Most of the Investment Casting foundries from China, Taiwan and other Asian Countries prefer Non filled or Unfilled Pattern Waxes for their mass production of precision Investment Casting. The main advantage of the Unfilled Pattern Waxes is the ability of recycling of the Pattern Wax. This ability enables users to recycle and reconstitute the Unfilled Pattern Wax after each cycle of dewaxing.
Also, the dewaxibility of the Unfilled Wax is better, resulting in simple shell and dewaxing system. Because of the improved dewaxing, defects like shell cracks can be avoided resulting in additional advantages.
Whereas the main challenges for Unfilled Pattern Wax user are to overcome the problems like wax pattern surface shrinkage, low productivity and the wide range of consistency. These issues can be solved with:
- Close Wax Injection Parameters.
- Injecting the Wax in minimum Wax Temperature and in Paste or Gel Condition.
- Providing uniform die Cooling, by circulating could water through Wax Pattern Moulds.
- Maintaining the Room temperatures in the Wax and Shell Room in the range of 20°C to 25°C.
- Using automatic Wax Dies for consistency and accuracy.
But we must consider that to get quality Wax Patterns from Filled Pattern Wax we also have to follow all these criteria. Then if we follow all these controls more precisely, we will get defiantly good results for Unfilled Pattern Waxes also. If we use Unfilled Wax in proper Paste or Gel condition, we will defiantly get dimensions same as to Filled Pattern Wax. At least for small to medium size of Wax Patterns and for bigger size of Wax Patterns we can use the Wax Chills.
What is SHINECAST UPW?
Waxes are formulated with different Waxes, Polymer Additives, Natural Waxes and different resins. Out of these formulations, the dimensional contraction increases with the higher Wax content. And if we increase the resin and polymer content, we get closer dimensions. Saffroshinehas finetuned the composition to get close dimensions and consistency of the Unfilled Pattern Wax Grade SHINECAST UPW. Because of the Uniform solidification technology SHINECAST waxes are having better dimensional performance. SHINECAST waxes can be injected in ultra-Paste or Gel Conditions.
Recommend Procedure: How to Use SHINECAST Unfilled Pattern for mass production of precision Investment Casting?
- Use Fully Automatic Wax Injection Tooling.
- Inject the Wax at super paste or Gel condition. Invest in Good Wax semi-automatic and automatic wax injection machines.
- Provide uniform die cooling in between 20° C to 22°C.
- Maintain Wax room and Shell room temperature in between 20°C to 25°C.
- Skilled and trained worker for operating the dies, wax and machines.
Once we get wax patterns with reliable consistency, dimensional accuracy and proper surface quality, further processes like wax pattern assembly, shell building, shell drying, and dewaxing are same as the Filled Pattern Waxes. Now the next important step is to recycle and refurbish the Used Waxes for reuse.
After dewaxing of the shells, the wax should be transferred to a wax tank. This tank should have low speed stirrer and heating through oil bath heaters. In case of autoclaved dewaxing, moisture is introduced in the wax. this moisture from the wax should be removed at 100°C at regular low speed stirring. Normally it takes 7 to 8 hours for removing the moisture completely from the wax. This is generally depending on the moisture content of the wax. After removing the moisture from the wax, it should be transferred to the wax settling tank. This tank also must have heating through Thermic Oil. In these tanks the impurities in the wax must be settled down by holding the wax at 120°C temperature, without any stirring and physical movements.
For SHINECAST wax we recommend removing the moisture from the dewaxed wax at 120°C. while moisture removal, slow wax stirring should be provided. This must be done in Oil Jacketed Heating Tank.
After moisture removal from the Used SHINECAST wax, it should be settled for 12 to 24 hours from proper removal of the impurities. Now this wax from the side valve of the tank should be passed through Centrifuge or Filtration Unit to remove maximum impurities. After this stage the ash percentage of the wax must be checked, and it must be less than 0.05 percent. This processed wax should be used for Runner making and pattern Production.
For runner making, 2 to 4 percent of Fully Refined Paraffin Wax must be added to the runner or system Wax.
For Wax Pattern Production 25 to 50 percent of the virgin wax should be added to the Wax to maintain its quality and fortify the losses.
If we assume there is 30 percent of yield of the casting and we use 50 percent fresh wax of the Pattern Wax, then the total fresh wax addition per cycle would be 10 to 15 percent of the total quantity. By this way refurbishing and using the 85 percent of the Used Wax for the production reduce the Wax Input Cost Considerable. The main advantage here is the Quality of the refurbished wax is maintained as good as the virgin wax.
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