Why Is There So Much Confusion About ABS Melting Point?
You may have seen different numbers for the melting point of ABS. One source says 105°C, another says 220°C, and another says 250°C. Which one is correct?
They are all partially right, but none of them is truly accurate. The reason is simple: ABS does not have a true melting point in the conventional sense.
This may sound like a technical detail, but for engineers and buyers selecting a material, this difference directly affects whether a part can pass a heat resistance test.
ABS Has No True Melting Point — What Does It Have Instead?
ABS is an amorphous polymer. Its molecular chains are randomly arranged, unlike semi-crystalline plastics such as PP or nylon, which have ordered crystalline regions.
When heated, ABS does not melt sharply like ice turning into water. Instead, it softens gradually, more like butter left at room temperature.
So when a supplier or datasheet says “ABS melting point,” they may actually be referring to one of three very different temperatures:
| When “melting point” is mentioned, it may actually mean | Temperature Range | What It Really Indicates |
| Vicat Softening Point | 95–110°C | Temperature at which a needle penetrates the surface; most commonly mislabeled as “melting point” |
| Glass Transition Temperature (Tg) | ~105°C | Temperature at which ABS changes from a glassy to a rubbery state |
| Injection Molding Processing Temperature | 200–250°C | Actual melt temperature during processing, which is completely different from a melting point |
The first two values are the ones you need to focus on for heat resistance. Processing temperature is mainly a machine setting. It does not directly show whether your part can withstand heat in service.
The Real Question: How Much Heat Can ABS Handle?
Most people searching for “ABS melting point” are not writing a research paper. They want answers to practical questions such as:
- Can my ABS part be used at 80°C continuously?
- Which material is more heat resistant, ABS or PC?
- Why did my ABS part deform in hot water?
These questions should be answered using three key thermal indicators.
1. Vicat Softening Point: 95–110°C
This is the temperature at which ABS starts to soften noticeably. Under no load, ABS parts begin to lose rigidity in this range.
2. Heat Deflection Temperature: 85–100°C at 1.8 MPa
Heat deflection temperature, or HDT, is often the most practical indicator. It measures the temperature at which a standard test bar deflects under a 1.8 MPa load.
If your part is exposed to both heat and mechanical stress, HDT is the number you should check first.
3. Continuous Use Temperature: 60–80°C UL RTI
This is the upper temperature range for long-term use. Above this range, mechanical properties may gradually decline over time, even if the part looks acceptable in the short term.
So, can ABS work at 80°C?
The answer is: it is borderline. If exposure is short-term and occasional, ABS may survive. But if the part is under load at 80°C continuously, ABS can slowly deform. In that case, consider PC, PP, or PA66.
What Are the Actual Thermal Values for Common ABS Grades?
The table below shows typical thermal data for ABS grades from four brands we distribute. Values are typical values from official technical datasheets. Actual batches may vary by about ±2°C.
| Brand | Grade | Vicat (°C) | HDT @ 1.8 MPa (°C) | Notes |
| Chimei Polylac® | PA-757 | 105 | 89 | General purpose, high gloss, high impact |
| Chimei Polylac® | PA-717C | 104 | 88 | High flow, good for large parts |
| FCFC Tairilac® | AG15A1 | 104 | 88 | General purpose, balanced properties |
| FCFC Tairilac® | AG12A0 | 103 | 87 | High flow, thin-wall parts |
| LG Chem | HI-121H | 103 | 87 | High impact, most widely used |
| LG Chem | AF-312A | 102 | 86 | High flow, complex molds |
| Ineos | Lustran® 348 | 102 | 90 | Medium impact, slightly better heat resistance |
| Ineos | Lustran® 433 | 101 | 89 | High impact, easy processing |
How to Read This Table
- The differences in Vicat and HDT are only about 2–3°C. In terms of heat resistance, these grades are basically similar.
- Flowability, impact strength, and surface gloss often matter more than heat resistance when selecting an ABS grade.
- Ineos Lustran® 348 has the highest HDT in this group at 90°C. If heat resistance is a critical requirement, this grade may be considered first.
What Factors Affect the Heat Resistance of ABS?
After seeing that the heat resistance difference among these grades is small, you may ask: can ABS heat resistance be improved? The answer depends on formulation and reinforcement.
1. Acrylonitrile Content
ABS is made from three monomers: acrylonitrile, butadiene, and styrene. Acrylonitrile contributes to heat resistance and chemical stability.
Heat-resistant ABS grades usually have higher acrylonitrile content, often around 25–35%. The trade-off is that flowability may decrease.
2. Glass Fiber Reinforcement
Adding 10–20% glass fiber can raise the HDT of ABS from about 90°C to around 100–110°C. It also improves rigidity and dimensional stability.
However, glass fiber can reduce surface gloss, increase density, and make the material more brittle.
3. Flame Retardants
Some flame retardants, especially halogenated systems, may reduce the heat deflection temperature of ABS.
Halogen-free flame retardants usually have less impact on heat resistance, but they often come at a higher cost. If a part requires both flame retardancy and heat resistance, grade selection needs extra attention.
4. Recycled Content
The thermal stability of recycled ABS may decrease with each recycling cycle. Adding regrind can reduce HDT and impact strength.
For general molded parts, recycled content is often controlled below 20–30%. For parts with higher heat resistance requirements, virgin ABS is strongly preferred.
Practical selection tip: If standard ABS cannot meet your heat resistance requirement, do not rush to choose a special heat-resistant ABS grade. First confirm whether the actual service temperature truly exceeds 80–100°C. In many cases, switching to PC or PA66 may be more economical.
ABS Processing Temperature: Why It Is Not the Melting Point
When injection molding ABS, barrel temperatures are usually set between 200°C and 250°C. Many people mistake this for the melting point. This is incorrect.
Processing temperature is higher than the softening point because ABS must be heated far above its Vicat temperature to reach a melt viscosity low enough to fill the mold.
If the barrel were set at 105°C, ABS would only soften. It would not flow properly into the mold.
Recommended ABS Injection Molding Parameters
| Parameter | Recommended Value | Notes |
| Drying temperature | 80–90°C, 2–4 hours | ABS absorbs moisture; insufficient drying causes silver streaks |
| Barrel temperature (rear → front) | 200 → 220 → 230–250°C | Nozzle is hottest; do not exceed 260°C |
| Mold temperature | 40–80°C | Higher mold temperature improves gloss but increases cycle time |
| Back pressure | 5–10 bar | Ensures uniform melt |
| Screw speed | 50–100 rpm | Medium speed, avoid excessive shear heat |
Common mistake: Setting the mold temperature too high, for example 100°C, may cause parts to deform after ejection. This is because 100°C is already within the softening range of ABS.
Mold temperature should normally be kept at 40–80°C, below the Vicat softening point, so parts can retain their shape during ejection.
Safety note: ABS may begin to decompose above 260°C and release irritating gases. Ensure good workshop ventilation and avoid prolonged residence time at high temperatures.
Quick Material Selection Guide: What If ABS Cannot Handle the Heat?
If you are considering another material because of heat resistance concerns, the table below can help you make a quick comparison.
| Actual Service Condition | Recommended Material | Reason |
| Continuous temperature below 70°C | ABS | Best cost-performance ratio |
| 80–100°C, with load | PC | HDT is 30–50°C higher than ABS |
| Chemical contact, around 80°C | PP | Good chemical resistance, long-term use at 80–100°C |
| Load plus heat, above 100°C | PA66 | Balanced strength and heat resistance |
| Short-term heat only, no load | ABS can cope | Short-term heat resistance up to about 100°C |
Typical failure case: A customer used ABS for the housing of an electric kettle. When the kettle body heated to 90°C, the ABS housing deformed. The problem was solved by switching to PC.
ABS may have a Vicat softening point around 105°C, but that value is measured under specific test conditions. In the kettle application, the housing had to withstand heat transfer from the inner pot and structural load, so deformation started at around 80°C.
Frequently Asked Questions
What is the actual melting point of ABS?
ABS has no true melting point. It begins to soften at about 95–110°C based on Vicat softening point, has a glass transition temperature of about 105°C, and is commonly processed at 200–250°C. Different sources may refer to any of these values when they mention “ABS melting point.”
Which is more heat resistant, ABS or PC?
PC is much more heat resistant than ABS. Typical PC grades have a Vicat softening point around 145–150°C and an HDT at 1.8 MPa of about 125–140°C. This is roughly 30–50°C higher than ABS.
If a part needs long-term heat resistance above 80°C, PC is usually the safer choice.
Can ABS be used continuously at 80°C?
It is borderline. Without load, ABS may work at 80°C for limited conditions. Under load, continuous service above 70°C is not recommended for standard ABS.
The UL RTI range of ABS is commonly around 60–80°C. Above this range, mechanical properties may gradually decline.
What temperature does ABS need for 3D printing?
For ABS 3D printing, the hot end temperature is usually 230–250°C, and the bed temperature is usually 95–110°C.
An enclosed chamber is strongly recommended to reduce warping. ABS filament should also be dried before printing because moisture can cause stringing and poor layer adhesion.
How can I improve the heat resistance of ABS?
You can choose a heat-resistant ABS grade with higher acrylonitrile content, use glass fiber reinforcement, or select a PC/ABS blend.
However, these options increase cost or affect other properties. In many practical cases, switching directly to PC or PA66 is more cost-effective.
Why do ABS parts deform in hot water?
The continuous use temperature of ABS is usually only 60–80°C. Hot water is often around 80–100°C, which can exceed the long-term heat resistance limit of ABS.
If the part needs to contact hot water, PP or PC is usually a better choice.
Need More Detailed ABS Grade Data?
This article provides typical values for material selection reference. If you are facing a specific heat resistance problem during material selection or mold trial, or if you need a detailed TDS for a specific ABS grade, feel free to contact us.
We can provide grade recommendations based on your mold design, processing conditions, service temperature, load condition, and application requirements.
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