270
Q. Alkhalaf et al.
FRE process helps to achieve an intricate part. The disadvantage of using Curing
agent (Dow Corning) is time taken hours. To overcome this issue ultraviolet (UV)
light is used so it can be achieved in less time as compared to the conventional
process.
Most of the researchers have been using Sylgard-184 and SE 1700 because they
have the ability to synthesis by UV light. With developments in processes of synthesis,
the PDMS was applied in DLP with Phenyl Phosphinate (TPO-L) photoinitiator. The
TPO-L helps to solidify the PDMS when it exposes to the light. The DLP with TPO-L
showed an increase in Young’s modulus up to 1.44 MPa. In the DLP and SLA process,
the resolution of PDMS is based on the absorption of the light. The TPO-L improves
the resolution, but the limiting parameter is the amount of TOP-L, it should be less
than 2 wt% to achieve better curing. The Orasol Orange is added in this process, to
increase the resolution. Though photoinitiation plays a vital role in PDMS, several
types of PDMS are insensitive to photoactivity. However, the photoinitiators should
have two basic characterizes, which are to be suitable in the synthesis of PDMS: first,
the ability to be soluble with PDMS; second, the ability to absorb the light. These
two things are more critical for any curing process based on UV light.
Irgacure 819 is another photoinitiator applied to cure PDMS. This photoinitiator is
advantageous over other available photoinitiators as it is cheaper, having less toxicity,
the ability to absorb the light. The percentage of Irgacure 819 in PDMS is 0.25 wt%.
The 2-Hydroxy-2-Methylpropiophenone (2H2M) photoinitiator achieves the absorption of the light and can add N-vinylpyrrolidone (NVP) to achieve proper curing. The
Polyethylene Glycol (PEG) can be applied in Liquid Deposition Modelling (LDM).
Almost all the agents change the properties of PDMS, but PEG does not change
the final properties. The LDM achieves the complex object, under the application of
any yield stress. The Young modulus increase with PEG percentage. The printing
of PDMS with silica isn’t possible without adding PEG because the yield stress of
PDMS is low. One of the drawbacks is the poor quality achieved in part with this
agent is poor. Figure 1 shows the details of various agents used in the additive manufacturing process. A detailed study of the advantages and disadvantages has also
listed in Table 2.
4 The Support Materials Applied with PDMS
The PDMS isn’t only with agent or photoinitiator can print. The PDMS has low yield
stress; for that purpose, it is challenging to print alone, especially in LDM, for that it
can print with other material as support such as PVA water-soluble. The success of
the process is based on the adhesive between the PVA and the silicone. It achieves
maximum Elastic modulus G
maximum value around 515.3 Pa and maximum shear
stress τ max is 127.3 Pa. Direct Ink Writing (DIW) prints the PDMS with Dragonskin
30 to accomplishes a better modulus of elasticity G
= 11,360 Pa. Besides, it can print
the PDMS with two types PDMS SE1700 and Sylgard 184. This process achieves an
Q. Alkhalaf et al.
FRE process helps to achieve an intricate part. The disadvantage of using Curing
agent (Dow Corning) is time taken hours. To overcome this issue ultraviolet (UV)
light is used so it can be achieved in less time as compared to the conventional
process.
Most of the researchers have been using Sylgard-184 and SE 1700 because they
have the ability to synthesis by UV light. With developments in processes of synthesis,
the PDMS was applied in DLP with Phenyl Phosphinate (TPO-L) photoinitiator. The
TPO-L helps to solidify the PDMS when it exposes to the light. The DLP with TPO-L
showed an increase in Young’s modulus up to 1.44 MPa. In the DLP and SLA process,
the resolution of PDMS is based on the absorption of the light. The TPO-L improves
the resolution, but the limiting parameter is the amount of TOP-L, it should be less
than 2 wt% to achieve better curing. The Orasol Orange is added in this process, to
increase the resolution. Though photoinitiation plays a vital role in PDMS, several
types of PDMS are insensitive to photoactivity. However, the photoinitiators should
have two basic characterizes, which are to be suitable in the synthesis of PDMS: first,
the ability to be soluble with PDMS; second, the ability to absorb the light. These
two things are more critical for any curing process based on UV light.
Irgacure 819 is another photoinitiator applied to cure PDMS. This photoinitiator is
advantageous over other available photoinitiators as it is cheaper, having less toxicity,
the ability to absorb the light. The percentage of Irgacure 819 in PDMS is 0.25 wt%.
The 2-Hydroxy-2-Methylpropiophenone (2H2M) photoinitiator achieves the absorption of the light and can add N-vinylpyrrolidone (NVP) to achieve proper curing. The
Polyethylene Glycol (PEG) can be applied in Liquid Deposition Modelling (LDM).
Almost all the agents change the properties of PDMS, but PEG does not change
the final properties. The LDM achieves the complex object, under the application of
any yield stress. The Young modulus increase with PEG percentage. The printing
of PDMS with silica isn’t possible without adding PEG because the yield stress of
PDMS is low. One of the drawbacks is the poor quality achieved in part with this
agent is poor. Figure 1 shows the details of various agents used in the additive manufacturing process. A detailed study of the advantages and disadvantages has also
listed in Table 2.
4 The Support Materials Applied with PDMS
The PDMS isn’t only with agent or photoinitiator can print. The PDMS has low yield
stress; for that purpose, it is challenging to print alone, especially in LDM, for that it
can print with other material as support such as PVA water-soluble. The success of
the process is based on the adhesive between the PVA and the silicone. It achieves
maximum Elastic modulus G
maximum value around 515.3 Pa and maximum shear
stress τ max is 127.3 Pa. Direct Ink Writing (DIW) prints the PDMS with Dragonskin
30 to accomplishes a better modulus of elasticity G
= 11,360 Pa. Besides, it can print
the PDMS with two types PDMS SE1700 and Sylgard 184. This process achieves an