【机械类⽂献翻译】CNC
机械专业中英⽂⽂献翻译
CNC
捉鬼记CNC stands for Computerized Numerical Control and has been around since the early1970s. prior to this, it was called NC,for numerical control. While people in most walks of life have never heard of this term, CNC has touched almost every form of manufacturing process in one way or another. If you'll be working in manufacturing, it's likely that you'll be dealing with CNC on a regular basis.
Before CNC
While there are exceptions to this statement,CNC machines typically replace (or work in conjunction with) some existing manufacturing process. Take one of the simplest manufacturing process,drilling holes,for example.
A drill press can of cour be ud to machine holes. A person can place a drill in the drill chuck that is cured in the spindle of the drill press. They can then (manually) lect the desired speed for rotation (commonly by switching belt pulleys), and activate the spindle. Then they manually pull on the quill lev
er to drive the drill into the workpiece being machined.
As you can easily e, there is a lot of manual intervention required to u a drill press to holes. A person is required to do something almost every step along the way! While this manual intervention may be acceptable for manufacturing companies if but a small number of holes workpieces must be machined, as quantities grow, so does the likelihood for fatigue due to the tediousness of the operation. And do note that we've ud one of the simplest machining operations(drilling) for our example. There are more complicated machining operations that would require a much higher skill level (and increa the potential for mistakes resulting in scrap workpieces) of the person running the conventional machine tool. (We commonly refer to style of machine that CNC is replacing as the conventional machine.)
By comparison, the CNC equivalent for a drill press (possibly a CNC machining center or CNC drilling & tapping center) can be programmed to perform this operation in a much more automatic fashion. Everything that the drill press operator was doing manually will now be done by the CNC machine, including:placing the
怎么做燕窝最简单做法drill in the spindle, activating the spindle,positioning the workpiece under the drill, machining the hole, and turning off the spindle.
消防安全工作总结How CNC works
As you might already have guesd,everything that an operator would be required to do with conventional machine tools is programmable with CNC machines. Once the machine is tup and running, a CNC machine is quite simple to keep running. In fact CNC operators tend to get quite bored during lengthy production runs becau there is so little to do. With some CNC machines, some of the specific programmable functions.
Motion control
司法考试报考条件All CNC machine types share this commonalty: They all have two or more programmable directions of motion called axes. An axis of motion can be linear(along a straight line) or rotary(along a circular path). One of the first specifications that imply a CNC machine's complexity is how many axes it has. Generally speaking, the more axes, the more complex the machine. The axes of any CNC machine are required for the purpo of causing the motions needed for the manufacturing process. In the drilling example, the axes would position then tool over the hole to be machined (in two axes) and machine the hole (with the third axis). Axes are named with /doc/811750010.html
mon linear axis named X,Y,and Z. Common rotary names are A,B,and C. There are related to the coordinate system. Programmable accessories
A CNC machine wouldn't be very helpful if all it could only move the workpiece in two or more axes. Almost all CNC machines are programmable in veral other ways. The specific CNC machine type has a lot to do with its appropriate programmable accessories. Again,any required function will be programmable on full-blown CNC machine tools. Here are some examples for one machine type(machining centers).旅程英语>梦见湖水
Automatic tool changer
Most machining centers can hold many tools in a tool magazine. When required,
the required tool can be automatically placed in spindle for machining.
Spindle speed and activation
The spindle speed(in revolutions per minute) can be easily specified and the spindle can be turned on in a forward or rever direction.It can also,of cour, be turned off.
Coolant
Many machining operations require coolant for lubrication and cooling purpos. Coolant can be turned on and off from within the machine cycle.
The CNC program
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Think of giving any ries of step-by-step instructions. A CNC program is nothing more than another kind of instruction t.
It's written in ntence-like format and the control will execute it in quential order,step by step.
A special ries of CNC words are ud to communicate what the machine is intended to do. CNC words begin with letter address(like F for feedrate,S for spindle speed,and X,Y,and Z for axis motion). When placed together in a logical method, a group of CNC words make up a command that remble a ntence.
The CNC control
The CNC control will interpret a CNC program and active the ries of commands in quential order. As it reads the program, the CNC control will activate the appropriate machine functions, cau axis motion, and in general, follow the instructions given in the program.
Along with interpreting the CNC program, the CNC control has veral other purpos. All current model CNC controls allow programs to be modified(edited) if mistakes are found. The CNC control allows special verification functions(like dry run) to confirm the correctness of the CNC program. The CNC control allows certain important operator inputs to be specified parate from the program, like tool length values. In general, the CNC control allows functions of the machine to be manipulated.
What is a CAM system?
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For simple applications (like drilling holes),the CNC program can developed
