Comparing ABS and PC Thermoplastics

Posted On August 4, 2022 By Protolabs

Whether your project requires CNC machining, injection molding, or 3D printing, you can reliably depend on ABS (acrylonitrile butadiene styrene) and PC (polycarbonate) thermoplastics to suit your specific needs. In fact, the two plastics can even be mixed together in order to form even stronger parts for projects that require added durability and stability.

While there are plenty of shared properties between ABS and PCs, there are also key differences that would make one thermoplastic a better choice over the other for your project. And in some circumstances, the ABS/PC combination will be the best option to meet your specifications and requirements.

A quick note: While Protolabs prints ABS-like materials every day using stereolithography, our Hubs network can handle any ABS 3D printing needs through their industrial FDM process.

ABS 3D Print build
Translucent ABS-like parts with support structures are shown after building on a stereolithography printer.

Benefits of ABS

It is more affordable than comparable thermoplastics, and has superb mechanical properties like toughness, hardness, and rigidity. ABS maintains a high impact resistance and surface hardness under high and low temperatures, has terrific dimensional stability, and a higher heat deflection temperature than its thermoplastic counterparts. ABS also has excellent aesthetic qualities thanks to its natural opaque and ivory tones, which make it easily modifiable into vibrant, colorful parts with variable gloss levels from matte to high gloss. So, how does ABS stack up for various manufacturing processes? Here’s the rundown:

CNC Machining 

  1. Quick and affordable way to make precise prototypes and mass-produced parts, reducing the need for injection molds
  2. Great impact strength and surface hardness over a wide temperature range, with high heat deflection temperature and good dimensional stability
  3. Good electrical insulator and is mostly unaffected by temperature, humidity, and frequency, so it can be used in most environments
  4. Resistant to most types of fluids, unaffected by water, alkali alcohols, inorganic salts, hydrocarbon solvents, and many acids

 

ABS Measurements and Specifications for CNC Machining

Property

Value

Density (g/cm3)

1.05

Yield tensile strength (MPa)

51.2-63.8MPa

Tensile strength (MPa)

64.7-79.1

Shrink rate (%)

0.4-0.9

Hardness (HV)

16.4-18.1

 

Injection Molding

  1. Ideal choice for molding applications that require an inexpensive, strong, stiff plastic
  2. Holds up well to external impacts due to its high tensile strength and impact resistance, maintaining high levels of toughness and stiffness under all conditions
  3. Good machinability and exceptional dielectric properties, with excellent dimensional stability and high stability under load
  4. Heat and creep resistant, and resistant to most oils, acids, and alkalis
  5. Maintains characteristics and performance in extreme temperatures

3D Printing

  1. Low-cost material ideal for producing tough and durable 3D parts
  2. Great mechanical properties with high resistance to heat and everyday chemicals
  3. Can endure more stress, heat, and pressure than comparable 3D printing materials
  4. Minimal oozing and stringing gives models a smoother finish
  5. Reliable results and familiarity of use, as one of the first plastics used with industrial 3D printers
resin pellets being poured into a hopper
A technician pours PC resin pellets into a hopper in preparation for making a molded part.

Benefits of PC

Polycarbonate is a lightweight, transparent thermoplastic that is extremely durable and highly resistant to impact and fracture. PC is 250 times stronger than glass, with comparable light transmission properties, but it’s significantly lighter and more durable than glass. Polycarbonates are fire-resistant, have insulating properties, and are easy to machine. PC also exhibits high heat resistance. Polycarbonates are available in multiple colors to suit any part requirements or project demands. PC and ABS stack up pretty closely. Here’s what PC looks like in short form for three major manufacturing processes:

CNC Machining

  1. Excellent dimensional stability and good strength and stiffness
  2. Superior impact strength and durability
  3. Good machinability, with excellent electrical and properties
  4. Extremely versatile plastic that is highly transparent
  5. Perfect for parts that require clarity, strength, and stiffness

 

Machined PC Properties

Type of PC

Tensile Strength at Yield

Flexural Modulus

Tensile Elongation at Break

Translucent

8,000 psi 

340,000 psi

50%

Clear

8,990 psi

338,000 psi

140%

20% Glass-Filled

16,000 psi

796,000 psi

5%

 

Injection Molding

  1. Good thermal resistance with high viscosity during processing
  2. Easy to work with via molding and thermoforming
  3. Parts and components have high impact strength, excellent rigidity, and clear transparency
  4. High strength retention at elevated temperatures, with superior resistance to temperature extremes
  5. High tensile, shear, and flexural strength, with excellent creep resistance

3D Printing

  1. Highly durable and heat resistant up to 135°C
  2. Impact and shatter resistant
  3. Withstands torsional stress better than other thermoplastics
  4. Flexibility allows it to be machine bendable at room temperature
  5. Transparent and electrically non-conductive

 

PC Block
A block of clear polycarbonate.

ABS vs. PC

Now, let’s put ABS up against PC using different manufacturing processes. In this case, PC wins out in terms of heat deflection and tensile strength, but looking at elongation, the process used makes quite a difference.

 

 

 

Comparing ABS and PC for Molding and Machining  

Property

ABS Molded

ABS Machined

PC Molded

PC Machined

Heat deflection

215°F (102°C)

214°F (101°C)

280°F (138°C)

280°F (138°C)

Tensile strength

6,091 psi (42MPa)

6,100 psi (42MPa)

10,442 psi (72MPa)

8,000 psi (55MPa)

Elongation at break

30%

40%

100%

50%

 

Benefits of ABS/PC

For projects that require the toughness and heat-resistance offered by PC along with the ductility, processability, and aesthetics offered by ABS, the combination of ABS/PC is potentially the best option for your parts. ABS/PC is also a more cost-effective alternative than using just polycarbonates. ABS/PC materials help minimize the thick molding concerns found in ABS or PC materials when molded alone and offer improved processing during injection molding. The electronic, automotive, and telecommunications industries have all found success in using an ABS/PC blend to meet their specifications. The benefits of using ABS and PC on their own are mostly reinforced when using a combination of ABS/PC.

  1. High strength, stiffness, and heat resistance
  2. Excellent impact resistance, at both high and low temperatures
  3. Retains dimensional stability over time
  4. Extremely workable due to enhanced flow characteristics and high processability
  5. Easily colorable and pigmented material, providing freedom of design

 

Mechanical Properties of ABS/PC

Property

Value

Tensile strength

5,900 psi (41MPa)

Tensile modulus

278,000 psi (19GPa)

Tensile elongation

6%

Flexural strength

9,800 psi (68MPa)

Flexural modulus

280 ksi (19GPa)

IZOD impact notched

3.7 ft-lb per in (196 J/m)

IZOD impact un-notched

9 ft-lb per in (481 J/m)

Build orientation on long edge side. The properties in this table are from Stratasys using their FDM technology.

 

Comparing ABS, PC, and ABS/PC by the Numbers

It’s important to look closely at the strength, heat resistance, and flexibility of ABS, PC, and ABS/PC ahead of any CNC machining, injection molding, and 3D printing projects. The thermoplastics all share similar properties and specifications, but there are differences to consider that might make one material more suitable than the other depending on the specific requirements for your parts and the material demands of your project.

 

 

 

Resin Pellets
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Injection Molding Material Alternatives Guide


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