Construction of a Pallet Changer with Automatic Setup Function in Flexible Manufacturing Cells

柔性制造单元(FMC)是车间式制造系统的基本加工单元。近年来，FMC作为一种用于小批量、多品种生产的新型制造单位，引起了人们的特别关注。在为本研究开发的FMC中，工件的对位操作是最重要也是最复杂的操作。这种操作很难实现自动化，即使在今天，在自动化作业车间中，居中操作也往往是由操作员进行的。本研究设计了一种具有自动设置功能的新型FMC，并构建了FMC的自动设置设备。该设置操作由工业机器人和工件夹紧装置自动执行。这种自动设置设备旨在将操作员从复杂的工件对中操作中解放出来，并促进完全无人值守的工厂。本研究取得了以下研究结果：1.开发了一种新型的柔性制造单元。FMC由分度托盘换向器、夹持架、装卸工位和工业机器人组成。FMC具有以下特点：(1)工业机器人具有两种功能：搬运工件和测量工件位置。(2)在分度托盘换向器上安装多个夹持架。当用数控机床或加工中心在其中一个夹具机架上加工零件时，工业机器人可以对待机加工的其他夹具机架上的零件进行对中操作。因此，在所提出的FMC中，加工和对中操作可以同时进行。(3)所有操作均由微型计算机系统控制。为了验证正确的定心操作的可行性，对工件的定心操作进行了计算机仿真。并用数值算例说明了FMC的有效使用步骤。

A flexible manufacturing cell (FMC) is a basic machining unit of a job-shop type manufacturing system. Recently, the FMC has attracted special interest as a new manufacturing unit for low-volume, variety production. In the FMC developed for this study, setup operation of a workpiece, especially centering of workpieces, is the most important and complicated operation. It is hard to automate this operation; even today, in automated job shops, centering operations are often conducted by operators.In this study, a new type of FMC with automatic setup function was designed, and an automatic setup equipment for FMC was constructed. This setup operation is automatically conducted by an industrial robot and a workpiece clamping device. This automatic setup equipment intends to free operators from complicated centering operations of workpieces and to promote complete unmanned factories. The following results were obtained from this study.1. A new type of flexible manufacturing cell was developed. The FMC is composed of an index-pallet changer, clamping stands, a loading-unloading station, and an industrial robot. The FMC has the following features:(1) An industrial robot conducts two functions: handling workpieces and measuring the position of workpieces.(2) A multiple number of clamping stands is installed on an index-pallet changer. While a workpiece is machined on one of the clamping stands by an NC machine tool or a machining center, the centering operation by the industrial robot can be conducted for workpieces on the other clamping stands which are on standby for machining. Thus, both machining and centering operations can be simultaneously processed in the FMC proposed.(3) All operations are systematically controlled by a micro-computer.2. Computer simulation of centering operation was conducted for workpieces in order to check the feasibility of correct centering operation.3. The procedure for effective use of FMC was explained with a numerical example.