CAE analysis of injection molding

Nowadays there are mechanical engineering softwares that help the mold makers and molding professionals to understand to evaluate the part design for plastic injection molding and also check the tool design before cutting the steel. Although the simulation software’s results are not 100% reliable, it saves time and cost by predicting the week area of the design.

Although the results are not reflecting 100% accurate results, it gives an idea to the designers to observe the tool functionality and evaluate their design before cutting the tool. Also, it will reduce development time and save money for companies. Moldflow and Moldex are two examples of software that are very useful to simulate injection molding of plastic.

Below you can see two graphs produced by Mold Flow analysis.







Mold Design Specification

The design of the mold will be divided into 2 stages:

1) Preliminary Drawings

The preliminary design is to be submitted within 1 week after receipt of purchase order. The purpose of this design is to determine the general layout and working of the tool to a degree that will allow steel to be purchased.
This stage should include :

  • Runner system
  • Basic position of water lines
  • Clamp slots
  • Gate locations
  • Gate size
  • Support/Pillar locations
  • Overall size of the mold
  • and any conditions special to the mold.

Project engineer approval is necessary for this stage.

2) Final Design

Drawings are to be fully detailed as follows:

  • Details of final gate designs, runner style, layout and style of sprue puller must be shown.
  • Complete CAD files of the tools to be submitted. ( 2D and 3D)
  • Cores, cavities, inserts or any other part of the mold which are not standard are to be fully detailed.
  • Assembly view should be stated the approximate weight of both mold halves.
  • A material list is required.
  • Detailed drawings are required for all inserts, slides, lifters, etc., with steel hardness specified.

To summarize, in the mold design process some general requirements have to be considered:

– Tool Design
– Materials
– Mold Bases
– Mold Makers Responsibilities
– Mold Venting Requirements
– Mold Cooling Requirements
– Core Pulls/ Lifters
– Electrical Systems
– Hydraulic Systems
– Finish Requirements
– Mold Identifications
– Mold Try-Out
– Warranty
– Tool Design Checklist
– Tool Sign-off