| The constant temperature mold of molding plastic | | | | with the ability to fabricate 3-D feature with almost |
| parts with high precision contours is of significance in | | | | arbitrary complexity is exceedingly useful to mould |
| determining not only the productivity of the injection | | | | design process (Xu et al., 2001). The remaining problem |
| molding process but also the product quality. A solution | | | | to be solved is how to optimize the design process of |
| to this challenge is the rapid thermal response molding | | | | the thermal system. In this paper, a systematic method |
| process in which uniform temperature overall the mold | | | | for designing cooling channel is proposed. Firstly, the |
| part ensures the product quality by preventing | | | | feature recognition algorithm is applied to identify and |
| differential shrinkage, internal stress and mold release | | | | decompose the moulded part into manageable |
| problems (Li, 2001). Many Computer-Aided-Engineering | | | | sections so-called cooling zones. In the next step, a |
| (CAE) and optimization methods have been carried | | | | sub-system of cooling channel is generated for each |
| out to observe and fine-tune the influences of the | | | | cooling zone. These sub-systems of cooling channels |
| thermal system (Park et al., 1998). The results of these | | | | are further decomposed into smaller elements called |
| research works are obtained by using thermal analysis | | | | cooling cells which are easy to be analysed. Lastly, the |
| modules of commercial CAE packages such as | | | | combination process of these sub-systems is done to |
| C-Mold or Moldflow which are based on the initial | | | | create a complete conformal cooling system for the |
| designs generated by the human. By given an initial | | | | whole plastic part based on the constraints of the |
| thermal configuration design, efficiency and quality of | | | | combination algorithm and design rules. |
| the molded part can be predicted before an actual | | | | Nowadays, feature-based modeling has been a |
| plastic mold is manufactured. One more necessary | | | | standard for 3D designs. Most of the complex shapes |
| step for the complete automation in the molding | | | | are obtained by synthesizing from sets of simple |
| thermal system is to generate the initial design for the | | | | features. This design strategy is not sensitive to the |
| conformal cooling channels.For example <a | | | | part geometry; therefore, it keeps the simplicity of the |
| rel="nofollow" | | | | design routine no matter how complicated the |
| onclick="javascript:pageTracker._trackPageview(' | | | | geometry of the part is. For the same purposes of |
| outgoing/article_exit_link');" href=" casting mould,mold | | | | simplicity and efficiency, the molded part is segmented |
| making,plastic injection mold </a> etc. In this paper, | | | | into sub-features that must be recognized for the |
| a featured-based approach to this problem is | | | | partial thermal system designs. Feature recognition has |
| proposed. Super-quadrics is presented as a tool for | | | | drawn much attention from researchers and been |
| recognizing the plastic part shapes and an algorithm is | | | | proposed in literatures (Lentz et al., 1993). The majority |
| applied for generating the center line of the thermal | | | | of these has based on machining feature recognition |
| sub-system of each individual surface. Finally, these | | | | techniques which can be classified in three categories: |
| sub sets of center lines are combined to create a | | | | graph-based methods, volumetric methods and |
| unique center line which is the guide line for generating | | | | hint-based methods. Although recent machining feature |
| the cooling channel of the thermal system. | | | | recognition technique can be a good solver for parts |
| Conformal cooling channel, as the name implies, refers | | | | with complicated intersecting feature, this technique is |
| to the channels that conform to the surface of the | | | | not appropriate for detecting shape feature for |
| mould cavity. Conformal cooling channels have | | | | thermal system design of plastic products. In plastic |
| demonstrated simultaneous improvement in production | | | | products, free-form surfaces are mostly used and |
| rate and part quality as compared with conventional | | | | hence, free-form features have to be processed. |
| production tools. In the previous researches, cooling line | | | | Furthermore, a shape feature in a plastic part may |
| design and fabrication have been confined to relatively | | | | blend smoothly to another feature and the boundaries |
| simple configuration, primarily due to the limits of the | | | | between features can not be explicitly defined. With |
| fabrication method used to make tools, but also due to | | | | these two reasons, neither graph-based methods, |
| the lack of appropriate design methodology. | | | | volumetric methods nor hint-based methods can be |
| Emergence of Solid Freeform Fabrication processes | | | | applied. |