Predicting shrinkage and warpage in injection molding: Towards automatized mold design

2017 ◽  
Author(s):  
Florian Zwicke ◽  
Marek Behr ◽  
Stefanie Elgeti
Keyword(s):  
Injection Molding ◽  
Mold Design

Optimal Layout and Sizing of Ejector Pins for Injection Mold Design

1998 ◽  
Author(s):  
Seongjoon Kwak ◽  
Kunwoo Lee
Keyword(s):  
Wavelet Transform ◽  
Injection Molding ◽  
Mold Design ◽  
Injection Mold ◽  
Optimal Layout ◽  
Rule Based ◽  
Rule Based System ◽  
Molded Part ◽  
Injection Mold Design ◽  
Local Stresses

Abstract Injection molding is the most prevalent technology used for processing thermoplastic polymers. At the end of the injection molding cycle, the plastic molded part should be ejected when the injection mold opens. Complex moldings with bosses, ribs, or other features are generally ejected by ejector pins because they are economical and easy to be installed. However, the ejector pins can cause high local stresses and strains in the molding at the stage of ejection leading to the part deformation and damage. This paper proposes a method to determine the layout and size of the ejector pins required to eject thermoplastic moldings with minimizing the part deformation and damage. The proposed method calculates the distribution of the necessary ejecting forces to overcome the friction between the part and its mold. Then, it transforms the ejecting forces into a certain number of representative forces by the wavelet transform. Finally, we can get the location and size of the ejector pins corresponding to the discrete ejecting forces with the help of a rule-based system. The proposed method helps an injection mold designer to systematically obtain an optimum ejector design.

Establishing a rapid cooling complex mold design for the quality improvement of microcellular injection molding

2020 ◽  
Vol 60 (12) ◽  
pp. 3072-3085 ◽  
Author(s):  
Yung‐Hsiang Chang ◽  
Min‐Chi Chiu ◽  
Shia‐Chung Chen ◽  
Che‐Wei Chang ◽  
Chia‐Yen Tseng
Keyword(s):  
Quality Improvement ◽  
Injection Molding ◽  
Mold Design ◽  
Rapid Cooling ◽  
Microcellular Injection Molding

Finite Element Design and Numerical Simulation on Non-Pneumatic Beehive Damping Tire

2011 ◽  
Vol 291-294 ◽  
pp. 418-422
Author(s):  
Ge Gang Zhu ◽  
Chen Xu ◽  
Long Yi ◽  
Ning Li
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Injection Molding ◽  
Simulation Analysis ◽  
Mold Design ◽  
Molding Process ◽  
Improvement Measures ◽  
Quality Issues

The design and numerical simulation and analysis on non-pneumatic beehive damping tire were discussed in this paper by finite element techniques. And use the molding software filling its experimental to analyze the process of injection molding qualities for the reasonable mold design. And the corresponding improvement measures, the rationality of mold design and molding process were arised for quality issues according to the simulation analysis.

Polyurethane Reaction Injection Molding: Process, Materials, and Properties

1980 ◽  
Vol 53 (3) ◽  
pp. 542-599 ◽  
Author(s):  
L. J. Lee
Keyword(s):  
Injection Molding ◽  
Flow Rate ◽  
Weight Reduction ◽  
Flexural Modulus ◽  
Impact Resistance ◽  
Mold Filling ◽  
Injection Molding Process ◽  
Mold Design ◽  
Thermal Coefficient ◽  
Reaction Injection Molding

Abstract Reaction injection molding includes aspects of polymerization reactor analysis as well as melt injection molding. Processing can be broken down into several unit operations: metering and machine performance, impingement mixing, mold filling, curing and mold design. Commercial RIM machines have been used successfully for non-filler systems. The results are generally satisfactory. Reactants are usually allowed to circulate through the mixhead, or even through impingement nozzles, such that uniform temperature control and appropriate agitation of reactants can be obtained. Most heads can switch from the recycle to injection mode under high pressure operation, to minimize the lead/lag problem. The mixing chamber is self-cleaned at the end of each shot by a hydraulically driven piston which pushes out all the residue mixture from the mixhead after mold filling. Flow rate/flow area can be adjusted externally by the nozzle size adjuster. Flow rate also can be controlled by the pressure setting. Two or four streams impingement mixing is the common mixing technology used in the present RIM machines. Static or impingement type after-mixers have been used extensively to improve the mixing. Mold filling seems not to be a problem for conventional RIM operation if mold design is appropriate. The typical pressure inside the mold cavity during filling is less than 350 kPa. With the help of slight foaming during curing, RIM polyurethanes usually have excellent, depression-free surfaces. A number of qualitative descriptions of automotive type RIM have appeared, and some basic studies of the process are being carried out. However, as yet there does not appear to be a complete understanding of how the process influences the structure and properties of the polymer formed. The majority of RIM parts have been made in the 140–300 MPa flexural modulus range for fascia applications, where appearance, weight-reduction, and impact resistance are the most important criteria. A representative formulation used to produce automotive fascia by reaction injection molding consists of a polyether/polyester polyol with molecular weight in the range of 1000–3000, a short chain extender like ethylene glycol, 1,4-butane diol or a diamine and a modified derivative of 1,4-diphenylmethane diisocyanate, MDI. The need for further weight reduction to meet government mileage requirements, and for improved corrosion and impact resistance, makes the extension of RIM materials to other external automotive body components increasingly attractive. For these applications, there will be several new requirements: flexural moduli in the 700–4000 MPa range to provide dimensional stability, but still with the desirable impact strength; a low thermal coefficient of linear expansion to allow satisfactory mating with sheet metal surfaces. An increased thermal stability would also be required for parts that would be painted and baked on the car, or for applications such as hoods with higher in-use thermal exposure.

Complicated Model Establishment and Second Development for Enterprises by MoldWizard

2010 ◽  
Vol 97-101 ◽  
pp. 3451-3454
Author(s):  
Wei Hua Kuang ◽  
Biao Biao Chen ◽  
Yu Cheng Lin
Keyword(s):  
Injection Molding ◽  
Cooling System ◽  
Design Flow ◽  
Location Analysis ◽  
Mold Design ◽  
Gating System ◽  
Second Development ◽  
Gate Location ◽  
Complicated Model

Injection molding is among the most widely used techniques for thermoplastics, and many complicated models are used in the mold enterprises. In the paper, the mold design flow by UG MoldWizard was analyzed. A mold for hair drier cover was successfully developed. How to search parting lines, create/edit parting surfaces, extract regions and create cavity and core were researched deeply. Best gate location analysis was studied by MoldFlow software, and a multi-cavity mold was designed. Angled-lift splits were developed to form the concave grooves. Lastly, the gating system and the cooling system were designed. It proved that MoldWizard can obviously improve the drafting efficiency and quality.

Numerical Simulation and Balance Design of Rubber Injection Mold Gating System Based on POLYFLOW

2012 ◽  
Vol 501 ◽  
pp. 190-195
Author(s):  
Lian Shuai Chen ◽  
Hui Min Zhang ◽  
Jia Teng Niu
Keyword(s):  
Numerical Simulation ◽  
Injection Molding ◽  
Injection Velocity ◽  
Mold Design ◽  
Injection Mold ◽  
Gating System ◽  
Processing Parameter ◽  
Inlet Flow ◽  
Injection Mold Design ◽  
Runner Design

Rubber injection molding is applied in more and more applications in rubber production process. Design of gating system is the most important in rubber injection mold design. Poor runner design will lead to uneven injection velocity and pressure which affect the size and shape and the quality of the rubber products. This paper first adopted POLYFLOW numerical simulation. Three different inlet flow rates for multi-cavity mold were simulated and analyzed by POLYFLOW software in this paper. Non-equilibrium gating system was further optimized by the calculation method of Balanced Gate Value and numerical simulation. The best inlet flow rate and the best runner size were ultimately obtained. It was proven that Numerical simulation results are of great significance for rubber injection mold design and injection molding processing parameter selection.

Conformal Cooling Versus Conventional Cooling: An Injection Molding Case Study With P-20 and 3DP™-Processed Tooling

2000 ◽  
Vol 625 ◽  
Author(s):  
Wayde R. Schmidt ◽  
Ronald D. White ◽  
Connie E. Bird ◽  
Joseph V. Bak
Keyword(s):  
Injection Molding ◽  
Design Approach ◽  
Mold Design ◽  
Simulation Tool ◽  
Conformal Cooling ◽  
Designed Experiments ◽  
Tool Fabrication ◽  
Conventional Cooling

AbstractA series of designed experiments was performed in an attempt to evaluate and quantify the historically “anecdotal” benefits of conformal cooling for injection molding tooling. The study considered different generic part geometries, gating schemes, mold materials, plastic resins and cooling approaches. This paper provides an overview of the mold design approach, cooling simulation, tool fabrication via the 3DP™ process, as well as part molding and inspection results.

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