《自动化课后答案ch14 single station-3e-si》由会员分享，可在线阅读，更多相关《自动化课后答案ch14 single station-3e-si（6页珍藏版）》请在金锄头文库上搜索。
1、Single Station-3e-SI 7-17, 17/06, 06/04/07, 09/13/07Chapter 14SINGLE STATION MANUFACTURING CELLSREVIEW QUESTIONS14.1 Name three reasons why single-station manned cells are so widely used in industry. Answer: The reasons given in the text are the following: (1) It requires the shortest amount of time
2、 to implement. (2) It requires the least capital investment of all manufacturing systems. (3) Technologically, it is the easiest system to install and operate. Its maintenance requirements are usually minimal. (4) For many situations, particularly for low quantities, it results in the lowest cost pe
3、r unit produced. (5) In general, it is the most flexible manufacturing system with regard to changeovers from one part or product style to the next.14.2 What does the term semi-automated station mean?Answer: As defined in the text, a semi-automated station is a machine that is controlled by some for
4、m of program during a portion of the work cycle, and the workers function is simply to load and unload the machine each cycle, and periodically change cutting tools.14.3 What is a single-station automated cell?Answer: A single station automated cell is a fully-automated machine capable of unattended
5、 operation for a time period longer than one machine cycle. A worker is not required to be at the machine except periodically to load and unload parts or otherwise tend it.14.4 What are the five enablers that are required for unattended operation of a single-model or batch-model automated production
6、 cell?Answer: As given in the text, the five enablers of unattended operation for a single-model or batch-model automated production cell are the following: (1) a programmed cycle that allows the machine to perform every step of the processing or assembly cycle automatically; (2) a parts storage sub
7、system and a supply of parts that permit continuous operation beyond one machine cycle; (3) automatic transfer of workparts between the storage system and the machine (automatic unloading of finished parts from the machine and loading of raw workparts to the machine); (4) periodic attention of a wor
8、ker who performs the necessary machine tending functions (e.g., parts loading and unloading of the storage subsystem) for the particular processing or assembly operation; and (5) built-in safeguards that protect the system against operating under conditions that may be unsafe or self-destructive to
9、itself or destructive to the work units being processed or assembled. 14.5 What are the additional three enablers that are required for unattended operation of a mixed-model automated production cell?Answer: As given in the text, the three enablers of unattended operation for a mixed-model automated
10、 production cell are (1) a work identification subsystem that can distinguish the different starting work units entering the station, so that the correct processing sequence can be used for that part or product style; (2) a program downloading capability to transfer the machine cycle program corresp
11、onding to the identified part or product style; and (3) a quick setup changeover capability so that the necessary workholding devices and other tools for each part are available on demand.14.6 What is an automatic pallet changer?Answer: An automatic pallet changer is a part handling subsystem that i
12、s used to exchange pallet fixtures between the machine tool worktable and the load/unload position or part storage system.14.7 What is a machining center?Answer: As defined in the text, a machining center is a machine tool capable of performing multiple machining operations on a workpart in one setu
13、p under NC program control. Typical cutting operations performed on a machining center are milling, drilling, reaming, and tapping.14.8 What are some of the features on a NC machining center used to reduce nonproductive time in the work cycle?Answer: The text lists the following features: (1) automa
14、tic toolchanger; (2) automatic workpart positioner; and (3) automatic pallet changer. 14.9 What is a machine cluster?Answer: As defined in the text, a machine cluster is a collection of two or more machines producing parts or products with identical cycle times and serviced (usually loaded and unloa
15、ded) by one worker.PROBLEMSUnattended Operation14.1 A CNC machining center has a programmed cycle time = 25.0 min for a certain part. The time to unload the finished part and load a starting work unit = 5.0 min. (a) If loading and unloading are done directly onto the machine tool table and no automa
16、tic storage capacity exists at the machine, what are the cycle time and hourly production rate? (b) If the machine tool has an automatic pallet changer so that unloading and loading can be accomplished while the machine is cutting another part, and the repositioning time = 30 sec, what are the total cycle time and hourly production rate? (c) If the machine tool has an automatic pallet changer that interfaces with a parts storage unit whose capac
