Lost wax investment casting can accurately reproduce complex components. Surface finish is its core quality highlight. QD has extensive experience in controlling casting surface quality, helping customers achieve high-quality products.
Key Factors Influencing Casting Surface Quality
| Influencing Factors | Specific Impacts | QD Control Advantages |
| Wax Pattern Basic Quality | Surface scratches and bubbles are directly transferred to castings, forming defects like dents and pits. | Establish a full inspection standard for wax patterns. Use special optical instruments to check for tiny defects below 0.1mm. Ensure 100% smooth wax patterns. |
| Properties of Surface Coatings | Uneven grain size and poor adhesion lead to rough casting surfaces. Insufficient high – temperature resistance causes coating shedding. | Customize coating formulas according to casting materials. For example, use ultra – fine grain aggregates for stainless steel castings. Automatically control coating thickness to ensure dense coatings. |
| Investment Casting Process Parameters | Excessively high temperature causes wax carbonization residues. Insufficient time leaves wax not completely removed. Both damage the surface. | The intelligent investment casting system automatically matches parameters. For complex wax patterns, use “segmented temperature rise”. Inspect the cavity with an endoscope after investment casting. |
| Melting and Pouring Control | Impure molten metal and improper temperature cause oxidation and slag inclusion, affecting surface cleanliness. | Real – time temperature control in the melting process. Equip with precise filtering devices. Ensure the purity of molten metal. |
| Subsequent Cleaning Methods | Wrong abrasives or excessive force may scratch the surface. Incomplete cleaning leaves impurities. | Customize cleaning schemes according to surface requirements. For mirror – like surfaces, use low – pressure glass bead blasting; acid – washing parameters precisely match the material. |
Strictly Control Wax Pattern Surface Quality
The surface condition of the wax pattern directly determines the initial surface quality of the casting. Therefore, it must be strictly controlled from the source.
1. First, choose high-purity, low-shrinkage wax. Avoid excessive impurities in the wax or uneven shrinkage after cooling, which can cause cracks.
2. Second, during the wax mold forming process, use precision injection molding techniques. Control the injection pressure and temperature to prevent problems such as bubbles, missing material, and scratches.
The QD team conducts 100% surface inspection on every wax pattern, using specialized optical instruments to identify minor defects. This ensures a smooth and even surface. Wax molding parameters are optimized based on the complexity of the casting, eliminating potential problems that could affect surface finish at the source.
Customize Matching Surface Coatings
The topcoat comes into direct contact with the molten metal. Its quality and application process significantly impact the surface finish of the casting.
1. High-purity refractory materials, such as alumina and zirconia, are required as the coating aggregate. A high-quality binder is used to ensure the coating’s adhesion and high-temperature resistance.
2. Also, the appropriate coating particle size should be selected based on the casting’s requirements. Fine-grained coatings can better fill tiny gaps in the wax pattern surface and reduce surface roughness.
We offer strong customization capabilities in this process：
We develop customized coating formulas for various casting materials, such as stainless steel, aluminum alloy, and titanium alloy.
For example, for stainless steel castings requiring a high mirror finish, we use ultra-fine alumina aggregate. Automated coating equipment is used to precisely control coating thickness. Dryness is monitored after each coat to prevent uneven drying that could cause coating flaking or dripping, ensuring a tight bond between the coating and the wax pattern.
Optimize Wax Removal Process
Improper dewaxing can lead to surface defects in the casting due to residual wax or damage to the mold cavity.
1. Select an appropriate dewaxing method based on the wax pattern’s material and structure, such as steam dewaxing or hot water dewaxing.
2. Precisely control the dewaxing temperature and time. Excessively high temperatures can lead to carbonized wax residue. Excessively low temperatures or insufficient time prevent the wax from being completely removed.
QD has an intelligent dewaxing system that automatically adjusts dewaxing parameters based on the wax pattern’s size, structure, and wax composition.
For wax patterns with complex cavities, a “staged heating” process is used. The wax is first softened at a low temperature, then gradually heated up to accelerate its flow, preventing damage to the cavity caused by large temperature differences.
After dewaxing is complete, QD uses an endoscope to inspect the interior of the cavity to ensure there are no wax residues or scratches. This minimizes the impact of the dewaxing process on the casting surface.
Fine – Tuned Post – Cleaning
During the cleaning process after casting, scientific processes are required to remove surface oxide scale, paint residue, etc.
- Sandblasting: Abrasives such as glass beads and aluminum oxide sand are selected based on the surface requirements of the casting. QD will develop sandblasting plans tailored to each casting. For example, for castings requiring a mirror finish, low-pressure, close-range sandblasting is used. This removes residue and reduces surface roughness.
- Pickling process: The acid concentration and pickling time must be precisely controlled according to the casting material to prevent excessive corrosion of the surface. For example, stainless steel castings require a specific ratio of nitric acid solution. The pickling time must be strictly controlled to ensure that the oxide scale is removed without damaging the casting surface structure.
- Electrolytic polishing: This process uses electrolysis to create a smoother surface. This requires real-time adjustment of current, voltage, and electrolysis time. QD has a specialized electrolytic polishing production line that dynamically optimizes parameters based on the surface condition of the casting. For example, for a casting with minor scratches, adjusting the electrolysis time can repair the scratches.
If you have any requirements for controlling the surface finish of lost wax casting or want to obtain customized solutions, please contact QD.
FAQ
1. Does the surface finish of lost wax castings meet the requirements of most industries?
Yes, the basic finish is quite high. We can also optimize the process based on industry needs, adapting to the requirements of various fields such as machinery and aviation.
2. Will tiny bubbles in the wax pattern affect the surface of the casting?
Yes. Bubbles can cause pitting on the casting surface. But, QD will detect such issues during the wax pattern inspection process to prevent defect transfer.
3. Does the topcoat formula need to be regularly updated?
It will be adjusted based on the casting material and requirements. We continuously optimize the formula to ensure coating compatibility and surface finish.
4. Is cavity inspection necessary after dewaxing?
It is essential. It can detect cavity damage or wax residue in a timely manner. QD inspection uses an endoscope to ensure subsequent casting quality.
5. Can we quickly adjust casting surface finish requirements by working with QD?
Yes, we have a sophisticated process adjustment system. We can efficiently optimize solutions based on your needs and guarantee delivery results.