Sanding and smoothing in 3D Printing - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the sentence to describe the first step in sanding a 3D print.

3D Printing

Start sanding with [1] grit sandpaper to remove rough surfaces.

Drag options to blanks, or click blank then click option'

Acoarse

Bwet

Cpolished

Dfine

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing fine grit first, which is too gentle for rough surfaces.

Coarse grit sandpaper is used first to remove rough surfaces effectively before moving to finer grits.

2fill in blank

medium

Complete the sentence to explain smoothing after sanding.

3D Printing

After sanding, apply [1] to fill small gaps and create a smooth finish.

Drag options to blanks, or click blank then click option'

Apaint

Bfiller

Cprimer

Dglue

Attempts:

3 left

💡 Hint

Common Mistakes

Using paint or glue instead of filler.

Filler is used to fill small gaps and imperfections before final finishing.

3fill in blank

hard

Fix the error in the sentence about sanding technique.

3D Printing

Use [1] sanding to avoid overheating and damaging the print.

Drag options to blanks, or click blank then click option'

Awet

Bdry

Crough

Dfast

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing dry sanding which can cause heat damage.

Wet sanding helps keep the surface cool and prevents damage during sanding.

4fill in blank

hard

Fill both blanks to describe the sanding process stages.

3D Printing

Start with [1] grit sandpaper, then finish with [2] grit for a smooth surface.

Drag options to blanks, or click blank then click option'

Acoarse

Bmedium

Cfine

Dpolished

Attempts:

3 left

💡 Hint

Common Mistakes

Reversing the order of grit sizes.

Coarse grit is used first to remove roughness, then fine grit smooths the surface.

5fill in blank

hard

Fill all three blanks to complete the smoothing workflow.

3D Printing

Apply [1] after sanding, then use [2] to protect the surface, and finally [3] for shine.

Drag options to blanks, or click blank then click option'

Afiller

Bprimer

Cclear coat

Dpaint

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up primer and paint or skipping filler.

Filler smooths imperfections, primer prepares the surface, and clear coat adds shine and protection.

Practice

1. What is the main purpose of sanding a 3D print?

easy

A. To make the print heavier

B. To remove rough spots and layer lines

C. To change the color of the print

D. To add new layers to the print

Solution

1. Step 1: Understand sanding purpose

   Sanding is used to smooth the surface by removing rough spots and visible layer lines from 3D prints.

2. Step 2: Eliminate incorrect options

   Changing color, weight, or adding layers are not done by sanding but by painting or printing processes.

3. Final Answer:

   To remove rough spots and layer lines -> Option B

4. Quick Check:

   Sanding = Remove rough spots [OK]

Hint: Sanding smooths surface imperfections [OK]

Common Mistakes:

• Thinking sanding changes color
• Confusing sanding with painting
• Believing sanding adds material

2. Which sequence of sanding grit is best for smoothing a 3D print?

easy

A. Start with coarse grit, then fine grit

B. Start with fine grit, then coarse grit

C. Use only medium grit

D. Use only coarse grit

Solution

1. Step 1: Recall sanding grit order

   Best practice is to start sanding with coarse grit to remove big imperfections, then move to finer grit for smooth finish.

2. Step 2: Check options

   Starting with fine grit won't remove rough spots well; using only one grit misses gradual smoothing.

3. Final Answer:

   Start with coarse grit, then fine grit -> Option A

4. Quick Check:

   Coarse to fine grit = Best sanding order [OK]

Hint: Coarse grit first, then fine grit for smoothness [OK]

Common Mistakes:

• Starting with fine grit only
• Skipping coarse grit
• Using only one grit type

3. Consider this sanding process: A print is first sanded with 100 grit, then 220 grit, and finally 400 grit. What is the expected result?

medium

A. The print will have a rough surface

B. The print will be damaged by too much sanding

C. The print will be very smooth with minimal layer lines

D. The print will change color

Solution

1. Step 1: Analyze grit progression

   Sanding from 100 (coarse) to 220 (medium) to 400 (fine) grit gradually smooths the surface and reduces layer lines.

2. Step 2: Evaluate options

   Rough surface is unlikely after fine sanding; damage is possible but not typical with proper technique; color change is unrelated to sanding.

3. Final Answer:

   The print will be very smooth with minimal layer lines -> Option C

4. Quick Check:

   Coarse to fine sanding = Smooth print [OK]

Hint: Gradual grit increase smooths print well [OK]

Common Mistakes:

• Assuming sanding damages print always
• Expecting color change from sanding
• Ignoring grit order importance

4. A user sands a 3D print starting with 400 grit and then switches to 100 grit. What is the main problem with this approach?

medium

A. It will add new layer lines

B. It will make the print change color

C. It will polish the print too much

D. It will make the surface rougher after smoothing

Solution

1. Step 1: Understand sanding grit order importance

   Starting with fine grit (400) then going to coarse grit (100) reverses smoothing, making surface rougher.

2. Step 2: Check other options

   Color change and adding layer lines are unrelated to sanding order; polishing too much is unlikely with coarse grit last.

3. Final Answer:

   It will make the surface rougher after smoothing -> Option D

4. Quick Check:

   Wrong grit order = Rougher surface [OK]

Hint: Always sand coarse to fine grit, not reverse [OK]

Common Mistakes:

• Reversing grit order thinking it's fine
• Expecting color change from sanding
• Confusing polishing with sanding

5. You want to prepare a 3D print for painting by sanding. Which of the following steps is the best approach?

hard

A. Sand with 80 grit, then 150 grit, then 300 grit; clean the surface; apply primer

B. Sand only with 300 grit; paint directly without cleaning

C. Use 400 grit first, then 80 grit; apply paint immediately

D. Skip sanding and apply primer directly

Solution

1. Step 1: Plan sanding for painting

   Start sanding with coarse grit (80) to remove roughness, then medium (150), then fine (300) for smooth finish suitable for painting.

2. Step 2: Prepare surface before painting

   Cleaning removes dust and debris; applying primer helps paint stick better and last longer.

3. Final Answer:

   Sand with 80 grit, then 150 grit, then 300 grit; clean the surface; apply primer -> Option A

4. Quick Check:

   Proper sanding + cleaning + primer = Best paint prep [OK]

Hint: Coarse to fine sanding, clean, then prime before painting [OK]

Common Mistakes:

• Skipping cleaning before painting
• Using wrong grit order
• Skipping primer application