Final Assembly

Part Studio vs Assembly

Before starting the assembly, let's clarify the difference between these two concepts:

• Part Studio -- Where you model parts. You can create multiple parts in a single Part Studio.
• Assembly -- Where you define the mechanical relationships between parts, such as which parts are fixed together and which can rotate.

We built the Base and Sensor Mount in the Part Studio during Chapters 7 and 8. Now we need to put them back into the Assembly and define their connections.

Insert Parts into the Assembly

Click the yellow button to insert parts into the assembly

Inserting Base and Sensor Mount into the assembly

1. In the Part Studio, click the "Insert and go to Assembly" yellow button
2. Select both the Base and Sensor Mount parts
3. Click the green checkmark ✓ to confirm

You'll be automatically taken back to the assembly, where the two new parts are now present.

Mate Connectors

Mate connectors are small coordinate systems automatically created by Onshape

Mate Connectors are small coordinate systems that Onshape automatically creates at circle centers, hole centers, edge midpoints, and other key locations on parts. When you create a mate, you're aligning two mate connectors together.

Add Mates

Clean Up Temporary Mates

1. In the left panel, find Fastened 2 (it was temporarily fixing the sensor)
2. Delete this mate
3. The sensor will detach from its position -- this is expected

Drag Parts Apart

Drag the parts slightly apart to make it easier to select mate connectors in the next steps.

Fix Base to Tube

Use a Fastened mate to fix the Base onto the tube

Adding Fastened mate connections

1. Create a Fastened mate
2. First connector: the hole center on the tube
3. Second connector: the corresponding hole center on the Base
4. Confirm the Base sits flush on top of the tube

Connect Sensor to Sensor Mount

1. Create a Fastened mate
2. First connector: the sensor's mounting hole center
3. Second connector: the Sensor Mount's corresponding hole center

Change to Revolute Mate

A Revolute mate allows the sensor mount to rotate around an axis

1. Change the mate between the sensor and Sensor Mount to a Revolute mate
2. First connector: the Sensor Mount's outer cylindrical face
3. Second connector: the Base's inner cylindrical face
4. After confirming, try dragging the sensor mount -- it should rotate around the axis!

Add Standard Hardware (Bolts and Nuts)

Insert Bolts

Insert bolts and nuts from the standard parts library to complete the assembly

Inserting #8-32 bolts into the mounting holes

1. Click Insert → Standard content (standard parts library)
2. Expand ANSI inch → Bolts and screws
3. Select Socket button head cap screws
4. Choose #10-32 x 0.375"
5. Click the two mounting holes on the Base to place the bolts

1. Insert #4-40 bolts into the sensor mounting holes
2. Insert #8-32 x 1.5" bolts into the long holes in the center support posts

Inserting the remaining bolts into all mounting holes

Insert Nuts

Inserting matching nuts

1. Click Insert → Standard content → Nuts
2. Insert #4-40 nuts at the bottom of the sensor bolts
3. Insert #8-32 nuts at the bottom of the center bolts
4. Insert #10-32 nuts at the bottom of the tube-side bolts

Press K to toggle mate connector visibility for a cleaner view.

Summary

Discussion Questions

• What is a mate connector? What role does it play in assemblies?
• What's the difference between a Fastened mate and a Revolute mate? When should you use each?
• Why design parts in In-Context mode instead of in a blank Part Studio?

Extra Practice Suggestions

• Try designing other custom parts in the drivetrain assembly (e.g., sensor brackets, battery mounts)
• Take the Managed In-Context Design course on Onshape Learning Center for advanced in-context modeling best practices
• Try modifying the Sensor Mount dimensions to fit different-sized sensors