Characterizations of Polymer Gears Fabricated by Differential Pressure Vacuum Casting and Fused Deposition Modeling

In recent years, polymer gears have gradually become more widely employed in medium or heavy-duty conditions based on weight reduction in transmission systems because of low costs and low noise compared to metal gears. In the current industry, proposing a cost-effective approach to the manufacture of polymer gears is an important research issue. This paper investigates the wear performance of polymer gears fabricated with eight different kinds of materials using differential pressure vacuum casting and additive manufacturing techniques. It was found that both additive manufacturing and differential pressure vacuum casting seem to be an effective and cost-effective method for low-volume production of polymer gears for industrial applications. The gate number of one is the optimal design to manufacture a silicone rubber mold for differential pressure vacuum casting since the weld line of the polymer is only one. Polyurethane resin, 10 wt.% glass fiber-reinforced polylatic acid (PLA), or 10 wt.% carbon fiber-reinforced PLA are suggested for manufacturing gears for small quantity demand based on the deformation and abrasion weight percentage under process conditions of 3000 rpm for 120 min; epoxy resin is not suitable for making gears because part of the teeth will be broken during abrasion testing.

Improving Cooling Performance of Injection Molding Tool with Conformal Cooling Channel by Adding Hybrid Fillers

Silicone rubber mold (SRM) is capable of reducing the cost and time in a new product development phase and has many applications for the pilot runs. Unfortunately, the SRM after injection molding has a poor cooling efficiency due to its low thermal conductivity. To improve the cooling efficiency, the thermal conductivity of the SRM was improved by adding fillers into the SRM. An optimal recipe for fabricating a high cooling efficiency low-pressure injection mold with conformal cooling channel fabricated by fused deposition modeling technology was proposed and implemented. This study proposes a recipe combining 52.6 wt.% aluminum powder, 5.3 wt.% graphite powder, and 42.1 wt.% liquid silicon rubber can be used to make SRM with excellent cooling efficiency. The price–performance ratio of this SRM made by the proposed recipe is around 55. The thermal conductivity of the SRM made by the proposed recipe can be increased by up to 77.6% compared with convention SRM. In addition, the actual cooling time of the injection molded product can be shortened up to 69.1% compared with the conventional SRM. The actual cooling time obtained by the experiment is in good agreement with the simulation results with the relative error rate about 20%.

Development of a Low-Cost Automatic Vacuum Degassing System for Rapid Tooling

Silicone rubber mold is frequently used in the indirect tooling. Automatic vacuum casting system is widely used to degas in the manufacturing of silicone rubber mold, but the cost of hardware is very expensive. A low-cost automatic vacuum degassing system is designed, build and test in this study. Optimized parameters for degassing process are investigated. The saving in the degassing time is about 23.4%.This system offers many advantages such as reducing human error of operator, reducing noise and air pollutions derived from the vacuum pump of the vacuum casting system.

Development of a High Precision Silicone Rubber Mold for Cylinder Block

This work demonstrates a technique for producing accurate wax patterns made from a high precision silicone rubber mold. Silicon rubber mold was cut into five components, which is the minimum number of components for assembling the silicone rubber mold. The advantages of this silicon rubber mold include savings in assembly time, reduction of human error while assembling the silicone rubber mold and good assembly precision. The shrinkage of critical dimensions can be controlled within 2.19%. Results reported here can speed up the velocity in the development of a new cylinder block in the motorcycle industry.

Analysis of the Quality of Rapid Manufacturing Technology Based on the Silicone Rubber Mold

The rapid manufacturing processes include making prototype mold, making silicone rubber mold and pouring parts. According to the study of rapid manufacturing based on silicone rubber mold, factors that impact the characteristics of products, the quality of surface and the accuracy of dimension are discovered. The curing temperature and time affect the properties of products. The smoothness of prototype surface, gate position, exhaust port position, channel distribution and pouring speed affect the quality of the products surface. The shrinkage of the material affects the accuracy of products dimension. Moreover, some measures and methods that improve the products quality also be illustrated.

Development of a High Efficiency Degassing System for Making Silicone Rubber Mold

Silicone rubber mold is regarded as an important method of reducing the cost and time to market in a new product development process. Commercial automatic vacuum machine is widely used to degas in the manufacturing of silicone rubber mold, but the cost of hardware is very expensive. A high efficiency degassing system is designed and implemented from regular vacuum machine. It is found that degassing process includes explosion phase, balance phase and convergence phase. The maximum saving in the degassing time is about 63.7%. The advantages of this system include reducing human error of operator, reducing noise and air pollutions derived from the vacuum pump.