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The cylinder material HT200 processed by this machine has a hardness of HB=170～241.
The machine is located at the end of the cylinder processing line consisting of 20 combined machine tools. It is divided into two stations: the first station is the top surface of the fine milling, and the process requirements are shown in Figure 1.
The machine is vertical, with German SFES sliding milling head and milling head motor P=15kW. When the milling head is working, the slide is moved to the end and held tight with the “Metron†platen. Using f315 American milling cutter, the cutter number is VMF85•19•315•34R-PD, the milling cutter with four polishing teeth rotates n=132r/min, the speed v=131m/min, Sr=0.14mm/r , SM = 594mm/min. The fixture realizes fast forward → work on the moving table. The movable table rail base adopts a welded structure, a steel guide rail, and a slide table.
After the milling process is completed, it is transported by the automatic raceway to the second station - fine. The process requirements for the fine boring process are shown in Figure 1. The layout of the tool is shown in Figure 2.
The processing method of this station is also vertical. There are two separate specially designed fine boring heads on the column. The structure is based on the similar prototype of Klaus. Each boring head completes the processing of three cylinder bores (the fixture is working on the move). Moved three times on the stage). The diameter of the main shaft of the hoe is f140, and the front bearing adopts C3182128, C226818 and air-tight structure. The front end of the spindle has a stop mechanism that controls the depth of the stop (see Figure 2). In the middle of the main shaft, the rod mechanism driven by the cylinder is cross-cut through the “rack slab†to complete the processing of f131D10 depth 10+0.06+0.01. Before the cross-cut, the hoe slide is moved to the front end and hung by the "Metron" platen. The moving table rails are also positioned with inlaid steel rails, three-station rails and cylinders.
Fig. 2 Tool layout diagram The machine tool fixture uses the plane formed by the four positioning points of the bottom plane of the cylinder block as the positioning reference. The positioning pin is fixed, the workpiece drops the pin, lifts the pin, and hydraulically clamps. The positioning surface has air gap detection and blowing. In addition to clamping the bottom surface, the milling fixture is also provided with auxiliary clamping on the upper part to avoid vibration during milling. In addition, there is a magnetic chip removal mechanism.
The rear end of the spindle is decelerated by a belt, and is driven by a narrow V-belt widely used internationally, which greatly increases the transmission efficiency of the transmission rigidity and power. The main motor is Y160M-6, P=7.5kW, n=970r/min.
The original design of the fine mouth knife with a knife "1", the fine car mouth plane with a knife "2" (see Figure 2). After two years of practice, it was found that the effect of machining the mouth and the plane with two knives was not good, and there were knife marks at the "å²”". In addition, due to the unreasonable structural design, the lever force that controls the lateral travel is applied to the main shaft, so that the blade "2" continues to be stressed when it reaches the end point, and the "scissor" phenomenon occurs. Therefore, it causes defects such as unclear roots, chipping, and end face buckling (up to 0.05), and roughness is deteriorated.
Now it is only used to process the stop and the plane with the knife "1". The blade path is ↓→, so that the tip of the blade has left the cross-section at the moment when the spindle is stressed, thus avoiding the bad caused by the above-mentioned bad force. Impact, but blade life is reduced. Blades "3", "4", "5" and "6" are used for the cylinder bore, and the blades "3" and "5" are used for semi-finishing. The fixed tool holder is used, and the blade is not re-grinded. 50 cutting. The blades "4" and "6" are used for fine boring. The elastic knives are used. The blade is not re-grinded. The cylinder rod passes through the inclined surface. When the reverse is retracted by 50, the blade is ejected for culling cutting, semi-precision and The total cutting allowance of the fine boring is 0.2 to 0.25 mm.
The SM of the file is stable at 60 mm/min for a long time. It has been one-sidedly believed that slower cutting can reduce roughness. This is not the case. We have analyzed the experience of Shanghai Volkswagen and Chaochai Jingjing cylinder bores. They use imported CBN inserts for high speed and large feed cutting. There are strict requirements for cutting speed and the amount of cutting. After repeated practice, the cutting amount of the pupil is specified as follows (see Table 1). Table 1 boring cutting amount fine boring hole fine boring fine car stop plane spindle speed (r/min) 1200
Cutting speed (m/min) 471 493.6
Feed per revolution (mm/r) 0.1
Feed per minute (mm/min) 120
Processing diameter 125 131
In order to machine high-precision workpieces, in addition to the advanced and reasonable cutting amount of the machine tool structure, the quality of the boring blade is also very important. The blades we have used in the past two years include Japan Mitsubishi MB710, Kennametal KD120, SECO CBN20, and ARNO CBN10. Taking into account the price factor, combined with the durability of the tool, we finally decided to use the Mitsubishi MB710 blade from Japan, and the tact time was shortened to 4 minutes (the milling and boring process time coincided).
After continuous improvement and debugging, the machine has been basically stable, reaching the "002" and beat requirements.
Design and use of fine-finishing cylinder head finishing machine
The DUM154 machine tool is a precision-cut combination machine designed and manufactured by Dalian Machine Tool Group in 1995 for use in the engine milling plant of the Group, which is used for the finishing of the 6110 cylinder top surface, the fine cylinder bore and the fine car stop.