Skip to main content
. 2022 May 23;15(10):3725. doi: 10.3390/ma15103725

Table 6.

Summary of research on RHCM technologies.

No. Researcher Plastic
Material Used		 Parameter Settings Output Response Technology Used Material for Mold Inserts Type of Analysis Result
Simulation Experiment
1 Chen et al., 2006 [39] ABS

  • Heating stage (110–180 °C and 110–200 °C)

  • Cooling stage (180–110 °C and 200–110 °C)

  • Mold temperature (50 °C)

  • Surface marks

  • Weld line strength

 Electromagnetic induction heating AISI 4130 steel ANSYS Yes

  • Heating times, 3–4 s for mold surface temperature to rise from 110 to 180 °C and 200 °C, along with 21 s for cooling time (return to 110 °C)

  • Eliminated the surface marks of the weld line and enhanced the strength of the related weld line
2 Huang and Tai, 2009 [43] PMMA

  • Mold temperature (25 °C)

  • Cooling time (20 s)

  • Melt temperature (260 °C)

  • Mold surface temperature

  • Replication heights of LGP’s microstructures

  • Residual stress in LGP

 N/A Not specified No Yes

  • Induction heating the mold surface to 110 °C could increase the replication rate of the microstructure’s height by up to 95%

  • There was no residual stress in the LGP produced by induction heating

  • Mold temperature (80 °C)

  • Cooling time (20 s)

  • Melt temperature (260 °C)

 Hot oil No Yes

  • Mold temperature (110 °C)

  • Cooling time (20 s)

  • Melt temperature (260 °C)

 Combination of hot oil and induction heating No Yes

  • Mold temperature (110, 130, and 150 °C)

  • Cooling time (20 s)

  • Melt temperature (260 °C)

 Induction heating No Yes
3 Huang et al., 2010 [44] PMMA

  • Injection speed (180–200 mm/s)

  • Packing pressure (1st stage 50–70 Mpa, 2nd stage 40 Mpa)

  • Packing time (4–8 s)

  • Mold temperature (60–80 °C)

  • Cooling time (30–40 s)

  • Mold surface temperature (110–150 °C)

  • Power rates

  • Optimum processing parameters

  • Quality of microfeature heights and angles

 Induction heating Ni No Yes

  • Optimum process parameters: injection speed (180 mm/s) packing pressure (70 Mpa), packing time (8 s), mold temperature (70 °C), cooling time (30 s), and mold surface temperature (150 °C).

  • Replication effect on microfeatures was significantly improved by induction heating
4 Tsai, 2011 [46] ABS

  • Two gates, cavity temperature = 75 °C, no vapor chamber

  • Two gates, cavity = 75 °C temperature, with vapor chamber

  • Two gates, cavity temperature = 110 °C, with vapor chamber

  • One gate, cavity temperature = 75 °C, no vapor chamber

  • Tensile strength

 Steam heating (vapor chamber) P20 mould steel No Yes

  • The two gate/vapor chamber system’s tensile strength increased by 3.2% when preheating temperatures increased from 75 to 110 °C
5 Wang, 2013 [54]

  • ABS/PPMA Fiber-reinforced plastic

  • PP + 20% glass fiber

  • Heating time (10, 20, 30, 40, 50, and 60 s)

  • Cooling time (20,30,40, 50, and 60 s)

  • High- and low-temperature holding time (10 s)

  • Weld line

  • Tensile strength

 Electric heating (cartridge heater) AISI H13 ANSYS Yes

  • RHCM process could improve the weld line factor for both materials

  • RHCM process reduced the tensile strength of the part without weld line
6 Wang, 2014 [47] PC

  • Mold heating time (18, 24, 25, and 36 s)

  • Mold cooling time (25, 32, 38, and 46 s)

  • Weld line

 Steam heating CENA1

  • Moldflow Insight

  • ANSYS

 Yes

  • Weld marks on the part surface could be significantly reduced by increasing the cavity surface’s temperature just before filling

  • Surface gloss of product produced by RHCM was more than 90%.
7 Nian et al., 2014 [45] Not specified

  • Mold temperature (between 120 and 150 °C)

  • Thicknesses of the heated target (10–20 mm)

  • Pitch of the coil turns (10–20 mm)

  • Heating distance (5–9 mm)

  • Position of the induction coil (0–12 mm)

  • Working frequency (30–40 kHz)

  • Waiting time (2–6 s)

  • Heating rate

  • Temperature difference

 Induction heating SKD61 COMSOL Multiphysics Yes

  • Heating rate was increased by 19.5%, from 3.3 °C/s to 4 °C/s

  • Heating uniformity was increased by 62.9%
8 Li, 2016 [48] iPP

  • Heated mold temperature for RHCM (120 °C)

  • Mold temperature for CIM (25 °C)

  • Packing pressure (50 Mpa)

  • Cooling time (30 s)

  • Weld line

  • Tensile strength

 Electric heating
(electrical heating rods)		 Not specified N/A Yes

  • Weld line decreased tensile strength, but RHCM reduced the weld line’s tensile strength reduction effect.
9 Xie, 2017 [49] PP

  • Silicon insert surface temperature (20, 60, 100, and 140 °C)

  • Melt temperature (230 °C)

  • Injection pressure (30 Mpa)

  • Injection speed (60 mm/s)

  • Screw back (20 mm)

  • Sample thickness (0.6 mm)

  • Weld line

 Electric heating (thin-film resistance heater, graphene coating) Silicon insert (coated with carbide-bonded graphene) N/A Yes

  • Width of weld lines: 16.4 µm at 20 °C, 11.24 µm at 60 °C, and 5.6 µm at 100 °C

  • Weld line disappeared completely at 140 °C
PS

  • Silicon insert surface temperature (20, 40, 80, and 100 °C)

  • Melt temperature (200 °C)

  • Injection pressure (30 Mpa)

  • Injection speed (50 mm/s)

  • Screw back (15 mm)

  • Sample thickness (1 mm)

  • Residual internal stress

  • Replication fidelity

 Yes

  • Residual stress decreased as the surface temperature of silicon insert increased

  • Coating the silicon insert with carbide-bonded graphene could improve replication fidelity
10 Liu, 2020 [50] PP with 30% short glass fiber

  • Melt temperature (240 °C)

  • Injection pressure (60 Mpa)

  • Injection velocity (45%)

  • Packing time (9 s)

  • Packing pressure (50 Mpa)

  • Mold heating temperature (60/90/120 °C)

  • Cooling time (30 s)

  • Microstructure

  • Tensile properties

  • Surface quality

 Electric heating (electrical heating rods) Not specified Autodesk Moldflow Yes

  • Tensile strength of RHCM parts reached peak at 60 °C mold heating temperature

  • The sample’s surface gloss increased as the mold cavity surface temperature increased, but decreased as the mold heating temperature increased above 90 °C