Print speed and acceleration in 3D Printing - Deep Dive

Overview - Print speed and acceleration

What is it?

Print speed and acceleration are key settings in 3D printing that control how fast the printer's parts move while creating an object. Print speed refers to how quickly the printer's nozzle moves while laying down material. Acceleration controls how fast the printer changes its speed, affecting how smoothly it starts and stops movements. Together, they influence print quality, time, and mechanical stress on the printer.

Why it matters

Without controlling print speed and acceleration, prints can be rough, inaccurate, or take too long. Too fast or abrupt movements can cause defects like blobs, layer shifts, or even damage the printer. Proper settings balance speed and quality, making 3D printing efficient and reliable for users from hobbyists to professionals.

Where it fits

Learners should first understand basic 3D printer mechanics and slicing software. After mastering print speed and acceleration, they can explore advanced topics like jerk settings, pressure advance, and firmware tuning to optimize print performance.

Mental Model

Core Idea

Print speed sets how fast the printer moves, while acceleration controls how quickly it reaches that speed, together shaping print quality and time.

Think of it like...

It's like driving a car: print speed is your cruising speed on the road, and acceleration is how quickly you press the gas pedal to reach that speed smoothly without jerking.

┌───────────────┐      ┌───────────────┐
│   Print Speed │─────▶│ Movement Rate │
└───────────────┘      └───────────────┘
         ▲                      ▲
         │                      │
┌─────────────────┐      ┌───────────────┐
│ Acceleration    │─────▶│ Speed Changes │
│ (rate of change)│      │ (smoothness)  │
└─────────────────┘      └───────────────┘

Build-Up - 7 Steps

1

Foundation

Understanding Print Speed Basics

Concept: Introduce what print speed means in 3D printing and its direct effect on printing time.

Print speed is how fast the printer's nozzle moves while depositing material. For example, a speed of 50 mm/s means the nozzle moves 50 millimeters every second. Faster speeds reduce print time but can lower quality if too high.

Result

Knowing print speed helps estimate how long a print will take and sets expectations for quality.

Understanding print speed is essential because it directly controls the balance between print duration and surface finish.

2

Foundation

Basics of Acceleration in Printing

Concept: Explain acceleration as the rate at which the printer changes its speed during movements.

Acceleration controls how quickly the printer speeds up or slows down. If acceleration is too high, the printer moves abruptly, causing vibrations and defects. If too low, prints take longer but are smoother.

Result

Recognizing acceleration's role helps prevent mechanical stress and print imperfections.

Knowing acceleration prevents common print issues caused by sudden starts and stops.

3

Intermediate

How Speed and Acceleration Affect Print Quality

🤔Before reading on: Do you think increasing speed always reduces print quality? Commit to yes or no.

Concept: Explore the trade-offs between speed, acceleration, and print quality.

Higher print speeds can cause poor layer adhesion and surface roughness. High acceleration can cause ringing or ghosting effects on prints due to vibrations. Balancing both is key to good quality and reasonable print times.

Result

Understanding this trade-off helps users tune settings for their specific printer and material.

Knowing the interplay between speed and acceleration allows smarter adjustments to optimize both quality and efficiency.

4

Intermediate

Common Default Settings and Their Limits

🤔Before reading on: Do you think default printer settings are always optimal for every print? Commit to yes or no.

Concept: Introduce typical default values and why they might not suit all prints.

Most printers come with default speeds around 50-60 mm/s and acceleration around 500-1000 mm/s². These are safe starting points but may be too slow or fast depending on the model complexity, material, or printer rigidity.

Result

Realizing defaults are starting points encourages experimentation for better results.

Understanding default limits prevents blindly trusting presets and promotes active tuning.

5

Intermediate

Adjusting Settings in Slicing Software

Concept: Show how to change print speed and acceleration in slicer programs and what to watch for.

Slicing software lets you set print speed per layer or feature (e.g., infill, perimeter). Acceleration is often set in printer firmware or advanced slicer settings. Adjusting these requires testing to avoid print defects or hardware strain.

Result

Learners gain practical skills to customize prints for different needs.

Knowing where and how to adjust these settings empowers users to improve prints beyond defaults.

6

Advanced

Firmware Role in Acceleration Control

🤔Before reading on: Does acceleration only depend on slicer settings? Commit to yes or no.

Concept: Explain how printer firmware enforces acceleration limits and smooths movements.

Firmware like Marlin controls acceleration at the hardware level, limiting how fast motors speed up or slow down. This protects mechanical parts and ensures consistent motion. Slicer settings request speeds, but firmware enforces safe acceleration.

Result

Understanding firmware's role clarifies why some speed changes don't behave as expected.

Knowing firmware controls acceleration helps diagnose print issues and guides proper tuning.

7

Expert

Surprising Effects of Acceleration on Print Artifacts

🤔Before reading on: Can too low acceleration cause print defects? Commit to yes or no.

Concept: Reveal how both too high and too low acceleration can cause unexpected print problems.

While high acceleration causes ringing, very low acceleration can cause under-extrusion or poor corner quality because the printer can't reach desired speeds quickly. This subtle balance is critical for high-precision prints.

Result

Experts learn to tune acceleration not just to avoid vibration but also to maintain extrusion consistency.

Understanding acceleration's dual impact prevents tuning mistakes that degrade print quality in less obvious ways.

Under the Hood

Inside the printer, stepper motors move the print head or bed by receiving electrical pulses. Acceleration controls how quickly the motor's pulse frequency increases or decreases, affecting motor torque and inertia. The firmware calculates motion paths and applies acceleration limits to avoid skipping steps or mechanical stress. Print speed is the target velocity for these motors during extrusion.

Why designed this way?

This design balances speed and mechanical safety. Early printers lacked acceleration control, causing missed steps and poor prints. Adding acceleration limits improved reliability and quality. Firmware enforcement ensures user settings don't damage hardware or cause print failures.

┌───────────────┐       ┌───────────────┐       ┌───────────────┐
│ Slicer Speed  │──────▶│ Firmware      │──────▶│ Stepper Motor │
│ Settings      │       │ Acceleration  │       │ Movement      │
└───────────────┘       │ Limits       │       └───────────────┘
                        └───────────────┘

Myth Busters - 4 Common Misconceptions

Quick: Does increasing print speed always reduce print quality? Commit to yes or no.

Common Belief: Faster print speed always means worse print quality.

Reality: While very high speeds can reduce quality, moderate increases with proper acceleration tuning can maintain or even improve quality by reducing heat buildup.

Why it matters: Believing this limits users from optimizing print times and discovering better settings.

Quick: Is acceleration only about making prints faster? Commit to yes or no.

Common Belief: Acceleration only affects how fast prints finish.

Reality: Acceleration mainly affects print smoothness and mechanical stress, not just speed. Poor acceleration causes defects even at low speeds.

Why it matters: Ignoring acceleration leads to print artifacts and hardware wear despite slow speeds.

Quick: Can default printer settings be perfect for all prints? Commit to yes or no.

Common Belief: Default speed and acceleration settings are always good enough.

Reality: Defaults are generic and often suboptimal for specific models, materials, or printers.

Why it matters: Relying on defaults prevents better print quality and efficiency.

Quick: Does lowering acceleration always improve print quality? Commit to yes or no.

Common Belief: Lowering acceleration always makes prints better by reducing vibrations.

Reality: Too low acceleration can cause under-extrusion and poor corner sharpness because the printer can't reach needed speeds quickly.

Why it matters: Misunderstanding this leads to tuning that worsens print quality.

Expert Zone

1

Acceleration interacts with jerk settings; ignoring jerk can cause unexpected print artifacts even with good acceleration.

2

Different printer mechanics (e.g., CoreXY vs. Cartesian) respond differently to acceleration changes, requiring tailored tuning.

3

Material properties affect optimal speed and acceleration; flexible filaments need slower, smoother movements than rigid ones.

When NOT to use

High acceleration is not suitable for printers with loose belts or weak frames; instead, use lower acceleration and improve hardware rigidity. For very detailed prints, prioritize quality over speed by reducing both speed and acceleration.

Production Patterns

Professional print farms often use tuned acceleration profiles per printer model and material. They combine firmware acceleration limits with slicer speed overrides for different print features, optimizing throughput without sacrificing quality.

Connections

Physics of Motion

Print speed and acceleration directly apply basic physics principles of velocity and acceleration.

Understanding Newtonian motion helps grasp why acceleration affects printer vibrations and print quality.

Human Motor Control

Similar to how humans control arm speed and acceleration for smooth movements, printers must manage motor acceleration for precision.

Knowing how smooth acceleration improves human motion helps appreciate its importance in mechanical systems.

Automotive Engineering

Print speed and acceleration settings resemble car speed and acceleration control systems designed for safety and comfort.

Recognizing this parallel aids in understanding trade-offs between speed, smoothness, and mechanical stress.

Common Pitfalls

#1 Setting print speed too high without adjusting acceleration.

Wrong approach:

Print speed = 100 mm/s; Acceleration = 1000 mm/s² (default)

Correct approach:

Print speed = 100 mm/s; Acceleration = 3000 mm/s² (increased to match speed)

Root cause:

Failing to increase acceleration when increasing speed causes the printer to struggle to reach target speed smoothly, leading to print defects.

#2 Lowering acceleration excessively to reduce ringing.

Wrong approach:

Acceleration = 100 mm/s² (very low)

Correct approach:

Acceleration = 800 mm/s² (balanced low value)

Root cause:

Too low acceleration prevents the printer from reaching needed speeds quickly, causing under-extrusion and poor corner quality.

#3 Changing acceleration only in slicer without firmware support.

Wrong approach:

Set acceleration to 2000 mm/s² in slicer, firmware limit remains 1000 mm/s²

Correct approach:

Update firmware acceleration limit to 2000 mm/s² to match slicer setting

Root cause:

Firmware limits override slicer settings; ignoring firmware causes no real change in acceleration.

Key Takeaways

Print speed controls how fast the printer moves while printing, directly affecting print time and quality.

Acceleration determines how quickly the printer reaches its set speed, influencing smoothness and mechanical stress.

Balancing print speed and acceleration is essential to avoid defects like ringing, under-extrusion, and layer shifts.

Firmware enforces acceleration limits to protect hardware, so both slicer and firmware settings must be tuned together.

Default settings are starting points; fine-tuning speed and acceleration per printer and material leads to better prints and efficiency.