1. Basic introduction
Laser screed machine is developed according to the increasing demands for ground quality such as strength, smoothness and levelness of modern industrial buildings, large shopping malls, warehouses and other large area cement concrete floors. The surface quality of cement concrete paved by precise laser screed machine is much better than that by conventional method – the surface smoothness and levelness increase more than three times, and the compactness and strength increase by more than 20%. At the same time, it can improve work efficiency by more than 50% and save about 35% of the labor. In addition, it can easily lay high-strength concrete, low slump concrete and fiber clay. The laser system is equipped with a variety of automatic control components, which can monitor the leveling head’s elevation at 10 times per second in real time to ensure the surface smoothness and levelness in an effective way. At the same time, the vibration frequency of its strong vibrator reaches 4000 times per minute, which ensures the compactness of concrete vibration and makes the whole concrete base homogeneous and compact.
The laser transmitter generates a rotating laser, and the laser receiver on the laser screed machine receives the signal, which is analyzed by the laser measurement and control system. The deviation will be fed back to the sensitive computer control system on the laser leveller. The left and right linear actuators will adjust the height of the scraper to ensure the leveling accuracy.
Laser screed machine is used to take the high concrete away with scraper and scrape it preliminarily to meet the design requirements of the elevation. Hydraulic drive vibration motor produces vibration, driving the whole vibration plate together to vibrate the concrete,4000 times per minute. Laser paver levels the ground without need to pull control lines, nor does it need side templates to control the ground elevation. The laser measurement and control system on the laser screed machine can control the ground elevation in real time. As long as the laser transmitter is not disturbed,it can ensure that the overall elevation of the paved ground is not affected no matter where the laser screed machine moves.
(1) The leveling principle of laser screed machine is realized by using precise laser technology, closed-loop control technology and highly precise hydraulic system under the automatic control of computer, which is the most prominent feature of the machine different from other floor construction technology.
(2) The leveling principle of precision laser screed machine is that the leveling head driven by hydraulic force is combined with the laser system and computer control system to complete the leveling work at the same time of automatic leveling. The leveling head is equipped with an integrated design of scraper, vibrator and flat plate, which integrates all leveling, leveling, vibration and compaction work and completes it at one time. The computer control system automatically adjusts the elevation 10 times per second, and the vibration frequency of the balanced vibrator reaches 3000 times per minute.
(3) The laser transmitter used to control the ground elevation is arranged independently, so that the ground elevation is not controlled by the template, and there are no cumulative errors.
(4) Laser screed machine can also automatically control the longitudinal and transverse gradient, which is also accomplished by laser system, computer system, hydraulic system and mechanical system. Three-dimensional special-shaped ground processing system can also be selected for complex ground with high requirement of drainage.
4. Application scope
With the development of laser technology and electronic technology and the higher requirement of modern industrial floor, laser paver has been used in the construction of concrete floor since 1980’s in the international engineering field, which realizes the precise leveling automation of concrete floor.
a). Indoor floor
(1) Underground garage, general industrial workshop, workshop and automated three-dimensional warehouse;
(2) Clean workshops for electronics, electrical appliances, food materials and pharmaceuticals;
(3) Large warehousing supermarkets, logistics centers, Convention and Exhibition centers, etc.
b). Outdoor floor
(1) Wharf, container yard and cargo yard;
(2) Airport runway, apron and parking lot;
(3) Plaza, residential ground, municipal road surface, etc.