The shrinkage rate of 3D printing materials is a critical factor in 3D printing projects—it directly impacts the dimensional accuracy, structural integrity, and final quality of printed parts. Whether you’re making a small prototype or a large industrial component, ignoring material shrinkage can lead to wasted time, money, and failed prints. This guide breaks down what material shrinkage is, why it happens, and how to control it effectively.
1. Basic Concepts: What Is 3D Printing Material Shrinkage?
Before tackling solutions, it’s essential to understand the core of 3D printing material shrinkage.
Definition
Shrinkage refers to the percentage of volume or size reduction that occurs when a 3D printing material cools down after being melted (in fused deposition modeling, or FDM) or cured (in resin-based printing). For example, if a PLA part is designed to be 100mm long but measures 99.8mm after printing, its shrinkage rate is 0.2%.
Key Influencing Factors
Several elements affect how much a material shrinks. Here are the most common ones, organized for clarity:
- Material Type: Different materials have unique thermal expansion coefficients (how much they expand when heated) and curing behaviors—this is the biggest driver of shrinkage.
- Printing Parameters: Settings like printing temperature (too high can increase shrinkage), fill density (higher density often means more shrinkage), and layer height (thicker layers may cause uneven cooling) all play a role.
- Environmental Conditions: Ambient temperature (fluctuations can disrupt cooling) and humidity (especially for hygroscopic materials like PETG) can worsen shrinkage.
Case: A team printing ABS brackets for a robotics project noticed parts were 0.6% smaller than designed. After checking, they found the workshop temperature dropped by 8°C during printing—this uneven cooling increased the shrinkage rate beyond ABS’s typical range.
2. Shrinkage Rates of Common 3D Printing Materials
Not all materials shrink the same way. Below is a detailed table of the most widely used 3D printing materials, their typical shrinkage rates, and use cases to help you choose wisely.
| Material Name | Chemical Composition | Typical Shrinkage Rate | Key Advantages | Suitable Applications |
|---|---|---|---|---|
| ABS | Acrylonitrile-Butadiene-Styrene Copolymer | 0.4% – 0.8% | High impact resistance, durable | Automotive parts, electronic housings |
| PLA | Polylactic Acid | 0.2% – 0.8% | Biodegradable, low odor, easy to print | Prototypes, toys, household items |
| PETG | Polyethylene Terephthalate Glycol | 0.8% – 1.2% | High transparency, shatterproof | Food-safe containers, clear prototypes |
Note: These rates are averages. For example, a PLA part printed at 210°C may have a 0.3% shrinkage rate, but the same PLA printed at 230°C could shrink by 0.6%.
3. How to Control the Shrinkage Rate of 3D Printing Materials
Controlling shrinkage doesn’t have to be complicated. Here are four practical methods, with actionable steps:
1. Design Optimization
Compensate for shrinkage in your 3D model before printing. If your material has a 0.5% shrinkage rate, enlarge the model by 0.5% in your CAD software (e.g., SolidWorks, Blender). For example, a 200mm-long ABS part should be designed as 201mm to end up at 200mm after shrinkage.
2. Smart Material Selection
Choose a material with a shrinkage rate that matches your project’s accuracy needs:
- Need high precision? Go with PLA (0.2% – 0.8%) instead of PETG (0.8% – 1.2%).
- Need durability? ABS (0.4% – 0.8%) works, but be sure to adjust printing parameters to minimize shrinkage.
3. Adjust Printing Parameters
Tweak these settings to reduce shrinkage:
- Printing Temperature: Lower the temperature by 5–10°C (e.g., from 250°C to 240°C for ABS) to slow cooling and reduce size loss.
- Fill Density: Use 50%–70% fill density instead of 100%—lower density means less material to shrink.
- Bed Temperature: Keep the print bed warm (e.g., 110°C for ABS) to ensure slow, even cooling.
4. Post-Processing
After printing, use these methods to fix minor shrinkage:
- Heat Treatment: For ABS parts, bake them at 80°C for 30 minutes to “relax” the material and reduce residual shrinkage.
- Chemical Smoothing: For PLA or PETG, use isopropyl alcohol (IPA) to gently smooth surfaces and correct small dimensional gaps.
Yigu Technology’s Perspective on 3D Printing Material Shrinkage
At Yigu Technology, we believe controlling the shrinkage rate of 3D printing materials is a mix of science and practice. Many clients struggle with failed prints due to uncompensated shrinkage—our solution is to pair material expertise with tailored tools. We recommend using our 3D printing material test kits (which include ABS, PLA, and PETG samples with pre-tested shrinkage rates) to find the right material fast. Additionally, our design software plugin automatically calculates and applies shrinkage compensation, cutting prototype rework by 40%. For high-precision projects, we also offer post-processing services like heat treatment to ensure parts meet exact dimensions.
FAQ
- Q: Why does my PLA part still shrink even though PLA has a low shrinkage rate?
A: PLA’s low rate (0.2% – 0.8%) doesn’t mean no shrinkage. Check your printing temperature—if it’s too high (over 220°C), shrinkage increases. Try lowering it by 5–10°C and ensure the print bed is at 60°C for even cooling. - Q: Can I use the same shrinkage compensation rate for all parts made with the same material?
A: Mostly, but adjust for part size. Larger parts (over 300mm) may shrink slightly more due to more material cooling. For example, a 400mm ABS part might need 0.6% compensation instead of 0.5% for a 100mm part. - Q: Does humidity affect the shrinkage rate of PETG?
A: Yes—PETG absorbs moisture, which causes uneven cooling and higher shrinkage. Dry PETG filaments in a dehydrator (50°C for 4 hours) before printing to reduce shrinkage by up to 0.3%.
