What is PLA?
PLA (Polylactic Acid) is a biodegradable, bio-based thermoplastic most commonly used in 3D Printing. Derived from renewable resources such as corn starch or sugar cane. PLA is valued for its ease of printing, low cost, environmentally friendly and comes in a variety of colours. PLA prints at relatively low temperatures and does not require an enclosure to print like other popular materials as well as producing minimal odour when printing. This makes it ideal for prototyping, low stress functional parts and beginners just starting out.
While PLA offers good stiffness and detail resolution, it has limited heat resistance and impact strength compared to other plastics, which restricts its use in high temperature or mechanically demanding applications.
What adhesives can bond PLA?
PLA can be bonded using a variety of industrial adhesives like methacrylates, cyanoacrylates and solvent adhesives. Which adhesive is used greatly depends on the application, including factors such as required bond strength, clarity or adhesive colour, curing speed, environmental exposure and flexibility required.
Instant Adhesives (Cyanoacrylates)
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Strengths |
Very fast fixture, high shear strength, no mixing (single part), great for high-speed production lines and low odour / low bloom (no fogging) variants available for aesthetic appeal. |
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Limitations |
Limited gap filling capability without activators, lower impact and peel strength compared to other structural adhesives, standard grades can bloom (white powdery residue) which aesthetically is not good for PLA Prints. |
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Recommendations |
Thicker viscosity grades of NEXTITE Instant Adhesives are generally best suited to bonding PLA, as they help bridge layer lines and surface irregularities common in 3D printed parts. While all NEXTITE Instant Adhesives will bond PLA effectively, thin viscosity cyanoacrylates can be absorbed into the layer lines, reducing bond strength. If a thin grade is used, minimising visible layer lines through post processing will help achieve a stronger, more consistent bond. For gap filling NEXTITE CA-1 Cyanoacrylate Activator will cure CA instantly bridging small gaps. |
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Most Suitable |
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Methacrylates (MMA)
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Strengths |
Structural adhesive, multi material bonding, toughened and flexible bond, various fixture times, good gap filling, widely used in industry manufacturing and prototyping. |
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Limitations |
No clear multi material variants available, generally viscosity is high, stronger odour, exothermic reaction (although limited). |
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Most Suitable |
AB200 (fast cure, high strength), AB210 (medium cure, high strength), AB422 (medium cure, high toughness), AB560 (long cure, high viscosity, high toughness). |
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Solvent Adhesives
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Strengths |
Strong bonding of PLA through chemically softening it and fusing it together, fast initial tack, cost effective. |
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Limitations |
Limited gap filling even with thickened grades, not much working time for complex or larger assemblies. |
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Most Suitable |
3D-BOND 135 (Water-thin) and 3D-BOND 140 PLA (Thickened Medium Set) |
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What Industries is PLA used in?
PLA is used for rapid prototyping and by hobbyists. It is widely used for its ease of printing, dimensional accuracy and ability to produce high quality finishing without an expensive printer.
Common uses of material
PLA is used in many industries including:
- Rapid prototyping and product development
- Model making and visual concept validation
- Jigs, fixtures and assembly aids
- Educational and training models
- Consumer product prototypes and housings
- Short run production parts
Challenges with this material
- Low heat resistance, parts can soften or deform at relatively low temperatures
- Brittle compared to engineering plastics, prone to cracking under impact or flexing
- Sensitive to certain solvents, which can cause degradation
- Visible layer lines in 3D printed parts can reduce bond strength if adhesives are not properly matched
- Adhesive selection must be matched to the application and expected service conditions
Properties of PLA
- Surface Energy: 38 - 40 mJ / m²
- Temperature Resistance: 45°C
- Softening Point: 60°C
- Various Options available: Transparent, Coloured, Colour shift, Modified Grades (PLA+ and Heat-Resistant PLA)
Surface Preparation
Proper surface preparation is critical to achieving a strong and reliable bond when working with PLA. Begin by lightly wiping the bonding area with a dedicated plastic cleaner such as ACRI-BOND CLEANER or NEXTITE PROPREP Surface Preparation Cleaner. This removes surface contaminants including dust, oils and residual adhesive that can interfere with bond strength. Allow the cleaner to fully evaporate before applying any adhesive.
PLA, like many plastics, is sensitive to solvents. Avoid using acetone or similar strong solvent cleaners, as they will cause surface crazing, cracking, discolouration and permanent damage that compromises both appearance and bond integrity. Using PLA-safe cleaners like isopropyl alcohol ensures the surface remains intact and properly prepared for bonding.Â
Summary
Choosing the best industrial adhesive to bond PLA comes down to understanding the application requirements and performance required from the joint.
If you would like to speak to our expert team about your next project, please contact us for tailored advice and product recommendations to suit your application.