Guidelines Design checklist

The goal of new product development or product improvement is to make the product have excellent performance while obtaining low production cost. Here, the design task mainly refers to the selection of raw materials, selection of suitable processing, strength calculation and mold design. Only when these steps are considered holistically and followed up systematically can high-quality, commercially viable molds be produced. Design departments are often just looking for practical solutions. However, it must be emphasized that practicality and cost-efficiency of plastics are not inevitable, and designers must pay great attention to developing the right solutions for raw materials and processing.

Plastic properties are not eternal The properties of plastics are affected by the use environment, processing process, mold design and operating conditions (as shown in Figure 1). Plastic properties obtained from tests in a laboratory environment. The test chart is produced by testing a high-gloss mold with optimized parameters under standard conditions of specified pressure. However, in reality, it is impossible for plastics to be produced under such conditions, nor can they be under the same pressure in use. Therefore, the precise requirements and defining conditions must be carefully analyzed and laid out when developing any plastic design scheme, and design checklists can provide useful assistance in this regard.

production of samples To develop a product, from the design stage to the market preparation stage, it is necessary to prepare samples for testing and correction. Make sure that the sample production method is broadly applicable to mass production scenarios. Partially injection molded samples are also made from injection molds. If no tooling is available, it is necessary to use a similar material or sheet and cut it into a test sample. However, there are always problems of one kind or another, for the following reasons:

1.The influence of weld lines on injection molded parts cannot be investigated.

2.Sometimes, grooves created during machining can reduce the strength properties of the component compared to injection molded parts.  Due to the high degree of crystallinity, extruded rods and sheets are stronger and harder than injection molded parts.

3.The effect of fiber orientation cannot be examined.

A sample for a light switch made of extruded material that can withstand 180,000 cyclic stresses. In the same case, the injection molded parts showed fatigue failure after 80,000 cycles. This difference is due to the difference in crystal structure during the injection molding process.