Материал: 2177
III. Work in pairs. Study the prompts in italics. Think of 2 or 3 statements using the words from Ex. I and Infinitive constructions.
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For an operator to work efficiently, he must be |
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aware of FMS problem. |
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He seems to be a skilled operator. |
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The aim of this project is to reveal the most signifi- |
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cant FMS problem. |
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* Find the sentences with Infinitives and Infinitive constructions in the |
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text below and translate them.
IV*. What can you see in the pictures (pic. 28 – 29)? Do you see any
difference? If yes, how do they differ? б А Д И
Pic. 28
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Pic. 29 |
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V. Read theбtext, and then go back to Ex. VI to answer the questions |
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once again. |
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AUTOMATING TOOLING IN FMS
The delivery and changing of cutting tools to the CNC machine tools seems to be a vital requirement in FMS. Typical CNC machine tools consist of permanently attached tool magazines, equipped with automatic tool changers, with capacities of from 30 to 120 cutting tools.
An optimum tooling system would haveИall required cutting tools stored in the various machine tool magazines. However, tooling requirements generally exceed the machine tool magazine capacities in most practical FMS. Also, due to cutter wear and breakage, tools must inevitably be replaced.
As for tool delivery two approaches should be mentioned: manual and automated. In a manual tool delivery environment, an operator brings the cutters to the machines and manually inserts them into the machine tool magazine. For this system to operate efficiently and with minimal human interference, each machine tool magazine capacity would have to be of the order of 120.
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Since the aim of FMS is to strive towards untended manufacturing, an automated tool delivery system is generally preferred. Such an automated tool delivery/changing system includes machine tools along with portable tool drums, each capable of storing up to 30 cutting tools.
A special gantry crane transports entire tool drums between the tool Сroom and columns located behind the machine tool. The machine’s central
column travels horizontally enabling the tool drums to be exchanged. Drawbacks to this system involve redundancy of tool drums, the
need for a large tool room to store the tool drums and the requirement of a gantry crane.
Nevertheless, a modified version of this system enables the tool drums to be transported by an automated-guided vehicle (AGV). A shuttle
cart exchanges the tool drum, which is stored alongside the machine tool. |
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Although this system is more flexible than the previous one, tool drum re- |
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dundancy and a large tool storage area are still required. |
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иA more common approach to tool transport is mounting a portable |
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tool magazine on a movable pallet which can then be transported by an |
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AGV to a total delivery receiving unit located behind each machine tool. |
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The receiving unit consists of a pallet cylinder capable of unloading and |
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loading the бtool magazine pallet from the AGV to the receiving unit. The |
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receiving unit also consists of an interchange arm which exchanges tools |
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between the portable tool magazine and the permanent machine tool maga- |
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zine. |
It should be noted that the major benefit of such a system is that the |
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machine tool can operate while tools are exchanged between the two tool |
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magazines. |
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Another method for transporting tools consists of using an overhead |
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transport carrier capable of deliveringДfive tools at the same time, all tools being protected by individual plastic cartridges during storage and transport. A robot arm located at each machine tool exchanges tools between the overhead transport carrier and the machine tool magazine. This system allows all machine tools to be automatically linked with the tool room and with each other.
And at last it is necessary to mention one more approach to automatic tool transport. Its solution is to store tools on racks behind the machining centres. A rail-guided cart, equipped with a tool transfer mechanism, travels up and down the rail system and transports tools from the storage rack to the individual machine tool magazines. Operators manually
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load new tools into a rotary tool station, and the rail-guided cart picks up a tool and loads it into the storage rack.
Generally speaking, tooling, essential part of an FMS, is given much
attention. It is recognized that tooling can have a major effect on FMS per- |
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formance. Automation of tooling seems to be a solution to a significant |
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FMS problem and it is a requirement for unmanned FMS operation. |
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VI. Look at the plan of the text “Automated tooling in FMS”. Is it nec- |
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essary to rearrange its items or add anything? |
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1. |
Tooling system |
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2. |
Manual tool delivery |
3. |
Automated tool delivery |
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a) Transportation with a gantry crane |
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b) Transportation with an AVG |
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c) Transportation with an overhead transport carrier |
VII. True or False? |
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1. |
Machine tool magazine capacity is usually less than it is required in |
practice. |
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2. In a manualбtool delivery, an operator inserts the machine tool magazine |
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manually. |
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3. A gantry crane is used to transport tool drums to CNC machine tools. |
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4. Transportation of tool drums by an AGV is more flexible than that by a |
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gantry crane. |
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5. A rail-guided cart can change tools itself. |
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VIII. Work in pairs. Make up 6 special questions to the text and let |
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your partner answer them. |
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What ______________________________________________________Д |
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Which _____________________________________________________? |
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How many __________________________________________________? |
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Where _____________________________________________________И? Why _______________________________________________________? Who _______________________________________________________?
IX*. Make a drawing of an automated tool delivery system, present it to your group and have a discussion.
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HOME TASK 13
A. Memorize the words from Ex. I and be ready to do a dictation.
B. Read an excerpt “Automated tool delivery and loading” from a Сbook “Tool and Manufacturing Engineers Handbook: Material and
Part Handling in Manufacturing” by Philip Mitchel
(https://books.google.ru/books?id=5HsU9ScZkU4C&dq=automated+t ool+delivery+system&hl=ru&source=gbs_navlinks_s) and translate it into Russian.
и б А Д И
C. Draw up a questionnaire for a CNC machine operator to check his knowledge on tool delivery systems.
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