簡(jiǎn)易工具磨削機(jī)設(shè)計(jì)
簡(jiǎn)易工具磨削機(jī)設(shè)計(jì),簡(jiǎn)易,工具,磨削,設(shè)計(jì)
48.2 Development of Machining Center and Turning Center
48.2.1 Machining Center
A machining center is a highly automated NC milling machine that performs multiple machining operations such as end milling, drilling, and tapping. It was devel-oped to realize process integration as well as machining automation, in 1958. Figure 48.8 shows an early ma-chining center equipped with an automatic tool changer(Al-C). Most machining centers are equipped with an ATC and an automatic pallet changer (APC) to per-form multiple cutting operations in a single machine setup and to reduce nonproductive time in the whole machining cycle.
Machining centers are classified into horizontal and vertical types according to the orientation of the spindle axis. Figures 48.9 and 48.10 show typical horizontal and vertical machining centers, respectively. Most horizontal machining centers have a rotary table to index the machined part at some specific angle relative to the cutting tool. A horizontal machining center which has a rotary table can machine the four vertical faces of boxed workpieces in single setup with minimal human assistance. Therefore, a horizontal machining center is widely used in an automated shop floor with a loading and unloading system for work-pieces to realize machining automation. On the other hand. a vertical machining center is widely used in a die and mold machine shop. In a vertical machining cen-ter, the cutting tool can machine only the top surface of boxed workpieces, but it is easy for human opera-tors to understand tool motion relative to the machined part.
Fig. 48.8 Machining center, equipped with an ATC (courtesy of Makino Milling Machine Co. Ltd.)
Fig.48.9 Horizontal machining center (courtesy of Yamazaki Mazak Corp.)
Fig. 48.10 Vertical machining center (courtesy of Yamazaki Mazak Corp.)
Automatic Tool Changer (ATC)
ATC stands for automatic tool changer, which permits loading and unloading of cutting tools from one machining operation to the next. The ATC is designed to exchange cutting tools between the spindle and a tool magazine, which can store more than 20 tools. The large capacity of the tool magazine allows a variety of workpieces to be machined. Additionally, higher tool-change speed and reliability are required to achieve a fast machining cycle. Figure 48. 11 shows an example of a twin-arm-type ATC driven by a cam mechanism to ensure reliable high-speed tool change.
Fig.48.11 ATC: automatic tool changer (courtesy of Yamazaki Mazak Corp.)
Automatic Pallet Changer (APC)
Automatic Pallet Changer (APC)APC stands for automatic pallet changer, which permits loading and unloading of workpieces for machining automation. Most horizontal machining centers have two pallet tables to exchange the parts before and after machining automatically. Figure 48.12 shows an example of an APC. The operator can be unloading the finished part and loading the next part on one pallet while the machining center is processing the current part on another pallet.
Fig. 48.12 APC: automatic pallet changer (courtesy of Yamazaki Mazak Corp.)
48.2.2 Turning Center
A turning center is a highly automated NC lathe to per-form multiple turning operations. Figure 48.13 shows a typical turning center. Changing of cutting tools is performed by a turret tool changer which can hold about ten turning and milling tools. Therefore, a turning center enables not only turning operations but also milling operations such as end milling, drilling, and tapping in a single machine setup. Some turning centers have two spindles and two or more turret tool changers to complete all machining operations of cylindrical parts in a single machine setup. In this case. the first half of the machining operations of the workpiece are carried out on one spindle, then the second half of the machining operations are carried out on another spindle, without unloading and loading of the workpiece. This reduces production time.
Fig. 48.13 Turning center or CNC lathe (courtesy of Yamazaki Mazak Corp.)
Turret Tool Changer
Figure 48.14 shows a tool turret with 12 cutting tools.A suitable cutting tool for the target machining operation is indexed automatically under numerical control for continuous machining operations. The most sophisticated turning centers have tool monitoring systems which check tool length and diameter for automatic tool alignment and sense tool wear for automatic tool changing.
Fig.48.14 Tool turret in turning center (courtesy of Yamazaki Mazak Corp.)
48.2.3 Fully Automated Machining: FMS and FMC
Flexible Manufacturing System (FMS)
The concept of the flexible manufacturing system(FMS) was proposed during the mid-1960s. It aims to perform automatic machining operations unaided by human operators to machine various parts. Machining centers are key components of the FMS for flexible machining operations. Figure 48.15 shows a typical FMS,which consists of five machining centers, one conveyor,one load/unload station. and a central computer that controls and manages the components of the FMS.
Fig. 48.15 Flexible manufacturing system (courtesy of Yamazaki Mazak Corp.)
No manufacturing system can be completely flexible. FMS are typically used for mid-volume and mid-variety production. An FMS is designed to machine parts within a range of style, sizes, and processes,and its degree of flexibility is limited. Additionally,the machining shape is changeable through the part programs that control the NC machine tools. and the part programs required for every shape to be machined have to be prepared before the machining operation. Therefore a new shape that needs a part program is not acceptable in conventional FMS, which is why a third innovation of machine tools is required to achieve autonomous machining operations instead of automatic machining operations to achieve true FMS.
An FMS consists of several NC machine tools such as machining centers and turning centers. material-handling or loading/unloading systems such as industrial robots and pallets changer, conveyer systems such as conveyors and automated guided vehicles (AGV),and storage systems. Additionally, an FMS has a central computer to coordinate all of the activities of the FMS,and all hardware components of the FMS generally have their own microcomputer for control. The central computer downloads NC part programs, and controls the material-handling system, conveyer system, storage system, and management of materials and cutting tools,etc.
Human operators play important roles in FMS, performing the following tasks:
l. Loading/unloading parts at loading/unloading stations
2. Changing and setting of cutting tools
3. NC part programming
4. Maintenance of hardware components
5. Operation of the computer system.
These tasks are indispensable to manage the FMS successfully.
Flexible Manufacturing Cell (FMC）
Basically, FMS are large systems to realize manufacturing automation for mid-volume and mid-variety production. In some cases. small systems are applicable to realize manufacturing automation. The term flexible manufacturing cell (FMC) is used to represent small systems or compact cells of FMS. Usually, the number of machine tools included in a FMC is three or fewer.One can consider that an FMS is a large manufacturing system composed of several FMC.
48.3 NC Part Programming
The task of programming to operate machine tools automatically is called NC part programming because the program is prepared for a part to be machined. NC part
programming requires the programmer to be familiar with both the cutting processes and programming procedures. The NC part program includes the detailed commands to control the positions and motion of the machine tool. In numerical control. the three linear axes(x, y, z) of the Cartesian coordinate system are used to specify cutting tool positions. and three rotational axes (a, b, c) are used to specify the cutting tool postures. In turning operations, the position of the cutting tool is defined in the x-z plane for cylindrical parts, as shown in Fig. 48. 16a. In milling operations, the position of the cutting tool is defined by the x-, y-, and z-axes for cuboid parts, as shown in Fig. 48. 16b.
Fig. 48.16a,b Coordinate systems in numerical control(a) Cylindrical part for turning (b) cuboid part for milling
Numerical control realizes programmable automation of machining. The mechanical actions or motions of the cutting tool relative to the workpiece and the control sequence of the machine tool equipments are coded by alphanumerical data in a program. NC part programming requires a programmer who is familiar with the metal cutting process to define the points. lines. And surfaces of the workpiece, and to generate the alphanumerical data. The most important NC part programming techniques are summarized as follows:
1. Manual part programming
2. Computer-assisted part programming - APT and EXAPT
3. CAM-assisted part programming.
48.3.1 Manual Part Programming
This is the simplest way to generate a part program. Basic numeric data and alphanumeric codes are entered manually into the NC controller. The simplest commands example is shown as follows:
N0010 M03 S1000 F100 EOB
N0020 G00 X20.000 Y50.000 EOB
N0030 Z20.000 EOB
N0040 G01 Z- 20.000 EOB
Each code in the statement has a meaning to define a machining operation. The "N" code shows the sequence number of the statement. The "M" code and the following two-digit number define miscellaneous functions; "M03" means to spindle on with clockwise rotation. The "S" code defines the spindle speed;"S1000" means that the spindle speed is 1000 rpm. The"F" code defines the feed speed; "F100" means that the feed is 100 mm/min. "EOB" stands for "end of block"and shows the end of the statement. The "G" code and the following two-digit number define preparatory functions; "G00" means rapid positioning by point-to-point control. The "X" and "Y" codes indicate the x-and y-coordinates. The cutting tool moves rapidly to the position x = 20 mm and y = 50 mm with the second statement. Then, the cutting tool moves rapidly again to the position z = 20mm with the third statement. "GOI" means linear positioning at controlled feed speed. Then the cutting tool moves with the feed speed, defined by "F100" in this example, to position z= -20 mm.
The positioning control can be classified into two types, (l) point-to-point control and (2) continuous path control. "G00" is a positioning command for point-to-point control. This command only identifies the next position required at which a subsequent machining operation such as drilling is performed. The path to get to the position is not considered in point-to-point control. On the other hand, the path to get to the position is controlled simultaneously in more than one axis to follow a line or circle in continuous path control. "G01" is a positioning command for linear interpolation. "G02"and "G03" are positioning commands for circular interpolation. These commands permit the generation of two-dimensional curves or three-dimensional surfaces by turning or milling.
Fig. 48.17 Example program list in APT
48.3.2 Computer-Assisted Part Programming: APT and EXAPT
Automatically programmed tools is the most important computer-assisted part programming language and was first used to generate part programs in production around 1960. EXAPT contains additional functions such as setting of cutting conditions. selection of cutting tool, and operation planning besides the functions of APT. APT provides two steps to generate part programs: (l) definition of part geometry, and (2) specification of tool motion and operation sequence. An example program list is shown in Fig. 48.17. The following APT statements define the contour of the part geometry based on basic geometric elements such as points, lines, and circles:
LN l =LINE/20, 20, 20. 70
LN2 =LINE/(POINT/20, 70), ATANGL, 75, LN1
LN3 =LINE/(POINT/40, 20), ATANGL, 45
LN4 =LINE/20, 20, 40. 20
CIR =CIRCLE/YSMALL, LN2,YLARGE, LN3, RADIUS, 10
where LN l is the line that goes through points (20, 20) and (20, 70); LN2 is the line that goes from point (20,70) at 750 to LNI; LN3 is the line that goes from point(40, 20) at 450 to the horizontal line; LN4 is the line that goes through points (20, 20) and (40, 20); and CIR is the circle tangent to lines LN2 and LN3 with radius10. Most part shapes can be described using these APT statements.
On the other hands, tool motions are specified by the following APT statements :
TLLFT. GOLFT/LNI, PAST, LN2
GORGT/LN2, TANTO, CIR
GOFWD/CIR, TANTO, LN3
where "TLLFT. GOLFT/LNI" indicates that the tool positions left (TLLFT) of the line LNI, goes left(GOLFT). and moves along the line LN l. "PAST. LN2"indicates that the tool moves until past (PAST) the line LN2. "GORGTfLN2" indicates that the tool goes right(GORGT) and moves along the line LN2. "TANTO,CIR" indicates that the tool moves until tangent to(TANTO) the circle CIR. GOFWD/CIR indicates that the tool goes forward (GOFWD) and moves along the circle CIR. "TANTO. LN3" indicates that the tool moves until tangent to the line LN3.
Additional APT statements are prepared to de-fine feed speed, spindle speed. tool size, and tolerances of tool paths. The APT program completed by the part programmer is translated by the computer to the cutter location (CL) data, which consists of all the geometry and cutter location information required to machine the part. This process is called main processing or preprocessing to generate NC commands. The CI_ data is converted to the part program, which is understood by the NC machine tool controller. This process is called post processing to add NC commands to specify feed speed, spindle speed, and auxiliary functions for the machining operation.
48.3.3 CAM-Assisted Part Programming
CAM systems grew based on technologies relating to APT and EXAPT. Originally, CAM stood for computer aided manufacturing and was used as a general term for computer software to assist all operations while realizing manufacturing. However. CAM is now used to indicate computer software to assist part programming in a narrow sense.
The biggest difference between part programming assisted by APT and CAM is usability. Part programming assisted by APT is based on batch processing.Therefore, many programming errors are not detected until the end of computer processing. The other hand.part programming assisted by CAM is interactive-mode processing with a visual and graphical environment.It therefore becomes easy to complete a part program after repeated trial and error using visual verification. Additionally, close cooperation between CAD and CAM offers a significant benefit in terms of part programming. The geometrical data for each part designed by CAD are available for automatic tool-path generation. such as surface profiling, contouring,and pocket milling, in CAM through software routines. This saves significant programming time and effort for part programming. Recently, some simulation technologies have become available to verify part programs free from machining trouble. Optimization of feed speed and detection of machine crash are two major functions for part program verification.These functions also save significant production lead time.
48.2 加工中心和車削中心的發(fā)展
48.2.1 加工中心
加工中心是一個(gè)高度自動(dòng)化的數(shù)控銑床，進(jìn)行多重加工端面銑，鉆，攻絲等操作。這是開發(fā)，1958年實(shí)現(xiàn)流程整合，以及加工自動(dòng)化。圖48.8顯示早期毫安的加工中心配備了自動(dòng)換刀裝置（ AL -C）。大多數(shù)加工中心配備ATC和自動(dòng)托盤交換裝置（ APC ） ，每在一臺(tái)機(jī)器上安裝的多個(gè)切割操作，并減少非生產(chǎn)性時(shí)間在整個(gè)加工周期。
加工中心的主軸軸線的方向分為水平和垂直類型。圖48.9和48.10顯示了典型的臥式，立式加工中心，分別。最受歡迎的臥式加工中心有一個(gè)旋轉(zhuǎn)的表的索引在一些特定的角度相對(duì)于切削刀具的加工零件。其中有一個(gè)回轉(zhuǎn)工作臺(tái)臥式加工中心機(jī)可以用最少的人力援助的盒裝工件在一次裝夾四縱面。因此，被廣泛應(yīng)用于臥式加工中心與裝載和卸載系統(tǒng)實(shí)現(xiàn)工件加工自動(dòng)化自動(dòng)化車間。另一方面。立式加工中心廣泛使用在模具加工車間。在立式加工中心，切削工具機(jī)只有盒裝工件的頂面，但它很容易為人類操作人員了解刀具相對(duì)運(yùn)動(dòng)加工部分。
圖48.8加工中心，配備ATC （禮貌牧野銑床有限公司）
圖.48.9臥式加工中心（山崎馬扎克公司提供）
圖48.10立式加工中心（山崎馬扎克公司提供）
自動(dòng)換刀裝置（ATC）
ATC站自動(dòng)工具更換裝置，它允許加載和卸載的切割工具從一個(gè)加工操作到下一個(gè)。 ATC是設(shè)計(jì)之間交換刀具主軸和刀庫(kù)，可存儲(chǔ)超過20個(gè)工具。刀庫(kù)的大容量的允許多種工件進(jìn)行機(jī)加工。此外，更高的換刀速度和可靠性要求，實(shí)現(xiàn)了快速的加工周期。圖48 。圖11顯示了一個(gè)示例的雙臂式ATC通過凸輪機(jī)構(gòu)驅(qū)動(dòng)，以確?？煽康母咚贀Q刀。
圖.48.11 ATC自動(dòng)換刀裝置（山崎馬扎克公司提供）
自動(dòng)托盤交換裝置（ APC ）
自動(dòng)托盤交換裝置（ APC ） APC代表自動(dòng)托盤交換裝置，它允許加工自動(dòng)化的工件裝卸。大多數(shù)臥式加工中心有兩個(gè)托盤交換前和加工后的零件自動(dòng)表。圖48.12顯示了一個(gè)例子，一個(gè)APC 。操作員可以被卸載完成的部分，而加工中心處理在另一個(gè)托盤上的電流的一部分裝載在一個(gè)托盤上的下一部分。
圖48.12 APC ：自動(dòng)托盤交換裝置（山崎馬扎克公司提供）
48.2.2 車削中心
車削中心是一個(gè)高度自動(dòng)化的數(shù)控車床每形成多個(gè)車削操作。圖48.13顯示了一個(gè)典型的車削中心。由刀架換刀，可容納約10車刀和銑刀進(jìn)行切削工具改變。因此，車削中心不僅能夠車削操作也銑削操作，如在一臺(tái)機(jī)器上設(shè)置的端銑，鉆孔和攻絲。一些車削中心有兩個(gè)主軸和兩個(gè)或兩個(gè)以上的刀架換刀完成所有加工操作，在一臺(tái)機(jī)器上安裝圓柱形零件。在這種情況下。在一個(gè)主軸上的工件的加工操作上半年進(jìn)行，然后第二個(gè)一半的加工操作的另一主軸上進(jìn)行，不卸載和加載的工件的情況下。這降低了生產(chǎn)時(shí)間。
圖48.13車削中心或數(shù)控車床（山崎馬扎克公司提供）
刀架換刀
圖48.14顯示了12切割tools.A合適的切削刀具為目標(biāo)的加工操作刀架數(shù)控連續(xù)加工操作下自動(dòng)索引。最先進(jìn)的車削中心的刀具監(jiān)控系統(tǒng)檢查刀具長(zhǎng)度和直徑刀具自動(dòng)對(duì)準(zhǔn)和檢測(cè)刀具磨損自動(dòng)換刀。
圖48.14刀架車削中心（山崎馬扎克公司提供）
48.2.3 全自動(dòng)加工：FMS和FMC
柔性制造系統(tǒng)（FMS)
柔性制造系統(tǒng)（FMS）的概念是在20世紀(jì)60年代中期提出的。它的目的是進(jìn)行自動(dòng)加工操作肉眼人工操作機(jī)器的各個(gè)部分。加工中心關(guān)鍵部件FMS柔性加工操作的。圖48.15顯示了一個(gè)典型的柔性制造系統(tǒng)，它由5個(gè)加工中心，一個(gè)輸送機(jī)，一個(gè)加載/卸載站。和一臺(tái)中央計(jì)算機(jī)控制和管理的FMS的組件。
圖48.15柔性制造系統(tǒng)（山崎馬扎克公司提供）
沒有制造系統(tǒng)可以完全靈活。 FMS通常用于中量和中期品種生產(chǎn)。 FMS的機(jī)械零件的設(shè)計(jì)風(fēng)格，尺寸，和進(jìn)程的范圍內(nèi)，以及其程度的靈活性被限制。此外，通過控制數(shù)控機(jī)床的零件程序加工形狀多變。和部分程序所需的各種形狀加工的加工操作之前必須做好準(zhǔn)備。因此，需要一個(gè)新的形狀的一部分程序是不能接受傳統(tǒng)的FMS ，這就是為什么第三個(gè)創(chuàng)新的機(jī)床需要實(shí)現(xiàn)自主加工操作，而不是自動(dòng)加工業(yè)務(wù)，以實(shí)現(xiàn)真正的柔性制造系統(tǒng)。
FMS的由幾個(gè)數(shù)控機(jī)床，如加工中心和車削中心。材料處理或裝載/卸載系統(tǒng)，如工業(yè)機(jī)器人和托盤更換器，輸送系統(tǒng)，如輸送機(jī)和自動(dòng)導(dǎo)向車（ AGV ） ，和存儲(chǔ)系統(tǒng)。此外， FMS的FMS ，以協(xié)調(diào)所有的活動(dòng)有一臺(tái)中央計(jì)算機(jī)，所有的硬件??組件的FMS一般都有自己的微機(jī)控制。中央電腦下載NC零件程序，并控制材料處理系統(tǒng)，輸送機(jī)系統(tǒng)，存儲(chǔ)系統(tǒng)，和管理的材料和切割工具等。
人力運(yùn)營(yíng)FMS中扮演著重要的角色，執(zhí)行以下任務(wù):
1. 在加載/卸載站的裝載/卸載部件。
2. 切削工具的更改和設(shè)置。
3. NC零件編程。
4.硬件組件的維護(hù)。
5.的計(jì)算機(jī)系統(tǒng)的操作。
這些任務(wù)是必不可少的管理FMS成功。
柔性制造單元（FMC）
基本上， FMS是中量和中期品種生產(chǎn)的大系統(tǒng)，實(shí)現(xiàn)生產(chǎn)自動(dòng)化。在某些情況下。適用于小型系統(tǒng)是實(shí)現(xiàn)制造自動(dòng)化。的術(shù)語(yǔ)柔性制造單元（ FMC ）是用來(lái)表示小的系統(tǒng)或緊湊型細(xì)胞的FMS 。一般，在FMC中的機(jī)床的數(shù)量是三個(gè)或三個(gè)fewer.One能認(rèn)為FMS的是一個(gè)大的制造系統(tǒng)中，由一些FMC。
48.3 數(shù)控零件編程
編程自動(dòng)操作機(jī)床的任務(wù)被稱為NC零件程序，因?yàn)槌绦虻囊徊糠直患庸?zhǔn)備。 NC零件編程要求程序員熟悉的切割工藝和編程程序。 NC零件程序包括詳細(xì)的命令來(lái)控制機(jī)床的位置和運(yùn)動(dòng)。在數(shù)控。 （的x，y ，z）的三個(gè)線性軸的直角坐標(biāo)系統(tǒng)是用來(lái)指定刀具位置。和三個(gè)旋轉(zhuǎn)軸（一，二，三）用于指定刀具姿勢(shì)。在車削操作的切削刀具的位置定義在x z平面上的圓柱形零件，如圖所示。 48。 16A。在銑削操作中，切削工具的位置被定義為在x ， y軸和z軸的長(zhǎng)方體部分，如圖所示。 48。 16b之間。
圖48.16a ， B坐標(biāo)系統(tǒng)（一）在數(shù)控圓柱型零件轉(zhuǎn)動(dòng)（二）長(zhǎng)方體部分用于銑削
數(shù)控加工實(shí)現(xiàn)可編程自動(dòng)化。編碼的字母數(shù)字?jǐn)?shù)據(jù)在一個(gè)程序中的切削刀具相對(duì)于工件和控制序列的機(jī)床設(shè)備的機(jī)械操作或動(dòng)作。 NC零件編程需要程序員誰(shuí)是熟悉金屬切削過程來(lái)定義點(diǎn)。線。工件的表面，以及生成的字母數(shù)字?jǐn)?shù)據(jù)。最重要的NC零件編程技術(shù)總結(jié)如下：
1. 手動(dòng)編程。
2.電腦輔助部分編程 - APT和EXAPT的。
3.CAM輔助部分編程。
48.3.1 手動(dòng)零件編程
這是最簡(jiǎn)單的方法來(lái)生成零件程序。手動(dòng)輸入到數(shù)控控制器的基本數(shù)值數(shù)據(jù)和字母數(shù)字代碼。簡(jiǎn)單的命令示例如下所示：
N0010 M03 S1000 F100 EOB
N0020 G00 X20.000 Y50.000 EOB
N0030 Z20.000 EOB
N0040 G01 Z- 20.000 EOB
每個(gè)語(yǔ)句中的代碼定義一個(gè)加工操作的意思。 “N”的代碼顯示了該語(yǔ)句的序列號(hào)。 “M”代碼和以下兩位數(shù)字定義輔助功能， “ M03 ”是指主軸順時(shí)針旋轉(zhuǎn)。 “S”的代碼定義了主軸轉(zhuǎn)速， “ S1000 ”表示主軸速度是每分鐘1000轉(zhuǎn)的。 “F”的代碼定義的進(jìn)給速度; “ F100 ”表示進(jìn)料為100毫米/分鐘。 “ EOB ”代表“塊結(jié)束” ，顯示的語(yǔ)句末尾。 “G”代碼和以下兩位數(shù)字定義準(zhǔn)備功能“ G00 ”是指由點(diǎn)到控制點(diǎn)的快速定位。的“X”和“Y”的代碼表示的x坐標(biāo)和y坐標(biāo)。刀具快速移動(dòng)的位置X = 20毫米， Y = 50毫米，第二條語(yǔ)句。然后，刀具再次快速移動(dòng)Z = 20毫米第三條語(yǔ)句的位置。 “印度政府”是指在控制進(jìn)給速度的線性定位。然后，切削刀具移動(dòng)，與進(jìn)給速度，所定義的“ F1OO ”在這個(gè)例子中，位置z = -20毫米。
可分為兩種類型， （升）的點(diǎn)至點(diǎn)的控制和（2）連續(xù)軌跡控制的定位控制。 “ G00 ”是一款定位點(diǎn)至點(diǎn)控制命令。此命令僅確定下一個(gè)位置，需要進(jìn)行后續(xù)加工如鉆孔操作。的路徑到達(dá)的位置不被認(rèn)為是在點(diǎn)對(duì)點(diǎn)控制。另一方面，路徑到達(dá)的位置控制，同時(shí)在一個(gè)以上的軸，在連續(xù)軌跡控制，遵循一個(gè)直線或圓。 “ G01 ”是一款定位命令線性插值。 “ G02 ”和“ G03”的定位指令圓弧插補(bǔ)。這些指令允許生成的二維曲線或三維表面通過車床或銑床。
圖48.17示例程序列表中APT
48.3.2 計(jì)算機(jī)輔助工藝過程設(shè)計(jì)：APT和EXAPT
自動(dòng)編程工具是最重要的計(jì)算機(jī)輔助編程語(yǔ)言，并首次用于生成部分計(jì)劃在1960年左右生產(chǎn)。 EXAPT包含額外的功能，如設(shè)置的切削條件。選擇刀具和操作規(guī)劃除了APT職能。 APT提供了兩個(gè)步驟來(lái)生成零件程序： （L）定義零件的幾何形狀，及（2）刀具運(yùn)動(dòng)和規(guī)范的操作順序。示于圖的一個(gè)例子的程序“列表中。 48.17 。 APT以下語(yǔ)句定義零件的幾何形狀的基礎(chǔ)上基本幾何元素，如點(diǎn)，線和圓的輪廓:
LN l =LINE/20, 20, 20. 70
LN2 =LINE/(POINT/20, 70), ATANGL, 75, LN1
LN3 =LINE/(POINT/40, 20), ATANGL, 45
LN4 =LINE/20, 20, 40. 20
CIR =CIRCLE/YSMALL, LN2,YLARGE, LN3, RADIUS, 10
其中LN l是經(jīng)過點(diǎn)（ 20，20）和（20 ，70 ）的行;液氮的直線，它從點(diǎn)（ 20,70 ） ，在750 LNI ; LN3的直線，它由點(diǎn)（ 40 ，20）在450對(duì)于水平線; ， LN4是經(jīng)過點(diǎn)（ 20，20）和（ 40，20 ）的行和CIR的圓相切的線LN2和LN3與radius10 。大部分的形狀也可以使用這些APT報(bào)表的描述。
另一方面，刀具運(yùn)動(dòng)指定由APT以下報(bào)表：
TLLFT. GOLFT/LNI, PAST, LN2
GORGT/LN2, TANTO, CIR
GOFWD/CIR, TANTO, LN3
哪里“ TLLFT ” GOLFT / LNI表明，刀具的位置留行LNI （ TLLFT ）， GOES左（ GOLFT ）。移動(dòng)沿線LN升?！斑^往液氮”表示刀具移動(dòng)，直到過去（過去）的線LN2 。 “ GORGTfLN2 ”指示該工具去（ GORGT ）和沿著線LN2 。 “ TANTO ， CIR ”表示刀具移動(dòng)，直到相切（ TANTO ）圓CIR 。 GOFWD / C
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