3D Printer Plastics Scientific Tests & Properties - Research

3D Printer Plastics Scientific Tests & Properties

sustainable-design-studio

Started 1y. Edited 5mo.Started almost 2 years ago. Last edit 6 months ago.

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As Precious Plastic grows to more advanced products and accurate machines, understanding the properties of the plastic becomes increasingly important. Currently, the database of melting temperatures and performances of the different materials is out of date and lacks valuable information for product designers. As a result, Sustainable Design Studio will be developing a series of standardised tests to understand the properties of different plastics, focusing initially on 3D printer materials. The project will focus on analysing the following criteria: • Optimum melting temperature. • Flow rate under controlled pressure conditions. • Shrinkage rate/percent. • Material stiffness. • Impact strength. • Temperature resistance. • Additional observations (Tips & Tricks). The materials that will be tested are as follows: • PLA • ABS • PETG • PA (Nylon) • TPU • PVB All materials will be compared to PP & HDPE as a baseline and injected using the same injection pressure.

researchinjectionPPHDPEmeltingLDPE

More Information

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1 Progress on Developing Material Property Tests

sustainable-design-studio

Published 1y. Edited 1y.Published over 1 year ago. Last edit over 1 year ago.

Following up on our previous post about the need for a deeper understanding of 3D printer material properties, we’re excited to share some progress on the standardization and development of our testing protocols. Over the past month, our team has been hard at work designing and refining tests that will provide the crucial data needed to better understand the plastics we use. Impact Strength Test One of the critical tests we’ve developed is the Impact Strength Test, designed to adhere as closely as possible to ISO 180 standards. The goal here is to measure the impact strength of different materials by striking a notched specimen with a controlled force. Our setup is pretty sleek: a vice designed specifically to hold the specimen in perfect alignment with the striker, which is engineered to hit at exactly 22 mm above the vice with a precision that would make any engineer proud. The modular design of the striker even allows us to adjust its mass, providing flexibility across various materials. We’ve designed the setup to be easily replicable, ensuring consistent results across different labs or setups. Flexural Bending Test We’ve also made significant strides in the Flexural Bending Test, which measures the stiffness of the materials—a critical factor in determining their usability in load-bearing applications. This test follows the principles laid out in ISO 178 and involves a three-point bend test where the specimen is subjected to a downward force at its midpoint. Our innovative setup includes 3D printed structures to support the test, with precise measurements ensuring accurate deflection readings. The test apparatus has been designed to be user-friendly while maintaining the strict requirements needed for reliable data. Heat Deflection Temperature Test We initially aimed to replicate the ISO 75 standard for Heat Deflection Temperature (HDT) testing, but due to safety concerns and the complexity of the setup, we opted for a modified approach. Our new method involves a safer, more replicable process that still yields valuable insights into how our materials perform under heat. A custom-designed frame, made from ultra-high-temperature resin, allows us to perform a three-point bend test while gradually heating the specimen. The moment the specimen deflects by 10 mm, we measure the temperature, providing a practical estimate of its heat resistance. Material Flow Test Finally, we’ve devised a Material Flow Test to measure how well different plastics move under pressure—a crucial factor for 3D printing. The test uses a specially designed mold that challenges the material to navigate a maze-like path, with sections of varying thickness to see how thin and far it can flow. This test is essential for understanding the material’s behavior during the printing process and will directly inform the optimal settings for different plastics.

2 Whats Next?

sustainable-design-studio

Published 1y.Published over 1 year ago.

Right now we are currently 3D printing all the design elements for the machines for assembly and fabricating the relevant CNC Aluminium Moulds to create the test samples.

3 The moulds are made!

sustainable-design-studio

Published 1y.Published over 1 year ago.

The moulds have now been fabricated and we have begun the basic tests. These two moulds include the standard dog bone, and break/bend test samples we need. At this stage, we are just injecting PP from Black DVD cases to see how the material flows using our Injection Mini machine (https://www.sustainabledesign.studio/injectionmini). The Pneumatic Injection Machine is a key reason we can do these tests, as until now most precious plastic machines have been human-powered, which unfortunately means that there would be far too many variables between the tests. The key will be to decide on the key control variables for all future injections. We will need to be able to maintain the following: - Injection Pressure - Melt Time - Mould Temperature - Hold Time We haven't decided on if the following will be fixed as we likely vary with the material: - Melt Temperature

4 Plastic Testing!

sustainable-design-studio

Published 1y. Edited 1y.Published over 1 year ago. Last edit over 1 year ago.

Over the last week, we have been testing the moulds to see how different variables affect the results to help decide on the final process. With a few test samples, we have chosen the final conditions that will remain constant for all future testing. These conditions will be as follows: Machine: Sustainable Design Studio - Injection Mini This machine is what we have available to us but it offers very consistent results based on our testing. Melt Time: 10min This will need to remain constant and from experience is the ideal amount of time to see a consistent melt throughout the barrel volume. Injection Pressure: 120psi Although this is machine-specific. We can consistently keep it at 120psi for testing with our 10 Bar compressor. Mould temperature: 45-55c This from our testing is a good stable temperature that is easy to reach and doesn't make the mould too hot to handle with gloves. It also has good results. Variation of mould temperature within this range doesn't seem to cause issues. The mould that is proving the most interesting currently is the flow test mould. From the results below you can see that between the 2 injections, with the same variables the results are almost identical.

5 Building the Material Database (Raw Data)

sustainable-design-studio

Published 1y. Edited 1y.Published over 1 year ago. Last edit over 1 year ago.

Now that we have defined our controls we have begun building a database of results. We expect this to take the most time out of the whole project as we will now need to generate a minium of 5 injections per flow mould and an additional of 5 injections to create the testing samples. Since we chose to have a 10min wait time between injections this means it will take atleast 100min for each material. Excluding purging and preheats. However the results are already very exciting and as we add more results to the database we will very quickly start to a build better a picture of flow rates, optimal temperatures and shrink rates of different materials. At the link below, we will begin uploading the photos and data for the raw results of the Material Flow Tests. https://www.sustainabledesign.studio/plastic-materialdatabase

6 Processing and Displaying the Raw Data

sustainable-design-studio

Published 1y. Edited 1y.Published over 1 year ago. Last edit over 1 year ago.

As a part of this database, one of the considerations is how we display this data in an easy-to-view, review and update manner. One of the beautiful elements of the Precious Plastic Academy is that it is online, as a web page and as a result can be easily translated using the browser to any language. (Much easier than a PDF or print out). So to test the formatting we have started building the web page for the data to be displayed. Adding important information about reading and understanding the data and why it's important for anyone trying to recycled these materials. We have picked a series of key values to display for each material (based on standard information found online), along with similar information based on the specific material tested. With the goal to have tested multiple different versions of the same plastic. Eg. PP from DVD cases vs PP from plastic lids. You can view the full page with all this information below. https://www.sustainabledesign.studio/plastic-materialdatabase

7 TPU Tested & Added to the Database

sustainable-design-studio

Published 1y. Edited 11mo.Published over 1 year ago. Last edit 12 months ago.

TPU has now been tested and added to the database. PLA is next. Other notable mentions are acyclic, and PP from fishing nets were added last month. Theromoplastic Polyurethane Abbreviated Name: TPU Average Shrink Rate Range: 0.5 - 1% Average MFI Range (Melt Flow Index): 5 - 15 g/10min Average Density (g/cm³): 1.23 g/cm³ Flexural Modulus (MPa): 35 MPa Advantages: Highly Flexible Good Abrasion Resistance Elasticity Chemical Resistance Weather and UV Resistance Disadvantages: Moderate Heat Resistance Prone to Hydrolysis Can Be Sensitive to Low Temperatures Limited Dimensional Stability Softness Limits Heavy Load Applications Material Source Tested: 3D Printer Filament Material Form Tested: Test Print Colour: Red Average Flow Score: 39.3cm Average Thickness Score: 0.7mm Shrinkage Rate: No Data Odor Levels: Low Optimum Melting Temperature: 180c Flexibility: No Data Observational Notes: When injecting TPU, flow behaviour is relatively limited, with test results ranging from 28.5 cm to 52 cm — well below the upper end of the 158 cm flow scale, meaning it may struggle to fully fill detailed or thin-walled moulds without the right conditions. Despite this, the thickness test results were consistently good, ranging from 0.5 mm to 1 mm, suggesting TPU is capable of producing thin, well-formed parts when processed correctly. Using a heated mould is recommended to prevent premature cooling, especially since TPU can become more viscous at lower injection temperatures. As with many hygroscopic plastics, drying the material beforehand is important. Moisture in the polymer can lead to bubbling, splaying, or weak areas in the final part. Careful temperature and pressure control are key to ensuring good surface finish and dimensional stability during injection.

8 PLA Now Added

sustainable-design-studio

Published 1y. Edited 1y.Published about 1 year ago. Last edit about 1 year ago.

PLA has now been added to the database with promissing results! Please see below our addition. Polylactic Acid Abbreviated Name: PLA Average Shrink Rate Range: 0.3 - 0.5% Average MFI Range (Melt Flow Index): 6 - 8 g/10min Average Density (g/cm³): 1.24 g/cm³ Flexural Modulus (MPa): 2996 - 3750 MPa Advantages: Biodegradable Easily thermoformed and 3D printed Low shrinkage Non-Toxic Disadvantages: Brittle Low heat resistance Prone to moisture absorption Limited chemical resistance Lower durability outdoors. Material Source Tested: 3D Printer Filament Material Form Tested: Test Print Colour: Yellow Average Flow Score: 69cm Average Thickness Score: 1.5mm Shrinkage Rate: No Data Odor Levels: Medium Optimum Melting Temperature: 200c Flexibility: No Data Observational Notes: When injecting, don't use a heated mould. The molten PLA is like a tacky sticky glue, you want it to be able to cool as soon as it's placed within the mould to allow for easy demoulding. Flowed out the nozzle like honey/syrup if the jack wasn’t in place. The material needed to be dried before testing, as a result, bubbles developed and these caused it to overflow out of the barrel when heating. When injected at a lower temperature, the material flows less but is less brittle.

9 PVB Added to the Database

sustainable-design-studio

Published 11mo. Edited 11mo.Published 12 months ago. Last edit 12 months ago.

Polyvinyl butyral Abbreviated Name: PVB Average Shrink Rate Range: 0.4 - 1.5% Average MFI Range (Melt Flow Index): 1 - 10 g/10min Average Density (g/cm³): 1.14 g/cm³ Flexural Modulus (MPa): 500 MPa Advantages: Good Chemical Resistance Impact Resistance Good Flexibility Disadvantages: Low Heat Resistance Sensitive to UV Degradation Moisture Absorption Flammable Not Biodegradable Material Source Tested: 3D Printer Filament Material Form Tested: Test Print Colour: Grey Average Flow Score: 8.6cm Average Thickness Score: 3mm Shrinkage Rate: No Data Odour Levels: High Optimum Melting Temperature: 225c Flexibility: No Data Observational Notes: When injecting recycled PVB, it's crucial to use a heated mould. The material has a relatively low flow rate, with results ranging from 5cm to 13cm in the flow test, meaning it doesn’t fill moulds as easily as more fluid materials. Using a warm mould helps improve the flow and surface finish by allowing the material to flow more smoothly and evenly. Drying the PVB is especially important, as moisture can cause issues like bubbling, weak spots, or inconsistent flow during moulding. Although we dried the plastic before injecting, we think that it may have still been fairly moist, impacting our testing. If not properly dried, trapped moisture can lead to steam pressure, which may cause the material to overflow or spit from the barrel. The thickness results varied from 2.5mm to 4mm, which indicates that the material can be challenging to inject evenly, particularly for thicker parts, as the material tends to cool quickly and cause uneven thickness. At lower temperatures, PVB becomes more viscous and may require higher injection pressure to fill moulds. However, excessively high temperatures can lead to material degradation and impact the part’s mechanical properties.

10 ABS Now Added

sustainable-design-studio

Published 11mo. Edited 10mo.Published 12 months ago. Last edit 11 months ago.

Acrylonitrile Butadiene Styrene Abbreviated Name: ABS Average Shrink Rate Range: 0.4 - 0.9% Average MFI Range (Melt Flow Index): 1 - 8 g/10min Average Density (g/cm³): 1.03 g/cm³ Flexural Modulus (MPa): 1,900 – 2,300 MPa Advantages: Strong and impact resistant Heat-resistant Excellent dimensional stability Balanced Mechanical Properties Disadvantages: Strong odour when molten Poor UV Resistance Low Chemical Resistance to Some Solvents Flammable Without Additives Not Biodegradable Material Source Tested: 3D Printer Filament Material Form Tested: Test Print Colour: Yellow Average Flow Score: 12 Average Thickness Score: 3.5 Shrinkage Rate: No Data Odour Levels: Extremely High Optimum Melting Temperature: 230 Flexibility: No Data Observational Notes: When injecting, it’s important to use a heated mould with ABS. The material cools quickly and can warp or stick if the mould is too cold. A warm mould helps improve surface finish and reduces internal stresses. Drying the plastic is essential, moisture causes bubbling, splaying, and weak spots in the final part. If not dried properly, steam pressure can cause the material to spit or even backflow out of the barrel. At lower injection temperatures, ABS becomes more viscous and harder to fill into fine details, but overly high temps can lead to burning.

11 PETG added to Database

sustainable-design-studio

Published 11mo.Published 12 months ago.

Polyethylene terephthalate glycol Abbreviated Name: PETG Average Shrink Rate Range: 0.2 - 0.6% Average MFI Range (Melt Flow Index): 6 - 12 g/10min Average Density (g/cm³): 1.27 g/cm³ Flexural Modulus (MPa): 2,000 – 2,400 MPa Advantages: Tough and Impact-Resistant Low Shrinkage Good Chemical Resistance Transparent and Glossy Finish Food Safe (in many grades) Disadvantages: Moderate Heat Resistance Prone to Scratching Can Be Brittle Under Stress Over Time UV Sensitivity Material Source Tested: 3D Printer Filament Material Form Tested: Test Print Colour: Green Average Flow Score: 74.9 Average Thickness Score: 0.66 Shrinkage Rate: No Data Odour Levels: High Optimum Melting Temperature: 240 Flexibility: No Data Observational Notes: When injection moulding PETG, the material shows moderate to good flowability, with flow test results ranging from 43 cm to 107 cm. This places it well above lower-flowing plastics like PVB and TPU, making PETG more suitable for parts with fine details or long, thin flow paths. The thickness results, ranging between 0.5 mm and 1 mm, indicate that PETG can produce thin, consistent sections when processed correctly. It benefits from a heated mould to prevent rapid cooling, which can cause internal stresses or poor surface finish. PETG is also hygroscopic, so thorough drying before processing is essential to avoid defects like bubbling or streaking. While it flows well at typical moulding temperatures, too high a temperature can cause stringing or degradation, so temperature control is important for ensuring stable, high-quality parts.

12 ePa (Nylon) Testing results

sustainable-design-studio

Published 10mo.Published 10 months ago.

Polyamide (Nylon) Abbreviated Name: PA Average Shrink Rate Range: 1.5 - 3% Average MFI Range (Melt Flow Index): 5–20 g/10 min Average Density (g/cm³): 1.14 g/cm³ Flexural Modulus (MPa): 1,200 – 1,600 MPa Advantages: Excellent Chemical Resistance High Strength and Durability Good Flexibility Good Impact Resistance Low Friction Disadvantages: High Moisture Absorption High Shrinkage Susceptible to UV Degradation Lower Heat Resistance Compared to Other Materials Material Source Tested: 3D Printer Filament Material Form Tested: Pelletised filament Colour: Clear Average Flow Score: NULL Average Thickness Score: NULL Shrinkage Rate: No Data Odour Levels: Medium - High Optimum Melting Temperature: NULL Flexibility: No Data Observational Notes: The testing of the ePA filament for injection moulding revealed significant challenges. Despite varying the barrel temperature and dwell times, all trials resulted in degradation of the material, with none producing successful outcomes. Higher temperatures led to burning and breakdown of the filament, while shorter heat times caused incomplete melting and still showed early signs of degradation. These results highlight that ePA, like the other filaments tested, is not suitable for injection moulding. It is specifically engineered for 3D printing applications, where it is quickly heated and extruded. Attempting to process it in bulk through an injection moulding barrel exceeds its thermal stability and intended use, ultimately confirming its incompatibility with this manufacturing method. The tests were run at; 230℃ with a 10-minute heat time 220℃ with a 10-minute heat time 210℃ with a 10-minute heat time 205℃ with a 10-minute heat time 190℃ with a 10-minute heat time 230℃ with a 3-minute heat time 210℃ with a 3-minute heat time 190℃ with a 3-minute heat time

13 Conclusion

sustainable-design-studio

Published 9mo. Edited 9mo.Published 10 months ago. Last edit 10 months ago.

PLA delivered the best results in terms of flow and thickness. In fact, it outperformed most other plastics we tested – not just limited to 3D printing filaments. However, these excellent results were offset by its extreme brittleness after injection. Even minor drops from low heights or not opening the mould quick enough caused the parts to shatter. PETG also performed very well in terms of flow and thickness. We would likely recommend this material over PLA, as it offers similar – albeit slightly inferior – flow results, without the overly brittle nature of the final product. TPU didn’t score highly for flow or thickness, but it’s well-suited for smaller, less complex moulds. Its flexibility opens up possibilities for creating unique and exciting moulded products. PVB produced fairly limited results regarding flow and thickness. This material requires a mould that runs hotter than usual to improve plastic flow during injection. ABS also showed poor results in terms of flow and thickness. However, it stood out with a pleasant matte finish and a nice tactile feel. It could be suitable for small, low-detail products, but it remains challenging to work with. Do keep in mind that results with ABS can be inconsistent. Nylon (ePA) was unfortunately the least successful material. Even at relatively low temperatures, it degraded and burned before fully melting in the barrel. This made it extremely difficult to process. It's important to note that all of these materials are designed for 3D printing, not injection moulding. They are formulated to be heated and extruded quickly through a nozzle, whereas injection moulding involves maintaining the plastic at high temperatures for extended periods. This prolonged exposure increases the risk of thermal degradation. Our testing has clearly highlighted the distinction between injection-grade and extrusion-grade materials. One common trait across all the filaments tested was their high sensitivity to temperature – making it very easy for the material to degrade during the process. Due to the poor flow and thickness performance of many materials, we were unable to fully fill the testing mould. This prevented us from completing the additional tests we had planned. Since those tests require fully formed samples to yield accurate results, we decided not to proceed, as incomplete parts would produce unreliable data. While disappointing, the flow tests alone have provided valuable insights – arguably the most important information from this round of experiments. Additionally, when we did these other tests on polypropylene (PP), It yielded results that closely matched those already available online, so we did not gain much new knowledge from them. We’ll be continuing these material experiments at https://www.sustainabledesign.studio/plastic-materialdatabase , where you can explore our Material Database. We regularly add new materials along with detailed notes and photos from each test.

14 Project Link

sustainable-design-studio

Published 5mo.Published 6 months ago.

For more information and files, check out the project here: https://community.preciousplastic.com/library/test-and-compare-your-material-properties

Precious Plastic Community is a project by One Army.Please sponsor the work or help us build the software.