数控专业外文翻译--换刀坐标-数控设计(编辑修改稿)

数控专业外文翻译--换刀坐标-数控设计(编辑修改稿)内容摘要：

y the operator. A skilled operator should be capable of recognizing the tools to be used for a particular machining operation especially when an operation schedule and tool detail sheet has been provided. For operators’ convenience there are various tool identification aids that can be used. One technique is to have a special stand in which the tools are held in numbered locations – the stand is linked to the control unit. The number of the tool required for a particular operation being called up from information stored in the part program, and a light at the required tool location in the stand is illuminated, or the location number displayed on the control unit’ s screen. With this arrangement it is essential that the tools are placed in the correct location at the setting up stage, and also replaced correctly after use. Automatic tool changers use a number of systems to identify the tool. One system used on machining centres of identifying the tools themselves has a series of rings or discs fitted on the body of the tool holder. The rings are all of equal thickness but are two different diameters. The largerdiameter rings activate microawitches at the reading head。 there is a microawitch for each rings are referred to as ‘ spacers’ and do not activate a microawitch. A signal in binary number format is created by placing activating and spacer rings at selected places, as shown in Figure . the number created by certain of the microawitches being activated is sent to the control unit. There is usually a screwed collar which can be removed so that the rings and spacers can be arranged in the designed sequence to create the tool number. It is essential to have a tool library which lists all the tools available. There are various ways in which the different types of tools can be identified. In Figure the binary by the top three rings can be used to indicate the type of tool, and the remainder of the rings can be used to indicate the size of the tool. Another tool identification system uses small sealed capsules embedded in the shank of the holder. The housings of the capsules are waterproof and are made of stainless steel。 the ceramic cover of the sensing face is resistant to hot metal chips. There are two forms of this system。 in one form there a number of capsules embedded in the shank of the holder with five capsules fitted into the shanks. Each capsule generates a single decimal digit at the reading station. The capsules which are 7 ㎜ diameter and 5 ㎜ thick can either be glued into holes in the shank or can be held in element holders which can easily be changed if necessary. The tool number is ‘ read’when the tool passes in the proximity of a sensing head. The reading head contains an electrical circuit and the number is generated by inductive coupling. It is reported that the reading of the number can be at speeds of up to of 30m/min. an individual capsule has a memory capacity to store up to 1 K bit of data. The information ‘ written and read’ can be the tool number of up to 16 digits, and also details on the tool setting length and diameter offsets, tool life etc. For CNC centres there are a number of tool holding systems available, but the contrast between the tyoe of tools used on machining and turning centered results in different turrent and magazine tool changing arrangements.  Tool holding on machining centres On milling and drilling machines there are a number of quick clawing action tool holders. One type has a clamping ring on the spindle nose that needs less than a plete turn to secure the tool holder into the spindle nose. Another type has a draw bar which passes through the centre of the spindle and screws into the end of the shank to pull the holders securely into the spindle nose. The draw bar can be rotated rapidly by a special mechanism. Figure shows an airactuated hydraulicpowered draw bar. Which has a safety interlock to prevent the spindle rotating if the tool is not correctly located. For manual loading the tool holder can be released when the operator pressed a button on the head of the machine. For automatic tool loading the releasing of the tools can be programmed. A mon type of shank has a nonstick taper which has an included angle of the order of 16 degrees。 rather than a friction type taper such as a Morse taper which has an angle of approximately 3 degrees. There are standard sizes of tool holder shanks, ranging in size from no. 10 ISO to no. 60 ISO。 these have tapers with maximum size of the order of 16 ㎜ and 108 ㎜ respectively. This type of holder derives the driving power keys on the spindle nose engaging in slots in the tool holder. The taper section is to ensure that when the tool holder is drawn into the spindle nose, the centre of the tool is coin cident with the centre of the spindle. The tool holder can be removed quickly and easily because the taper does not lock, and the tool holder is free when the clamping mechanism is released. The tool holders with the Morse taper shanks derive the driving power from the friction beteewn the shank and the spindle, and there has to be some form of ejection device to remove the tool holder. 译文三 刀库 刀库较为普遍比车削中心上铣削和钻孔机。 这是因为铣削和钻孔作业需要较大的品种比不转动的切削工具。 杂志举办的工具数量是非常仔细地考虑。 在使用工具的数量更大，更多的问题是在工具维护和加工成本较高。 此外，作为该杂志的容量增加，以容纳更多的工具，杂志较大，因此较重的是，需要更多的维修。 需要更多的能量移动较大的 库。 必须有工具一应俱全，增加刀具更换所需的时间成本之间的平衡。 工具杂志的一个优点是可以被复制，这样，当一个工具，已经达到了其寿命的终点，另一个是准备使用的手段，受到过度磨损。 该设备是特别有用，当机 器下的计算机控制 原文三。