Draft analysis for molding in Solidworks - Step-by-Step Guide

Introduction

Draft analysis helps you check if your 3D model has the right angles for easy removal from a mold. It shows where the surfaces have enough slope to avoid sticking during molding.

When you want to make sure your plastic part can be removed from the mold without damage

When you need to find areas on your model that have no draft angle and might cause problems

When preparing a design for injection molding and want to reduce manufacturing defects

When you want to visually see which surfaces have positive or negative draft angles

When you need to communicate draft issues clearly to your manufacturing team

Steps

Step 1: Open your 3D model file

- SolidWorks main window

Your model appears in the workspace

Step 2: Click the Evaluate tab

- CommandManager toolbar

Evaluation tools become visible

Step 3: Click Draft Analysis

- Evaluate tab

Draft Analysis property manager opens on the right

Step 4: Select the mold pull direction

- Draft Analysis property manager under 'Pull Direction'

The direction arrow appears on the model showing the mold opening direction

💡 Use the model's main axis or a face normal that matches the mold opening

Step 5: Set the minimum draft angle value

- Draft Analysis property manager under 'Minimum Draft Angle'

Surfaces with draft angles below this value will be highlighted

Step 6: Click Calculate

- Draft Analysis property manager

Model surfaces are colored to show draft quality: green for positive draft, red for negative draft, yellow for zero draft

Step 7: Review the color-coded results

- 3D model workspace

You see which areas need design changes to improve draft angles

Before vs After

Before

Model surfaces all appear in default gray color with no indication of draft quality

After

Model surfaces show green, yellow, and red colors indicating positive, zero, and negative draft angles respectively

Settings Reference

Pull Direction

📍 Draft Analysis property manager

Defines the direction the mold opens to check draft angles correctly

Default: User selected

Minimum Draft Angle

📍 Draft Analysis property manager

Sets the threshold for acceptable draft angles

Default: 1 degree

Color Scheme

📍 Draft Analysis property manager

Visualizes draft quality on model surfaces

Default: Standard color scheme

Common Mistakes

Not setting the correct mold pull direction

Draft angles are calculated relative to this direction, so wrong direction gives incorrect results

Always select the mold opening direction carefully by choosing the correct face or axis

Ignoring surfaces colored red or yellow

These surfaces can cause molding problems like sticking or damage

Modify the model to add proper draft angles on these surfaces

Summary

Draft analysis shows if your model has the right angles for easy mold removal

You must set the mold pull direction correctly for accurate results

Color coding helps quickly find problem areas needing design changes

Practice

1. What is the main purpose of Draft Analysis in SolidWorks molding?

easy

A. To measure the thickness of the part

B. To design the mold cooling channels

C. To calculate the weight of the molded part

D. To check if part surfaces have the correct angles for easy mold release

Solution

1. Step 1: Understand Draft Analysis purpose

   Draft analysis is used to verify if surfaces have the right draft angles to allow easy removal from the mold.

2. Step 2: Compare options with purpose

   Only To check if part surfaces have the correct angles for easy mold release matches this purpose; others relate to different mold design aspects.

3. Final Answer:

   To check if part surfaces have the correct angles for easy mold release -> Option D

4. Quick Check:

   Draft analysis = check draft angles [OK]

Hint: Draft analysis checks angles for mold release [OK]

Common Mistakes:

• Confusing draft analysis with thickness measurement
• Thinking draft analysis calculates weight
• Assuming draft analysis designs cooling

2. Which of the following is the correct step to start a draft analysis in SolidWorks?

easy

A. Open the mold tool and select 'Thickness Check'

B. Select the part, then click on 'Evaluate' tab and choose 'Draft Analysis'

C. Go to 'Insert' menu and select 'Mass Properties'

D. Right-click on the part and select 'Add Material'

Solution

1. Step 1: Identify correct menu path for draft analysis

   Draft analysis is found under the 'Evaluate' tab in SolidWorks.

2. Step 2: Match options with correct path

   Select the part, then click on 'Evaluate' tab and choose 'Draft Analysis' correctly describes selecting the part, then using 'Evaluate' > 'Draft Analysis'. Others are unrelated.

3. Final Answer:

   Select the part, then click on 'Evaluate' tab and choose 'Draft Analysis' -> Option B

4. Quick Check:

   Draft analysis location = Evaluate tab [OK]

Hint: Find draft analysis under Evaluate tab [OK]

Common Mistakes:

• Confusing draft analysis with thickness check
• Looking under Insert menu incorrectly
• Trying to add material instead of analyzing draft

3. Given a part with a pull direction set incorrectly, what will the draft analysis color code likely show?

medium

A. Incorrect color coding, possibly red or no draft shown

B. No color changes, draft analysis will not run

C. Only the edges highlighted in blue

D. All surfaces green indicating good draft

Solution

1. Step 1: Understand pull direction role in draft analysis

   Pull direction defines how the mold opens; incorrect setting causes wrong draft angle evaluation.

2. Step 2: Predict color code effect

   Wrong pull direction leads to incorrect or misleading color coding, often showing red or no draft indication.

3. Final Answer:

   Incorrect color coding, possibly red or no draft shown -> Option A

4. Quick Check:

   Wrong pull direction = wrong color code [OK]

Hint: Wrong pull direction causes wrong draft colors [OK]

Common Mistakes:

• Assuming all green means good draft despite wrong pull
• Thinking edges only get highlighted
• Believing draft analysis won't run at all

4. You ran draft analysis but the colors do not match expected draft angles. What is the most likely error?

medium

A. Draft analysis was run on a 2D sketch

B. The part has no material assigned

C. Pull direction is set incorrectly

D. The computer graphics driver is outdated

Solution

1. Step 1: Identify common causes of wrong draft colors

   Incorrect pull direction is the most common cause for wrong draft color results.

2. Step 2: Evaluate other options

   No material or 2D sketch won't run draft analysis properly, but usually cause errors, not wrong colors. Graphics driver affects display but not analysis logic.

3. Final Answer:

   Pull direction is set incorrectly -> Option C

4. Quick Check:

   Wrong colors = wrong pull direction [OK]

Hint: Check pull direction first if colors seem wrong [OK]

Common Mistakes:

• Ignoring pull direction as cause
• Blaming material assignment
• Thinking 2D sketches can show draft colors

5. You want to ensure a part has a minimum draft angle of 3 degrees for molding. How do you set this in SolidWorks draft analysis?

hard

A. Set the draft angle value to 3 degrees in the draft analysis property manager

B. Change the pull direction to 3 degrees

C. Apply a 3-degree fillet to all edges

D. Increase the part thickness by 3 mm

Solution

1. Step 1: Identify how to specify draft angle in analysis

   In draft analysis, you set the minimum draft angle to check surfaces against that value.

2. Step 2: Evaluate options for setting draft angle

   Set the draft angle value to 3 degrees in the draft analysis property manager correctly describes setting the draft angle in the property manager. Others change geometry or pull direction incorrectly.

3. Final Answer:

   Set the draft angle value to 3 degrees in the draft analysis property manager -> Option A

4. Quick Check:

   Minimum draft angle set in property manager [OK]

Hint: Set draft angle in property manager, not geometry [OK]

Common Mistakes:

• Changing pull direction instead of angle value
• Adding fillets instead of setting draft angle
• Modifying thickness unrelated to draft