1、 Cylinder block machining process design Engine parts engine block is a more complex structure of spare parts box, its high precision, complex process, and the processing quality will affect the overall performance engine, so it has become the engine manufacturers focus parts one. 1.Technical Charac
2、teristics of the engine cylinder block Cylinder cast for a whole structure, and its upper part 4 cylinder mounting hole; cylinder standard cylinder is divided into upper and lower divisions into two parts; cylinder to the rear of the front-side arrangement of the previous three coaxial mounting hole
3、 of the camshaft and the idler axle hole. Cylinder process features are: the structure of complex shape; processing plane, more than holes; uneven wall thickness and stiffness is low; processing of high precision typical of box-type processing part. The main processing of the surface of cylinder blo
4、ck top surface, the main bearing side, cylinder bore, the main and camshaft bearing bore holes and so on, they will directly affect the machining accuracy of the engine assembly precision and performance, mainly rely on precision equipment, industrial fixtures reliability and processing technology t
5、o ensure the reasonableness. 2.Engine block process design principles and the basis for Design Technology program should be to ensure product quality at the same time, give full consideration to the production cycle, cost and environmental protection; based on the enterprises ability to actively ado
6、pt advanced process technology and equipment, and constantly enhance their level of technology. Engine block machining process design should follow the following basic principles: (1) The selection of processing equipment ,the principle of selection adopted the principle of selection adopted the pri
7、nciple of combining rigid-flexible, processing each horizontal machining center is located mainly small operations with vertical machining center, the key process a crank hole, cylinder hole, balancer shaft hole High-speed processing of high-precision horizontal machining center, an upper and lower
8、non-critical processes before and after the four-dimensional high-efficiency rough milling and have a certain adjustment range of special machine processing; (2) focus on a key process in principle process the body cylinder bore, crankshaft hole, Balance Shaft hole surface finishing and the combinat
9、ion of precision milling cylinder head, using a process focused on a setup program to complete all processing elements in order to ensure product accuracy The key quality processes to meet the cylinder capacity and the relevant technical requirements; According to the technological characteristics o
10、f automobile engine cylinder block and the production mandate, the engine block machining automatic production line is composed of horizontalmachining center CWK500 and CWK500D machining centers, special milling/boring machine, vertical machining centers matec-30L and other appliances. (1) top and b
11、ottom, and tile covered only the combination of aperture rough milling machine dedicated to this machine to double-sided horizontal milling machine, using moving table driven parts, machine tools imported Siemens S7-200PLC system control, machine control cabinet set up an independent, cutting automa
12、te the process is completed and two kinds of automatic and adjust the state; (2) high-speed horizontal machining center machining center can be realized CWK500 the maximum flow of wet processing, but because of equipment, automatic BTA treatment system through the built-in tray under the wide-type c
13、hip conveyor and the completion of the machining center can be dry processing; machine tool spindle speed 6000r/min,rapid feeding speed 38m/min; (3) The combination of front and rear face rough milling machine tool using hydraulic transmission; control system imported Siemens S7-200PLC system contro
14、l, machine tools have a certain flexibility; (4) The special machine TXK1500 this machine vertical machining center by the modification ofshape, with vertical machining center features and performance, this machine has high strength,high wear-resistant, high stability, high accuracy, high-profile et
15、c.; (5) high-speed vertical machining center matec-30L of the machining center spindle high speed 9000r/min.Control system uses Siemens SINUMERIK840D control system; (6) high-speed horizontal machining center spindle CWK500Dhighest speed 15000r/min. 3.Engine block machining process design the main c
16、ontent Engine block complex structure, high precision, arge size, is thin-walled parts, there are a number of high precision plane and holes. Engine block machining process characteristics; mainly flat and the hole processing, processing of flat generally use planing, milling methods such as process
17、ing, processing of hole used mainly boring, processing and multi-purpose drilling holes. As the cylinder complex structure. so how to ensure that the mutual position of the surface processing precision is an important issue. 3.1 The selection of blank Engine block on the materials used are generally
18、 gray cast iron HT150,HT200,HT250,there is also cast aluminum or steel plate, this engine block using high-strength alloy cast iron. Cylinder in the processing prior to aging treatment in order to eliminate stress and improve the rough casting mechanical properties. Improve the rough accuracy, reduc
19、tion of machining allowance, is to improve the automated production line system productivity and processing quality of the important measures. As the foreign box-type parts of rough quality and high precision, and its production-line system has been implemented directly on the blank line, not only e
20、liminating the need for blank check device also saves the rough quality problems due to waste of machining time, increaseoverall efficiency. Therefore, the refinement of rough is to improve the productivity of the most promising way out. For the engine block production line, can be rough in parts on
21、-line pre-milling six face, removing most of the margin, to facilitate direct on-line parts. 3.2 Machining process selection and processing of the benchmark Choose the right processing technology base is directly related to the processing quality can ensure the parts. Generally speaking, process ben
22、chmarking can be divided into coarse and fine reference base. (1) The baseline for the on-line thick rough, which is particularly important the choice of benchmark crude, if crude benchmark choice unreasonable, will the uneven distribution of machining allowance, processing and surface offsets, resu
23、lting in waste. In the cylinder production line, we have adopted for the coarse side of the base; (2) Refined the base of this box for the engine block parts, the general use of “side two sales “for a full range of uniform benchmarks, For the longer automated production positioning, therefore, will
24、be divided into 2-3 segment pin holes used. In the cylinder pin hole of the process, we have adopted to the side, bottom and the spindle hole positioning, in the processing center on the process. 3.3 Machining Processing Stages and processes of the arrangements Often a part of many apparent need for
25、 processing, of course, the surface machining accuracy are different. Processing of high precision surface, often after repeated processing; As for the processing of the surface of low precision, only need to go through one or two on the list. Thus, whenthe development process in order to seize the
26、“processing high precision surface, “this conflict, the reasonable arrangement processes and rational division stage of processing. Arrange the order of the principle of process is: after the first coarse refined, the first surface after the hole, the first benchmark other. In the engine block machi
27、ning, the same should follow this principle. (1) roughing stage engine block machining process, the arrangements for roughing process, to fully carry out rough rough, trim most of the margin in order to ensure production efficiency; (2) semi-finishing phase of the engine block machining, in order to
28、 ensure the accuracy of the middle of some important surface processing, and arrange some semi-finishing operations, will be required accuracy and surface roughness of the surface of the middle of some processing to complete, while demanding the surface of semi-finished, to prepare for future finish
29、ing; (3) The finishing stage of requiring high accuracy and surface roughness of the surface processing; (4) secondary processing, such as small surface screw holes, you can finish of the major surface after the one hand, when the workpiece deformation process little impact at the same time also red
30、uced the rejection rate;In addition,if the main surface of a waste,these small the surface will not have to be processed,thus avoiding a waste of man-hours.However,if the processing is very easy for a small surface bumps the main surface,it shouldbe placed on a small surface finish prior to the main
31、 surface finishing; (5) should make proper arrangements for secondary processes such as product inspection process,in part roughing stage,the key process before and after processing,spare parts all the processing has been completed,should be appropriate arrangements. Stage of processing division,has
32、 the following advantages:First,it can take measures to eliminatethe rough workpiece after the stress,to ensure accuracy; second,finishing on the back,and will not damage during transport the surface of the workpiece has been processed;again,first roughing the surface defects can be detected early a
33、ndpromptly deal with rough,do not waste working hours.But most small parts,do not sub very thin.3.4 cylinder surface of the main processing and secondary processes Cylinder surface and support the main processing operations are: (1) plane processing at present, the milling of engine blocks is the pr
34、imary means of planar processing,domestic milling feed rate is generally 300-400mm/min,and foreign 2000-4000mm/min milling feed rate compared to far cry,to be on increasing,therefore,improve the milling feed rate,reduce overhead time is to improve the productivity of the major means of finishing a n
35、umber of plane engine block when the milling feed rate to reach 2399mm/min,greatly improved efficiency; Top surface of the cylinder milling is a key process in the process,the flatness requirements for 0.02/145mm,the surface roughness of Ra1.6um.Processing in the cylinder,the use of side and spindle
36、 bearing bore positioning,top,bottom and middle vagay only aperture while processing used in the processing line outside of the knife device can better meet the engine block machining accuracy; (2) General holes machining holes in general are still using the traditional processing of drilling,expans
37、ion,boring,reaming,tapping and other craft approach. Issues in the design process of specific programs,use of coated cutting tools,cutting tools and other advanced tools within the cooling,and using a large flow of cooling systems,greatly improving the cutting speed,improved productivity; (3) deep h
38、ole processing of the traditional processing method is used to grade twist drill feed,low efficiency of their production,processing and quality is poor.The deep hole in the engine block processing,the use of gun drilling process; (4) The three-axis machining holes for the cylinder-axis machining hol
39、es holes of high precision,long working hours of the restrictive process.Thus,work arrangements,processing methods,tools and so on should be special attention.All cover pre-processing,that is,semi-circular hole and the cylinder block main bearing cap of the shortage of processing,its main purpose is
40、 to remove blank margin,release stress,to prepare for the post-order processing;in crankshaft machining processing center hole,using double-sided Boring,boring the first holes in the crankshaft hole at one end to 1/2 length,and then turn 180 degrees workbench,form the other end and then bore another
41、 1/2 length. (5) The cylinder bore machining cylinder hole cylinder machining processing is a key process in the one,under normal circumstances,the machining process as a rough boring,semi-fine boring,precision boring and honing.Cylinder bore wall for the early detection of casting defects,eliminate
42、 stress,should be thick cylinder boring holes in advance;due to the structural characteristics of the different cylinder bore,must be in honing process to improve the cylinder bore surface quality.In the high-volume production,the cylinder bore honing generally use the multi-axis grinding machine or
43、 honing Automatic Line.Here we use honing automatic lines,from the coarse-heng.Fine-heng and testing equipment,composed of three; (6) Cleaning cleaning isdivided into wet cleaning and dry cleaning.Machining cylinder automatic production line using a large flow of wet cleaning; (7) Detect points outs
44、ide the line detection and line detection of two kinds. Quality inspection in the engine block,according to the actual situation with lines outside the detection,the main use of coordinate measuring machine integrated measurements of the cylinder,each 200 samples 1-5 pieces,each class random one. 4.
45、Summary Through the engine block of the structure and process characteristics of the analysis,discusses the engine block machining process design principles and basis of the choice of cutting parameters,and U-turn at high speed milling and boring,for example,design,analysis of the engine cylinder bo
46、dy of high-speed milling and turnover boring process,and in the processing need to pay attention to. 缸体机械加工工艺设计 发动机缸体是发动机零件中结构较为复杂的箱体零件，其精度要求高，加工工艺复杂，并且加工加工质量的好坏直接影响发动机整个机构的性能，因此，它成为各个发动机生产厂家所关注的重点零件之一。 1. 发动机缸体的工艺特点 缸体为一整体铸造结构，其上部有 4 个缸套安装孔；缸体的水平隔板将缸体分成上下两部分；缸体的前端面从到后排列有三个同轴线的凸轮轴安装孔和惰轮轴孔。 缸体的工艺特点是：
47、结构、形状复杂；加工的平面和孔比较多；壁厚不均，刚度低；加工精度要求高，属于典型的箱体类加工零件。缸体的主要加工表面有顶面、主轴承侧面、缸孔、主轴承孔及凸轮轴孔等，它们的加工精度将直接影响发动机的装配精度和工作性能，主要依靠设备进度、工夹具的可靠性和加工工艺的合理性来保证。 2. 发动机缸体工艺方案设计原则和依据 设计工艺方案应在保证产品质量的同时，充分考虑生产周期、成本和环境保护；根据本企业能力，积极采用国内外先进的工艺技术和装备，不断提高企业工艺水平。发动机缸体机械加工工艺设计应遵循以下基本原则： （1 ）加工设备选型原则 加工设备选型采用刚柔结合的原则，加工设备以卧式加工中心为主，少量采
48、用立式加工中心，关键工序曲轴孔、缸孔、平衡轴孔加工采用高精度高速卧式加工中心，非关键工序上下前后四个平面的粗铣采用高效并有一定调整范围的专用机床加工； （2 ）集中工序原则 关键工序曲轴孔、缸孔、平衡轴孔的精加工缸盖结合面的精铣，采用在集中在一道工序一次装夹完成全部加工内容方案，以确保产品精度满足缸体关键品质的工艺性能和有关技术要求。 根据汽车发动机缸体的工艺特点和生产任务要求，发动机缸体机械加工自动生产线由卧式加工中心 CWK500 和 CWK500D 加工中心、专用铣/ 镗床、立式加工中心 matec-30L 等设备组成。 （1 ）顶底面及瓦盖止口面粗铣组合机床 本机床为双面卧式专用铣床，
49、采用移动工作台带动工件，机床采用进口西门子 S7-200PLC 系统控制，机床设独立电控柜，切削过程自动化完成，有自动和调整两种状态； （2 ）高速卧式加工中心 CWK500 该加工中心可实现最大流量的湿加工，但由于设备自动排屑处理系统是通过位于托盘下的内置宽式排屑器而完成，该加工中心可以进行干加工；机床主轴转速 6000r/min，快速进给速度 38m/min； （3 ）前后端面粗铣组合机床 机床采用液压传动；控制系统采用进口西门子 S7-200PLC 系统控制，机床具有一定的柔性； （4 ）采用机床 TXK1500 本机床有立式加工中心改造而成形，具备立式加工中心的特点及性能，该机床具有高精度、高强度、高耐磨度、高稳定性、高配置等优点； （5 ）高速立式加工中心 matec-30L 该加工中心主轴最高转速 9000 r/min。控制系统采用西门子公司 SINUMERIK840D 控制系统 （6 ）高速卧式加工中心 CWK500D 主轴最高转速 15000 r/min。 3. 发动机缸体机械加工工艺设计的主要内容 发动机缸体结构复杂，精度要求高，尺寸较大，是薄壁零件，有若干精度要求较高的平面和孔。发动机缸体机械加工的工艺特点是：主要是平面和孔的加工，加工平面一般采用刨、铣削等方法加工，加工孔主要采用镗削，加工小孔多用钻削。由于缸体结构复杂，因此
