Design of a Ten-Link Type Double-Toggle Mold/Die Clamping Mechanism and its Mechanical Error Analysis and Performance Verification

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Project title

Code/計畫編號

MOST105-2221-E019-028

Translated Name/計畫中文名

十連桿型雙肘節鎖模機構之設計及其機械誤差分析與性能驗證

Project Coordinator/計畫主持人

Wen-Tung Chang

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Mechanical and Mechatronic Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=12450698

Year

2016

Start date/計畫起

01-08-2016

Expected Completion/計畫迄

01-10-2017

Bugetid/研究經費

791千元

ResearchField/研究領域

電子電機工程

射出成型機與壓鑄機在使用時都必須藉由夾模單元提供足夠的鎖模力以平衡模具上的模流壓力。現今廣泛採用的九連桿型雙肘節鎖模機構從學理上分析是一種自由度為零的矛盾機構。當機件形狀及尺寸的加工誤差（即機械誤差）太大，使得鎖模機構不再保持對稱的幾何關係時，為使機構能產生預定的拘束運動，必須對其施加相當大的外力，以使機件產生補償性的變形量來抵消鎖模機構實際上不再對稱之真實尺寸的偏差量，如此必然會導致機件的過度磨耗、極大變形甚至疲勞破壞。因此，使得九連桿型雙肘節鎖模機構在其機件加工以及機器組裝和保養上都會增加許多成本。自由度為一的十連桿型雙肘節鎖模機構可望克服九連桿型雙肘節鎖模機構因矛盾機構之拘束狀態所導致的各項缺點。本計畫的目的在於針對十連桿型雙肘節鎖模機構進行其拓樸構造上的學理分析與尺寸合成，然後進行鎖模機構的機械誤差分析，最後並進行性能驗證的工作。本計畫以一年的時間完成研究目標。本研究首先進行拓樸構造分析與合成，並合成出30種具有拓樸構造上之創新設計的十連桿型雙肘節鎖模機構。然後，本研究進行九連桿組與十連桿組之位置分析與力量傳遞性分析的相關理論推導，並列舉實例以進行演示。接著，本研究提出一最佳化模型以進行鎖模機構的尺寸最佳化合成，其藉由全域正規化力量傳遞性指標作為目標函數以找出能達到最大指標值的桿件幾何尺寸組合，該最佳化模型並透過一案例以進行演示。再者，本研究進行九連桿組與十連桿組之機械誤差分析，並以最佳化設計結果為對象以進行演示與探討。最後，本研究以最佳化設計結果進行了九連桿組與十連桿組之實體模型的設計與製作，並進行了性能驗證實驗。由實驗的結果顯示十連桿組相較於九連桿組在行程定位準確度上雖僅略微提升，然其在輸入力的穩定性上則明顯地優於九連桿組，故仍可望改善現有鎖模機構因桿件的微小變形量而造成其運行時因矛盾機構之拘束狀態所導致的各項缺點。因此，本計畫所探討的十連桿型雙肘節鎖模機構可望取代傳統的九連桿型鎖模機構以改善其相關缺點，故而具有實際的產業應用性。 Injection molding machines and die casting machines both possess mold/die clamping units that can provide sufficient mold/die clamping force for balancing the pressure occurred inside molds/dies. The nine-link double-toggle mold/die clamping mechanism widely used nowadays is theoretically a paradoxical mechanism with zero degree-of-freedom. When manufacturing errors (i.e. mechanical errors) of the shapes and dimensions of link members are too large so that the geometric relation of a symmetric mechanism cannot be maintained, the mold/die clamping mechanism may transform into a structure that cannot easily produce a prescribed constrained motion. In other words, large driving force must be applied in order to produce a constrained motion, which causes compensative deformations of link members for counteracting the asymmetry due to dimensional deviations and thus leads to excessive wear, large deformations and even fatigues of link members. Hence, the nine-link double-toggle mold/die clamping mechanisms require higher manufacturing, assembling and maintaining costs. The ten-link double-toggle mold/die clamping mechanism with one degree-of-freedom may overcome the drawbacks of the nine-link type mechanism as a paradoxical mechanism. The purposes of this project are: (1) to analyze the topological structure and to carry out the dimensional synthesis of the ten-type type double-toggle mold/die clamping mechanism; (2) to analyze mechanical errors in mold/die clamping mechanisms; and (3) to conduct performance verification. The term of the project is one years. First, the topological structure analysis and synthesis are performed, and 30 types of innovative ten-link double-toggle mold/die clamping mechanisms are synthesized. Then, position analysis and force transmissibility analysis for both the nine-link type and the ten-link type mechanisms are performed, and examples are given for demonstration. An optimization model, in order to maximize the force transmissibility of the mold/die clamping mechanism, is then proposed to perform the dimensional optimal synthesis, and the proposed model is demonstrated through a case study. Furthermore, mechanical error analysis for both the nine-link type and the ten-link type mechanisms are performed, and the analysis for the optimization result is given for demonstration and evaluation. Finally, prototypes of both the nine-link type and the ten-link type mechanisms were designed and fabricated, and experiments for performance verification were conducted. The experimental results showed that the stroke positioning accuracy of the ten-link type mechanism was merely slightly better than that of the nine-link type mechanism, but the driving force stability of the ten-link type mechanism was obviously better than that of the nine-link type mechanism. Thus, the ten-link type mechanism might still be able to improve the drawbacks of the nine-link type mechanism as a paradoxical mechanism. Therefore, the ten-link double-toggle mold/die clamping mechanism studied in this project may be able to replace the nine-link type mechanism and be used for industrial applications.

Keyword(s)

鎖模機構
平面連桿組
十連桿型雙肘節機構
拓樸構造合成
尺寸最佳化合成
機械誤差分析
性能驗證
Mold/Die clamping mechanism
Planar linkage
Ten-link type double-toggle mechanism
Topological structure synthesis
Dimensional optimal synthesis
Mechanical error analysis
Performance verification

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Design of a Ten-Link Type Double-Toggle Mold/Die Clamping Mechanism and its Mechanical Error Analysis and Performance Verification

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