Why design review catches errors before fabrication in PCB Design - Business Case Study

Scenario Mode

👤 Your Role: You are a PCB design engineer

📋 Request: Your manager wants a report explaining how design reviews help catch errors before fabrication to reduce costs and improve quality.

📊 Data: You have data on PCB projects including number of errors found at design review, errors found after fabrication, cost impact of errors, and project timelines.

🎯 Deliverable: Create a dashboard showing error counts before and after fabrication, cost savings from early error detection, and timeline improvements.

Sample Data

Project	Errors at Design Review	Errors After Fabrication	Cost Impact ($)	Time Delay (Days)
Alpha	5	1	500	2
Beta	8	3	1200	5
Gamma	2	4	1500	7
Delta	6	0	0	0
Epsilon	4	2	800	3
Zeta	7	1	400	1
Eta	3	5	2000	10
Theta	9	0	0	0

1

Step 1: Create a table showing total errors found at design review and after fabrication for all projects.

SUM of 'Errors at Design Review' and SUM of 'Errors After Fabrication' columns.

Expected Result

Total Errors at Design Review = 44, Total Errors After Fabrication = 16

2

Step 2: Calculate total cost impact caused by errors found after fabrication.

SUM of 'Cost Impact ($)' column.

Expected Result

Total Cost Impact = $6400

3

Step 3: Calculate average time delay caused by errors found after fabrication.

AVERAGE of 'Time Delay (Days)' column.

Expected Result

Average Time Delay = 3.5 days

4

Step 4: Create a bar chart comparing errors found at design review vs errors after fabrication by project.

X-axis = Project, Y-axis = Number of Errors, Series = 'Errors at Design Review' and 'Errors After Fabrication'.

Expected Result

Bar chart showing higher errors caught at design review than after fabrication for most projects.

5

Step 5: Create a card visualization showing total cost savings by catching errors early (assume each error after fabrication costs $400).

Cost Savings = (Total Errors at Design Review) * $400

Expected Result

Cost Savings = $17,600

6

Step 6: Create a line chart showing time delay impact by project due to errors found after fabrication.

X-axis = Project, Y-axis = 'Time Delay (Days)'.

Expected Result

Line chart showing projects with higher delays correspond to more errors after fabrication.

7

Step 7: Summarize insights in a text box explaining how design review reduces errors, cost, and delays.

Text summary based on data visualizations and calculations.

Expected Result

Design reviews catch most errors early, reducing costly fixes and delays after fabrication.

Final Result

Bar Chart: Errors by Project

↓

Card: Cost Savings $17,600

↓

Line Chart: Time Delay by Project

✓Most errors are caught during design review, preventing costly fixes later.

✓Errors found after fabrication cause an average delay of 3.5 days and $6400 in costs.

✓Early error detection through design review saves approximately $17,600 across projects.

✓Projects with more post-fabrication errors experience longer delays.

Bonus Challenge

Create a predictive measure to estimate potential cost savings if design review errors increase by 10%.

Show Hint

Calculate 10% more errors caught at design review and multiply by $400 per error to estimate savings.

Practice

1. Why is a design review important before PCB fabrication?

easy

A. It eliminates the need for testing after fabrication.

B. It speeds up the manufacturing process directly.

C. It reduces the number of components needed.

D. It helps find errors early to avoid costly mistakes.

Solution

1. Step 1: Understand the purpose of design review

   Design review is done to catch errors before the PCB is made.

2. Step 2: Identify the benefit of early error detection

   Finding errors early prevents costly mistakes and rework later.

3. Final Answer:

   It helps find errors early to avoid costly mistakes. -> Option D

4. Quick Check:

   Early error detection = It helps find errors early to avoid costly mistakes. [OK]

Hint: Design review = find errors early to save cost [OK]

Common Mistakes:

• Thinking design review speeds manufacturing directly
• Believing it reduces components needed
• Assuming it removes need for testing

2. Which of the following is the correct step in a PCB design review process?

easy

A. Checking component placement and routing carefully

B. Ignoring schematic errors until after fabrication

C. Skipping the review if the design looks simple

D. Starting fabrication before review completion

Solution

1. Step 1: Identify correct review steps

   Design review includes checking component placement and routing.

2. Step 2: Eliminate incorrect options

   Ignoring errors, skipping review, or starting fabrication early are wrong.

3. Final Answer:

   Checking component placement and routing carefully -> Option A

4. Quick Check:

   Review step = Checking component placement and routing carefully [OK]

Hint: Review = check placement and routing carefully [OK]

Common Mistakes:

• Ignoring errors until fabrication
• Skipping review for simple designs
• Starting fabrication too early

3. During a design review, a PCB schematic shows a missing connection between two components. What is the likely outcome if this error is not caught before fabrication?

medium

A. The PCB will function perfectly without issues.

B. The PCB will fail or behave unpredictably.

C. The fabrication cost will decrease.

D. The error will fix itself during manufacturing.

Solution

1. Step 1: Understand impact of missing connection

   A missing connection means the circuit is incomplete and won't work properly.

2. Step 2: Predict outcome if error is not fixed

   The PCB will fail or behave unpredictably, causing problems.

3. Final Answer:

   The PCB will fail or behave unpredictably. -> Option B

4. Quick Check:

   Missing connection = PCB failure [OK]

Hint: Missing connection causes failure [OK]

Common Mistakes:

• Assuming PCB works fine without all connections
• Thinking fabrication cost decreases due to errors
• Believing errors fix themselves automatically

4. A design review checklist missed verifying the power supply connections. After fabrication, the PCB does not power on. What is the best way to fix this issue?

medium

A. Ignore the problem and use the PCB as is.

B. Add extra components on the existing PCB to fix power.

C. Redesign the PCB to correct the power connections and fabricate again.

D. Change the software to compensate for power issues.

Solution

1. Step 1: Identify the cause of power failure

   Power supply connections were not verified, causing no power.

2. Step 2: Determine correct fix

   Redesigning and refabricating the PCB to fix power is necessary.

3. Final Answer:

   Redesign the PCB to correct the power connections and fabricate again. -> Option C

4. Quick Check:

   Fix power by redesign and refabrication [OK]

Hint: Fix power issues by redesigning PCB [OK]

Common Mistakes:

• Ignoring the problem
• Trying to fix power with extra components
• Changing software instead of hardware

5. A PCB design review process includes schematic check, layout verification, and design rule check (DRC). If the DRC flags a clearance violation, what should be the next step to ensure fabrication success?

hard

A. Adjust the layout to fix the clearance violation before fabrication.

B. Remove components to avoid the violation.

C. Proceed with fabrication and fix errors later.

D. Ignore the violation if it looks minor.

Solution

1. Step 1: Understand what a clearance violation means

   Clearance violation means components or traces are too close, risking shorts or failures.

2. Step 2: Decide the correct action

   Adjusting the layout to fix the violation before fabrication prevents costly errors.

3. Final Answer:

   Adjust the layout to fix the clearance violation before fabrication. -> Option A

4. Quick Check:

   Fix clearance violation by layout adjustment [OK]

Hint: Fix DRC errors before fabrication [OK]

Common Mistakes:

• Ignoring minor violations
• Fabricating with known errors
• Removing components unnecessarily