数控火焰切割机的设计(共25页).doc

《数控火焰切割机的设计(共25页).doc》由会员分享，可在线阅读，更多相关《数控火焰切割机的设计(共25页).doc（25页珍藏版）》请在淘文阁 - 分享文档赚钱的网站上搜索。

1、精选优质文档-倾情为你奉上编号无锡太湖学院毕业设计（论文）相关资料题目： 数控火焰切割机的设计 信机 系 机械工程及自动化专业学 号： 学生姓名： 王文佳 指导教师： 龚常洪（职称：副教授 ） （职称： ）2013年5月25日专心-专注-专业目 录一、毕业设计（论文）开题报告二、毕业设计（论文）外文资料翻译及原文三、学生“毕业论文（论文）计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计（论文）开题报告题目： 数控火焰切割机的设计 信机 系 机械工程及自动化 专业学 号： 学生姓名： 王文佳 指导教师： 龚常洪（职称：副教授 ） （职称： ）2012年11月28日 课题来源生活实践科

2、学依据（包括课题的科学意义；国内外研究概况、水平和发展趋势；应用前景等）（1）课题科学意义 在机械加工过程中，经常需要对板材进行切割操作，板材切割常用方式有手工切割、半自动切割机切割及数控切割机切割。手工切割灵活方便，但手工切割质量差、材料浪费大、尺寸误差大、后续加工工作量大，同时往往工作条件恶劣，生产效率低。半自动切割机中仿形切割机，切割工件的质量较好，由于其使用切割模具，不适合于单件、小批量和大工件切割。其它类型半自动切割机虽然降低了工人劳动强度，但其功能简单，只适合一些较规则形状的零件切割。数控切割机切割相对手动和半自动切割方式来说，可有效地提高板材切割的切割质量、效率，减轻操作者的劳动

3、强度。目前在我国的一些中小企业甚至在一些大型企业中使用手工切割和半自动切割方式还较为普遍。随着现代机械工业的发展，对板材切割加工的工作效率和产品质量的要求也同时提高，因而数控切割机的发展和提高迫在眉睫。数控火焰切割机作为最常见的切割金属板材的设备，对于它的设计课题符合现代工业发展的要求。（2）数控火焰切割机的研究状况及其发展前景目前，我国机械加工行业中钢板下料普遍采用手工乙炔切割，这种现象不仅存在于小规模单件生产的小型企业，也存在于大批量生产的大型企业中，而国外企业的下料工序大部分采用了数控氧乙炔或数控等离子切割方法，不仅可提高材料利用率，而且改善了产品质量，优化了工作环境，使人员工作效率得到

4、了提高。之所以数控下料不能在我国普及主要有三个方面原因：资金问题、设备故障维护问题、操作问题。因此研制功能不是很强大但操作简单，性能可靠，价格相对便宜的实用型的火焰切割机就迫在眉睫这也就意味着目前设计和制造经济型数控火焰切割机在国能将有广阔的市场。研究内容 熟悉数控火焰切割机的发展历程，特别是近十几年来的龙门式火焰切割机 熟练掌握火焰切割机机械部分的设计； 熟练掌握电气控制系统的设计 掌握单片机的原理及选取方法 能够熟练使用UG，CAD。针对三维UG图，将UG图转换为二维CAD。 熟练使用CAD提供的图层工具。拟采取的研究方法、技术路线、实验方案及可行性分析（1）实验方案通过不同的零件的选取与

5、比较，选择最佳方案，以避免设计过程中可能出现的计算结果与设计要求不符的严重情况，再参考国内外类似产品的数据，以避免设计结果难以符合市场需求的后宫。（2）研究方法用UG对产品进行三维设计，仔细观察产品的外观，思考产品的可能缺陷 在不同的原始数据下，对同一个方案做不同的计算，在不同的零件组成下，比较各个方案的优劣。研究计划及预期成果研究计划：2012年11月7日-2012年11月27日：按照任务书要求查阅论文相关参考资料，填写毕业设计开题报告书。2012年11月28日-2013年2月12日：填写毕业实习报告。2013年2月17日-2013年3月2日：按照要求修改毕业设计开题报告。2013年3月5日

6、-2013年3月16日：完成毕业设计的绪论。2013年3月19日-2013年5月11日：设计方案计算。2013年5月14日-2013年5月18日：完成零件与装配图。2013年5月19日-2013年5月20日：毕业论文撰写和修改工作。预期成果：完成数控火焰切割与三维图的的机械部分与电气控制系统的设计，以及二维图与三维图的成型。特色或创新之处使用UG画图，将三维图转为二维图。 采用固定某些参量、改变某些参量来研究问题的方法，思路清晰，简洁明了，行之有效。已具备的条件和尚需解决的问题 实验方案思路已经非常明确，已经具备使用UG制图能力和图像处理方面的知识。 使用UG制图的能力尚需加强。指导教师意见

7、指导教师签名：年 月 日教研室（学科组、研究所）意见 教研室主任签名： 年 月 日系意见 主管领导签名： 年 月 日英文原文CNC flame cutting basic common sense The basic knowledge of CNC flame gas cutting (A) the basic working principle of gas cutting and gas cutting processHeat using a gas flame cutting the workpiece is preheated to at a certain temperature,

8、 the discharge speed cutting oxygen stream, so that combustion and gives off heat to achieve cutting method is called torch cutting. The oxygen cutting process has the following three stages: 1, the beginning of the preheating gas cutting, using a gas flame (oxygen-acetylene flame, oxygen, propane f

9、lame) of the workpiece to be cut at the ignition of the metal material is preheated to approximately 1100 to 1150 C) (For low carbon steel.Combustion emit high-speed cutting oxygen flow reached lighted metal intense burning in an oxygen stream. 3, blowing slag metal oxide combustion generated by the

10、 oxygen stream to blow off the incision is formed, so that the metal separation, the completion of the cutting process. (B) gas welding, gas cutting equipment used in the composition of theGas welding, gas cutting equipment, oxygen bottles, oxygen regulator, acetylene bottles (acetylene generator),

11、acetylene regulator, the tempering insurance, torch (torch) and rubber tube. (C) what is good notchedCutting the middle of the notched surface after the whitening did not burn scar notched without waste side of the phenomenon (D) gas cutting metal shall comply with the following conditions: 1) the m

12、elting point of the metal oxide should be less than the melting point of the metal. Table 1 - 1 are some common melting point of the metal and its oxide. 2) metal with oxygen combustion can release a lot of heat, and the thermal conductivity of the metal itself. The gas cutting conditions metal iron

13、, low carbon steel, medium carbon steel and low alloy steel and titanium. Other commonly used metals such as cast iron, stainless steel, aluminum and copper, etc., must use special method or melting method of oxyfuel cutting.8mm sheet, it is not easy to CNC gas cutting. CNC flame cutting Gas cutting

14、 accuracy is the error between After cutting geometry with its drawing size comparison, cutting the quality of the workpiece is cut off The surface roughness of the surface, the melting degree of collapse section on the edge of the incision, the incision edge is dross and the uniformity of kerf widt

15、h.First, the impact of steel flame cutting quality three basic elements (gas, cutting speed, cutting nozzle height) 1. Gases (oxygen, combustible gas and the flame adjusted) (1) Oxygen Oxygen is necessary for combustion of the combustible gas, in order to provide the energy required for steel reache

16、s the ignition temperature; addition, oxygen is carried out after the steel is preheated achieve ignition combustion as necessary. Cutting steel with oxygen must have a high purity of more than 99.5%, the general requirements, some advanced countries by industry standards, the oxygen purity of 99.7%

17、. The oxygen purity decreasing by 0.5%, steel plate cutting speed should be reduced by about 10%. If the oxygen purity is reduced by 0.8% to 1%, not only cutting speed decreased by 15% -20%, while the slotted also will be wider, hanging at the bottom of the incision the Residue and clean difficult,

18、significant deterioration of the quality of the cutting section, gas consumption also increases. Obviously, this reduces the production efficiency and cutting quality, the production costs are also significantly increased (see Figure 9-1).Figure 9-1 under the same oxygen pressure, oxygen purity of c

19、utting time and oxygen consumption. The use of liquid oxygen cutting, although the one-time investment, but in the long run, its comprehensive economic indicators are much better than imagined. The stability of the gas pressure on the cutting quality of the workpiece is also essential. The oxygen pr

20、essure fluctuations will cut the apparent deterioration of the quality of cross-section. The air pressure is adjusted according to the type of the cutting nozzle, the cutting of the plate thickness. Cutting if the oxygen pressure exceeds a predetermined value, does not improve the cutting speed, but

21、 the cutting section decline in the quality of the dross is difficult to be cleared, increasing the processing time and cost of cutting. Table 9-1 is commonly used in gas welding machine factory production the GK1 series of fast cutting nozzle (ie the Laval nozzle structure cutting nozzle) using the

22、 parameter (manufacturers may at any time modify the parameters should be cutting nozzle subject to the attached document, this table is for reference). (2) flammable gas flame cutting, commonly used flammable gases such as acetylene, gas, natural gas, propane, some foreign manufacturers also use MA

23、PP, namely: methane + ethane + propane. Generally, the combustion speed, high combustion value of the gas is suitable for sheet metal cutting; low combustion value, the slow combustion of flammable gas is more suitable for cutting slab, especially steel sheet of a thickness of more than 200mm, such

24、as a gas or gas be cut, you will get the desired cut quality, but the cutting speed will be slightly lower. In comparison, the acetylene is much more expensive than natural gas, owing to resource constraints in the actual production, the general use of acetylene gas, but at the same time cutting the

25、 slab require high cutting quality and adequacy of resources, it will consider the use of natural gas. (3) The flame can be adjusted by adjusting the proportion of the oxygen and acetylene the three cutting flame: neutral flame (ie, normal flame), oxidizing flame, reducing flame, as shown in Figure

26、9-2. The normal flame characterized in that no free oxygen in the reduction zone and the activated carbon, there are three distinct regions, the flame core distinctive outline (approximately cylindrical). The flame core component of acetylene and oxygen, and its ends were uniformly round and shiny s

27、hell. The housing is made of red hot carbon particles. Flame core temperature up to 1000 C. Reducing zone in the flame core, a significant difference with the flame core is its brightness is darker. Reduction zone by the product of incomplete combustion of acetylene - carbon monoxide and hydrogen, t

28、he reduction zone temperature up to 3000 C or so. Completely Waiyan i.e. the combustion zone is located outside of the reducing zone, it is composed of carbon dioxide and water vapor, nitrogen, its temperature varies between 1200 to 2500 C. Oxidizing flame is generated in the case of excess oxygen,

29、the flame core conical, length shortened significantly, the outline is not clear, the brightness is dim; Similarly, the reduction zone and outer flame has been shortened, the flame was purple blue combustion accompanied by sound, the sound of the size of the pressure of oxygen, oxidizing flame tempe

30、rature is higher than normal flame. If you are using the oxidizing flame cutting will make the cut quality significantly deteriorated. Reducing flame is generated in the case of excess acetylene flame core is no obvious silhouette green edge, the flame end of the core, to determine the excess of ace

31、tylene in accordance with the green edge; reducing zone is unusually bright, almost The flame core lumped together; Waiyan the yellow. When the excess acetylene is too far, black smoke, which is caused because of the lack of necessary oxygen acetylene flame in combustion. Preheat the energy of the f

32、lame size and cutting speed, cut quality are all very close. With the cut workpiece thickness increases and the cutting speed to accelerate, the energy of the flame also should increase as, but not too strong, particularly when the slab is cut, the the metal combustion heat of reaction generated inc

33、reases, strengthening the cutting point preheat capabilities, cutting-edge, then, too strong preheating flame will make serious melting collapsed on the edge of the cut edge. Too weak to preheat flame, the steel will not get enough energy to force to reduce the cutting speed, even cutting process is

34、 interrupted. So preheating flame strength and cutting speed relationship of mutual restraint. In general, the steel cutting 200mm neutral flame can get a better cut quality. Used in the cutting of steel plates should restore preheat flame cutting, because the reducing flame of the flame length, fla

35、me length should be at least a thickness of 1.2 times or more. (2) cutting speed The cutting speed of the steel sheet is corresponding with the burning rate of the steel in an oxygen. In the actual production should be based on the performance parameters of the cutting nozzle, gas type and purity, s

36、teel plate thickness to adjust the cutting speed. Cutting speed directly affects the stability of the cutting process and the quality of cutting section. If you want to artificially increase the cutting speed to improve production efficiency and slow down the cutting speed to best improve the qualit

37、y of the cutting section, it is impossible, only make the poor quality of the cutting section. Too fast cutting speed can cause the cutting sections with quality defects such as dents and dross, serious may result in cutting interrupt; too slow cutting speed make the incision on the edge of the melt

38、ing edge of collapse, the lower edge rounded, cutting cross-section in the second half part of the flush-shaped deep groove pit. By observing the characteristics of the slag discharged from the incision, adjust to the appropriate cutting speed. In the normal flame cutting process, cutting oxygen str

39、eam relative to the vertical cutting torch slightly at an angle, and its corresponding offset is called drag amount (see Figure 9-3). Speed is too low, there is no amount of post-drag, offset the workpiece cut below the mouth of the fire bouquets to the cutting direction. Improve the running speed o

40、f the torch, the fire bouquet will be offset in the opposite direction, when the fire bouquet and cutting oxygen flow parallel to the cutting speed. Speed is too high, the fire bouquet significantly after partial, as shown in Figure 9-4.Cutting nozzle and cut the height of the workpiece surface Stee

41、l plate flame cutting process, the cutting nozzle to cut the height of the work surface is one of the main factors in decision notch quality and cutting speed. Different thickness of the plate, using different parameters of the cutting nozzle, adjust the height. In order to obtain high quality cuts,

42、 the cutting nozzle to the height of the workpiece surface to be cut in the cutting process must be kept basically the same. Second, the thermal deformation of the control Will allow to be cut due to the unevenness of the steel sheet heating and cooling, the material of internal stress the role of t

43、he workpiece in the cutting process, different degrees of bending or displacement of - i.e. heat deformation, the specific performance is the deviation of the shape of the twisting and cutting size . Material internal stress can not be balanced and completely eliminated, it can only take some measur

44、es to try to reduce the thermal deformation. Third, the steel surface preparation The steel from the steel plant through a series of intermediate links to the cutting workshop, during that time, the steel surface will inevitably produce a layer of oxide. Furthermore, the steel sheet is also produced

45、 during the rolling process the layer of oxide is attached to the surface of the steel sheet. These oxide has a high melting point, is not easy to burn and melt, warm-up time, reducing the cutting speed; heated at the same time, scale splash, can easily cause congestion, reduce the service life of t

46、he cutting nozzle cutting nozzle. Therefore, prior to cutting, it is necessary on the surface of the steel sheet rust pretreatment. The common method is to shot blasting, rust after painting. Upcoming small iron sand blasting machine sprayed into the surface of the steel plate, rely on the impact of iron ore to steel descaling, then sprayed flame retardant, electrical conductivity and good anti-rust paint. Rust paint pretreatment before steel cutting has become an indispensable part in the production of metal structures. F