Lost Wax Investment Casting Of Eccentric Wheel Of 600 Lasting Machine

Product Introduction

The basic process of the lost wax investment casting process

Wax pressing>Surface quality inspection of wax parts>Correction of wax parts>Mold assembly

To give a brief description, first use the mold to inject the desired shape with wax, and then check whether the surface quality of the wax part meets the standard. If it is qualified, the wax part will be corrected. Why it needs to be corrected will be discussed later. If it is not qualified, it will be handed over. The mold assembly personnel will perform surface repairs. If the parts are not suitable for repair, they will be scrapped directly. The wax parts that have been molded for a period of time will be assembled and liquid-sealed again. Finally, the wax molds will be transported to the next shell process.

Technical introduction to each process

1. Pressed wax

The closing, injection, and opening times of a wax pressing cycle are approximately one to one (yes, the ratio of golden fish blended oil), but it is not necessarily the same, as the aero-engine blade mold I came into contact with, because There are too many single-piece key blocks, so the fitting time is longer.

In order to easily take out the wax parts after molding, usually after 3-4 sets of parts are pressed, a release agent will be sprayed on the mold. However, the release agent must first choose a solvent that does not contain hydrophilic groups, which is not easy. Causes mold corrosion. Secondly, the amount of release agent must be controlled. Sometimes operators spray too much release agent to facilitate the pickup of parts, which will affect product quality, easily cause streamlines, and affect wax materials stability.

During the injection process, important parameters such as temperature, flow rate, flow rate, injection pressure, injection time, and mold clamping force will affect the quality of wax parts.

Injection pressure can avoid defects such as insufficient pouring, rough surfaces, flow lines, shrinkage cavities, etc. However, excessive injection pressure will cause serious flashes. However, the flash problem can also be dealt with by increasing the mold clamping force. However, the mold clamping force should generally not exceed the mold's designed maximum load-bearing strength, otherwise, it will easily reduce the mold life.

Temperature and pressure have similar effects on wax parts, except that they have opposite effects on shrinkage. The higher the temperature, the more serious the wax parts will shrink. Why? Because the inside of the wax object has not completely solidified and the heart is unstable, there is no way for the wax object to be strong. The same goes for being a human being. You need to cultivate your mind before doing anything. In addition, if the temperature is too high, bubbles will easily be involved, which is mainly related to the properties of the wax parts.

The flow rate and flow rate can be said to be a set of oviparous parameters, Q=mv, and the flow rate is directly proportional to the flow rate. So I’ll just talk about the flow rate below. Properly reducing the flow rate can improve the insufficient pouring. The reason is related to the solidification of the wax parts. However, if the flow rate is too low, the wax parts will solidify prematurely, affecting the fluidity of the wax in the subsequent flow channels, resulting in rough surfaces and streamline defects. Likewise, if the flow rate is too fast, too many bubbles will be entrained.

2. Surface quality inspection of wax parts

This step is usually visually judged by the wax-pressing personnel, and the blades can be placed under high-illumination LED lights for defect observation. For defects such as insufficient pouring, rough surface, and bubble clusters, they are generally scrapped directly. Other defects can be repaired appropriately, such as large bubbles, which can be repaired by popping the bubbles with a needle and then filling them with wax.

However, we should follow the principle of cost front control - we would rather expose defects at the front end of the process than at the back end. Therefore, we usually use a picky approach to try to ensure that the wax model is flawless.

3. Wax-up correction

Let’s consider where the deformation of Lost wax investment casting of the eccentric wheel of 600 lasting machines comes from.

It may be that the tolerance of the wax parts has accumulated during the design process; it may be that the wax parts were pulled and deformed during the pick-up process; it may be that the wax material is not solidified enough and gravity affects the deformation; it may also be that the shape of the part causes the internal tension of the material to expand.

These four reasons are all uncontrollable or very costly to control. Rather than controlling deformation, it is better to add a correction process to compensate for the deformation.

Therefore, correction tooling with soft materials such as nylon and aluminum alloy as the contact surface is introduced. Ensure that the shape of the wax parts will not be seriously deformed during the process from removal to assembly.

4. Assemble the model

The mold assembly mainly includes the assembly between the product wax parts and the sprue, the assembly of the dewaxed pin, and the assembly and liquid sealing of the sprue cup.

When assembling the wax parts and the sprue, ensure that the module is not distorted and the sprue does not pull the product.

Leveling and symmetry must also be ensured during the assembly process of the sprue and sprue cup, otherwise, it will affect subsequent processes, such as shell making and cutting.

During the assembly process, it is also necessary to use a relatively high-viscosity bonding wax to connect the modules. The requirement is to ensure that the bonding joint is firm without affecting the surface quality. In addition, for defective parts, ordinary wax should be used for secondary repair. A certain height of wax material needs to be poured into the connection between the overall wax mold and the sprue cup to ensure a tight connection between the wax mold and the sprue cup.

After the assembly is completed, liquid sealing wax must be used to re-encapsulate the sprue connection parts to ensure strength and surface quality. During the liquid sealing process, the operator needs to insert the liquid sealing passage from an angle of 45 degrees, enter slowly, and gradually keep the module vertical to the ground. After the liquid sealing is completed, the opposite process is used to slowly take out the module to avoid damage to the surface of the module. Too many air bubbles.

Hydrogen-oxygen flame wax mold repair equipment: After the hydrogen-oxygen gas passes through the filtered solution, the humidity will increase, thereby greatly reducing the flame temperature when the gas is burning and making the temperature more stable: the welding equipment is equipped with a gas regulator to facilitate the control of the gas flow, thus By controlling the flame size and flame length, the entire device is suitable for welding medium-temperature wax of small and complex shapes. The welding quality is good. The needle tube does not come into direct contact with the wax mold during operation, and no impurities are brought in. It is also safe and reliable. The generated hydrogen and oxygen gas are pollution-free and green. Environmental friendly.

Using a water-fueled hydrogen-oxygen machine to weld wax parts is the best choice for wax mold casting.

Detection Systems

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