Material selection can determine whether a 3D printed part simply looks right or performs reliably in service. For demanding SLS applications, engineers often need more than a standard polymer. Strength, stiffness, weight, temperature resistance, electrical behaviour and surface finish can all influence the decision.
SinterWorx G4 and SinterWorx C6 are two reinforced SLS materials available from Graphite Additive Manufacturing. Both are lightweight engineering plastics designed for functional applications, but their different reinforcement and mechanical properties make them suited to different priorities.
This guide compares the benefits and typical use cases of each material, helping you decide which may be the better starting point for your component.
What are SinterWorx G4 and C6?
SinterWorx G4 is Graphite AM’s proprietary graphite-reinforced plastic. Developed in-house for Selective Laser Sintering (SLS), it combines useful mechanical performance with toughness, a graphite grey in colour surface finish and anti-static properties. It is exclusive to Graphite AM.
SinterWorx C6 is a specialised carbon fibre-filled plastic created through extensive development work focused on Formula One requirements. It is designed for functional components where high strength and rigidity must be achieved without unnecessary weight. Graphite AM is the only 3D printing bureau in the UK to offer it.
SinterWorx G4 vs C6 at a glance
| Property | SinterWorx G4 | SinterWorx C6 |
| Reinforcement | Graphite | Carbon fibre |
| Colour | Graphite grey | Dark graphite grey |
| Temperature resistance | 177°C | 179°C |
| Density | 1.1 g/cm³ | 1.1 g/cm³ |
| Tensile modulus | 4,240 MPa | 7,100 MPa |
| Tensile strength | 58 MPa | 76 MPa |
| Elongation at break | 6% | 4% |
| Electrical behaviour | Anti-static; independently ESD tested | Conductive |
| Layer thickness | 100 microns | 100 microns |
| Best suited to | Tough, cost-effective functional parts with a good finish. Has anti-static properties and has passed independent Electrostatic Discharge (ESD) tests. | Where highest stiffness to weight ratio matters |
The figures above are based on Graphite AM’s published test data. They provide a useful comparison, but material selection should always consider the complete operating environment, geometry, loading and finishing requirements of the part.
The benefits of SinterWorx G4
A tough, cost-effective all-round material
G4 is intended to balance functional performance with cost. Its 6% elongation at break is higher than the 4% published for C6, while Graphite AM describes the material as tough and lighter than comparable glass-filled nylon materials.
That makes G4 a useful option when a component needs dependable mechanical properties but does not require the additional strength and stiffness offered by C6.
A graphite grey in colour surface finish
The material produces an attractive graphite grey coloured finish, which can be valuable for visible components, presentation models and parts that need to look close to a finished product. A suitable finish may reduce the amount of secondary work required, depending on the application and final specification.
G4 can also be Vapor Smoothed, hand sealed, sanded, painted or given an RF-shielding finish.
Anti-static performance
G4 has anti-static properties and has passed independent Electrostatic Discharge tests. This makes it particularly relevant when controlled static dissipation is part of the brief, including certain electronics enclosures and components used in dust-rich production environments.
Anti-static performance should still be assessed against the specific electrical and safety requirements of the application. Material selection alone does not replace appropriate testing or system-level risk assessment.
Suitable for automotive and marine applications
Graphite AM regularly recommends G4 for automotive parts, including ducts, intake plenums, interior trim and electronic enclosures. Its saltwater resistance also broadens its potential within marine applications such as enclosures, brackets and exterior trim.
The best use cases for SinterWorx G4
G4 is well suited to applications that value toughness, a clean graphite grey coloured appearance and balanced mechanical performance. Typical examples include:
- Electronic and sensor enclosures
- Cooling and airflow ducts
- Intake plenums
- Automotive interior trim
- Presentation models
- Sports equipment
- Marine brackets and exterior trim
- Low to medium-volume end-use parts
It is also worth considering when anti-static behaviour is an important design requirement.
The benefits of SinterWorx C6
Higher strength and stiffness
C6 is the more mechanically demanding option of the two. Its published tensile strength is 76 MPa, compared with 58 MPa for G4, while its tensile modulus is 7,100 MPa rather than 4,240 MPa.
Those figures indicate a stronger, substantially stiffer material. This makes C6 especially valuable when a part must resist deformation or carry functional loads while remaining lightweight.
High performance without the weight of metal
C6 has a density of 1.1 g/cm³ and was developed around the need for strong, lightweight Formula One components. It can therefore provide an alternative route for geometries where a polymer solution is appropriate but standard plastics do not offer sufficient rigidity.
Graphite AM has also supported customers moving from laminated carbon fibre to C6. No need for tooling and more design freedom, reducing manufacturing lead time and improving function.
Proven in extreme engineering projects
C6 was selected for several components on the Bloodhound land-speed vehicle. These included jet intake airboxes, external ducts, wishbone seals, camera housings, brake-cooling ducts, sensor mounts and brackets.
This does not mean every C6 component is automatically suitable for an extreme environment. It does, however, demonstrate the type of lightweight, function-led engineering challenge for which the material was developed.
Conductive material behaviour
Graphite AM identifies C6 as conductive. That can be useful in some specialised applications, but it is important to distinguish conductivity from a defined ESD-safe specification. The required electrical properties should be confirmed with Graphite AM against the intended application.
The best use cases for SinterWorx C6
C6 is best considered when strength, stiffness and mass reduction are central to the design. Typical applications include:
- Motorsport vents, ducts and grilles
- Wings, gurneys and aerodynamic components
- Lightweight brackets, guides and trunking
- Oil and water couplings
- Instrument housings and lighting pods
- Intake plenums
- Oil baffles and flow-control parts
- Radio-controlled cars, aircraft and drones
- Cycling accessories
For components subject to meaningful loads, pressure, heat or safety requirements, the design and material should be validated under representative service conditions before production use.
Should you choose G4 or C6?
The right choice depends on which requirements carry the greatest weight.
Choose SinterWorx G4 when you need:
- A tough and cost-effective reinforced SLS material
- A good graphite grey in colour surface finish
- Anti-static properties supported by independent ESD testing
- Functional enclosures, ducts, plenums or visible components
- A balanced material for automotive, marine or general engineering use
Choose SinterWorx C6 when you need:
- Higher tensile strength and stiffness
- A strong stiffness-to-weight or strength-to-weight balance
- Lightweight parts for motorsport or other performance-led applications
- Functional brackets, aerodynamic parts, couplings or flow-control components
- Access to a specialist carbon fibre-filled SLS material unavailable from any other UK bureau
In some projects, the answer may only become clear after reviewing the geometry and operating conditions. Graphite AM can assess the application, recommend the most suitable SLS material and advise on any finishing or validation requirements.
Exclusive SLS materials from Graphite AM
The availability of G4 and C6 is not simply a matter of ordering a standard powder from a catalogue. G4 was developed in-house and is proprietary to Graphite AM. C6 grew from extensive material development focused on the demands of Formula One, and Graphite AM remains the only UK 3D printing bureau offering it.
This gives UK engineers access to two distinctive material options from the team that developed and applies them. It also means material selection can be supported by practical knowledge of how each behaves during manufacture, finishing and real-world use.
Conclusion
SinterWorx G4 and C6 solve different engineering problems. G4 offers a tough, cost-effective combination of mechanical performance and anti-static behaviour. C6 provides greater strength and stiffness for lightweight, performance-critical parts.
If neither choice is immediately clear from a datasheet, speak to Graphite AM about the loads, temperatures, environment, geometry and finish your component requires. Early material input can prevent unnecessary redesign and help ensure the finished part is genuinely fit for purpose.
Frequently Asked Questions
No. SinterWorx G4 is Graphite AM’s proprietary graphite-reinforced SLS material. It was developed in-house and is exclusive to Graphite Additive Manufacturing.
Graphite Additive Manufacturing is the only 3D printing bureau in the UK that offers SinterWorx C6.
G4 is graphite reinforced and prioritises toughness, surface finish, cost-effectiveness and anti-static performance. C6 is carbon fibre filled and offers higher published tensile strength and stiffness, making it better suited to weight-critical, high-performance functional parts.
Graphite AM publishes a temperature resistance of 177°C for G4 and 179°C for C6. Suitability still depends on the duration and nature of the exposure, mechanical loading and complete operating environment, so the application should be reviewed before manufacture.
Yes. Graphite AM offer Vapor Smoothing as an available finish for both materials. Other options include hand sealing, sanding, painting and RF shielding.
