Optimization of plastic injection moulding process parameters using taguchi and face centered cubic (FCC) techniques

Optimization of plastic injection moulding process parameters using taguchi and face centered cubic (FCC) techniquesByK.Poornima (SM21677)Supervisor : Dr. Mohammed Ansari M. NainarDepartment of Mechanical Engineering, College of Engineering, Universiti Tenaga Nasional

1AgendaIntroductionProblem StatementsObjectivesLiterature ReviewMaterials and MethodsPreliminary ResultsWork ScheduleExpected OutcomeReferencesPublications

2Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

2introduction3Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

Chart 1-Plastic Injection Moulding Process Flow

Figure 1 -Plastic Injection Moulding Cycle3Problem Statements4Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

Improper selection of injection moulding process parameters (melt temperature and mould surface temperature) leads to manufacturing/moulding defects such as shrinkage, warpage, etc.

Moulding defects cause higher part rejection as the assembly of parts require dimensional precision and tolerance.

Part rejection leads to material wastage, low productivity level, higher production cost as well as time constraint.45Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

Melt temperaturePP is a crystalline material-doesnt have a sharp melting point-due to different level of crystallinityIn terms of PIM, melt temperature is referred as processing temperature of the material PP with different Melt Flow Index (MFI)Low viscosity - easier flow and vice-versaMelt temperature is the actual temperature of the polymer as it exits the nozzle and enters the mould.Melt temperature has a higher impact on final properties of parts produced -final molecular weight of the polymer in the moulded part.

Figure 2-Melt temperature and cylinder settings56Mould surface temperatureDifferent temperatures can affect polymer flow, causing asymmetrical flow, should be kept uniformed throughout the processOptimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

Heat is extracted out of mould through the circulation of coolant.In semi-crystalline materials the mould temperature is an important factor in determining the degree of crystallinity in the polymer.

Sources: Michael Sepefrom Michael P. Sepe LLC [1]Figure 3 Effect of mold temperature on modulus vs. Temperature behaviour of a PPAHigher mould temperature- longer cycle timeLower mould temperature-Shorter cycle timeThe relationship between mould surface temperature and melt temperature7Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

A study was done on thermokinetical asymmetry [2]. If melt flows inside a mould channel, the flow front is formed in a fountain flow. The flow is symmetrical to axis of symmetry. It happens only if the conditions of flow are the same near both mould walls . ( equal temperature, surface roughness etc.) In a case of temperature difference, flow front is not symmetrical. It shifts towards one of the walls which is of a higher temperature. This is caused by lower viscosity of melt which is in contact with higher temperature mould wall and therefore is heated up.

Figure 4 Symmetrical flow front Figure 5 Asymmetrical flow front [2]7objectives8Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

To investigate the influence of process parameters (melt temperature and mould surface temperature) on moulding defects such as shrinkage, warpage, etc.

To optimize the process parameters (melt temperature and mould surface temperature) for plastic injection moulding using Taguchi and Face Cubic Centered (FCC) techniques.

To determine the warpage before and after the moulding process parameters (melt temperature and mould surface temperature) optimization.8Literature review9Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

The need to optimize-To increase productivity by improving the cycle time [3,4]Benefits of Computer Aided Simulations-Simulations help to identify the possible shrinkages, orientation effects, warpage & sink marks without re-producing the mould [5,6]Cooling phase-Many researches were done on cooling channels [7-10]. Feature based approach (FBA), Configuration space method, visibility based approach and solid freeform fabrication (SFF) supporting on conformal cooling channels (CCC).Recent methods of optimization-Taguchi method, Artificial neural network (ANN), Fuzzy logic, Genetic algorithm (GA), Finite element method, Response surface methodology, Blackboard- based expert system a case-based reasoning (CBR), Linear regression model, Grey relational analysis and Cavity pressure signals and principals component analysis [11].

Figure 6 Types of cooling channels

9Materials and methodsProject methodology10Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

10Materials and methodsami simulation methodology11Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

11Materials and methodsoptimization methodology12Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

Taguchi technique is used as a screening method to rank the importance of the input variables on overall quality. The relationship of variables over the quality criterion is shown in terms of percentages.Face centered cubic design is to examine the non-linear interactions between input variables and a set of criteria that define part quality. The result is shown in terms of a response plot indicating how sensitive each quality criterion is to the selected input variable.

12Materials and methodsgeneral specifications and design geometries of the parts13Optimization Of Process Parameters Of Plastic Injection Moulding Using Taguchi And FCC Techniques

CharacteristicsParts (3mm wall thickness)Rectangular plateOverall dimension (mm)120 x 50 x 3Total part weight (g)13.703Shot volume (cm^3)18.0000Table 2 - Characteristics of the imported rectangular plate

Figure 7-CAD Model of a rectangular plateMelt MaterialPPMold MaterialTool Steel P-20CoolantMediumWater (pure)Temperature20 CFlow rate10.00 (lit/min)Reynolds Number20000