14
Remanufacturing and Advanced Machining
a homogenous polymer–SCF solution and processing of traditional dense materials. The unit is equipped with special gas injection ports and additional pressure
sensors to monitor polymer melt pressure in the cylinder. Other differences compared to conventional IMMs consist of an improved hydraulic system and control
software. MuCell technology may use various drive units, e.g., hydraulic, electric,
or mechanic. In any case, an additional module for SCF preparation, storage, and
dosing is necessary.
At present, many international and local companies in North America, Europe,
and Asia offer complete IMMs, based on their own technical solutions, able to perform high-quality microcellular injection molding processes.
1.3 GASODYNAMIC DENSIFICATION OF CASTING MATERIALS
Development of vacuum die casting technologies led to the expanded application
of dry sand without binding substances. The sand molds are prepared by physical
means, in particular, pressing the sand with a gas pressure drop. The pressure drop
is able to transform loose sand into a stone-like substance around a mold cavity to be
filled with molten metal. The process is sometimes referred to as the vacuum mold
casting (The Library of Manufacturing, 2021), while the standard ISO 23472-1:2020
recommends the term “vacuum sealed molding” or the V-process.
In the thickness of the sand mold, vacuum is applied to the sand medium, while
atmospheric pressure is applied to the top and bottom sand surfaces sealed with
plastic films. Control factors of the V-process and molding sand, such as vibration
frequency, vibrating time, degree of vacuum imposed, and pouring temperature
may affect the quality of castings (Prasath Manikanda and Vignesh, 2017). In the
modified process, where a pattern is made out of polystyrene foam, pressure from
its gasification is combined with the atmospheric pressure. This is achieved in the
lost foam casting (LFC) method or in combinations of LFC and low-pressure casting
(Fan et al., 2014).
FIGURE 1.2 MuCell equipment: 1 – Reciprocating screw, 2 – Polymer feed, 3 – Inert gas
injection port, 4 – Shut-off nozzle, 5 – Mold cavity filled with polymer-gas solution, 6 – Mold
body.
Remanufacturing and Advanced Machining
a homogenous polymer–SCF solution and processing of traditional dense materials. The unit is equipped with special gas injection ports and additional pressure
sensors to monitor polymer melt pressure in the cylinder. Other differences compared to conventional IMMs consist of an improved hydraulic system and control
software. MuCell technology may use various drive units, e.g., hydraulic, electric,
or mechanic. In any case, an additional module for SCF preparation, storage, and
dosing is necessary.
At present, many international and local companies in North America, Europe,
and Asia offer complete IMMs, based on their own technical solutions, able to perform high-quality microcellular injection molding processes.
1.3 GASODYNAMIC DENSIFICATION OF CASTING MATERIALS
Development of vacuum die casting technologies led to the expanded application
of dry sand without binding substances. The sand molds are prepared by physical
means, in particular, pressing the sand with a gas pressure drop. The pressure drop
is able to transform loose sand into a stone-like substance around a mold cavity to be
filled with molten metal. The process is sometimes referred to as the vacuum mold
casting (The Library of Manufacturing, 2021), while the standard ISO 23472-1:2020
recommends the term “vacuum sealed molding” or the V-process.
In the thickness of the sand mold, vacuum is applied to the sand medium, while
atmospheric pressure is applied to the top and bottom sand surfaces sealed with
plastic films. Control factors of the V-process and molding sand, such as vibration
frequency, vibrating time, degree of vacuum imposed, and pouring temperature
may affect the quality of castings (Prasath Manikanda and Vignesh, 2017). In the
modified process, where a pattern is made out of polystyrene foam, pressure from
its gasification is combined with the atmospheric pressure. This is achieved in the
lost foam casting (LFC) method or in combinations of LFC and low-pressure casting
(Fan et al., 2014).
FIGURE 1.2 MuCell equipment: 1 – Reciprocating screw, 2 – Polymer feed, 3 – Inert gas
injection port, 4 – Shut-off nozzle, 5 – Mold cavity filled with polymer-gas solution, 6 – Mold
body.