Part shrinkage anomilies from stereolithography injection mould tooling

Harris, Russell A.; Newlyn, H; Hague, Richard; Dickens, Phill

doi:10.1016/s0890-6955(03)00080-4

Cited by 31 publications

(22 citation statements)

References 4 publications

(3 reference statements)

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“…More generally as demonstrated by Harris et al [135], also the material of the mold affects shrinkage. By using a metal (Al) and an epoxy mold, the mold temperature profile varied.…”

Section: Design Influencesmentioning

confidence: 87%

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

Annicchiarico¹,

Alcock²

2014

Materials and Manufacturing Processes

122

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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.

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“…More generally as demonstrated by Harris et al [135], also the material of the mold affects shrinkage. By using a metal (Al) and an epoxy mold, the mold temperature profile varied.…”

Section: Design Influencesmentioning

confidence: 87%

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

Annicchiarico¹,

Alcock²

2014

Materials and Manufacturing Processes

122

View full text Add to dashboard Cite

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“…More specifically, the modelling works of VP focus on the topology and dimensional accuracy ( [12][13][14] numerical) and mainly on the mechanical properties ( [16] analyticalempirical, [17][18][19][20][21] numerical and [21][22][23][24] empirical) and finally in [25] an analytical-empirical approach models heat transfer related issues.…”

Section: Vat Photopolymerization Processesmentioning

confidence: 99%

“…Process parameter (Variable) [12] Strain Temperature [13] Part shrinkage Thermal compensation, amorphous/crystalline polymer, mould material, cooling conditions [14] Deformation compensation [15] Dimensional Accuracy Layer thickness, part position on the platform, shrinkage compensation, retraction, hatch spacing, alternate hatching, blade gap, stagger weave [16] Cure depth Penetration depth of UV radiation, scattering coefficient [17][18][19] Etching, deposition, lithography mechanics Surface type, material, shape [20] Tool strength, ejection forces, decision about the quality of a tool according to the previous two [21] Separation force Pulling-up speed, others [22] Strength of parts Layer thickness, orientation, hatch spacing [22] Tensile, flexural and impact strength Layer thickness, orientation, hatch spacing [23] Part strength (tensile, impact, flexural) Layer thickness, post-curing time and orientation [24] Tensile strength, crystallographic orientationdensity analysis…”

Section: Kpimentioning

confidence: 99%

Modelling of additive manufacturing processes: a review and classification

Stavropoulos

Foteinopoulos

2018

Manufacturing Rev.

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Abstract. Additive manufacturing (AM) is a very promising technology; however, there are a number of open issues related to the different AM processes. The literature on modelling the existing AM processes is reviewed and classified. A categorization of the different AM processes in process groups, according to the process mechanism, has been conducted and the most important issues are stated. Suggestions are made as to which approach is more appropriate according to the key performance indicator desired to be modelled and a discussion is included as to the way that future modelling work can better contribute to improving today's AM process understanding.

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“…This section of work has been described in depth in an earlier paper published in the International Journal of Machine Tools & Manufacture [5]. For the purpose of clarity and continuity a brief description of this work is contained in this paper.…”

Section: Section 1 -Part Shrinkage Evaluationmentioning

confidence: 99%

The structure of parts produced by stereolithography injection mould tools and the effect on part shrinkage

Harris

Hague

Dickens

2004

International Journal of Machine Tools and Manufacture

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Stereolithography (SL) tooling for plastic injection moulding provides a low cost and quick alternative to hard tooling methods when producing a small quantity of parts. However, work by the authors has shown that a different rate of polymer shrinkage was experienced in semi-crystalline parts when produced from SL moulds as compared to those from conventional metal tooling methods.Different shrinkage means the parts are not truly the same as those that would be produced by metal tooling and highlights a disadvantage to SL tooling. This work associates the increased shrinkage experienced to a greater percentage crystallinity developed in the parts due to their thermal history during processing. In these experiments the cooling rate, which is imparted due to the 2 heat transfer characteristics of the mould has been identified as the controlling factor of a parts % crystalline content and the cause of shrinkage anomalies.The morphology analysis results show that there is 30% more crystallinity developed in the nylon (PA66) parts produced in SL moulds than those produced from aluminium moulds. The results also reveal different characteristics during thermal analysis that may also be due to the thermal history imparted by the mould. The work utilises the thermal analysis technique Differential ScanningCalorimetry (DSC) to quantify the different levels of crystallinity in the parts. The thermal characteristics of the mould are demonstrated by real-time data acquisition.

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Part shrinkage anomilies from stereolithography injection mould tooling

Cited by 31 publications

References 4 publications

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

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

Modelling of additive manufacturing processes: a review and classification

The structure of parts produced by stereolithography injection mould tools and the effect on part shrinkage

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