How To Clean And Inspect Jewelry Castings_ Techniques For Different Mold Types.pptx

Hey jewelry peeps! Cleaning and inspecting jewelry castings might sound boring, but trust me, it's like giving your jewelry a spa day! 🛁
Let's start with cleaning. Imagine your jewelry just got out of a muddy puddle. We need to get it sparkly again! For ordinary gypsum molds, we use a water explosion technique. It's like a mini tsunami for your jewelry! Then, we soak it in acid (don't worry, it's safe) and give it a high-pressure shower. After that, we cut off the sprue (the extra metal bits) and polish it until it shines like a star.
For wax-set gypsum molds, we use a special machine to push the casting out. It's like giving the jewelry a gentle nudge to come out of its mold home. Then, we clean it again with water and acid.
Now, for the tough stuff—ceramic molds. These are like the strongest castles for your jewelry. We use water explosion, high-pressure cleaning, and even stronger acid to get rid of any leftover mold material. It's like a superhero team-up to clean your jewelry!
Finally, we inspect the jewelry with magnifying glasses and fancy microscopes. We look for tiny holes, rough spots, or any imperfections. It's like playing detective, but for jewelry!
Whether you're a jewelry store, designer, or even a celebrity looking for custom pieces, this process makes sure your jewelry is perfect. Ready to make your jewelry shine? Let's do it!

1. How To Clean And Inspect Jewelry Castings: Techniques For Different Mold Types Get entire article, please visit: https://sobling.jewelry/how-to-clean-and-inspect-jewelry-castings-techniques-for-different-mold-types/

2. CONTENTS Cleaning of Jewelry Castings Using Ordinary Gypsum Molds 01. Cleaning of Jewelry Castings Using Wax-Set Gypsum Molds 02. Cleaning of Jewelry Castings Using Acid-Bonded Ceramic Molds 03. Jewelry Casting Quality Inspection 04.

3. 01 Cleaning of Jewelry Castings Using Ordinary Gypsum Molds

4. Background Knowledge

5. Background Knowledge Mechanical Investment Powder Remover Water Explosion Cleaning Pool High-pressure Casting Plaster Mold Cleaner Automatic Gypsum Investment Cleaner

6. Background Knowledge  Gypsum Waste Liquid Collection Tank Large Settling Tank Sprue Polishing Machine Principle of Magnetic Polishing

7. Task Implementation -   The cleaning method for 18K platinum jewelry castings made from gypsum molds Water Explosion Cleaning of the Mold  Metal tree after washing Metal tree soaking in acid Drying Determining the Water Explosion Cleaning Time : The optimal water explosion cleaning time for 18K platinum molds depends on the flask size and product structure, balancing stress reduction and cleaning effectiveness to avoid deformation or poor cleaning. Water Explosion Cleaning : High-temperature molds are immersed in water to create an explosion effect, ensuring thorough contact with water for effective cleaning while maintaining water depth in the tank. 4.Acid Immersion : Metal trees are soaked in 25% hydrofluoric acid for 20 minutes, rinsed, and checked for residual casting powder, with acid solution effectiveness monitored and adjusted. 3.High-Pressure Washing : Metal trees are washed with high-pressure water jets in a plaster mold cleaner, ensuring all parts are thoroughly cleaned by moving and flipping the tree. 5.Cleaning and Drying : Metal trees are cleaned, dried, weighed, and analyzed for melting and casting losses to prepare for further processing.

8. Task Implementation -   The cleaning method for 18K platinum jewelry castings made from gypsum molds Cutting the sprue with a pneumatic crimping machine Uses cutters to trim the residual sprue Polishing the residual sprue  Magnetic Polishing Cleaning 6.Cutting Blanks : Jewelry castings are cut from the tree core using a two-step method or pneumatic crimping machine, ensuring minimal damage and optimal sprue length for subsequent processing. 7.Polishing the Residual Sprue : Residual sprues are polished using a sprue polishing machine, with careful attention to avoid damaging the workpiece and efficient collection of metal powder to minimize precious metal loss. 8.Magnetic Polishing Cleaning : Workpieces are polished in a tumbler with steel burs and polishing liquid, with rotation speed and time adjusted based on material, and equipment maintained for optimal performance.

9. 02 Cleaning of Jewelry Castings Using Wax-Set Gypsum Molds

10. Background Knowledge Breakage of wax-set gemstones Gemstones falling from wax-set casting jewelry Structure of the head used in mechanical extrusion demolding Wax setting in jewelry enhances efficiency and reduces costs but risks gemstone damage due to thermal and mechanical stresses, requiring careful handling and cooling to prevent breakage and loosening. The Loosening and Breaking of Wax-Set Gemstones Acid immersion for cleaning wax-set castings must consider gemstone compatibility, as hydrofluoric acid can damage silica and silicate-based gemstones like quartz and emerald. Acid Immersion Treatment of Wax-Set Castings

11. Task Implementation - U se a casting extruder and an automatic gypsum casting cleaner to clean the metal casting tree of wax-set gemstone jewelry Mold cooling in place Extrusion demolding of the steel flask Washing of the wax-set metal tree Fixture for magnetic polishing and cleaning of wax-set castings Static Casting : The mold is cooled evenly on a rack until it reaches about 100℃. 2.Mechanical Extrusion Demolding : The mold is inverted and clamped, then an extruder slowly pushes out the metal tree. 3.High-Pressure Cleaning : The mold and metal tree are cleaned in a rotating cleaner at 11MPa, with a filter to prevent gem loss. 4.Cutting the Sprue : After cleaning and drying, the metal tree is weighed, and residual sprues are cut and polished. 5.Magnetic Polishing Cleaning : Metal cores and wax-set castings are polished separately, with fixtures used to prevent damage during cleaning.

12. 03 Cleaning of Jewelry Castings Using Acid-Bonded Ceramic Molds

13. Background Knowledge 03. 01. 02. Cleaning of Acid-Bonded Ceramic Molds with Water Explosion Cleaning Water explosion cleaning is prioritized for acid-bonded ceramic molds used in high melting point jewelry casting, leveraging steam's explosive force for efficient mold removal while considering material thermal shock sensitivity. Cutting the Sprue Platinum jewelry's thicker sprue, designed to enhance metal flow, requires careful cutting techniques to prevent casting deformation during removal. Magnetic Polishing Cleaning Magnetic polishing effectively cleans castings but demands adjusted speeds for different metals to avoid surface damage, especially with softer platinum grades.

14. Task Implementation - I nvolves cleaning acid-bonded ceramic molds and vacuum centrifugal casting of Pt950 jewelry castings Pt950 metal tree after water explosion cleaning Using hand tools for auxiliary cleaning of castings Cutting the sprue Water explosion cleaning effectively removes mold material from Pt950 jewelry castings, leaving a metal tree with interconnected crack networks after quenching. 2.High-pressure cleaning , supplemented by manual tools, is necessary to thoroughly remove residual ceramic mold from intricate casting areas. 3.Acid immersion with high-concentration hydrofluoric acid efficiently cleans dense ceramic molds due to Pt950's excellent corrosion resistance. 4.Cutting thick sprues requires a combination of pneumatic crimping pliers and sawing to prevent casting deformation. 5.Residual sprues are polished using a specialized sprue polishing machine for precise removal. 6.Magnetic polishing cleans castings effectively at 800~900 r/min, with direction changes every 5 minutes for 20~30 minutes.

15. 04 Jewelry Casting Quality Inspection

16. Background Knowledge 01 Magnifying glasses and stereo microscopes are essential tools for detailed jewelry inspection, with stereo microscopes offering 3D imaging and digital capabilities for enhanced analysis. Appearance Inspection Tools and Equipment 02 Porosity defects in castings, caused by trapped gases, result in round or irregular holes that impact surface quality and mechanical properties, classified as reactive, precipitative, or entrapped pores. Porosity Defects 03 Shrinkage defects, arising from volume reduction during cooling, lead to issues like shrinkage cavities and porosity, affecting casting density, mechanical properties, and surface finish. Shrinkage Defects 04 Fluidity defects, such as incomplete filling and cold shuts, occur due to poor molten metal flow, resulting in incomplete castings or unfused metal areas with smooth edges. Fluidity Defects 05 Surface roughness defects, including burrs and sand holes, stem from mold quality issues, casting powder flaking, or foreign inclusions, leading to uneven and non-smooth casting surfaces. Surface Roughness Defects

17. Background Knowledge Magnifying glass for jewelry inspection Stereomicroscope with digital imaging system Pores on the Pt950 ring shank Surface shrinkage porosity defects in jewelry castings Jewelry casting defects Surface Roughness of Jewelry Castings

18. Task Implementation - Use a magnifying glass and stereomicroscope to observe jewelry casting samples, take photos of typical defects, and analyze their possible causes Defects and Possible Causes of Jewelry Casting Samples Casting defect Defect legend Possible causes Appearance of flash, burr   ① improper proportion of casting powder and water, water is too much ② open powder casting in the static mold was mixed ③The burnout furnace is too fast to raise the temperature ④ casting into the furnace before placing too long, the cavity inside the dry cracks Raised gold beads on the surface   ① improper water-powder ratio, the water is too little ② mixing powder operation working time is too long ③Vacuum extractor operation is not normal Surface roughness   ① rough surface of castings ②Poor quality or failure of casting powder ③The temperature of burnout is too fast Defective casting   ①Irrational sprue setting or wax model tree planting ② low temperature of casting metal ③Low casting temperature during pouring ④Insufficient amount of casting metal Appearance of Porosity   ① casting metal temperature is high ② casting mold is not completely burned through ③The proportion of reused material in casting is too high ④Severe gas absorption during melting Appearance of shrinkage cavity   ① liquid metal pouring temperature is too high ② casting mold temperature is too high ③ improper location or size of the sprue ④Insufficient pouring pressure

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