Current Situation and Development on Production of Milky Glass Tableware

——a lever for prying a new round of development of the Chinese container glass product industry

Abstract: performance features of the milky glass tableware are profoundly elaborated, and huge potential of the milky glass tableware products is pointed out. In terms of market, investment and key forming technique, the production situation of the Chinese milky glass tableware is analyzed, the experience in utilizing mass production management is coming up with, and a new round of development of the traditional container glass product industry is brought by improving technical equipment and process technique.

 

 Key words: Milky Glass / Glass Strength and Thermal Shock Property / Glass Presser / Glass Centrifugal Formation / Glass Fire-polishing

 

 

1. Features of Milky Glass Tableware

 

The milky glass tableware has its unique performance features which are not fully and deeply understood, and such misunderstanding affects the development of the milky glass tableware products. Besides the features of high hardness, stable chemical performance, smooth surface and easy cleaning existing in the common glass products, the milky glass tableware also has two features: firstly, by micro-crystallizing the milky glass, strength and thermal shock property of the glass are improved, so that the common glass can be prepared into roasting tools and baking tools besides common containers, and pans made of the milky glass can challenge traditional pans made of steel and iron; and secondly, huge changing consciousness is brought to excellent forming manufacturability and surface decoration of glass along with the development of the modern forming technique equipment, which will change the dominance of ceramics in the kitchen field. The need of the tableware market is scores of times that of the glass bottle and glass cup market, the products which were organically made of ceramics are now made of glass, which means the production technique and the management ability have huge potential of making the tableware made of milky glass, and this is also an important opportunity for self-development of the glass industry.

 

2. Current Production Situation of Milky Glass Tableware

 

In the world, America, Japan, Italy and France have mastered the production technique of the milky glass, for example, Coning and Arc International are both glass giants and have large-scale production sites. In China, Wenzhou Huishunda was the first to massively produce the milky glass and has achieved great success. Its supply falls short of demand, so that the Wenzhou Huishunda becomes the leader of exporting glass products in China, and has gained a lot of profits. Since 2004 and 2005, investment boom was happened, Hubei Huimeida, Anhui Sanhele, Zhejiang Taizhou Chengtai, Jiangsu Aobo Crystal Ceramics, etc., with dozens of production lines, were built sooner or later and all became important support targets of the local governments. These investments all have a background of Wenzhou capital and belong to the new glass product industry. Only five production lines invested by Guangdong Raoping Huajie and Sanyuan are changed from daily use ceramics production lines. Only Anhui Deli Glassware Co., Ltd. in the glass industry invests in the milky glass industry. Anhui Deli Glassware Co., Ltd., one of domestic leading companies in the glass product industry, boasts its quite strong internal, foreign trade power, and largest domestic market share of glass products; and in 2006, it started to build the milky glass production lines, in the first half of 2008, the newly built production lines stopped after preliminary debugging, and the declared reason is that the market readiness was not done, and the investment decision was hastily made. Sanhele and Chengtai were inviting businessmen to cooperate in order to continue production. Huimeda and Aobo, which were relatively well operated, publicized that they will invest several hundreds of million Yuan to the milky glass industry, but their words are not met up to now. On one hand, that shows the original idea, that the investment is expanded and attracted by the output of the preliminary input, is wrong. The reasons of economic crisis and substantial shrinkage of export markets do exist, but the deeper reasons found from investment structure and product grade are not excluded. The Nanking factory of French Arc hires foreigners for all management and technology positions, the foreigners live in hotels other than dormitories, so that the its cost is quite high; at present it declares that it will invest several hundreds of million yuan to the milky glass tableware project. The Raoping production lines are the local model for the adjustment of the ceramic industry, and stepped out of the economic slowdown at the earliest. We analyze the newly inputted milky glass tableware projects, who can tell that process equipment, product indexes and management level of these projects are better than those of original projects? The newly built production lines have problems immediately after preliminary debugging, and are continuously adjusted by new equipment factories according to the original mode, so that by the production lines, high-grade products can’t be manufactured, the cost of low-grade products can’t be lowered, domestic markets aren’t opened, and the majority of production lines aren’t well operated. We sum up three main reasons: (a), the original factories have the capability of independent adjustment, and newly produced products can’t compare with original products; (b), the common faults of the Chinese glass equipment industry are that the technical input is low, the service consciousness is not high, and more attention is paid on orders but product quality; and (c), investors and managers don’t quite understand the features of the glass industry, and lack experience and capability on mass production of high-quality glass products.

 

3. Comparison and Development of Forming Process of Milky Glass

 

1. Comparison between original forming lines and currently inputted forming lines in China: the original forming lines all adopt the pressing process and use feeding machines to directly add materials dropwise, and main machine types are 12 to 16-station aerostatic presses, the stamping force is 1.5 to 2 tons for single cylinder and 4 to 5 tons for double-cylinder, and hydraulic presses have introduced to replace the double-cylinder aerostatic presses to manufacture large-size products and die-sinking products. A big disk of a press is driven by an imported cam wheel, products are taken out by an independent three-jaw manipulator, a mechanism, having functions of material feeding along with movement and fire polishing after pressing, is developed, mouths and surfaces of the products are processed by an intermittent rotary type fire polishing machine, the orienting function is possessed, the polishing is done by a polishing disk, and the shaping mechanism is equipped. Transmissions of products all adopt a non-relative friction mode. The majority of the newly inputted production lines use the aerostatic press, so that the early mode is still adopted. Some local adjustments are canceled due to design and manufacturing reasons, for example, the taking-out mode of using manipulator is changed into the press-attached horizontal taking-out mode which is commonly adopted by foreign prototype machines, and then the taking-out mode is returned to the three-jaw mode, but an electromagnetic valve and an air cylinder are easily damaged, and the maintenance cost is high. Some fire polishing machines are changed into a following rotary type, these fire polishing machines are high in efficiency, but the products are continuously transferred by shifting, so that the product quality is affected. From concerns about low cost, some production lines use a grooved pulley press which has big driving force, but the design and manufacturing level is not kept up with, so that the old road that the majority of domestic glass equipment is poor in stability and structure is returned.

 

2. New development of oversea glass product forming equipment: internationally famous glass product manufacturers have tried their best to promote the advanced forming process and the high-efficiency equipment by utilizing their historical experience in glass process technology, advancement on machinery and electrical appliances and advanced ideas on design and manufacturing, which makes it possible improve quality of milky glass tableware and simultaneously lower cost. Firstly, it is the centrifugal forming process, because the products have the advantages of smooth surface, raw material conservation and simple mould, and the continuous type high-precision centrifuge with a big rotary disk and multiple stations is developed, the problem on the production rate is solved, and the centrifuge is the best equipment for producing basins and dishes which are widely used in the milky glass tableware. But the oversea centrifuge is quite expensive, and has not been introduced by domestic factories up to now. In fact, in terms of mechanical structure, the centrifuge is not high in complexity, the reason for failed development in China lies in the understanding of technical features of glass and the mastering of high-precision and high-stability control technique; and secondly, it is the multi-cylinder multi-station pressing forming process, because the single-cylinder press is affected by glass forming time and mechanical inertia, the speed of the single-cylinder press is limited. The good way to increase the output is to develop the multi-cylinder press, which has the same principle as the use of the multi-group I.S. machine and the servo multi-drop material feeding machine in the glass bottle-making industry. The three-cylinder press and the forming line are mainly promoted overseas, the double-cylinder press is relatively mature in China, and the development of the three-cylinder forming line is feasible. 

 

3. Topic on the necessary development of the forming process of the milky glass tableware: (a) whether can the internationally updated forming technology be adopted? (b) the fire polishing treatment of elliptical disks and abnormally shaped tableware can improve quality and simultaneously lower energy consumption, which is a big breakthrough point; and (c) it is required to reduce the difference between the domestic glass forming equipment and oversea equipment as much as possible, build the true brand awareness, improve the requirements on design and manufacturing, and greatly improve the advancement and the stability of the mechanical structure.

 

The economic crisis brought by the world financial storm is caused by backward products and overcapacity in the final analysis. All walks of life are reviewing their conditions and try to find a solution. For example, the automobile industry in the world is taking the time to research and develop eco-friendly and energy-saving electric automobiles in order to get out of the trouble. Based on the plate glass in the glass industry, the coated glass with excellent thermal property, the solar photovoltaic glass with excellent light-passing property and so on are actively developed, and the development of the glass tableware products will make the container glass product industry with huge users and old traditions face a new round of development. 

 

Author’s excursus: the article, originally an analytic part of a project feasibility report for a large-scale glass bottle manufacturer, was issued in China’s Glass Network, the glass information-market research column, on September 30, 2009 at the earliest, and then was slightly adjusted and published in the sixth period of the China’s Glass Industry Information in 2009. Over the past six months, we found that many leaders of glass factories still didn’t know the article and try to get it. These glass factories are all major factories in the glass industry, some of them are manufacturing the milky glass tableware, so that it is necessary to republish the article in the China’s Glass Network.