Review of Factors that Affect Shrinkage of Molded Part in Injection Molding

Abstract

Purpose: This paper reviews the factors affecting shrinkage of molded parts in injection molding. Methods: A selective screening of the papers published in the last 10 years was adopted. The review was organized according to molding scale (macro or micro) and by considering four branches of influence: material behaviors, processing parameters, mold, and specimen design. Results: Within the interval of confidence, at the macroscale, critical processing parameters were the temperatures, the packing parameters, cooling time, and injection speed; temperatures and packing parameters resulted critical factors at the microscale as well. Concerning the design aspects, the runner size and the ribs affect shrinkage at the macro and microscale, respectively. The analysis of the literature review has shown an absence of statistical approach for determining the material influences, a lack of information on shrinkage occur in powder-molded parts and the absence of data in specimen with dimensions below 10 m. Conclusions: The review collected the factors that affect shrinkage in injection molding, and identified three possible areas for further works.

Optimisation of warpage on plastic injection moulding part with MGSS conformal cooling channels moulds using response surface methodology (RSM)

“…Warpage is difficult to avoid due to the design complexity and numerous of influence factors which affect the assembly process because of uneven clearance or interference problems. With an appropriate setting of injection moulding processing parameters, warpage condition can be reduced [4]. Previously, most of the injection moulding industries have used trial-and-error approach in order to obtain an appropriate processing parameters setting which consume time and production cost [5].…”

Warpage Optimisation on the Moulded Part using Response Surface Methodology (RSM) and Glowworm Swarm Optimisation (GSO)

“…Warpage is difficult to prevent due to design complexity and numerous influencing factors which affected the assembly process because of uneven clearance or interference problems. With an appropriate setting of injection moulding processing parameters, warpage condition can be reduced [4]. Previously, most of injection moulding industries have used try-and-error approach in order to obtain an appropriate processing parameters setting which consume time and production cost [5].…”

Warpage Optimisation on the Moulded Part with Conformal Cooling Channels using Response Surface Methodology (RSM) and Glowworm Swarm Optimisation (GSO)

“…Warpage is difficult to avoid due to design complexity and numerous of influence factors which affect the assembly process because of uneven clearance or interference problems. With an appropriate setting of injection moulding processing parameters, warpage condition can be reduced [4]. Previously, most of injection moulding industries have used try-and-error approach in order to obtain an appropriate processing parameters setting which consume time and production cost [5].…”