Brief introduction of the first author: Liu Fuyu, member of the third artificial products professional committee of China Bao Association, and director of Fuyu Sanyou Gem Machinery Factory in Wuzhou, Guangxi.

Wuzhou man-made products industry originated in the early 1980s. At that time, the processing machinery of artificial products, such as gem cutting machine, forming machine and grinder (angle grinder), were all imported products. With the further development of Wuzhou artificial products industry, all kinds of artificial products processing machinery are gradually localized and the technology is constantly improved. By the end of 1990s, almost all machines had been localized. The price of local machinery is about 25% of that of imported machinery, which greatly promotes the development of Wuzhou man-made products industry.

Wuzhou artificial products processing machinery is mainly faceted gem processing machinery, and the machine improvement is also mainly faceted gem processing technology. The improvement work can be roughly divided into localization stage, transformation stage and creation stage according to the process. The localization stage began in the early 1980s and was basically completed in the late 1990s. In the middle and late 1990s, it entered the stage of mechanical technical transformation. After 2000, mechanical equipment entered the era of creation and transformation. Typical examples of improvement are as follows.

Figure 1 single-knife stone knife

First, the improvement of stone knives.

Stone cutting machine is also called cutting machine and cutting machine. At first, it was a single-blade machine, which moved the gemstone to the saw blade by hand, which had some shortcomings, such as inaccurate cutting position (different slicing), dangerous operation and low efficiency (only one piece can be cut at a time) (Figure 1). Later, a gem feeding platform was added, which improved the accuracy of stone cutting position and unified the thickness and width of slicing and cutting. After 2000, it was transformed into positioning multi-knife cutting, which not only can control the cutting position, but also can cut several pieces at a time. The efficiency was improved by 5 ~ 6 times, and the shape, size and thickness of the cut blank were unified, which laid the foundation for the mechanized and industrialized processing of gemstones (Figure 2).

Fig. 2 Multi-knife stone cutting machine

Second, the improvement of wrapping machine.

Surrounding machine is also called stone circle machine and universal forming machine. At first, the spheronization machine can only wrap flat or convex stone blanks, and only synthetic cubic zirconia, synthetic ruby, sapphire, olivine and other stones will be broken. After improvement, it can not only surround the flat convex stone blank, but also surround the concave and pit stone blank. After improvement, the rotating speed of some profilers can be adjusted flexibly, and high-speed gears can be used for high-hardness gems, and low-speed gears can be used for fragile gems such as olivine and garnet, which greatly expands the adaptability.

Third, the improvement of stone mill.

The improvement of stone mill is the most, not only the transformation, but also the creation of many new models and parts.

1. automatic facet machine

In the past, gemstone facets were all polished by hand, but now they have been automatically polished by machine (Figure 3), but the polishing effect of some varieties is not ideal, and the polishing process needs to be improved. Some manufacturers adopt the method of "machine+labor", that is, the machine automatically polishes the facets and manually polishes them. One machine is equipped with four people to polish, which is four times as efficient as before. Moreover, the product has neat facets, uniform size and ideal finish, reaching AA and AAA levels.

Fig. 3 Automatic Gem Faceting Machine

2. Mechanical octagonal machine

Traditional gem carving and grinding machines are basically divided into two categories, mechanical mobile phones and octagonal mobile phones. The advantage of manipulator (manual operation) is high precision, but the disadvantage is low efficiency and high cost; The advantages of octagonal hand are high efficiency and low cost, while the disadvantages are low precision and quick replacement of spare parts. The mechanical octagonal hand created now combines the advantages of both, avoids their own shortcomings, and greatly improves the product quality and processing efficiency, especially suitable for professional round product processing plants. The mechanical octagonal hand is designed for the professional processing of a single product, and different handles are needed to process different shapes. This is the short board of the mechanical octagonal hand, so 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" gems use mechanical octagonal hands (Figure 4).

3. Three-plate lifting platform

There is only one platform for the lifting seat of the common octagonal machine, but it generally needs three grades of middle, high and low when processing gems, and it is inefficient and inaccurate to move the platform up and down when using it. Now it is transformed into a lifting chair with three platforms. When processing gems, it is not necessary to move the platform up and down, and it can be used according to the grade, which not only improves the efficiency but also improves the accuracy (Figure 5).

Figure 4 Mechanical octagonal hand

Fig. 5 Three-plate lifting platform

4. Turn over the docking device

Traditional sticking stones and turning stones are all glued flat and straight by hand. After grinding the countertop, you have to turn over the gems to grind the bottom. This is turning over a stone. When turning a stone, you should take off the gem first, and then stick it on the other end. Ask for leveling. If the technology is not skilled, it will often stick crooked, resulting in defects such as shovel edge and sharp crooked, which is not suitable for mass production. Now, the docking equipment has been created. When turning stone, the gem is first glued to another stick, and then separated from the original stick, which largely avoids the defects of uneven turning stone and the occurrence of defects such as shovel edge and crooked tip.

5. Stone blank polishing machine

In the process of processing stone blanks, it is inevitable that some stone blanks with uneven end faces (one end or both ends are uneven) will appear, which generally accounts for 10% ~ 20% (multi-cutting is rare). Most of the stone blanks of natural gemstones are uneven. Traditionally, there is no good way to solve this problem when processing, so we can only stick the gem on a stick and then straighten it carefully. When processing natural gemstones, it can be straightened slowly, but the efficiency is very low; When processing artificial products, high efficiency and large quantity are required, and there is no time to straighten them slowly, so improper fitting often occurs, resulting in defects such as sharp tilt, edge collapse, thick waist line and thin waist line. It is easy to solve the problem of uneven stone blank by using the stone blank grinding device (flat end device): put the stone blank on the fixture and clamp it firmly, and flatten it with the surface pressing device, which can be used to press the stone blank and polish the table top without using adhesive or rod. Therefore, the stone blank flattening device (flattening device) is also called non-adhesive dough pressing device (Figures 6 and 7).

Fig. 6 Glueless dough press

Fig. 7 Jaws of Non-sticky Dough Press

6. No glue stick

Sticky bars are commonly known as iron bars, and non-stick bars are also known as non-stick iron bars in the market (Figure 8). The traditional method of grinding stone is to stick the stone blank with an iron bar and straighten it, then press the table, grind the surface, smooth the table, then take off the gem, turn around and stick the iron bar to polish the bottom. There are two difficulties in processing: first, it is difficult to stick the stone blank straight, especially the uneven stone blank, and there are many cases of sticking it crooked; Second, it is difficult to turn the stone flat and straight, and the waist line is often unbalanced (the waist line is not perpendicular to the iron bar). Both of these situations will cause defects such as sharp tilt, shovel edge and thin waist line.

Fig. 8 Non-stick and its nip

These problems are almost completely solved by using glue-free iron bars. The operation method is as follows: clamp the stone blank with the clamp, then fasten it with screws (there will be no clamping deviation), then press the table top, grind the surface, smooth the surface and smooth the table top. After grinding the table top, push the gem from the middle of the clamp to the other end, leave the processed crown in the clamp, and the waist line is just right. Expose the pavilion to the outside for processing, and then grind the bottom and smooth the bottom. There is no problem of unbalanced waist line when grinding the bottom. The only disadvantage of non-stick iron bars is that one specification of clamping mouth can only process one specification of stone blank, and it is no problem for professional manufacturers to process another specification of stone blank by changing clamping mouth. About 80% of the defective products produced by traditional technology are caused by sticking stones and uneven turning stones, such as scraping edges, crooked tips, thick edges and thin edges. These defects can be completely avoided by using glue-free iron bars, which is a great leap.

The above examples are some typical examples of the improvement of machinery and equipment in the artificial products industry, and there are many technical improvements, which are not listed here.

In a word, the improvement of gem machinery has played a great role in the development of man-made products industry, but these achievements are all successfully studied by individuals or private enterprises. Researchers are reluctant to promote this technology in the whole industry, and the technical exchange in the artificial products industry is not active. If the research work is supported by the government, such as the establishment of scientific and technological projects, you can apply for some project funds, and the technology developed through the establishment of projects can naturally be popularized and used in the whole industry, which will play a greater role in promoting the economic development of Wuzhou artificial products. For example, because the length of octagonal hand is not uniform, the length of iron bar is not uniform, and the processed gems are in a mess, resulting in uneven products, and jewelry factories return goods from time to time. It can be seen that it is necessary to unify the standards in order to improve the product quality of the whole industry, but no one has done this research work yet. The problem now is often that enterprises with economic strength do not do research, and people with research ability do not have the economic strength to do research. It is suggested that the science and technology system should focus on supporting the technological development of the artificial products industry.