A brief discussion on the role of gem machinery improvements in promoting the development of gem economics

Liu Fuyu Qin Binrong

About the first author: Liu Fuyu, member of the Third Artificial Gemstone Professional Committee of the China Jewelry Association, director of Fuyu Sanyou Gemstone Machinery Factory in Wuzhou City, Guangxi.

Wuzhou’s artificial gemstone industry originated in the early 1980s. At that time, the artificial gemstone processing machinery, such as gemstone cutting machines, shaping machines, grinding machines (angle machines), etc., were all imported products. As the artificial gemstone industry further developed in Wuzhou, various types of artificial gemstone processing machinery were gradually localized, and technology was continuously improved. By the end of the 1990s, almost all machinery had been localized. The price of local machines is about 25% of that of imported machines, which has greatly promoted the development of Wuzhou's artificial gemstone industry.

Wuzhou artificial gemstone processing machinery is mainly used for processing faceted gemstones, and machine improvements are also made around the faceted gemstone processing technology. The improvement work can be roughly divided into the localization stage, transformation stage and creation stage according to the process. The localization stage started in the early 1980s and was basically completed in the late 1990s; it entered the mechanical and process transformation stage in the mid-to-late 1990s; after 2000, machinery and equipment entered an era of both creation and transformation. Typical examples of improvements include the following.

Figure 1 Single-knife stone cutting machine

1. Improvement of stone cutting machine

Stone cutting machine is also called a cutting machine and a cutting machine. Initially, it was a single-blade machine that held the gemstone by hand and moved it to the saw blade for cutting. It had shortcomings such as inaccurate cutting position (inconsistent slices), dangerous operation, and low efficiency (only one piece could be cut at a time) (Figure 1); later A gemstone feeding platform was added, and the accuracy of the stone cutting position was greatly improved, and the thickness and width of the slices and strips were unified; after 2000, it was transformed into positioning and multi-knife cutting, which can not only control the cutting position, but also cut several pieces at a time, improving efficiency. It is 5 to 6 times faster, and the shape, size, and thickness of the cut blanks are uniform, laying the foundation for mechanized and industrialized processing of gemstones (Figure 2).

Figure 2 Multi-knife stone cutting machine

2. Improvement of the ring-shaped machine

The ring-shaped machine is also called a ring-shaped stone machine and a universal shaping machine. Initially, the enclosing machine could only enclose flat or convex stone blanks, and was limited to a few varieties such as synthetic cubic zirconia, synthetic ruby ??and sapphire. Stones such as peridot would break. After improvement, it can not only encircle flat and convex stone slabs, but also concave and pit-shaped slabs; the speed of some encircling machines can be flexibly adjusted after improvement, and the high-speed block can be used to enclose gemstones with high hardness, such as olivine, garnet, etc. Gemstones that are easily broken use low speed, and the adaptability is greatly expanded.

3. Improvements in stone grinding machines

Stone grinding machines have undergone the most improvements, not only transforming them, but also creating many new models and parts.

1. Automatic faceting machine

In the past, gemstone facets were polished manually, but now machines have been created to automatically grind and polish facets (Figure 3), but some varieties The polishing effect is not ideal and the polishing process needs to be improved. Some manufacturers adopt the "machine + manual" method, that is, using machines to automatically grind facets and manually polish facets. One machine is equipped with 4 people for polishing, and the efficiency is 4 times that of the original. Moreover, the facets of the products are neat, consistent in size, and smooth. It is also ideal to reach AA and AAA levels.

Figure 3 Automatic gemstone faceting machine

2. Mechanical octagonal machine

Traditional gemstone engraving and grinding machines are basically divided into two categories, mechanical and octagonal. cell phone. The advantage of the manipulator (manual operation) is high accuracy, but the disadvantage is low efficiency and high cost; the advantage of the octagonal hand is high efficiency and low cost, but the disadvantage is low accuracy and fast replacement of spare parts. The mechanical octagonal hand created now combines the advantages of both and avoids their respective shortcomings. The product quality and processing efficiency have been greatly improved, and it is especially suitable for application in professional round product processing plants. The mechanical octagonal hand is designed for professional processing of a single product. Different handles are required for processing different shapes. This is the disadvantage of the mechanical octagonal hand. Therefore, the mechanical octagonal hand is only used in professional factories and cannot be popularized. At present, most factories that process "Eight Arrows and Eight Hearts" gemstones use mechanical octagonal hands (Figure 4).

3. Three-plate lifting table

The lifting base of an ordinary octagonal machine has only one platform. When processing gemstones, three grades of medium, high and low are generally required, so the lifting table should be used when using it. Moving the platform up and down has disadvantages such as low efficiency and low accuracy; now it is transformed into a lifting seat with three platforms. When processing gems, there is no need to move the platform up or down. It can be used according to the grade. This has improved Efficiency also improves accuracy (Figure 5).

Figure 4 Mechanical octagonal hand

Figure 5 Three-plate lifting platform

4. Turning stone docking device

Traditional stone sticking and turning The stones are glued flat and straight by hand. After grinding the countertop, you have to turn over the stone to grind the bottom. This is called a turning stone. When turning the stone, you must first take off the gem, then transfer it to the other end and then glue it on. It is required to be glued flat. If you are not skilled in the craftsmanship, it will often be glued crookedly, resulting in defects such as shovel edges and crooked tips. It is not suitable for mass production. Now a kind of docking device has been created. When turning over a stone, first stick the gem on another sticky rod, and then separate it from the original sticky rod. This avoids the defect of turning over unevenly, and to a large extent avoids shoveling edges and crooked edges. The occurrence of defects such as sharp edges.

5. Stone slab grinder

In the processing of stone slabs, there will inevitably be some slabs with uneven end faces (one or both ends are uneven), which generally occupy 10% ~ 20% range (multi-knife cutting and processing of stone blanks is less). Most of the stone blanks of natural gemstones are uneven. Traditionally, there is no good way to solve this problem during processing. We can only make do with sticking the gemstones to sticky rods and then carefully straightening them. When processing natural gemstones, you can take time to slowly straighten them, but the efficiency is very low; when processing artificial gemstones, high efficiency and large quantities are required, and there is no time to slowly straighten them, so misalignment often occurs, resulting in products with crooked tips and scraped edges. , waistline is thick on one side and thin on the other, and other defects appear. It is easy to solve the problem of uneven stone slabs by using a stone slab smoother (flat-end device): put the slab on the clamp to hold it firmly, and use a surface press to flatten the slab. There is no need to use glue or glue. The rod can be used both for pressing stone blanks and for polishing countertops. Therefore, the stone flat-end device (smoothing device) is also called a glueless surface press (Figures 6 and 7).

Picture 6 Glue-free dough press

Picture 7 Glue-free dough press

6. Glue-free rod

Adhesive rods are commonly known as iron rods, and adhesive-free rods are also called glueless iron rods in the market (Figure 8). The traditional method of grinding stone is to first glue the stone blank to an iron rod and straighten it, then press the table, grind it, smooth it, and polish it. Then take off the gemstone, turn around and stick it on the iron rod for grinding and polishing. end. There are two difficulties in the processing process: first, it is difficult to stick the stone slabs straight and straight, especially uneven stone slabs, which tend to stick crookedly; secondly, it is difficult to turn the stones flat and straight when turning them over. Difficult, the waistline is often unbalanced (the waistline is not perpendicular to the iron rod). Both situations will cause defects such as crooked tips, shovel edges, and waistlines that are thick on one side and thin on the other.

Figure 8 Glueless rod and its clamping mouth

Using glueless iron rods almost solves all of these problems. The operation method is: use the clamping nozzle to clamp the stone blank, and then tighten it with screws (no clamping distortion will occur), then press the table, polish the surface, smooth the surface, and smooth the table. After polishing the table, remove the gem from the clamping mouth. Push the middle to the other end, leave the processed crown inside the clamp, the thickness of the waistline is just right, and the pavilion is exposed to the outside for processing, then polish the bottom and smooth the bottom. There is no problem of waistline imbalance when grinding. The only disadvantage of glueless iron bars is that the clamping mouth of one specification can only process one specification of stone blanks. When processing another specification of stone blanks, the clamping mouth must be changed. This does not pose any problem for professional manufacturers with a single specification. About 80% of the defective products produced by traditional craftsmanship are caused by sticking stones and uneven turning of stones, which cause defects such as shovel edges, crooked tips, thick edges and thin edges. Using glue-free iron bars can completely avoid the occurrence of such defects. , which is a big leap.

The above examples are some typical examples of the improvement of machinery and equipment in the artificial gemstone industry. There are also many process improvements that are not listed here.

In short, the improvement of gemstone machinery has played a great role in the development of the artificial gemstone industry, but these results are all the result of successful individual research or research by private enterprises. Researchers are unwilling to transfer the technology Promoted throughout the industry, technical exchanges are not active in the artificial gemstone industry.

If the research work is supported by the government, such as the establishment of a science and technology project, and some project funds can be applied for, the technology developed through the establishment of the research will naturally be promoted and used in the entire industry, which will play a greater role in the development of Wuzhou's artificial gemstone economy. promotion effect. For example, due to the uneven length of the octagonal hand, the uneven length of the iron rod, and the very messy shape of the processed gemstones, products are uneven and returns from jewelry factories often occur. It can be seen that it is necessary to unify its standards in order to improve the product quality of the entire industry, but no one has yet done research in this area. The current problem is often that companies with financial strength do not conduct research, and people with research capabilities do not have the financial strength to conduct research. It is recommended that the science and technology system focus on supporting the technological development of the artificial gemstone industry.