GCI 3D Printing Lab · 90-Minute Block
Day 4
Logo Keychain + Print Prep
Logo Selection · Keychain Generator · Export & Slice
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- As students arrive: Have the Keychain Generator open on the projector. Direct students to Day 4 student page.
- Prerequisite check: Ask students to show you their school logo image file (PNG/JPG). If anyone doesn't have it, give them 3 minutes to find and download it before starting.
- Say: "Today your keychain gets its identity. You're going to upload your school logo to a generator that builds the 3D keychain for you — then you slice it and queue it for printing."
- Energy tip: Day 4 has a lot of steps. Keep the pace brisk in instruction and give maximum time to hands-on work.
⏱ 2 min
Today's Agenda
- Step 1 — Get Your Logo (5 min)
- Step 2 — Upload to Keychain Generator (10 min)
- Step 3 — Adjust Settings (10 min)
- Step 4 — Add the Keyring Hole (10 min)
- Step 5 — Export STL + Slice (15 min)
- Step 6 — Save Your File (5 min)
- Step 7 — Print + Reflect (30 min)
- Step 8 — Submit (5 min)
🎯 Goal: By the end of class you'll have a print-ready 3MF file with your school logo keychain, submitted and in the queue.
🧠 Brain break built in around the midpoint
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- Manage expectations upfront: "The Keychain Generator is fast, but you may need to try a couple of logos before you get a clean result. That's normal — pick the simpler version of your logo first."
- File management reminder: Students will create at least two files today — an STL from the generator and a 3MF from Bambu Studio. Encourage them to save everything to a class folder on their desktop.
- Student page: Remind students to follow the student page (day4.html) — all 8 steps are there in order.
⏱ 2 min
I Can…
- ✅ Evaluate a logo and decide whether it will print successfully at keychain scale
- ✅ Upload a PNG/JPG logo to the Keychain Generator and adjust size, thickness, and keyring hole settings
- ✅ Enable a keyring hole that meets specs (4–6 mm, with ≥2 mm of material around it)
- ✅ Export the STL, slice it in Bambu Studio, and save a properly named 3MF file
- ✅ Use the Print Readiness Checklist to confirm my design is print-ready
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- Ask: "Has anyone used an online 3D generator before?" — gauge familiarity.
- Clarify the new workflow early: "Today we're not using TinkerCAD. Instead, we're using a web tool that turns your logo image directly into a 3D keychain. No CAD skills needed for the shape — just good judgment about your logo."
- Transition: "Before we generate anything, let's talk about what makes a logo good for printing — because not all logos work."
⏱ 3 min
🤔 Warm-Up
What Makes a Good Printable Logo?
Think of your school logo. Would you describe it as simple and bold or detailed and complex?
Turn and talk: what parts of your logo might be hard to print on something the size of a keychain?
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- Give 60 seconds for pair discussion. Then cold call 2–3 students.
- Listen for: mentions of fine lines, small text, gradients, or multi-color elements — all of these are red flags for 3D printing.
- Bridge: "You have good instincts. Let's look at some concrete examples that show the difference between a printable logo and one that will cause problems."
⏱ 2 min
Today's Goal — School Logo Keychain
1
Get Logo
PNG or JPG from Google
→
2
Generate
Upload to Keychain Generator
→
3
Configure
Size, thickness, keyring hole
→
4
Export
STL from the generator
→
5
Slice
Save 3MF from Bambu Studio
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- This workflow is new today — the Keychain Generator is the key tool. Everything else (Bambu Studio) they've already done.
- Frame it as simpler than what they've done: "The generator does the CAD work for you. Your job today is choosing a logo that works, setting the right dimensions, and making sure the hole is correct. Then it's just export and slice — exactly like Day 2."
⏱ 5 min
Simple vs. Complex — Which Prints Better?
✅ Simple Logo — Great for Printing
- 🟢 Bold, thick shapes with clear outlines
- 🟢 Minimal fine lines or detail
- 🟢 Strong, recognizable silhouette
- 🟢 No tiny text or microscopic details
- 🟢 Converts cleanly — generator processes it easily
- 🟢 Easy to scale to keychain size
❌ Complex Logo — Printing Challenges
- 🔴 Many thin lines and micro-details
- 🔴 Small text within the logo
- 🔴 Overlapping shapes and gradients
- 🔴 Multiple colors (we print in one color)
- 🔴 SVG conversion creates messy paths
- 🔴 Generator may not process cleanly
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- Use real examples if you have them. Pull up 2 logos on your browser — one simple school logo and one complex crest. Ask "Which would you choose?"
- Key teaching moment: "3D printing is a single color, single material process for us. A logo that depends on color to be readable (like the colors of a flag) won't translate to a 3D print — the shape is all you have."
- Good rule of thumb to share: "Imagine your logo as a shadow — just a flat black silhouette. If you can still tell what it is, it will probably print well. If it's unrecognizable as a silhouette, look for a simpler version."
- Student action: After this slide, give students 60 seconds to look at their logo and decide if it's simple or complex. Discuss as needed.
⏱ 3 min
Why Simple Designs Print Better
- Printer nozzle is 0.4 mm wide — it cannot reproduce lines thinner than that
- At keychain scale (50 mm), tiny details disappear or merge together
- Complex logos with many separate shapes may not process cleanly in the Keychain Generator
- Simple outlines = stronger walls and cleaner prints
🎯
A logo that prints clearly at 50 mm is more impressive than a complex logo that comes out as a blob.
Clean beats complicated.
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- The 0.4 mm nozzle fact is powerful — students immediately understand why hair-thin lines won't print.
- Relate to scale: A 1 cm wide element on a screen becomes 5 mm when scaled for a keychain. If it was already thin on screen, at 5 mm it disappears entirely.
- Encourage simplification: "If your logo has a complicated crest, see if there's a simpler version — often there's a logo-mark or icon version that's just the mascot head or a letter. That's the one to use."
⏱ 3 min
Choosing a Printable Logo
💡 5 Rules for a Logo That Will Print Successfully:
- Bold shapes win — thick outlines and filled areas print clearly at keychain size (40–60 mm)
- Avoid tiny text — letters smaller than ~5 mm will blur or disappear in the print
- Fewer shapes = cleaner result — the more separate pieces a logo has, the harder it is for the generator to process it cleanly
- Check the silhouette — could you recognize your logo if it was a solid black shape? If yes, it'll print well
- When in doubt, simplify — a clean simple design always beats a messy complex one at keychain scale
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- These rules are also on the student page (Day 4 → Step 1). Students can refer back to them.
- Walk around briefly — look at each student's logo and give a quick thumbs up/down on printability. Redirect anyone with a problematic logo now, before they spend 20 minutes on a logo that won't process cleanly.
- Transition: "OK — let's get your logo and head to the generator. Open your Downloads folder and find your logo, then go to teachingtech.site/3D/keychain."
⏱ 4 min
🎯 Step 1
Get Your Logo Image
- Go to Google Images and search: "[your school] logo PNG transparent"
- Look for the simplest version you can find — skip the detailed crest if there's a simpler option
- Right-click → Save Image As → save to your Desktop
- Preferred format: PNG with transparent background (easier to convert)
- If only JPG is available — that will work too
💡 If you already have your logo from yesterday — great! Skip the search and go straight to the Keychain Generator.
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- Monitor during this 4 minutes. Students sometimes find overly complex logos or download a logo that's not for their school. Redirect quickly.
- PNG with transparent background is best — a logo on a white background may cause the generator to include the white background as part of the 3D shape. Transparent or solid-color background on a contrasting logo works best.
- If a student can't find a good logo: Have a backup collection ready — a folder of clean PNG logos for local schools or mascot silhouettes. This prevents a 10-minute search derailing the whole session.
- Transition: "Everyone should have an image. Now let's head to the generator."
⏱ 5 min
🎓 Step 2
Upload to Keychain Generator
How to upload
- Go to teachingtech.site/3D/keychain
- Click Choose File (or drag your logo onto the upload area)
- Select your PNG or JPG logo
- Wait a moment — the generator processes the image and shows a 3D preview
- Rotate and zoom the preview to check the logo shape looks right
What a good preview looks like
- Logo shape is clearly recognizable in the 3D preview
- Clean raised relief — not a blob or a mess of thin lines
- Background is not part of the 3D shape
⚠️ If the preview looks wrong, try a simpler logo image — good contrast between logo and background helps the generator.
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- Demo on projector first — upload a sample logo and show the 3D preview live. Let students see what a clean result looks like before they do it themselves.
- Common issues: (1) White background included as a flat slab — student needs a logo with transparent or contrasting background. (2) Very complex logo creates a messy preview — redirect to a simpler version. (3) Generator slow to respond — normal; give it 10–15 seconds.
- Quality check: Walk around and look at each student's 3D preview. If the shape is unrecognizable, they need a simpler logo. Intervene early.
- Transition: "Brain break next — when you come back, we're configuring the settings and adding the hole."
⏱ 2 min
⏸ Pre-Break Check
Where Are We?
Thumbs up if you have this ready:
- 👍 School logo image downloaded (PNG or JPG)
- 👍 Logo uploaded to the Keychain Generator
- 👍 3D preview looks right — logo shape is recognizable
After the break: set size and thickness, add the keyring hole, then export.
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- Anyone with a bad 3D preview needs to fix it before the break ends. Give them a task: "Find a simpler logo OR try a version with a cleaner background before you take your break."
- Use the break to stage the generator settings panel on the projector — you want to walk through size, thickness, and hole settings as soon as students return.
- Transition: "Good — brain break time. 10 minutes. Come back ready to configure."
🧠
Brain Break!
Your keychain is almost done. Breathe. Reset.
10:00
🚶 Walk a lap
🤸 Stretch your hands and wrists
💬 Show a classmate your generator preview — would they recognize the logo?
🧘 Eyes closed, deep breath
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- During the break: Stage the Keychain Generator on the projector with settings panel open. When students return, walk through size, thickness, and hole settings live.
- Check on struggling students — if any student still doesn't have a usable preview, sit with them during the break and help. They'll need it immediately after.
- 2-minute warning: "Two minutes — get back to your screens and open the Keychain Generator."
⏱ 5 min
🎓 Step 3
Import SVG into TinkerCAD
How to import
- In the Keychain Generator, find the Settings panel (usually on the right or below the preview)
- Set Width to 40–60 mm — fits well in hand and on the build plate
- Set Depth / Thickness to 3–5 mm — strong enough to use, light enough to carry
- Make sure Base layer is enabled — gives the logo something to sit on
- Check the preview after each change — the model should update live
Good settings quick reference
- Width: 40–60 mm
- Thickness: 3–5 mm
- Base layer: On
💡 Wider isn't always better — at keychain scale bold shapes show up cleanly, tiny lines don't.
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- Live demo immediately: Show the settings panel on the projector. Change width, thickness, toggle base layer and watch the preview update. Do it slowly so students can follow along.
- Common mistake: Students set the width too large (100 mm+) — the keychain won't fit on the build plate or will take too long to print. Keep it under 60 mm.
- Base layer: This creates a solid backing behind the logo relief — important for strength. If a student turns it off, the logo may be too thin to survive as a keychain.
⏱ 8 min
🎯 Step 4 — Required
Add the Keyring Hole — Required
⚠️ A keychain without a hole is just a charm. This step is required.
- In the generator settings, find the Hole or Keyring option and enable it
- Set hole diameter to 4–6 mm — fits a standard keyring
- Make sure there is at least 2 mm of solid material around the hole — if the walls are too thin, it will snap
- Position: near the top edge of the keychain (most generators place it automatically)
- Verify the hole is visible in the 3D preview — it should appear as a circular cutout
✋ Hole check before exporting: 4–6 mm diameter, ≥2 mm material around it. Without it, your design won't be approved to print.
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- Walk the room during this step. The hole is a blocking requirement — no hole = no print approval. Check that every student has it enabled and the preview shows the cutout.
- Common issues: (1) Hole enabled but diameter too small (<3 mm) — standard keyring won't fit. (2) Hole placed at the bottom instead of the top — cosmetically fine but functionally awkward. (3) Student can't find the hole toggle — help them locate it in the generator UI.
- For advanced students: Suggest adjusting the hole position or adding their name/initials if the generator supports it.
- After everyone has a valid hole: Pause the class and have 2 students show their preview on the projector.
⏱ 3 min
📚 Vocabulary
Key Terms — Day 4
Keychain Generator
A free web tool that turns an uploaded image into a printable 3D keychain. It handles the base shape, thickness, and keyring hole automatically.
Keyring Hole
The circular cutout at the top of a keychain that a ring passes through. Must be 4–6 mm wide with at least 2 mm of material around it for strength.
Silhouette
The outer shape of a design when viewed as a solid. A strong silhouette = a design that prints clearly at small scale.
Orientation
How the model sits on the build plate. Lay the keychain flat (face down) for the strongest result and cleanest top surface.
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- Quick vocabulary pause during work time — review while students continue working.
- Ask: "Why does orientation matter for a keychain?" (Face-down = the logo surface is printed on the plate = smooth finish on the logo side. On its side = logo surface is a vertical wall = rougher quality.)
- Transition: "Last two steps — export and slice."
⏱ 5 min
🎓 Step 5
Export STL + Slice in Bambu Studio
Export from the Keychain Generator
- Click Download STL (or Export)
- Save to your Desktop or Downloads folder
In Bambu Studio
- Drag the STL onto the build plate or use File → Import
- Make sure keychain is lying flat (face down) — right-click → Lay on Face if needed
- Settings: 0.2 mm layer height · 20% infill · supports off
- Click Slice Plate → review Preview
- Check print time (< 2 hours is fine)
Save the 3MF file
- After slicing → File → Save Project
- Filename:
LastName_Keychain.3mf - This is the file you'll send to the printer on Day 5
- Keep both STL (from the generator) and 3MF (print-ready)
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- This is the most critical file management moment of the entire lab. A lost 3MF on print day = student can't print. Be explicit about where files should be saved.
- Naming convention is not optional: "If your file is named 'keychain.3mf' and so is your neighbor's, we have a problem on print day. Your name must be in the filename."
- What to check in Preview: (1) Keychain is lying flat (face down). (2) Keyring hole goes all the way through — visible in the layer preview. (3) First layer is solid. (4) Print time is reasonable.
- If the model is on its side in Bambu Studio: Right-click → Lay on Face to flip it flat. Printing on its side weakens the keychain.
⏱ 3 min
✅ Print Readiness Checklist
Is Your Design Ready to Print?
- Size is correct (40–60 mm in the longest dimension)
- Thick enough (3–5 mm) — nothing thinner than 2 mm around the hole
- Keyring hole present (4–6 mm, visible as a cutout through the preview)
- Model is lying flat (face down) on the Bambu Studio build plate
- File sliced correctly — Preview looks right
- Saved as 3MF with correct name:
LastName_Keychain.3mf
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- Walk through this list with students as a whole class, then give 2 minutes for students to verify each item on their own machine.
- Teacher sign-off: Consider having each student show you the Bambu Studio Preview before you sign off. A 30-second check per student during this time is realistic.
- Students who aren't print-ready: Common reasons: logo not recognizable in the preview, hole missing or too small, model on its side, or file naming issues. Address before exit ticket.
⏱ 5 min
🎯 Finish Up
Finalize Your Keychain
Last chance to fix anything before exit ticket:
- Go through the Print Readiness Checklist
- If anything is wrong → go back to the generator, fix settings, re-export, re-slice
- If you're print-ready → move on to the reflection and exit ticket
- If you're early → see the "Want to Go Further?" section on your student page (SVG + Tinkercad advanced path)
🖨️ Day 5 is print day. If you're not ready today, you may not get to print. Get your 3MF saved and verified.
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- Use urgency appropriately: The Day 5 print warning is real, but don't stress students out. Frame it as motivating: "Five minutes to make sure you're set up for success tomorrow."
- What to verify per student: (1) Do they have a 3MF file? (2) Is it named correctly? (3) Did they preview it in Bambu Studio with the model face-down? Those three things are the minimum.
- For students behind: Focus on getting the most basic version exportable — generator output with keyring hole enabled + correct size. Logo quality is secondary to having a printable file.
⏱ 3 min
✅ Check for Understanding
Quick Check
- What does the Keychain Generator do with the logo image you upload?
- Why does a simple logo work better than a complex one in the generator?
- What should a keyring hole be — and why does it need material around it?
- What should you check in the Bambu Studio Preview before approving a print?
- What two files should you have saved by end of class today?
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- Answers: (1) It converts the image into a 3D relief keychain model (STL) automatically. (2) Complex logos have thin lines / many shapes — these don't process cleanly and lose detail at keychain scale. (3) 4–6 mm diameter; at least 2 mm of material around it — otherwise the keychain snaps when a ring is attached. (4) Hole visible, model lying flat, logo recognizable, print time reasonable. (5) STL (from generator) and 3MF (from Bambu Studio).
- Q5 is the most practical — if students can't answer it, they may not have saved their files. Use this question to trigger a final file check.
⏱ 3 min
Exit Ticket & Submit
Before you leave:
- 3MF saved as
LastName_Keychain.3mf - Step 7 checklist on student page — all boxes checked
- Part 8 on student page — click Generate My Responses
- Paste into your Digital Notebook in Google Classroom
Tomorrow: Day 5 — Print Day 🖨️
- Bring your 3MF file — this is your print
- Know your print lab role
- Be ready to monitor the first layer
- Have fun — you made this.
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- Make the Day 5 preview exciting. Students should feel genuinely pumped about print day — they've spent 4 days building toward this moment.
- File insurance: Encourage students to email their 3MF to themselves or upload it to Google Drive as a backup. "Don't let a dead laptop battery on Day 5 erase 4 days of work."
- After class: Review student responses. Identify students who are not print-ready — contact them or have a plan to support them at the start of Day 5.
Day 4 Complete
Your keychain has a logo. 🏷️
Tomorrow you print it.
Day 5: Run the print lab. Watch your design come to life.
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- End with genuine energy. Students are one day away from holding a physical object they designed entirely themselves. That's remarkable — say so.
- Final reminder: "Your 3MF file is your print. Guard it. Back it up. Don't lose it overnight."