my father's shoulder. He could spend hours and hours looking at a geometric problem that he was trying to solve in CAD. For him, it was almost like playing a computer game. The knowledge he gained here also helped him to be successful in his job.
He had many very forward thinking ideas for that time. It was in the early 2000s. He was passionate about discussing his ideas at work and at home as well. So I grew up hearing stories of science emailing, of the 3D printer, and of course, the machine arm. This is the reason why I decided for a technical career.
Before joining Autodesk in 2018, I worked for more than 10 years as a mechanical design engineer for various companies in different industries. In addition to my day to day job, I have always been happy to accept other challenges. For example, I planned and conducted a course for 130 engineers. The topic was standard compliant drawing creation and geometric dimensioning and tolerance. Today, I see my role in helping our customers to be successful.
Have you ever asked yourself the same question, why do we need drawings? Technical drawings are very important for communication between all parties involved in order processing. The part or assembly is completely described so that it can be manufactured without any further questions. As a result, drawings are important for documentation.
In addition, drawings are the foundation for technical communication within a company. Drawings are so important that they are almost like a contract. And because they are so important, we at Autodesk do not believe that companies will be able to eliminate drawings completely in the next few years. Nevertheless, we are convinced we can help you to save a lot of time with drawing creation.
Before we go into the future workflow, let's take a look at what I hear from my customers and how they are doing it today. Let us hear the fictitious story of Jake and Ryan. Any resemblance to existing personas is purely coincidental. So the mechanical design engineer Jack has an idea. Immediately, Jack start to transfer the idea into the computer. This is the first translation.
Jack creates drawings of all components, which is already the second translation. This drawing is then passed to the production engineering. And the production engineer, Ryan, looks at the drawing and asks himself, what do I see here actually? So Ryan calls Jack, and he adds all the missing information, and now, having all required information, Ryan can continue working.
Since Ryan only got the drawing and no 3D data, he has to start from scratch to create the machine code. I think after this short story, nobody is really surprised about the fact that the finished component is not very similar to the mechanical design engineer's idea. This is where the concept of MBD becomes effective, because the model already contains much information and is provided to the production engineer. He has better data and creates the program much faster.
And the concept of model based definition is to add all information to the model and use it downstream, which means reuse the same data for 2D different creation, reuse it in 3D PDFs, use it for tolerance analysis, use it for exporting it as in step AP242, use it as a basis for an NC Toolpaths, as we heard in the story before, or for creating CMM paths.
But what is model based definition? Model based definition has four elements. This first is geometry. That's the ideal and mathematical correct description of a part. The second element is annotations, tolerance information, GNP surface dimensioning, and all other important information for downstream use.
MBD also includes metadata, like material information or other ed properties. And last but not least, model based definition includes all the different views you have on your file or on your data, on your model. Why are we doing this? All this information is definitely human readable. That's the beauty of model based definition. It's machine readable as well. But machines do not really need views that just look great.
So I want to focus in today's session on the annotation part. Let's have a look at this pretty simple sheet metal part. You, as a mechanical design engineer, you have two options to tolerance this part, on the left hand side, the traditional way of tolerancing, and on the right hand side, GD&T.
Which option would you choose? Or what makes the difference? Let's have a look at the finished part, which, of course, looks a bit different from the ideal geometry we create in CAD. If the measure was finished part and we align it for measurement on the long edge, it fits good.
And what if we align it to the short edge? Not so good, because it's out of step. What if we align it somewhere in between? Then it's very good. So we have the challenge, one tolerance, three different measurements, three different results. That could be a little bit of risk if it's really important for the function of that product to be within risk tolerance.
Let's have a look at the other version, the GD&T version. Here it's clearly defined how to measure the path, to align it on the primary reference A and then have your tolerance sewn. And with this description, you see the big benefit of geometric dimensioning and tolerancing. GD&T promotes a common understanding of a part, how to manufacture it, and how to measure it.
GD&T is unique. GD&T enables a description based on the function. So properly applied, GD&T clearly communicates the design intent. But incorrect application often creates inefficiencies that exceed the benefits. This is where the GD&T Advisor comes in. GD&T Advisor allows you to quickly apply accurate standard based GD&T annotations seamlessly integrated in Inventor.
It uses precise mathematics to recommend the most appropriate GD&T controls for the feature selections, while providing messages on why others are not recommended or appropriate. Unlike common 3D annotation solutions, GD&T advisor will not allow the user to create invalid annotations. This accuracy and speed moves you one step closer to a true model based environment.
GD&T Advisor uses color coded highlighting to indicate where GD&T has been completely defined, where this only partially defined, or where nothing has been defined. The advisor window provides information about the current status of GD&P application to the part and where attention may be needed.
With this, I want to jump directly in the demo. The top of a mechanical design engineer is much more than just creating a correct 3D geometry. The real skill is to describe the function of a component accurately. That's where GD&T comes in. Let's take a closer look at the pink part in this assembly.
We see some contact surfaces to other components. These functional surfaces require specific attention during manufacturing. This is the only way that a component can fulfill its function within the assembly.
For example, the surface that lies next to the orange component needs a certain flatness. In my example, I also defined the surface as Reference A. The shaft for mounting the ball bearing also need special attention. This surface should be perpendicular to my primary reference. I do the same with the other two shaft shoulders for the other bearings.
From the seamlessly integrated tolerance advisor in Inventor, I get feedback that it makes sense to tolerance every surface that got GD&T. To ensure the function of the bearing, I provide it with a tolerance of k6 for shafts. Which tolerance is exactly right here is something you know much better than I do. This is your know how and competitive advantage.
By doing the same with the other two bearing seats on the shaft, I see that the list of messages in the tolerance advisor is getting shorter and shorter. And so I can proceed step by step and specify further functional surfaces in my design.
The shoulder here, for example, is supposed to be perpendicular to Reference B. But I cannot select it at all. To be able to select a reference, it must be defined as a DRF. Once Reference B is defined as a datum reference frame, I can also select it as a reference for perpendicularity. It can also easily define a new DRF while creating a new tolerance feature.
The tolerance advisor gives me feedback that some surfaces are not completely defined. To get a better understanding, I can turn on phase status coloring. So as you can see very quickly that the message refers to the lateral contact surface of the bearings. For me, it's technically OK that these are not fully constrained.
Much more important is to fully define a fit for the inner bearing. It's the same procedure as we have seen before. And because I learned from the tolerance advisor that every bearing seat needs a fit and now define it together as a position tolerance. Important information can be kept early in the design process. The function of a part can be described directly in an assembly context. This is a true value of model based definition.
All this information is important, for example, in collaboration with other departments, such as manufacturing or metrology. The fact that this information is included directly in the model can eliminate the need to create a drawing in the early stages of product design. This means that it could be enough to create a drawing late in the process instead of creating it early on and changing it several times during the project.
The Autodesk Viewer is the easiest way to align on a 3D model. You can upload the model directly from Inventor. Autodesk Viewer browser based, so you can access it from any device and anywhere. For collaboration with other departments, you can use a variety of capabilities, such as up the model or share it with key stakeholders.
Communication on a design has never been easier. Early designs can be shared securely with suppliers or other experts. This is a great way for them to influence the later product quality at a very early stage of development and ensure that the component functions as intended later on.
Nowadays, this kind of discussion is often done very late in development process because the exchange of drawings is experienced as very time consuming. In Autodesk fewer markups can be added to designs quickly and easily. Knowing that we all think in 3D, this makes it easier for us to understand what we see.
In Inventor, we see all markups and comments on the shared view panel. We can start now to detail our 3D annotation. In Inventor 3D annotations are managed by views, so we create a new view called GD&T. Already existing annotations can be changed at any time if necessary. For a better understanding, another annotation plane can be selected easily.
This allows us to quickly and easily update the annotations to our single source of truth as requested in the markups. We have to change our datum reference frame. Here we can see how the GD&T advisor supports our work in the background. I cannot create the desired reference system here. Why? The order of my tolerance feature in the browser is essential here. First, I must have a reference. Then I can select it in a new DRF.
With this strategy, the model can be detailed step by step. To make the model human readable, it is helpful to manage the annotations with views. Good to know, all changes apply to all unlocked views. You find all relevant features from model based definition in the Annotate tab. Please refer to Inventor Help and Tutorials to get more details. And how to use them.
Model dimensions can be easily reused as 3D annotations. To do this show dimensions, select, and promote them. Sometimes you may need dimensions that do not exist in the model. This can be easily created. Just select the geometry, choose the annotation plane, and place your dimension. Here you can also select easily the required tolerance for this dimension.
In downstream views, promoted and created dimensions show different behaviors. Promoted dimensions are linked to the model parameter. If you go to the parameter list and reset the tolerance to upper, medium, nominal, or lower, you see the different behavior of created and promoted dimensions. Created dimensions are great for downstream use and tolerance analysis.
As you are done with detailing, you can start to create a drawing from your model. This is business as usual. Create your drawing fields, select the right sheet, and so on. For downstream use of 3D annotation, you can retrieve the model annotations and select the annotations you need for your drawing.
If some information is missing, you add it to the 3D model, your single source of truth, and your drawing will update automatically. The good thing is that all important information is already saved in the model and can be reused directly.
Drawing creation is much faster because you don't have to think about the following questions first. What fit do I need here? Where do I start with my datum reference system? What functions will my component have to fulfill later? All this has already been done and aligned with all relevant experts. Creating a drawing is now a trustworthy task.
Using model based definition significantly simplifies or even eliminates the necessity to create a drawing. Companies who subcontract their manufacturing have greater success using this workflow. Instead of producing a full drawing to get a quote, model based definition can be attached to the model and shared. The advantage is a quicker turnaround for quotations with better feedback from the manufacturer early in the design process.
The contract documents can be prepared later in the procurement process when a vendor has been selected. Companies who manufacture in house can implement a consistent version dependent and associative process from design to production and quality management. These customers report about significant time savings in every day work.
What is the actual potential behind model based definition? Our customers tell us the following. In product development, the need of redundant data input and control of important product information is eliminated. This can reduce the effort and product development by up to 30%. In combination with an associative cam system, the effort to create an NC program can be significantly reduced.
Some customers report time savings of up to 40%. The same also applies to the programming of the coordinate measuring machines. The biggest benefit you will not find in the individual disciplines. Remember back the story of Jack and Ryan and all the broken data?
Model based definition is about bringing all disciplines together in a continuous version dependent and associative process from design to manufacturing to the measuring machine. Avoiding data breaks reduces the risk of errors.
Your top benefits by using model based definition are document your design and can easily an early design phase, detail your annotations on the models for downstream use, finalize 3D annotations for communication with other stakeholders and suppliers, finalize your design before drawing, no need of creating drawings again and again, do your drawing to when you're already done with your work at the end and only once.
With this session, you learned how to apply GD&T by using the integrated tolerance advisor. You assessed the value for downstream use of model based definition. You identified the benefits of using model based definition to create GD&T. You learned how to get started with 3D annotation in Inventor. And last but not least, you can now collaborate with data at the center.
Thank you very much for watching this video. I hope you can try to learn how easy it can be to define a complete tolerance and concept of your assembly by answering just a few questions about the function. Some of you might say this is all terribly complicated.
No worries, it's like learning a new language. As soon as you understand it, you have a wonderful toolbox to promote a uniform understanding and interpretation among all involved personas and departments. It might look complicated at first glance, but it's worth to learn it. So what are you waiting for? Start now and describe your next part, the GD&T by using model based definition in Inventor. Good luck.