So, you’ve mastered PLA and are ready for the next challenge. Welcome to the world of PETG! It’s a fantastic material known for its strength, temperature resistance, and durability, making it perfect for functional parts, mechanical components, and anything that needs to withstand a bit more stress than your average decorative print.
But switching from PLA to PETG can be intimidating. You might have heard horror stories of stringy messes, poor bed adhesion, or stubborn clogs. Don’t worry! With a few key adjustments, making the material change is a straightforward process. This guide will walk you through everything you need to know for a successful first PETG print.
Our Setup for This Guide
For this walkthrough, we’re printing a simple yet functional battery holder. Here’s the hardware and filament we’re using:
- 3D Printer: Creality Ender 3 V2 (with an all-metal hotend upgrade)
- Filament: Overture PETG (Transparent Blue), 1.75mm
- Bed Surface: PEI-coated flexible steel sheet
- Other Tools: Isopropyl alcohol, glue stick (as a release agent)
The Heart of the Matter: Slicer Settings
The biggest difference between printing PLA and printing PETG lies in your slicer settings. PETG is less forgiving than PLA and requires a different approach to temperature, cooling, and speed. A good starting point is to duplicate your existing PLA profile and then make the following adjustments.
Here are the crucial settings we used in Cura for our PETG profile:
- Layer Height: 0.2mm
- Nozzle Temperature: 240°C
- Bed Temperature: 80°C
- Print Speed: 40 mm/s (First layer at 20 mm/s)
- Part Cooling Fan: 30% (Off for the first 3 layers)
- Retraction Distance: 5mm
- Retraction Speed: 40 mm/s
- Z-Offset: +0.02mm (slightly higher than for PLA)
- Bed Adhesion: Skirt (or Brim for smaller parts)
Why these changes?
- Higher Temps: PETG needs more heat than PLA to melt properly and stick to the bed.
- Reduced Cooling: This is the most critical change! PETG needs to stay hot to bond well between layers. Too much cooling makes it brittle.
- Slower Speed: Printing PETG slower gives it time to lay down smoothly and helps prevent nozzle buildup.
- Higher Z-Offset: Unlike PLA, which likes to be “squished” onto the bed, PETG prefers to be laid down gently. A slightly higher Z-offset prevents the nozzle from dragging through the filament and creating blobs.
The Printing Process: A Step-by-Step Guide
Follow these steps for a smooth material change from PLA to PETG.
Step 1: Prepare Your Filament
PETG is hygroscopic, meaning it loves to absorb moisture from the air. Wet filament will pop and sizzle as it prints, leading to weak, stringy results. For best results, always dry a new roll of PETG in a filament dryer for 4-6 hours at around 65°C before printing.
Step 2: Purge the Old Filament
You need to get all the old PLA out of your hotend.
- Heat your nozzle to the higher end of your PLA’s temperature range (e.g., 215°C).
- Remove the PLA filament.
- Manually push the new PETG filament through the hotend until you see the color change completely and the filament flows smoothly.
- Crank the temperature up to your PETG printing temp (e.g., 240°C) and push a little more filament through to ensure any PLA residue is fully melted and purged.
Step 3: Prepare the Print Bed
PETG can stick too well to some surfaces like glass or PEI, sometimes tearing chunks out of them upon removal.
- Clean your build plate thoroughly with isopropyl alcohol.
- Apply a thin, even layer of a release agent. A standard purple glue stick or a spritz of hairspray works perfectly. This creates a micro-layer that helps the print pop off easily once it cools.
Step 4: Level the Bed and Set the Z-Offset
Re-level your bed with the nozzle and bed heated to your PETG printing temperatures. Then, fine-tune your Z-offset. Remember, you want a tiny bit more space between the nozzle and the bed than you’d use for PLA. The first layer should look like a rounded bead, not a flat, squished line.
Step 5: Start the Print!
Load your G-code and start the print. Watch the first layer carefully. If it’s not sticking, your nozzle might be too high. If it’s globbing up on the nozzle, it might be too low. Make small, live adjustments to the Z-offset if your printer allows it.
Post-Processing Your PETG Print
Once your print is finished, let the bed cool down completely. As it cools, the part will often self-release with a satisfying “pop.”
- Support Removal: PETG supports can be tougher to remove than PLA supports because the layers bond so strongly. Use a pair of flush cutters and needle-nose pliers. Tweaking support interface settings in your slicer can make a big difference for future prints.
- Stringing: You will likely have some fine “hairs” or strings on your print. This is normal for PETG. A quick pass with a heat gun will instantly zap them away, leaving a clean surface. Be careful not to warp the print!
- Sanding & Finishing: PETG can be sanded just like PLA. Start with a lower grit sandpaper and work your way up to a finer grit for a smooth finish.
Final Thoughts & Showcase
Making the switch to printing PETG is a rewarding step in your 3D printing journey. While it requires more attention to detail than PLA, the superior strength and heat resistance of the final parts are well worth the effort. The key takeaways are: dry your filament, slow down, reduce cooling, and don’t squish your first layer.
Our battery holder came out beautifully. The layers are strong, the finish is glossy, and it’s more than tough enough to handle life in a busy workshop—something PLA might struggle with over time.
Don’t be afraid to experiment! Your first print may not be perfect, but by following this filament guide and tweaking your slicer settings, you’ll be printing PETG like a pro in no time. Happy printing