“ZEISS”, the Choice by a Hidden Champion of Hydraulic Valve Block Industry

An interview with Chen Zhengwei, General Manager of Wuxi Maytag Machinery Co. Ltd

Wuxi, as one of the central cities in China‘s Yangtze River Delta, the core city of China‘s manufacturing industry, as well as the leading area of advanced manufacturing industry, has experienced rapid development in recent years, witnessing the explosion of emerging superior manufacturing enterprises and quite a few specialized and well-organized hidden champions.

“The company enjoys annual sales revenue of 30 million RMB and 1 million RMB per capita output and sustains the unique leadership in processing technology and quality assurance of hydraulic valve block parts. We follow the Amoeba management model while promoting the implementation of intelligent manufacturing to actual production process, with the reputation as an innovative technology enterprise and a private sci-tech company with Grade II intelligence maturity...” introduced by Chen Zhengwei, General Manager of Wuxi Maytag Machinery Co. Ltd.

He attributed these data and honors to highly advanced production capacity manifested by potent software and hardware, high level of interconnection and intelligence of workshops. All these advantages have consolidated Maytag, the company he founded, as a leading manufacturer in Wuxi. However, the company also encountered some difficulties in production, namely, how to better convince their users of product quality, how to organize the machining workshop with a more scientific flow, and how to integrate digital management into the internal system effectively...

Since the founding of company, Maytag has supplied the market with large size and high-quality hydraulic cartridge valve blocks. Chen Zhengwei noted that “Our company has accumulated many years of experience in the processing of cartridge valve and deep oil passage hole of hydraulic valve block, and is equipped with various kinds of cartridge valve cutters. All of our valve blocks are manufactured in the machining center, which not only ensures the product quality, but also ensures the high efficiency of processing and the consistency of batch products.”

When walking into the seemingly compact production area of Maytag, we found a total of 17 machining centers in the three production lines are carrying out their respective processing tasks in an orderly manner, involving the processing of small valve blocks (below 30 kg), large valve blocks (above 30 kg), as well as precision parts.

„Our workshop operates 24 hours a day. In general, equipment debugging and product switching are performed during day-shift, while each staff is responsible for a production line at night-shift.“ As manager Chen commented, this schedule is much more economical than previous one in which each member of the staff is assigned to one machine. „Increasing staff also indicates higher management costs.“

“Good” Product Worthy
Higher Prices

As known, Maytag is mainly specialized in the field of wind power generation, devoting itself to the processing of supporting valve block parts, „Currently in China we are at a leading position in this field, in which the market share of valve blocks is also the highest.“ When manager Chen thinks about how to improve the automation, overall efficiency and quality of processing, he also follows “one piece flow” method advocated by lean production, with the purpose of minimizing the semi-finished products in the production process, thereby obtaining precise process steps and clearer procedures.

Many holes can be seen in valve block parts. Several peer enterprises adopt a combination of radial drills and vertical machining centers for production, which is much more likely to result in fewer parts and missing parts during the production process. What’s more, it takes at least half a month to produce from raw materials to finished products. „However, we can perform the whole process with only one machining center, and each program-controlled step will undoubtedly prevent the above-mentioned problems. Meanwhile, we also take the obvious advantage of time - the parts are clamped to the machining center in the morning and can be processed as finished products in the afternoon.”

The overall improvement of measure methods is essential to realize such modern production. In the past the measurement of valve block parts in Maytag was mainly performed by inspectors and domestic measurement equipment, concerning the measurements of depth, position and dimensional precision. „It usually takes at least one day for the inspectors to carry out one-by-one measurement of a product with 1000 sizes. In addition, the measurement duration will be much longer in case of some unfavorable factors during the process.

In this situation the machine tool is also required to keep the standby mode for one day or more days to perform further processing until the completion of size confirmation. „Therefore, while planning the layout of the intelligent workshop, manager Chen also takes a proactive step in looking for advanced measurement machine. Finally, ZEISS CONTURA 776 was initiated in the factory in 2018. The rotating probe equipped with user-friendly software is easy for inspectors to operate.

„The good products are worthy higher prices, which should be easy to use.“ Talking about the reasons for choosing ZEISS, manager Chen presented with a smile, „There are only two types of coordinate measurement machine on the market, namely ZEISS and other brands, so we chose ZEISS.“ As manager Chen states, the relatively expensive ZEISS machine is a treasure. „As far as I’m concerned, the cheap price is not a point I will focus on while purchasing something, as cheapness will also bring costs and expenses.“

Before purchasing ZEISS machine, manager Chen also consulted several inspectors, „They all agreed that ZEISS is definitely the best, therefore ZEISS is the best and most correct choice for our company.“ He insisted on minimizing the cost of „trial and error“ upon choosing, „the cost of trial and error is often the highest.“

Development in Wind Energy Requires High Product Quality

At the same time, ZEISS machine has also brought many potential orders to Maytag, a small enterprise. “When many people know that we are using ZEISS machine for measurement, they think that we are not only competitive, but also value quality. With the first impression on emphasis of quality, they are willing to deal with their orders with our company”,- Manager Chen presented to us.

In particular, while producing samples for customers, we must ensure that the measurement data of parts is accurate to ensure the reliability of finished parts delivered to customers. „If there are problems with the measurement data in our company, how can we assure the quality of parts? Therefore, after purchasing the ZEISS coordinate measuring machine more customers are willing to put their new products in our factory for producing samples.

„In 2020 many enterprises were affected by the COVID-19, with shrinkage of orders and stagnancy of business. However, the wind power industry has benefited from the development of clean energy, thus achieving a contrary growth. Manager Chen commented that traditional energy sources have their respective weaknesses, such as nuclear power (negative effects to the ecological environment), thermal power (high pollution to the environment) and hydroelectric power (negative effects to the ecological environment), so they are no longer suitable for large-scale application. It’s generally acknowledged that one of the cleanest energy sources is solar energy and the other one is wind energy.

Development in Wind Energy Requires High Product Quality

Since wind energy equipment is installed at a relatively high altitude, once the parts arise some problems, both danger and expensive maintenance cost will come out. „Therefore, the product quality is of particular significance in this field.“ At present, 70% of Maytag‘s business comes from wind power. Manager Chen adopts a clear strategy that the enterprise shall focus on a certain subdivision with the goal of becoming larger and stronger.

„With the increase of orders this year, it’s evident that the measurement capability is required to be further improved, so we have purchased an additional ZEISS CONTURA 10126 without hesitation. We hope that more equipment can bring more production capacity to make good reserves for future development.“ Manager Chen commented with a smile that waiting in line was necessary for previous measurements, while parallel measurements can be realized at present.

ZEISS CONTURA 776 can achieve multi-angle measurement with rotating probe, while CONTURA 10126 can also perform automatic replacement of multiple probes to achieve various measurements with larger strokes. With the measurement precision of 1.7 μm, it’s sufficient for Maytag to deal with various measurement requirements easily. „Actually, the ZEISS machines are easy-to-use. First, the software generates convenience and improves speed; second, some functions are more convenient with faster operation compared with other similar measuring equipment.“

The inspection engineer of Maytag still remembered that programming could only be initiated until the parts were sent to the measurement rooms, which took much time and energy to perform measurements while waiting for parts. Currently, by importing the 3D model of parts to create the program in advance the parts can be directly used for computer operating after being sent to the measurement room, which is free of manual work and improves efficiency.

In addition, ZEISS supporting software enjoys full-featured functions, compared with our previous measurement equipment, which consists of a series of single incoherent operation, for example, each hole had to be collected one by one, while using ZEISS CALYPSO to collect one hole, hole arrays can be realized, with 10 or 20 holes becoming available. Whether it is a circular array, a 1D array or a 2D array, horizontal or vertical, ZEISS measurement machines are applicable.

Furthermore, it should be noted that ZEISS also takes meticulous consideration into operational ease. For example, the function of format painter is very easy-to-use. Another very important point is that „In the past, when domestic measurement machines were applied, users sometimes made arguments with us about the accuracy of measurement data. Now since we use ZEISS machines such problems no longer appear. As evidenced by this situation, ZEISS is highly recognized in terms of quality within the industry“,- Manager Chen added.

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