The difference between HP MJF and SLS
HP MJF vs. SLS
Get to know the differences, advantages and disadvantages of the two powder-bed-based 3D printing processes!
Both selective laser sintering and HP Multi Jet Fusion belong to the powder-bed-based 3D printing technologies of additive manufacturing. The respective system manufacturers always recommend their own machines. We see the advantages and disadvantages of the technologies from the direct user perspective and assess the use of a system from a purely technological point of view. Both processes are very advanced and produce excellent results. They deliver very similar components, which, however, differ significantly in some facets. When using the technologies, the differences should therefore be precisely known. In the following article, we compare both methods and provide information on which application HP MJF or SLS should be used for.
Technological differences between HP MJF and SLS
In principle, very similar components can be produced from the same basic material using selective laser sintering and the HP Multi Jet Fusion process. However, there are significant procedural differences. In both processes, the base material - usually PA12 - is in powder form. The difference lies in how this fine plastic powder is fused into 3D printed components.
HP Multi Jet Fusion (HP MJF)
Selective laser sintering (SLS)
The fusion of the plastic powder in the HP Multi Jet Fusion is completely different from the SLS technology. A print head is used here, which extends over the entire width of the installation space. This head now prints black fusing agent and white detailing agent on a prepared powder layer. Basically, it is black and white ink or binding agent that is used to mark the component on the one hand (black color) and on the other hand to depict the edges sharply (white color). Additional infrared heat sources are attached to the movable printhead, which then fuse the component in the black areas. More about the HP MJF process ...
Greater attention to detail
Due to the agents used, the MJF process creates more uniform surfaces with a higher level of detail compared to the SLS process. The layer thickness of 80 µm is also less than with selective laser sintering, which usually works with 120 µm.
More stable parts
The HP Multi Jet Fusion process creates more stable components than selective laser sintering. Due to the agent used, the components are fused more evenly and are therefore almost isotropic.
Selective laser sintering uses a fine laser beam to bake (sinter) the material, which scans the individual print layers at breakneck speed. This process can be seen very well in the video above. The resulting darker areas are the already sintered areas. A new powder layer is then applied and the sintering process of the next component layer starts. In contrast to the HP Multi Jet Fusion process, no binding agent is required here. For this reason, sintered components are usually white (depending on the base material color), since no agents or binders are necessary, as is the case with the HP process. More about selective laser sintering ...
More finishing options
Due to the white basic color, SLS components are particularly suitable for further refinement steps, such as coloring in a color of your choice. In contrast to this, HP MJF components that are gray in their basic color can only be colored black by us.
More dimensionally stable with larger parts
Larger components are much more dimensionally stable and can be manufactured more precisely with the SLS process than with the HP MJF process. This is due to the lower energy input during laser sintering.
Comparison of HP MJF and SLS
One cannot say in general which powder bed-based process is fundamentally better. It always depends on the application. In the following comparison, we list the advantages and disadvantages of both methods and give recommendations for different fields of application:
HP MJF
SLS
Advantages and disadvantages
The much more recent HP MJF process does not offer that much freedom, but it should always be compared with selective laser sintering. The main advantages and disadvantages are:
Advantages and disadvantages
You usually can't go wrong with choosing the established and versatile SLS process. The main advantages and disadvantages are:
- Better surfaces
- Greater attention to detail
- Isotropic material properties
- Faster printing process
- Wider field of application
- More dimensionally stable components
- Higher temperature resistance
- Thicker walls
- Materials partly for food contact (FDA)
- Only possible in gray and black
- More expensive than selective laser sintering
- Quality losses possible with high wall thicknesses (approx. >5mm)
- A little "softer" compared to the HP MJF
- Not possible with thin wall thicknesses
Applications
The HP MJF is clearly designed for series production of medium lot sizes. For prototypes where dimensional accuracy is important, the SLS process should be used. Typical fields of application are:
- Medium series (100-10,000 pieces) of smaller components
- Small functional prototypes
- Detailed components
- Production aids
Applications
Compared to the HP process, selective laser sintering has many important advantages for prototype production, but it can also be used for small batches production. Typical fields of application are:
- Prototypes
- Dimensionally accurate installation samples
- Colored components
- Small batches for larger components