Papers by Keyword: Drill

Abstract: The facade of the old school is registered in the list of cultural monuments and located in the conservation zone of the urban monument reservation. Due to the construction of a new building, it was necessary to reinforce and structurally support (by means of an anchored reinforced concrete wall) the south wing of the old section of the school. No fissures were allowed to develop because they could damage the valuable art nouveau facades. Therefore, great emphasis was given to the technological and structural design of the reinforced concrete gunite wall. Precise geodetic measurements confirmed that the decline of the south wing of the school of the gunite wall was minimum, specifically 1,5 mm, after the completion. No cracks appeared. The building won first place in the “Building of the South Moravian Region” competition in 2018 in the category of public utilities in the Czech Republic – see www.gero.cz.

Abstract: The author of the article considers the scientific approaches to increasing the longevity of high-loaded operating parts of small agricultural machines by forming the technological repair units when choosing the optimal methods of hardening the functional surfaces with anti-wear low-cost material.

Abstract: In order to deal with subway emergency, the paper builds the emergency drill system based on scenario analysis for the security of persons and property within the subway. By participating in the drill system, make sure that units and division involved in the rescue and command system learn their responsibilities by heart under emergency, enhancing collaboration of various departments, improving the efficiency of emergency rescue, thus the rescue can be conducted orderly. This paper introduces the concept of subway emergency, emergency management and organization and the drill system.

Abstract: To the problem that drills are easy to break off during working, apply micro-pool lubrication technology in the field of drill cutting. Drill a micro hole with a diameter of 70μm, a depth of 30μm and a space of 100μm on the oblique plane of the front-end blade of a common drill with HDM-50 semiconductor side pump YAG laser to form a micro-pool drill which constitutes a contrast group with a common drill. Lubricate both of the two kinds of drills with 2# micro high pressure lithium grease and use them to drill holes on a 25mm A3 plate. The experiment indicates that: when the depth of the processed holes are 5mm, the average powers of the micro-pool drill at the speeds of 600R/min, 850R/min and 1100R/min are 3.243% higher than those of the common drill; and the average power of the micro-pool drill is 4.547% lower than that of the common drill when the depth is 12mm; and the average power of the micro-pool drill is 4.09% lower than that of the common drill when the depth is 22mm.

Abstract: Accurate measurement for the flute curve of drill is essential to its design and the evaluation of cutting performance of drill. The helical flute curve of the drill has a big influence on the shape of the　main blade, the exhaust of the chip, and the supply of the coolant etc. In this paper the measuring method of flute curve is described. As the measuring method,　the lead, helical angle, normal section shape (flute curve) was measured respectively. Then the measured data are analyzed with digital filtering, smoothing etc., thus the normal section shape and cross-section shape data are gained. The measured data agree well with the known values. The proposed measuring method may be applied not only to the measurement of flute curve of the drill but also to the measurement of the other helical flute curves.

Abstract: The drilling of composite materials can produce, around the hole, defects and damages which decrease the mechanical resistance of the drilled workpiece. This study shows the influence of several tools (drill, mill and reamer) on the hole quality obtained, in the context of reference parts where surface integrity is a priority. An experimental study is suggested and the criteria used to assess the hole quality are defined. Results show the behavior of each type of cutting tool and their influence on the defects generated. Finally, this study helps creating a scale of recommended cutting conditions to reduce the tool wear and improve the hole quality.

Abstract: Detection of a tool fracture is necessary to ensure cutting accuracy and to avoid a tool breakage because tool fracture is one of the significant prediction signals of the tool breakage. For monitoring the tool condition, generally additional sensors are used. However using these sensors causes high cost and increase of failure rate. In this paper, a novel sensor-less detection method of tool fracture in drilling process is proposed on the basis of a disturbance observer theory. It is applied to the x-y stage of the machine tool. The proposed method requires no external sensor because it uses only the servo information of the spindle control system. Since structures of normal drills with two floats are symmetrical with respect to a point, theoretically the cutting force in the x and y directions does not work. When the drill is fractured, its structure becomes asymmetry so that unbalanced forces would exert in the x and y directions at intervals of the spindle speed. Therefore, it is possible to detect a tool fracture by the frequency analysis of estimated disturbance force with a wavelet transform. The experimental results show that the proposed method is available for detection of the small tool fracture effectively.

Abstract: This paper describes the process optimization of compressor cylinder block machining and supporting technology, which ensures the implementation of this optimization. This paper also provides detailed instructions about the design of quick change type semi automatic hydraulic jig and combination cutting tool of fine boring crankshaft hole. The practical experience evidenced that the process optimization is a good way to improve the product quality.

Abstract: Based on investigation and survey, the conformation and the distribution for underground goaf are gotten. The goaf can be completely filled by drilling holes and grouting with the mixture of sand and water, using masonry border to isolate and filtrate the filled space and unfilled space. The shaft fills with cement stabilized soil without settlement. The result shows that latent threats remove during expressway opening for 10 years and achieve expected technical feasibility, economy, and rationality.

Abstract: As drilling deep, large diameter, high drilling efficiency, adapting to a wide range of rocks, the down-the-hole drill is widely used currently as a large-scale rock drilling equipment. Integrated with the hydraulic rotary cutting pneumatic impacting drill and the down-the-hole hammer, the HZCLQ120 multifunctional hydraulic down-the-hole rock drilling rig was developed. The technical principle, main innovations, technical specification and test results were introduced. The new drilling rig can be widely used in rock blasting of railway, highway, water and electricity, mining, and urban construction.