Sub-assembly creation in Solidworks - Step-by-Step Guide

Introduction

Sub-assembly creation helps you group multiple parts into one smaller assembly. This makes managing complex designs easier by breaking them into simpler sections.

When you want to organize parts that work together as a unit inside a bigger assembly

When you need to reuse a group of parts in different assemblies without rebuilding them

When you want to simplify the main assembly by hiding details of smaller groups

When you want to test or modify a section of your design separately

When you want to speed up loading and editing by working on smaller chunks

Steps

Step 1: Open

- SolidWorks main window

You see the main interface with menus and toolbars

Step 2: Click

- File menu > New > Assembly

A new empty assembly document opens

Step 3: Insert

- Insert Components toolbar or menu

A dialog opens to select parts to add

Step 4: Select and add

- Parts list in the dialog

Parts appear in the assembly workspace

Step 5: Select multiple parts

- Assembly workspace or FeatureManager design tree

Parts are highlighted for grouping

Step 6: Right-click

- Selected parts > choose Make Subassembly

A new sub-assembly is created containing the selected parts

Step 7: Save

- File menu > Save As

Sub-assembly is saved as a separate file for reuse

Before vs After

Before

Main assembly shows 10 separate parts cluttering the workspace

After

Main assembly shows 3 sub-assemblies each grouping related parts, workspace is cleaner

Settings Reference

Sub-assembly type

📍 Make Subassembly dialog

Choose if the sub-assembly moves as one unit or allows internal motion

Default: Standard

Component display state

📍 FeatureManager design tree > right-click component > Properties

Control visibility and performance of parts inside sub-assembly

Default: Show

Common Mistakes

Trying to create a sub-assembly without selecting parts first

SolidWorks needs parts selected to know what to group

Select the parts you want to group before choosing Make Subassembly

Saving sub-assembly without a unique name

It can overwrite existing files or cause confusion

Always save sub-assemblies with clear, unique file names

Summary

Sub-assembly creation groups parts into manageable units inside larger assemblies

It helps organize, reuse, and simplify complex designs

Remember to select parts before creating sub-assemblies and save them properly

Practice

1.

What is the main purpose of creating a sub-assembly in SolidWorks?

easy

A. To group related parts for easier management

B. To create a new part from scratch

C. To export the assembly as a 2D drawing

D. To change the color of parts automatically

Solution

1. Step 1: Understand sub-assembly concept

   Sub-assemblies group related parts to manage them easily within a larger assembly.

2. Step 2: Compare options

   Options A, B, and D describe unrelated tasks, not the main purpose of sub-assemblies.

3. Final Answer:

   To group related parts for easier management -> Option A

4. Quick Check:

   Sub-assembly = Group parts [OK]

Hint: Remember: sub-assemblies simplify complex assemblies [OK]

Common Mistakes:

• Confusing sub-assembly with part creation
• Thinking sub-assembly changes part colors
• Assuming sub-assembly exports drawings

2.

Which of the following is the correct way to create a sub-assembly in SolidWorks?

1. Insert parts into a new assembly document
2. Save the assembly with a clear name
3. Use the sub-assembly inside a larger assembly

easy

A. Create a new part, then save as sub-assembly

B. Export parts as separate files and link them

C. Open a drawing and add parts as sub-assembly

D. Insert parts into a new assembly, save it, then use it inside a larger assembly

Solution

1. Step 1: Identify correct sub-assembly creation steps

   Insert parts into a new assembly document, save it clearly, then use it inside a bigger assembly.

2. Step 2: Eliminate incorrect options

   Create a new part, then save as sub-assembly creates a part, not a sub-assembly. Open a drawing and add parts as sub-assembly uses drawings incorrectly. Export parts as separate files and link them exports parts separately, not sub-assembly.

3. Final Answer:

   Insert parts into a new assembly, save it, then use it inside a larger assembly -> Option D

4. Quick Check:

   Sub-assembly steps = Insert + Save + Use [OK]

Hint: Think: assemble parts first, then save as sub-assembly [OK]

Common Mistakes:

• Saving a part as sub-assembly
• Trying to create sub-assembly inside a drawing
• Not saving the assembly before using it

3.

Given a main assembly with two sub-assemblies, each containing 3 parts, how many total parts will the main assembly show?

medium

A. 2

B. 3

C. 6

D. 9

Solution

1. Step 1: Calculate parts in each sub-assembly

   Each sub-assembly has 3 parts, so 2 sub-assemblies have 3 x 2 = 6 parts.

2. Step 2: Add parts from sub-assemblies to main assembly

   Main assembly includes all parts from sub-assemblies, so total parts = 6.

3. Step 3: Check if main assembly has extra parts

   Since main assembly contains 2 sub-assemblies only, total parts = 6 parts inside sub-assemblies plus 0 extra parts = 6.

4. Final Answer:

   6 -> Option C

5. Quick Check:

   2 sub-assemblies x 3 parts = 6 parts [OK]

Hint: Multiply sub-assemblies by parts inside each [OK]

Common Mistakes:

• Counting sub-assemblies as parts
• Adding sub-assemblies and parts incorrectly
• Ignoring parts inside sub-assemblies

4.

What is wrong with this sub-assembly creation process?

1. Insert parts into assembly
2. Save assembly as a part file (.sldprt)
3. Use it inside main assembly

medium

A. Inserting parts before saving is wrong

B. Saving assembly as a part file is incorrect

C. Using sub-assembly inside main assembly is not allowed

D. Parts should be inserted after saving

Solution

1. Step 1: Identify file type error

   Assemblies must be saved as assembly files (.sldasm), not part files (.sldprt).

2. Step 2: Confirm correct workflow

   Insert parts, save as assembly file, then use inside main assembly.

3. Final Answer:

   Saving assembly as a part file is incorrect -> Option B

4. Quick Check:

   Assembly file extension = .sldasm [OK]

Hint: Save assemblies as .sldasm, not .sldprt [OK]

Common Mistakes:

• Saving assemblies as part files
• Confusing file extensions
• Thinking parts insert order matters

5.

You have a complex assembly with 50 parts. To improve performance, you want to create sub-assemblies. Which approach is best?

hard

A. Group related parts into sub-assemblies and save them separately

B. Keep all parts in one assembly without sub-assemblies

C. Create sub-assemblies but do not save them separately

D. Convert all parts into drawings before assembly

Solution

1. Step 1: Understand performance benefits

   Grouping related parts into sub-assemblies reduces complexity and improves performance.

2. Step 2: Importance of saving sub-assemblies

   Saving sub-assemblies separately allows reuse and better management.

3. Step 3: Evaluate other options

   Keeping all parts together slows performance; not saving sub-assemblies loses benefits; converting parts to drawings is unrelated.

4. Final Answer:

   Group related parts into sub-assemblies and save them separately -> Option A

5. Quick Check:

   Sub-assemblies + save separately = better performance [OK]

Hint: Save sub-assemblies separately to improve performance [OK]

Common Mistakes:

• Not saving sub-assemblies separately
• Keeping all parts in one big assembly
• Confusing drawings with assemblies