Coal mining methods

The goal of coal mining is to economically remove coal from the ground. Coal is valued for its energy content, and since the 1880s is widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United States, United Kingdom, and South Africa, a coal mine and its structures are a "colliery". In Australia, "colliery" generally refers to an underground coal mine.

Mountaintop removal coal mining is the removal of mountains to expose coal seams, and fills the elimination of congestion associated with nearby mining valleys and hollows. This method combines the surface and contour strip mining methods.

Surface mining is used for about 40% of coal production in the world. If coal is near the surface, can be cost-effective to extract coal by this method. The different types of contour strip mining and removing mountains.

Or strip mining is most suitable for areas with flat terrain. It exposes the charcoal for the earth above the coal seam or cut into long strips. If all the earth above the coal seam is removed, the underlyingcoal seam will be exposed. The exposed carbon-block can be drilled and jump. Once this bar is empty of coal, the extraction process is with a new strip next to it repeatedly created.

The contour extraction method is more common in areas with steep rolling terrain. This method involves the removal of earth above the coal seam in a model follows the contours along an edge or a slope. This method can lead to serious landslides and erosion problems. To resolve thisProblems, a variety of methods have been developed for use freshly cut overburden fill worked-out area. There are no restrictions on mining contour. When the process reaches a predetermined value stripping is not profitable to continue.

Modern OpenCast new methods, a greater proportion of the coal deposit than underground methods.

Deep mining is required when coal deposits are too deep to see the world. The main methods of underground mining are long wall, continuous Blast Short Wall Mining and Mining withdrawn.

Continuous mining is used for about 45% of underground coal. It 's like a machine with a large rotating drum with carbide teeth to scrape coal from the seam.

Quick extraction method, the wall is only less than 1% of coal used in depth. This method also uses a continuous mining machine with mobile armor, similar to longwall mining method.

Longwall mining accounts for about 50% of underground production. It uses a sophisticated machine with a rotation that moves back and forth mechanically on a large drum coal seam. Longwall mining helps highThe levels of production with high security standards. The sensors used in the extraction process helps to determine the amount of carbon that remains in the seam while robotic controls by helping to increase process efficiency.

Retreat mining method used in columns or coal to keep ripping up to my roof. This mining method is one of the most dangerous, because it is impossible to predict when crushing collapse of the ceiling or roof and is the case or the miners.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

ISO6336 标准的一些问题及其哲学方法论根源

ISO6336 标准的一些问题及其哲学方法论根源
（长安大学工程机械学院
陕西西安
710064） 冯守卫
张伟社

ISO6336标准，第六部分，给出了有载荷普的情况下的计算方法。
累计疲劳计算可以理解，附录中还给出了Ka的计算，这时候如果计算出了Ka是应用在额定扭矩上，还是在载荷普各工况的扭矩上？
这时会有比较大的差别，不知道哪位对ISO6336理解，请给予指点。

(附言：该文本应属于个人工科本行的母鸡蛋，而且自感是所下的约30个母鸡蛋中最好的一个，也是其他"蛋"们诞生的基础。但因沾了些公鸡蛋味，故正式的母 鸡窝和公鸡窝内均无处下，只好下在这里。）
摘要
文献[1～10]中论述了ISO6336齿轮承载能力计算标准中的一些问题和矛盾。本文中从哲学方法论角度对这些问题作了进一步的论述。并说明存在问题的 方法论根源，通过具体问题论述了唯物辩证法的一些观点。启发性地显示了如何用辩证法的观点来指导具体研究工作，以及如何通过具体问题的分析来学习唯物辩证 法。形象地说明了养成辩证思维习惯对善于发现分析问题、提高思维能力和创新能力的极端重要性。作者也再次认为，ISO 6336标准在几个核心问题上有进一步研究改进的必要。
关键词
齿轮强度
ISO 6336
唯物辩证法
思维能力
创新能力

0 引言


ISO 6336标准（GB3480与之等效）自发表以来，对齿轮承载能力计算方法的研究起了很大的指导和推动作用。但因为这个问题的复杂性，故该标准尚未完善。 在国际上也并未取得真正统一地位。如美国、苏联、日本等国家可能尚未采用。我国GB3480标准制订和修订组的负责人等也均谈到各国对该标准的争论尚颇 多。在文献[1～9]中，我们曾分析了该标准的一些问题和矛盾。从哲学方法论角度来看，这些问题产生的根源是存在着违背唯物辩证法的现象。而掌握辩证法并 养成辩证思维习惯对善于发现分析问题，提高思维能力和创新能力是极端重要的。故本文中准备从ISO中一些问题及其方法论根源相结合角度加以分析。
1
齿根应力计算中的客观性、主要矛盾、全面性及发展观点

唯物辩证法的一个基本观点是要严格地按照事物的客观本来面目去探索，反对主观性。目前世界上各种齿轮强度计算标准中的齿根应力计算方法，都是以对轮齿的悬 臂梁假设为基础，再用应力修正（集中）系数来修正。由于悬臂梁假设与实际齿形相差极大，而且悬臂梁弯曲应力公式也不适用于这种悬臂长度仅相当于或小于(载 荷作用于单对齿啮合区外侧点时)梁的宽度的情况。因此，在这种悬臂梁应力与齿根最大拉应力之间的规律（即应力修正系数公式）就难以找到或不存在。同时这种 方法在轮齿受载情况、齿根应力状态和应力修正系数中，也还是一个又一个的假设。所以这种方法先天缺陷很大，各标准之间也相当纷纭，且难以统一完善。如 ISO与美国AGMA中公式的分歧很大。ISO中的相对齿根圆角敏感系数，在持久寿命时与悬臂梁长度和重合度无关，在静强度时却与它们有关（包含在YS 中）。ISO中还存在着下述现象：当齿数较多时，正变位时的弯曲强度反小于负变位时，且变位系数的影响反大于齿数较少时。对多种钢材的齿轮，在静强度下的 齿根应力计算仅仅只取决于悬臂梁应力系数（服从悬臂梁应力规律）。详见[4~6]。

此外这种方法也相当复杂。ISO中公式和参数多达20多个，并包含迭代运算。AGMA中则更复杂，它还要通过作图测量来计算。这使人联想起爱因斯坦的话： "上帝不会创造这么复杂的公式"。

造成这种现象的根本原因在于悬臂梁假设的主观牵强性。为此我们在文献[1～6]中提出了新的方法：直接从实际齿形出发，以相似理论为基础，通过引入对应于 真实齿形和实际齿根最大拉应力的应力齿形系数，来直接建立齿根最大拉应力的计算公式。并通过边界元采样计算和回归分析，得到应力齿形系数的回归公式。从哲 学角度来看，应力齿形系数仅与齿数、变位系数和载荷作用高度系数有关，故在它们之间必然存在着精确的客观规律。我们又严格地按照客观内在联系去探索回归模 型，果然得到了精度极高的回归公式[4~6]。我们还发现齿根应力只是与齿数的倒数（1/z）而不是与齿数本身有良好的抛物线关系。这里的客观必然性在 于：因为渐开线齿廓的曲率是曲率半径的倒数，而曲率半径与齿数成正比。仿型法加工的刀具编号基本服从按1/z值的等间距规则。

这种新方法不需要种种假设，理论基础先进，实际准确性好，且计算大为简化。它提供了使齿根应力计算完善化统一化的可能。该方法的关键在于采样数据的准确 性。如果采用应变片测量方法，根据边界元计算可知，应变片应小于0.05mn，且在不同齿形和载荷位置下，应变片的大小和粘贴位置均应不同。而且还要在完 全同等条件下进行大量概率实验，且还不一定精确，故难度和费用是极大的。不知是否有更好的实验方法。

在文献[5,6]中，我们还用同样的方法给出了轮齿挠度和啮合刚度的回归公式。并从多个方面佐证了文中的计算结果，这也使我们感受到边界元法的先进性和可 信性。而且由于回归模型合理、回归精度极高，回归公式相当于多维空间的连续光滑流型，故用文中回归公式计算基本相当于直接用边界元法计算。

辩证法的另一重要观点是要善于抓主要矛盾，抓关键。这一点对发现分析问题是极其重要的。毛泽东讲："万千的学问家和实行家，不懂得这种方法，结果如堕烟 海，找不到中心，也就找不到解决矛盾的方法"。目前国际上的齿轮强度计算标准有约十种，但其齿根应力计算方法都是仅限于对悬臂梁宽度、长度及应力修正系数 的不同假设，以及对悬臂梁弯曲应力公式的不同修改上，而没有突破悬臂梁假设本身这个要害。因此形成了各执一说而又无法统一的不正常局面。又由于齿轮失效的 随机离散性及强度计算的保守处理，故其中的问题也难以判断和容易掩盖。所以这种不正常的局面得以长期延续。这里关于悬臂梁宽度的假设可能还存在着一种错 觉：好像只要通过危险点就是合理的。实际上这个考虑并不应该是出发点。因为一方面要想通过这种方法或对悬臂梁公式的某些改动来逼近齿根最大拉应力是徒劳 的。另一方面这里的出发点应是：要找到这样一种悬臂梁，它的应力与齿形参数和载荷位置的变化规律与齿根最大拉应力的变化规律之间有客观必然的联系规律（修 正公式）。显然这是很难找到的。

辩证法还告诉我们要全面的分析问题，防止片面性和以偏概全。我们在应力齿形系数的边界元采样计算时已注意到了这点，而且所用齿轮样本空间过分密集。根据最 新分析，齿轮样本空间可精简如下表（略），载荷作用高度系数取2.2,1.8,1.4三种即可。在ISO 6336中不同基本齿条标准时也共用同样的公式。但我们见到的资料是，其有限元计算数据仅取了x＝0，z＝14，24，48，3种载荷作用高度，分别为 6、3、2种刀具齿顶圆角的共33个数据。故仅在这个范围内ISO中的悬臂梁齿形系数与应力修正系数的乘积（YFS值）才与我们边界元计算的真实应力齿形 系数相吻合（ISO约高2～5％）。但ISO中YFS值随着变位系数的相对变化很难理解[4~6]。

辩证法还要求我们要有不断发展的观点。W.Lewis的悬臂梁假设方法已经110多年了，它应当已经完成了它的历史贡献。我们没有必要再在这个圈子里钻来 钻去。既然有一步平坦的捷径，为什么还要再走那两步都是泥潭的弯路？即使ISO中计算没有缺陷，似也应改用新的方法。钱学森前辈同温总理的谈话中，谈到全 面和创造型人才的培养问题。爱因斯坦也还说，想象力比知识本身更重要。而传统的惯性和保守的惰性是不利于发展进步和培养创新能力的。一个新的东西总要顶着 石块弯曲的生长似乎也是一种无奈的规律。突破这种规律并敏于发现新的苗头，是有利于发展和创新。

2
重合度系数、端面载荷系数及联系分析的观点
辩证法还强调要互相联系地分析问题。重合度系数是考虑双对齿承载时有利影响的系数，端面载荷系数是又考虑到由齿轮误差等引起双齿对载荷分担不均的抵消作用 的系数。它们是紧密相关的，故必须互相联系起来分析。而且它们的乘积（复合系数）必须满足极值条件——大于等于重合度系数而小于等于1。但在ISO中却把 两者互不相关的弧立分析，因此其复合系数值的相对关系存在着诸多矛盾和混乱。如存在着复合系数大于1的矛盾。在一些情况下复合系数反而随着重合度的增大而 增大。复合系数随着精度等级的相对变化情况及其在直斜齿轮之间的相对关系也是混乱难解的。从定性分析来看，ISO中计算的大前提均是单位齿宽载荷，多对齿 对啮合应是对整个齿宽而言的，故端面重合度应是唯一代表啮合齿对数多少的参数。轴向重合度本质上是代表齿轮宽度的参数，不能认为它也重复地代表了啮合齿对 数的多少。ISO中端面载荷系数公式把二者视为等同，主要与总重合度相关。这是很难解释或明显错误的。ISO中直齿轮的接触强度重合度系数公式也是人为假 设公式。在文献[5,6]中，我们对这两种系数有详细的分析，并从整体联系上给出了具有明确的含义和推导的新的公式 。

3
曲率系数等计算中的深入性

辩证法还教导我们要深入地研究问题，防止表面性。在接触应力中曲率系数（ISO称为区域系数）计算的关键是，应该选取哪一个啮合点的综合曲率半径作为计算 依据。在AGMA中，直齿轮采用小齿轮单齿对啮合区内界点作依据，普通斜齿轮采用过连心线上两轮顶圆间中点的小齿轮半径与啮合线的交点作依据。在 ISO6336——1980中均是以节点作依据。而在1993版中作了较大修改。一是改为以节点和单齿对啮合区内界点中综合曲率半径较小者作依据；二是认 为对小直齿轮和大直齿轮的计算应力也要分别采用不同的点计算。对普通斜齿轮和内齿轮，则仍是按节点算。至于窄斜齿轮，两标准都用插值原则。
在AGMA中直齿轮的重合度系数等于1，即在计算载荷中不考虑重合度的影响。H.Winter（ISO前负责人）曾对此提出批评。而 E.J.Wellauer（AGMA负责人）反驳说因为AGMA中直齿轮曲率系数计算采用了单齿对啮合区内界点，故在此已经考虑了重合度的影响[11]。
在文献[8]中我们对这个系数作了深入分析。首先我们认为重合度的影响不应且也难以与曲率系数混在一起，它只应在计算载荷的重合度系数中去考虑。曲率系数 只应作为一个纯粹代表齿面耐久性的几何系数。其次我们从能正确反映齿面相对强度高低等方面出发，从理论分析和有关实验结合中分析了ISO与AGMA中的一 些疑问和矛盾。提出了以小齿轮齿根部啮合区的平均综合曲率半径作为曲率系数计算依据的商榷意见。
关于深入性的例子还可见对斜齿轮接触线长度变化规律的分析中，对此目前大都只关心固定的接触线长度最小值。AGMA认为接触强度重合度系数计算完全要从这 个最小值甚或瞬时最小值出发（无论直斜齿轮）。ISO中直齿轮和窄斜齿轮是折中的从此出发。在文献[9]中，我们一方面给出了接触线长度计算的改进公式， 分析了其极值大小随端面、轴向重合度的变化规律。而且分析了在不同极值大小时其持续时间长短的动态变化规律。并得出结论：重合度系数计算只能从动态的接触 线长度统计平均值出发。
在文献[10]中有对齿向载荷分布系数的深入分析。文中指出ISO中这个系数存在着当载荷较小时其值无限增大等问题，并提出了改进意见。
在齿轮强度计算中各种相对关系和整体关系的合理性较绝对数值的准确性更为重要，因为后者只是反映在试验齿轮许用应力的相对高低上。而ISO对此点似注意不 够。此外该标准似有过分烦琐倾向（我国GB3480已作了简化），日本专家仙波正庄也曾说，这个标准是很难懂的[11]。

4
要善于从差异矛盾中发现分析问题并敢于创新
善于发现分析问题首先就是要善于发现分析事物的矛盾。目前ISO、AGMA等标准之间的差异很多。"差异就是矛盾"，矛盾就是问题。这种局面本身就说明这 方面值得深入研究的地方尚很多。同时这两种标准各自本身中也存在一些问题和矛盾。我们要善于从这些差异矛盾之中比较分析，揭示矛盾，发现问题并敢于创新。 我们一方面要尊重继承前人的伟大贡献，另一方面也不能只因为是权威标准就不去思索分析或不敢分析触及。我们需要树立这样的信心：无论在实际工作或科学研究 中，一方面总是需要参考借鉴和继承的，另一方面也总是可以有所发现有所前进的。而关键就在于要善于发现分析和解决问题。

5
如何培养辩证思维习惯
善于发现分析问题归根结底就是要善于用唯物辩证法的观点来观察分析问题。毛泽东讲："要学会辩证法，这个用处很大"。如何才能学会辩证法并养成随时随事都 能自觉地用辩证法的观点来分析观察问题的习惯呢？这当然首先需要认真深入的理论学习，但仅仅这样还不够。因为这样的情况是很多的：往往谈起理论条文来，似 乎也还知道和明白，但是一到具体问题的分析应用当中，就忘到九屑云外或陷于糊涂之中。所以最主要的是要通过具体问题的分析从理论与实际应用相结合上来学习 领会。这要求我们一方面要随时注意有意识的用辩证法观点来指导对具体问题的分析研究，另一方面要善于从对具体问题的分析研究当中抽象上升到辩证法的理论 上。本文的目的也是希望对这两方面有所帮助启发。
培养辩证思维习惯是一个要下大力气、不断积累的从必然到自由的过程，决不是可以一蹴而就和一劳永逸的。稍有疏忽或不用气力，"就会滑到唯心论和形而上学方 面去。"在实际生活的许多方面，违背唯物辩证法的现象是很多的
哲学是自然科学与社会科学的概括和总结。所以我们还可以读一些真正从客观实际出发、严格"追踪蹑迹"，真正有人生意义和思想深度的如同血管之血的文学作 品，和一些善于分析的文章。例如鲁迅的小说和杂文。以锻炼思维深度和精度，学习分析方法。

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

ISO6336 ISO1328 DIN3968

DIN 3968 Tolerances for Single-start Hobs for Involute Spur Gears
Deutsches Institut Fur Normung E.V. (German National Standard) / 01-Sep-1960 / 8 pages



ISO 1328-1:1995

Cylindrical gears -- ISO system of accuracy -- Part 1: Definitions and allowable values of deviations relevant to corresponding flanks of gear teeth

Cancels and replaces ISO 1328 (1975). Establishes a system of accuracy relevant to corresponding flanks of individual cylindrical involute gears. Specifies appropriate definitions for gear tooth accuracy terms, the structure of the gear accuracy system and the allowable values of pitch deviations, total profile deviations and total helix deviations. Applies only to each element of a toothed wheel taken individually. Does not cover gear pairs as such.



ISO 1328-2:1997

Cylindrical gears -- ISO system of accuracy -- Part 2: Definitions and allowable values of deviations relevant to radial composite deviations and runout information


ISO 6336-1:2006 Calculation of load capacity of spur and helical gears -- Part 1: Basic principles, introduction and general influence factors

ISO 6336-1:2006 presents the basic principles of, an introduction to, and the general influence factors for, the calculation of the load capacity of spur and helical gears. Together with ISO 6336-2, ISO 6336-3, ISO 6336-5 and ISO 6336-6, it provides a method by which different gear designs can be compared. It is not intended to assure the performance of assembled drive gear systems. It is not intended for use by the general engineering public. Instead, it is intended for use by the experienced gear designer who is capable of selecting reasonable values for the factors in these formulae based on knowledge of similar designs and awareness of the effects of the items discussed.

The formulae in ISO 6336 are intended to establish a uniformly acceptable method for calculating the pitting resistance and bending strength capacity of cylindrical gears with straight or helical involute teeth.


ISO 6336-2:2006  Calculation of load capacity of spur and helical gears -- Part 2: Calculation of surface durability (pitting)

ISO 6336-2:2006 specifies the fundamental formulas for use in the determination of the surface load capacity of cylindrical gears with involute external or internal teeth. It includes formulas for all influences on surface durability for which quantitative assessments can be made. It applies primarily to oil-lubricated transmissions, but can also be used to obtain approximate values for (slow-running) grease-lubricated transmissions, as long as sufficient lubricant is present in the mesh at all times.


ISO 6336-3:1996  Calculation of load capacity of spur and helical gears -- Part 3: Calculation of tooth bending strength

Gives the fundamental formulae for use in tooth bending strength calculations for involute internal and external gears with a minimum rim thickness under the root.

ISO 6336-5:2003 Calculation of load capacity of spur and helical gears -- Part 5: Strength and quality of materials

SO 6336-5:2003 describes contact and tooth-root stresses, and gives numerical values for both limit stress numbers. It specifies requirements for material quality and heat treatment and comments on their influences on both limit stress numbers. Values in accordance with it are suitable for use with the calculation procedures provided in ISO 6336-2 and ISO 6336-3 and in the application standards for industrial, high speed and marine gears. They are also suited to the calculation procedures given in ISO 10300 for rating the load capacity of bevel gears. It is applicable to all gearing, basic rack profiles, profile dimensions, design, etc., covered by those standards. The results are in good agreement with other methods for the range indicated in the scope of ISO 6336-1.



ISO 6336-6:2006 Calculation of load capacity of spur and helical gears -- Part 6: Calculation of service life under variable load


ISO 6336-6:2006 specifies the information and standardized conditions necessary for the calculation of the service life (or safety factors for a required life) of gears subject to variable loading. While the method is presented in the context of ISO 6336 and calculation of the load capacity of spur and helical gears, it is equally applicable to other types of gear stress.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

Milling Machine Questions and Answers

(mechanical engineering) A machine for the removal of metal by feeding a workpiece through the periphery of a rotating circular cutter. Also known as miller.

Architecture:milling machine

A machine consisting of a rotating mandrel carrying a milling cutter, and a movable table, operated by a feed screw, to which is bolted the object to be milled.

Britannica Concise Encyclopedia:??milling machine

Machine tool that rotates a circular tool with numerous cutting edges arranged symmetrically about its axis, called a milling cutter. The metal workpiece is usually held in a vise clamped to a table that can move in three perpendicular directions. Cutters of many shapes and sizes are available for a wide variety of milling operations. Milling machines cut flat surfaces, grooves, shoulders, inclined surfaces, dovetails, and T-slots. Various form-tooth cutters are used for cutting concave forms and convex grooves, for rounding corners, and for cutting gear teeth.

Wikipedia:Milling machine

A milling machine (also see synonyms below) is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines. Unlike a drill press, which holds the workpiece stationary as the drill moves axially to penetrate the material, milling machines also move the workpiece radially against the rotating milling cutter, which cuts on its sides as well as its tip. Workpiece and cutter movement are precisely controlled to less than 0.001 in (0.025 mm), usually by means of precision ground slides and leadscrews or analogous technology. Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC).

Milling machines can perform a vast number of operations, from simple (e.g., slot and keyway cutting, planing, drilling) to complex (e.g., contouring, diesinking). Cutting fluid is often pumped to the cutting site to cool and lubricate the cut and to wash away the resulting swarf.

Milling Machine Q&A

What are the defect of milling appliance (metal milling machine)?
It depends what you plan to make with it. A milling electrical device is less than ideal for making round parts, for example - these are better made on a lathe. There are adjectives kinds of limitations dependent on the machine itself too. size of parts, speed of chuck, tool...

How to obtain out melt contained by sugar from Food Mill (grinder machine)?
I had the bright idea to trade name powdered sugar using a food mill, the heat solidified the sugar in the actual grinder piece, which I cannot open up or access. Any inventive tips or ideas? If this is a place where on earth the grinder can???

I am brand new to a Cincinnati macron milling contraption and want to identify the Sybil???s on the controls?
on a okuma machine the symbols are named eg slb single block but not on the cinncinati Maybe you should read the mitt book. Or ask your employer.

What does CNC be a sign of , resembling a cnc milling appliance?
Computer Numerically Controlled ... I have several Lathes and mills and am looking for work. Feel free to e-mail me with any ? slimer11(a)prodigy.lattice cnc u take a sheet of steel it punches out holes and the shape of the steel then they bend the quantity into...

What should we share the clients to conservation the MTM mill machines during they are using them?
(1).In order to ensure normal operation of the equipment ,a almanac containing strict rules and procedures for its operation, maintenance should be well prepared and followed .Tools ,replacement parts for maintain ,repairing and lubricating oil and grease must be available for immediate use....

Whats a milling mechanism is used for?
Could any 1 tell me what a milling machine is used for. For example roughing. Thanks. In engineering it's a tool which has a vice to clamp the metal which is to be milled and a cutter which rotates and cuts the metal to size. The cutter could be anything from a small...

Whats are the benifites of milling tool?
Machines have to have parts, that's a given. As machines obtain more and more complex so do the parts that make them up. Since a lot of machinery requires metal parts, here are effectively two options to make complex parts: cast and machining. Unless the number of parts is extremely high, casting can...

Information on Menards 30 drilling and milling Machine?
Need to know where to get parts and information roughly speaking this machine???the company has went out of business. I tried to rach Menards they could not lend a hand. I would get a hold of some well established device shops for advice, if anyone would know it would be them. Good???

What are the differences between mill, factory and plant? And between mill and electrical device?
between wire rod mill and wire rod plant, between flex rod mill and wire rod machine. All handle similar activities. But are different surrounded by the way it is handled. Totally, adjectives of them are engaged in industrial happenings. Look in a apposite dictionary. I...

How to operate a milling apparatus?
It???s like operating an Etch-a-Sketch, but in three dimensions, and next to more opportunities to injure yourself. Plus, you get bits of hot metal thrown at you. I enjoy to assume that you are referring to a milling machine in a piece of equipment shop, if that is the case some one will show???

What are the disadvantages and advantages of the following:milling ,turning,grinding and drilling machines ?
on manufacturing processes.(techniques) No direct comparison, since they are all designed to do different things.

How to stop getting cramp surrounded by calf when running on tread mill (other than stop going on the contrivance!!)? Thanx?
Have lately been getting real impossible cramp when running and then cant run or use exercise equipment for quite a while. Any reason why this shold start happening? Eat Bananas before you go on and stretch for 5 to???

What are the limitations to the contraption design of a milling apparatus?
this is for my engineering work, even my teacher can't find any of the information on the internet. please help me answer this. The problem really is what type of milling contrivance you are interested in, the main makeshift types are Horz. Mill, End Mill, universal mill. In...

How to turn digital calipers into digital read outs on a micro milling gadget.?
I have recently purchased a micro milling piece of equipment. It does not come with Digital readouts. I am wondering if anyone out there can illustrate to me how to turn three calipers into an X, Y, and Z digital readout. I would buy a DRO???

What does "power down feed" suggest for a instruction manual milling contrivance?
It means that the lowering of the tool into the work, or raising the work and table into the tool, is assisted or completely operate by a motor.

Information on Turning, Milling and Grinding machines?

Hi does anyone know where I can can get detailed information on Turning, Milling and Grinding machines and within applications? Hi, I???am Sourav Banerjee ??? A Man with a Mission. A mission to Make Things Easier for you! Take This ??? You simply register here on this website, and post or upload any???

Is at hand any contrivance to verbs coolant solution contained by a tube mill short effecting on the juice characteristic?
There are some pollution in the tube mill when coolant liquid circulating surrounded by the system ,after a period of time this pollution effected on the juice and gradually the fat is seperated from the juice and the percentage comes???

If you are looking to buy a Beneficiation Equipment for your plant, please visit us online at??www.mhmhd.com??to view the range we have available.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

What is Rolling Mills?

Rolling mills was said to be one of the tools that a jewelers must have. It is a tool that is used to make a sheet or wire from a scrap of gold. It is being used to apply pressure to a metal to flatten it and to make it longer.

A rolling mill, also known as a reduction mill or mill, has a common construction independent of the specific type of rolling being performed:

• Work rolls
• Backup rolls - are intended to provide rigid support required by the working rolls to prevent bending under the rolling load
• Rolling balance system - to ensure that the upper work and back up rolls are maintain in proper position relative to lower rolls
• Roll changing devices - use of an overhead crane and a unit designed to attach to the neck of the roll to be removed from or inserted into the mill.
• Mill protection devices - to ensure that forces applied to the backup roll chocks are not of such a magnitude to fracture the roll necks or damage the mill housing
• Roll cooling and lubrication systems
• Pinions - gears to divide power between the two spindles, rotating them at the same speed but in different directions
• Gearing - to establish desired rolling speed
• Drive motors - rolling narrow foil product to thousands of horsepower
• Electrical controls - constant and variable voltages applied to the motors
• Coilers and uncoilers - to unroll and roll up coils of metal

Slabs are the feed material for hot strip mills or plate mills and blooms are rolled to billets in a billet mill or large sections in astructural mill. The output from a strip mill is coiled and, subsequently, used as the feed for a cold rolling mill or used directly by fabricators. Billets, for re-rolling, are subsequently rolled in either a merchant, bar or rod mill. Merchant or bar mills produce a variety of shaped products such as angles, channels, beams, rounds (long or coiled) and hexagons.

Before using the rolling mill, anneal the metal you'll be working with. Annealing is basically the heating and then cooling (the speed of cooling depends on the metal you're working with; some need to sit until cool, some may be quenched with water or other solutions) of a piece of metal to improve its toughness and to eliminate its potential brittleness. Before working with your metal, make sure that it is clean of contaminants. This can be done by pickling your metal using an acidic solution (which is often heated), neutralizing the acid by dipping the metal in a base solution and then rinsing it in clean water and drying it. Try to keep the oils from your hands off your metal as much as possible as this can cause tiny pits to form.

Place the end of your metal piece into the machine (as close to the middle of the rollers as possible so that the pressure will be even) and tighten the mill down until the rollers are snug (but not tight) on the piece. It should be fairly easy to move the crank. If it is very difficult to roll your piece through, the rollers need to be loosened or you will risk damage to both them and your piece.

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BCaiWa is Technical support at Luoyang Moheman Heavy-duty Machinery Co.Ltd

Ball Mill: Cement Mill

Ball Mill Application:

Cement ball mill is mainly used in grinding of finished products and raw materials in cement production. It's also applied to grind various ore and other grinding materials in metallurgical, chemical, electricity and other industrial and mining enterprises. It can be used to open-circuit grinding, as well as close-circuit grinding system together with separator. Cement mill has a strong adaptability to materials to production. It can be in operation continually and easy to control grinding fitness of production and so on. Ball mill of cement production is suitable to both drying production and wet production. What's more, the operation of grinding and drying can be done simultaneously.


The machine is composed by feeding part, discharging part, turning part and driving part (reducer, small driving gear, electric motor and electric control). The quill shaft adopts cast steel part and the liner is detachable. The turning gearwheel adopts casting hobbing process and the drum is equipped with wear-resistant liner, which has good wear-resistance. The machine is with stable and reliable working condition.
Moreover, according to different materials and discharging methods, there are dry ball mills and wet ball mills for choice.

Ball Mill Working Principle:

The ball mill is a horizontal rotating device transmitted by the outer gear. The materials are transferred to the grinding chamber through the quill shaft uniformly. There are ladder liner and ripple liner and different specifications of steel balls in the chamber. The centrifugal force caused by rotation of barrel brings the steel balls to a certain height and impact and grind the materials. The ground materials are discharged through the discharging board thus the grinding process is finished.

Quality Carbon Structure Steels

GB/T 699-1999 Quality Carbon Structure Steels

Implementation Date: 1999
Chinese Name: Quality Carbon Structure Steels
Issued By:
English Version: Available
File Format: Word
Word Quantity: 4000 words

1. Aspect(s) Covered

This standard regulates size, shape, weight, tolerance, specification,
testing method, inspection rules, package, mark and quality certificate
of hot-rolled or hot-forged quality carbon structure steel.
This standard is applicable to quality carbon structure steel rod whose
diameter or thickness is not greater than 250mm. Through negotiation
between buyers and sellers, quality carbon structure steel rod whose
diameter or thickness is greater than 250mm can also be supplied.
Grades and chemical composition prescribed in this standard are also
applicable to steel ingot and steel billet products.

2. Normative References

The following standards contain provisions which, through reference in
this text, constitute provisions of this standard. All the Standards
stated below are effective at the publication of this Standard. All
standards are subject to revision, and parties to agreements based on
this standard are encouraged to investigate the possibility of applying
the most recent editions of the standards indicated below.

GB/T 222-1984 Method of Sampling Steel for Determination of
Chemical Composition and Permissible Variations for Product Analysis
GB/T224-1987 Determination of Depth of Decarburization of Steel
GB/T 226-1991 Etch Test for Macrostructure and Defect of Steels
GB/T 228-1987 Metallic Materials - Tensile Testing
GB/T 229-1994 Metallic Materials - Charpy Notch Impact Test
GB/T 231-1984 Metallic Materials - Brinell Hardness Test
GB/T 233-1982 Method for Forging Test of Metals
GB/T 702-1986 Hot-rolled Round and Square Steels -
Dimension, Shape, Weight and Tolerance
GB/T 908-1987 Forged Round and Square Steels - Dimension,
Shape, Weight and Tolerance
GB/T 1979-1980 Diagram of a Low Magnification Texture Blemish
Grading of Structural Steel
GB/T 2101-1989 General Requirements of Acceptance, Packaging,
Marking and Certification for Section Steel
GB/T 2975-1998 Steel and Steel Products - Location and
Preparation of Test Pieces for Mechanical Testing
GB/T 4336-1984 Method for Photoelectric Emission Spectroscopic
Analysis of Carbon Steel Medium and Low Alloy Steel
GB/T 6397-1986 Metallic Materials - Test Pieces for Tensile Testing
GB/T 7736-1987 Ultrasonic Inspecting Method for
Macro-structure and Imperfection of Steel
GB/T 10561-1989 Steel - Determination of Content of Non-metallic
Inclusion - Micrographic Method Using Standard Diagrams
GB/T 17616-1998 Unified Numbering System for Designations of
Iron, Steel and Alloy
GB/T 13299-1991 Steel - Determination of Microstructure
GB/T 15711-1995 Steel Products - Method for Etch Test of Tower
Sample
GB/T 17505-1998 Steel and Steel Products - General Technical
Delivery Requirements
YB/T 5148-1993 Metal - Methods for Estimating the Average
Grain Size