As-Built Joints in Fusion

If you've ever imported a model from another CAD system or grabbed parts from a website, you know it’s often missing the relationships that tell the software how parts move together. This is where the As-Built Joint command shines. It helps you add movement and relationships to models that are already assembled, saving hours of rework.

Understanding Fusion Joints: From Traditional to As-Built

What Are Joints in Fusion?

Joints are like virtual connections that tell Fusion how parts are linked and how they should move. Usually, you create these by selecting edges or points, then defining the type of movement—revolute, slider, rigid, etc. This approach works well for new assemblies you build from scratch.

The Limitation with Imported Models

However, what happens when you import a design from another software or a vendor? These models often come as a bunch of separate bodies, with no relationships or movement rules. Trying to add joints to such models can be tedious because you need to disassemble and reassemble parts, which wastes time.

Introducing the As-Built Joint Command

The As-Built Joint command offers a smarter way. It allows you to create movement relationships in assemblies that are already put together. No need to disassemble; you just specify which parts should move and how. This makes it ideal for quick modifications, simulations, or testing how a product would work in the real world.

When to Use the As-Built Joint

• When you've imported models from other CAD programs, websites, or vendors

• In assemblies that are already fully put together but need motion analysis

• To save time during initial setup of your simulation or animation

  
  

Step-by-Step Guide to Using the As-Built Joint Command

Preparing Your Assembly for Joints

Start by converting bodies to components, if necessary. This step is crucial because joints only work with components, not raw bodies. Right-click on bodies, then select Create Components from Bodies.

Next, pin the base part that won’t move. Right-click on it and select Pin. Fixing stationary parts keeps the assembly stable during simulation.

Creating Joints for Simple Assemblies

Example 1: Adding a Revolute Joint to a Toggle Clamp

Suppose you imported a toggle clamp from McMaster-Carr. First, search for and select the part, then convert bodies into components. Pin the base part you want to keep stationary.

Next, choose the As-Built Joint command. In the menu, pick the components you want to connect. Choose the Revolute motion type, because the part rotates around a pin. Pick a snap point—usually an edge that represents the hinge or pin.

Once you confirm, you see an instant preview. If you move the part, the joint moves accordingly.

Using Rigid Groups for Accurate Movement

Sometimes, multiple parts need to move as one. Use Rigid Group to combine these parts. Select them, then click Rigid Group. Now, when you move one, everything in the group follows.

Creating Joints for Complex Assemblies

Example 2: Simulating a DVD Packaging Machine

This more complicated project involved many parts. First, I grouped related components using Rigid Group. For example, the motor, shafts, and holders got bundled together.

Next, I added joints to define how each part moves. For example, the motor’s shaft rotated around an axis; I used Revolute joints. I then added As-Built Joints to connect different parts, like the shaft to the gear.

Building relationships step-by-step helped me understand how the machine functions without disassembling everything. Rigid groups kept sub-assemblies moving as one, simplifying the setup.

By combining rigid groups and joints, I could simulate the entire operation easily, saving time compared to traditional joint creation.

Managing Many Joints and Groups

When working on large models, it pays to plan your groups first. Break the machine into manageable chunks, then connect each with joints. Use Rigid Group to keep parts together, and As-Built Joint to specify movement points accurately.

Tips for Efficient Joints Creation

• Use the Repeat Last command by right-clicking and dragging straight up; it duplicates the previous joint faster.

• Select snap points that reflect real-world pivots—edges or faces that match the physical part's movement.

• Group parts into Rigid Groups to simulate sub-assemblies. This reduces the number of joints needed, speeding up your process.

• Fix stationary parts early to keep everything stable during testing.

Conclusion

Using the As-Built Joint command in Fusion transforms how you prepare models for simulation. It offers a quick, accurate way to add joint relationships to pre-assembled or imported parts without breaking everything apart. This saves valuable time while giving you a clear view of how your design will work in real life.

Incorporate As-Built Joints into your workflow, and you'll streamline your projects, reduce errors, and enhance your understanding of complex assemblies. Whether you're working with simple toggles or intricate machines, this tool makes your modeling faster and smarter.