Plastic product development - An overview

In this article, we discuss the types of analysis conducted to ensure product quality while developing a plastic part.

The most popular production method for creating plastic parts is injection moulding. Injection moulding is used to create a vast range of items, each with a unique size, level of intricacy, and use. The injection molding process requires the use of an injection molding machine, raw plastic material, and a mold. The plastic is melted in the injection molding machine and then injected into the mold, where it cools and solidifies into the final part.

Before creating the first prototype of a plastic injection molding die is started, a mold flow analysis should be completed.  Not every application requires mold flow analysis. Depending on the product geometry and tolerance requirements, plastic engineers will make recommendations for including mold flow analysis in the production budget.

What is a Mold Flow Analysis In Plastic Product Design?

Through the use of software to simulate plastic flow, mould flow analysis enables manufacturers to improve the design of their injection moulds and produce better products.

By conducting mold flow analysis, manufacturers can get a glimpse into how the material that they are using will fill the cavity of a mold, and spot possible problems. This will forecast how to make each cavity in the mould into the lightest, strongest, and most consistent pieces possible. The programme will display an exact prediction of the resin flowing into each cavity in the injection moulding tool when you choose the resin for your pieces. Before the first piece of art is created, this can also present an opportunity to optimise the melt temperature, moulding pressures, fill cycle periods, etc. Prior to the actual cutting, you can make modifications to the mould virtually and save manufacturing costs by using software for mould flow analysis.

Results of a Mold Flow Analysis In Plastic Product Design

i) Fill/Pack Analysis  

The designer and toolmaker can see how the chosen resin will react as it passes through the mould to create your pieces thanks to the filling and packing analysis. The following characteristics will need to be improved in order to optimise the fill and pack for an injection moulding tool: 

• Correction of the gate and runner size to enable smooth resin flow.:
• Tool will be sized correctly for tonnage requirements. 
• Effective identification of sink marks
• Gate positioning can be improved.
• Molding variables, like pressure, can be modified and validated
• The chosen resin can be validated.
• The gas traps location can be identified.

Fill/Pack Analysis results can be visualized as given below

ii) Cooling Analysis (Steady State And Transient Analysis)

The cooling phase is often a critical phase for determining cycle time. The coolant conditions required to maximise the effectiveness of the suggested cooling architecture can be determined by analysing the cooling phase. It is possible to compare the efficiency of high conductivity mould inserts and cooling elements like baffles and bubblers ahead to prevent making expensive and challenging alterations to the mould. A cooling analysis can assist in:

• Cycle time optimization
• Optimization of coolant paths through the injection molding tool
• Selection of high-conductivity inserts
• Effect on warpage can be identified
• Evaluation of baffles and bubblers
• Circuit pressure drops detection

Cool Analysis results can be visualized as given below

iii) Warp Analysis 

A warp analysis is used to identify the cause of warping and suggest a remedy, such as changing the location of the gate, altering the design parameters, or reducing the variations in wall thickness. Injection moulding is a method used by designers to mass-produce complicated, high-precision products.

After designing the part it is important to ensure the part can be manufactured well within tolerance and will not exhibit excessive warp. The part design, resin choice, fibre orientation, the moulding process, and cooling system are a few of the variables that might affect warp. By doing a warp analysis, we may identify the causes of part distortion after moulding and lay the groundwork for future adjustments that will reduce or even remove the distortion. Warp studies can be used to compare materials, find methods to prevent warp, and detect design and manufacturing process variances that produce warp. The variables that require ongoing monitoring in production to lower variation, mitigate scrap, and create favourable circumstances for moulding can also be identified by the warp analysis. The findings of the warp analysis are shown below.

iv) Structural Finite Element Analysis (FEA)

Engineers require a way to assess the design of a part to assure its performance for its intended lifetime when plastics are incorporated and utilised in more performance-demanding applications. Each part cavity's strength is forecasted via FEA analysis. By using this prediction, the designer will be able to modify the part design, mould design, or moulding circumstances to ensure that the parts produced to satisfy the requirements of your design structure. The FEA study forecasts the weak spots (as well as the strongest spots), which can be improved for breakpoints, fracture points, and durability during the course of the product's existence. From there, the choice of material or resin, part designs, moulding techniques, and assembly techniques can all be improved to provide a part at a lower cost with the highest level of functionality.

FEA Analysis results can be visualized as given below.

Conclusion

All these types of analysis are interrelated and need to be considered collectively.  Information that is commonly extracted from these analyses includes Displacement, Temperature profile, Stress, Creep behavior, Strain, etc. These analysis types help in solving plastic problems to drive product development towards lower costs and higher quality. Understanding how the plastic will behave in the environment and the operational stress it will be subjected to is crucial when developing plastic parts. We can make sure that the design and mould will function flawlessly thanks to our understanding of plastic processing and Moldflow's technology.