What Is Print Speed – And Why It’s More Than Just Time Savings
Defining Print Speed (mm/s)
In 3D printing, print speed measures how fast the print head moves while extruding material—typically expressed in millimeters per second (mm/s). At first glance, it may seem like just a variable that determines how long a print takes to complete. But in reality, print speed plays a far more critical role—it directly influences how well each layer bonds to the next, defining the mechanical strength, surface quality, and overall success of your print.
Print Speed vs. Total Print Time
It’s easy to assume that increasing print speed simply shortens total print time. However, each speed change affects extrusion rate, temperature balance, and layer cooling. A print might finish faster at 100 mm/s, but if layers don’t adhere properly, you’ll lose more time reprinting the failed part. Finding the balance between efficiency and adhesion is where expertise with PLA+ truly comes in.
PLA+ Specifics: What Makes It Different from Standard PLA
PLA+ differs from standard PLA by including polymer modifiers that enhance toughness, flexibility, and layer adhesion. Yet, these same additives alter the way heat flows through the material. PLA+ generally requires slightly higher nozzle temperatures (205–220°C) and slower print speeds than pure PLA to achieve strong bonding between layers. Managing speed ensures that melted filament has enough time to fuse properly before cooling.
Typical Print Speeds for PLA+ — What You Should Expect
Benchmark Speeds in Consumer 3D Printing
Most PLA+ filaments perform best between 40 and 70 mm/s for general prints. For high-detail work, speeds closer to 30–40 mm/s yield cleaner finishes and stronger adhesion. For larger, less intricate parts, you can push speeds toward 80 mm/s if your printer’s extrusion system keeps up with flow demand.
Limits Imposed by Your Hardware
Your printer’s hardware is just as important as the filament itself. A high-quality hotend ensures consistent melting, while a direct-drive extruder maintains pressure accuracy. Poor cooling fans or weak stepper motors will limit speed performance. When print speed exceeds what your setup can handle, extrusion inconsistencies appear as weak spots and poor layer bonding.
When PLA+ Flow Becomes the Bottleneck
PLA+ is slightly more viscous than PLA, meaning it doesn’t flow as freely. If your extruder can’t push enough material at higher speeds, you’ll get under-extrusion, which results in weak layer adhesion. Proper calibration of your flow rate (extrusion multiplier) is key to achieving a stable melt at faster speeds.
How Print Speed Impacts Layer Adhesion in PLA+
Heat Transfer & Melt Pool Time
When layers are printed too quickly, the filament doesn’t stay hot long enough to merge effectively with the layer below. This lack of thermal bonding creates invisible weak points that can lead to delamination. By reducing print speed, the nozzle lingers slightly longer, transferring more heat and improving interlayer diffusion.
Cooling, Crystallization, and Bonding
Cooling fans help solidify layers, but excessive airflow or fast movement can cool the surface before proper adhesion occurs. Optimal print speed allows controlled cooling—so that the filament sets firmly, not prematurely. PLA+’s additives also crystallize differently than pure PLA, demanding a careful balance between heat and time.
Too Fast → Weak Interlayer Bridges
High speeds can produce prints that look fine on the outside but fail under stress. The internal layers don’t have enough bonding time, making them brittle or hollow-feeling.
Too Slow → Overheating, Smearing, Loss of Detail
Conversely, printing too slowly can cause heat buildup, leading to smearing, stringing, or overly shiny layers. The sweet spot is where each layer cools just enough to support the next while maintaining solid adhesion.
Fine-Tuning Print Speed Settings for Better Adhesion
Default (Base) Print Speed
Start at 50 mm/s for general PLA+ prints. Adjust upward for faster builds or downward for stronger interlayer bonds and finer surface finishes.
First Layer & Initial Layers Speed
Always print the first layer at a slower speed (20–30 mm/s). This ensures maximum bed adhesion and establishes a stable base for subsequent layers.
Gradual Speed Ramp (Number of Slower Layers)
Some slicers allow a gradual speed increase after the first few layers. This helps reduce warping while ensuring early-layer adhesion remains strong.
Infill, Walls, Top/Bottom Speeds
Outer walls should generally print slower (40–50 mm/s) to maintain surface quality, while infill can print faster (60–80 mm/s). Top layers benefit from slower speeds to achieve solid, airtight closure.
Travel Speed & Retraction Considerations
Fast travel speeds (120–150 mm/s) minimize stringing without affecting layer adhesion, but retraction settings must align to prevent oozing between layers.
Risks and Trade-offs of Speed Adjustments
Common Failure Modes from High Speeds
- Weak interlayer bonding
- Inconsistent extrusion lines
- Layer shifting due to vibration
Pitfalls of Very Slow Speeds
- Heat accumulation in small parts
- Degraded surface finish from overheating
- Increased chance of nozzle clogging
Balancing Quality, Strength & Print Time
Every project has a different ideal balance. Mechanical parts demand slower, stronger bonds; decorative pieces can tolerate higher speeds for shorter print times.
Testing & Iteration: Finding the Sweet Spot
Using Speed Towers or Test Models
Speed towers are invaluable for dialing in PLA+ settings. They show how different speeds affect texture, gloss, and adhesion in a single print.
Evaluating Layer Bond Strength Visually & Mechanically
Perform simple tests—like bending thin walls—to evaluate internal strength. Look for visible separation between layers as a sign to slow down slightly.
Documenting Settings & Results
Keep a print log or spreadsheet for each filament brand. Recording temperature, speed, and fan settings builds a personal reference guide for future projects.
Enhancing PLA+ Performance Beyond Speed
Hotend Upgrades and Higher Flow Systems
Upgrading to an all-metal or high-flow hotend lets you print PLA+ faster without sacrificing adhesion, as it maintains stable melt zones at higher throughput rates.
Cooling System Optimization
Dual-fan or directional cooling ensures even airflow, reducing thermal stress and improving consistency.
Filament Quality & Additives for Better Flow
Premium PLA+ filaments have consistent diameters and optimized polymer blends for better layer fusion even at moderate speeds.
Firmware, Motion, and Acceleration Tuning
Optimizing acceleration, jerk, and pressure advance reduces vibrations that weaken layer bonding at high speeds.
Summary & Best Practices for PLA+ Print Speed
Quick Recommendations per Use Case
- High detail: 30–40 mm/s
- General parts: 50–60 mm/s
- Large infill-heavy models: up to 80 mm/s
Cheat Sheet: Speed Ranges for Layers & Features
| Feature | Ideal Speed (mm/s) |
|---|---|
| First Layer | 20–30 |
| Outer Walls | 40–50 |
| Infill | 60–80 |
| Travel Moves | 120–150 |
Final Thoughts: Why Speed Matters for Strong, Reliable PLA+ Prints
Mastering print speed with PLA+ is about precision, not haste. By finding the right balance between speed, temperature, and cooling, you’ll produce prints that are not only faster—but stronger, smoother, and more reliable. With every adjustment, you’re crafting better performance layer by layer.