Application of milling machine in pavement marking construction

I. Introduction:

Road traffic markings are the lifeline of the majority of motorists, but traffic accidents caused by unclear markings and unrecognizable signs are not uncommon. After 3.15, the Ministry of Transport deployed a one-year special treatment for quality control of highway markings in the whole industry, and carried out investigation and control from the entrance of the marking products, engineering design, construction, acceptance, and maintenance to build traffic safety. Firewall". Under this background, the setting of many provincial highway marking lines in various cities and towns is still exposed to serious safety hazards. This is not only the neglect of government and industry supervision, but also the indifference to the safety of life and property of motorists.

Road traffic markings are an important line of defense for driving safety. It is not an exaggeration to pay attention to. Ignoring the quality of road markings is not responsible for the safety of the general public and is also a disregard for the safety of the people. The competent authorities directly face the problem, conduct a comprehensive and systematic investigation of the safety hazards of the road markings in the country, conduct a comprehensive inspection of the quality and safety of the highway traffic markings under construction, and make the road traffic markings truly a solid line of defense for the safety of people's lives and property.

This matter is imperative!

It is imperative to carry out comprehensive inspection of the quality and safety of highway traffic markings under construction.

Second, the construction case:

In many areas of northern China, there is a large amount of snowfall in winter, which will destroy the original markings of the road during the snow removal operation. The milling machine can be used to mill a certain depth of the pit, and then the marking material is filled into the pit. After the construction, the marking line is not higher than the road surface, so that the marking can be protected from damage.

The technical requirements for milling the pits using a milling machine are as follows: first, the flatness requirement is high, and the lateral and longitudinal flatness should be less than 2 mm, because the depth of the pit is relatively shallow, at 3-5 mm, If the flatness is not good, there will be a case where the protruding part is higher than the marking line; the second is that the precision of the milling depth is high, the pit depth is too deep, the amount of the marking material is increased, and if the shallow is too small, the quality of the marking line is affected; It is the requirement that the straightness of the pit is high. It is obvious that the straightness of the pit affects the straightness of the marking. The fourth is that the construction efficiency is high, and it is required to complete the construction as soon as possible and open the traffic.

In the construction of a highway expressway in Jilin Province, in order to better meet the construction requirements, we used a XCMG XM503 milling machine with a special milling drum with a knife spacing of 6×2mm and a milling width of 220mm. The effect is good and the construction efficiency is high, which has been unanimously recognized by the owner and the construction party.

Figure 1 Xugong XM503 milling machine for marking line construction

Figure 2 Milling drum with a knife spacing of 6 × 2 mm and a milling width of 220 mm

Figure 3 pit groove milling effect

Third, the milling flatness analysis:

The milling cutter spacing refers to the distance between adjacent milling trace lines. The cross-section of the milled pavement is theoretically jagged, the larger the knife spacing, the greater the difference in height between the high and low points of the serration, and the rougher the road surface. As shown in Figure 4. Conversely, the smaller the knife pitch, the smaller the height difference of the saw teeth and the finer the road surface. We generally say that the milling drum with a knife spacing of 12-15mm becomes a standard milling drum. The milling drum with a knife spacing of ≤8mm becomes a fine milling drum. The milling drum with a knife spacing of more than 20mm becomes an economical milling drum. These three types of milling drums are suitable for different working conditions. For marking milling, what we need is a fine milling drum.

Figure 4 Cross section of the milled road surface

Since the tool is discretely distributed on the milling drum, the longitudinal section of the milled surface is not theoretically completely flat. As shown in Figure 5. The degree of unevenness is related to several factors: the milling machine operating speed, the milling drum speed, and the number of teeth on the same milling trace. The milling drum speed is determined by the engine output speed and gear ratio, which is generally a relatively fixed value. The faster the milling machine works, the more uneven the longitudinal section, and the slower the working speed, the flatter the longitudinal section. The number of teeth on the same milling trace line is generally only one for the standard milling drum, and the fine milling drum can have two, namely one-line single-tooth and one-line double-tooth. Each rotation of the one-line double-tooth milling drum has two knives involved in the milling, so the longitudinal flatness is higher.

Figure 5 : Longitudinal section of a milled road surface

We use a 6×2mm milling drum with a knife spacing in the construction, that is, the distance between adjacent trajectories is 6mm, and the first line is double-toothed. Through theoretical analysis, it can be concluded that the theoretical height difference of the horizontal milling texture is 1.7mm; when the milling speed is 10m/min, the theoretical height difference of the longitudinal milling texture is 0.9mm, both less than 2mm, meeting the construction requirements. As shown in Figure 6-7. In order to carry out sufficient verification, we have tested a milling drum with a knife spacing of 3 mm. Although the lateral milling problem is more elaborate, in order to achieve the same longitudinal flatness, the milling machine's working speed will be limited, a comprehensive comparison The arrangement of the knife pitch of 6×2mm is better.

Figure 6 Height difference of the horizontal milling texture

Figure 7 : Height difference of longitudinal milled texture  

Fourth, product introduction:

The XM503 is a high performance, versatile half-meter milling machine. With a higher power reserve, hydraulically driven milling drums, three-wheeled travel system, can be equipped with small feeders. In addition, XCMG's small milling machine includes two other models: the industry's smallest XM353, and the XM503K, which is equipped with a four-wheel drive and can be equipped with a long conveyor belt. As shown below.

The above are XM353 milling machine, XM503 milling machine and XM503K milling machine

These three models can be widely used in the maintenance of small-scale roads such as municipalities and residential quarters. They can be combined as auxiliary machines for large-scale milling machines, and can be milled around the manhole cover by installing specific tools. Can perform other special working conditions.

Xugong's small milling machine has the following features, which makes it easy to complete the marking and slot milling:

(1) Power is strong. The engine with a larger power reserve is used for high efficiency.

(2) Maneuverable and flexible. Thanks to the compact size of the machine and the ultra-small milling radius, it is suitable for milling in the city and in various narrow areas, and can be milled around the manhole cover.

(3) Easy to operate. The ergonomically designed console has a reasonable layout and a good view.

(4) Various functions. Long sound wheel can be installed for rough belt milling; special milling wheel can be installed to grind pits and grooves; hydraulic shovel can be connected for partial crushing.

V. Conclusion:

The method of milling and grooving is used to solve the problem of broken marking, which is especially suitable for promotion in many regions of China. This method requires a high level of milling operations, requiring proper equipment, specific configurations, and proper construction methods. Xugong's small milling machine has excellent working performance and can meet the quality requirements of marking milling. It is a good choice.

Attached: main performance parameters of Xugong small milling machine

Xugong small milling machine main performance parameters

(This article comes from Xu Hongwei, Xie Xiaobing, Yang Junqing, Xugong Road Machinery Division)