Absolute and relative coordinate system. Second workshop - auxiliary elements of the Coordinate System in Nx7.5
Programming in absolute coordinates - G90. Programming in relative coordinates - G91. The G90 instruction will interpret the movements as absolute values relative to the active zero point. The G91 instruction will interpret the movements as increments relative to previously reached positions. These instructions are modal.
Setting coordinate values - G92. The G92 instruction can be used in a block without axis (coordinate) information or with axis coordinate information. In the absence of axial information, all coordinate values are converted to the machine coordinate system; in this case, all compensations (corrections) and zero offset are removed. If axial information is available, the specified coordinate values become current. This instruction does not initiate any movements and is valid within one frame.
N…G92 X0 Y0 /The current values of the X and Y coordinates are set to zero. The current Z coordinate value remains unchanged.
N…G92 / Corrections and zero offsets are removed.
Plane selection – G17 (XY plane), G18 (XZ plane), G19 (YZ plane). The instructions specify the choice of work plane in the part or program coordinate system. The operation of instructions G02, G03, G05, polar coordinate programming, and equidistant correction are directly related to this choice.
Motion paths (interpolation types)
Linear interpolation involves moving along a straight line in three-coordinate space. Before interpolation calculations begin, the CNC system determines the path length based on the programmed coordinates. During movement, the contour feed is controlled so that its value does not exceed the permissible values. Movement along all coordinates must be completed simultaneously.
With circular interpolation, movement is carried out along a circle in a given working plane. The parameters of the circle (for example, the coordinates of the end point and its center) are determined before the movement begins, based on the programmed coordinates. During movement, the contour feed is controlled so that its value does not exceed the permissible values. Movement along all coordinates must be completed simultaneously.
Helical interpolation is a combination of circular and linear.
Linear interpolation during rapid traverse - G00, G200. During rapid traverse, the programmed motion is interpolated and the motion to the end point is carried out in a straight line at maximum feedrate. The feed rate and acceleration for at least one axis are maximum. The feedrate of the other axes is controlled so that the movement of all axes ends at the end point simultaneously. While the G00 instruction is active, motion slows to zero every frame. If there is no need to slow the feed rate to zero in each block, then G200 is used instead of G00. The value of the maximum feed rate is not programmed, but is set by so-called “machine parameters” in the memory of the CNC system. Instructions G00, G200 are modal.
Linear interpolation with programmed feedrate - G01. The movement at the specified feedrate (in the F word) towards the block end point is carried out in a straight line. All coordinate axes complete the movement simultaneously. The feed rate at the end of the block is reduced to zero. The programmed feed rate is contour, i.e. The feedrate values for each individual coordinate axis will be smaller. The feed rate value is usually limited by the “machine parameter” setting. A variant of the combination of words with the G01 instruction in the block: G01_X_Y_Z_F_.
Circular interpolation – G02, G03. Movement in the block is carried out in a circle at the contour speed specified in the active F-word. Movement along all coordinate axes is completed in the frame simultaneously. These instructions are modal. Feed drives specify circular motion at a programmed feed rate in a selected interpolation plane; in this case, the G02 instruction determines clockwise movement, and the G03 instruction determines counterclockwise movement. When programming, a circle is specified using its radius or the coordinates of its center. An additional option for programming a circle is defined by the G05 instruction: circular interpolation with access to a tangent path.
Programming a circle using a radius. The radius is always specified in relative coordinates; in contrast to the end point of an arc, which can be specified in either relative or absolute coordinates. Using the position of the start and end points, as well as the radius value, the CNC system first determines the coordinates of the circle. The result of the calculation can be the coordinates of two points ML, MR, located respectively to the left and to the right of the straight line connecting the start and end points.
The location of the center of the circle depends on the sign of the radius; with a positive radius the center will be on the left, and with a negative radius it will be on the right. The center location is also determined by instructions G02 and G03.
Option for combination of words with G03 instruction in a block: N_G17_G03_X_Y_R±_F_S_M. Here: G17 instruction means selecting circular interpolation in the X/Y plane; the G03 instruction specifies circular interpolation in the counterclockwise direction; X_Y_ represents the coordinates of the end point of the circular arc; R is the radius of the circle.
Programming a circle using the coordinates of its center. The coordinate axes, relative to which the position of the center is determined, are parallel to the X, Y and Z axes, respectively, and the corresponding coordinates of the center are named I, J and K. The coordinates establish the distances between the starting point of the circular arc and its center M in directions parallel to the axes. The sign is determined by the direction of the vector from A to M.
N… G90 G17 G02 X350 Y250 I200 J-50 F… S… M…
Example for programming a full circle: N… G17 G02 I… F… S… M…
Circular interpolation with access to a circular path along a tangent – G05. The CNC system uses the G05 instruction to calculate such a circular section, the exit to which from the previous block (with linear or circular interpolation) is carried out tangentially. The parameters of the formed arc are determined automatically; those. Only its end point is programmed, and the radius is not specified.
Helical interpolation – G202, G203. Helical interpolation consists of circular interpolation in the selected plane and linear interpolation for the remaining coordinate axes, for a total of up to six circular axes. The circular interpolation plane is determined by instructions G17, G18, G19. Circular movement in a clockwise direction is carried out according to instruction G202; counterclockwise movement in a circle - G203. Programming a circle is possible both using the radius and using the coordinates of the circle center.
N... G17 G203 X... Y... Z... I... J... F... S... M...
Moscow 2011
To change the sheet background in AutoCad:
Service
setting
Screen
Colors
accept > OK
Selecting objects
Draw several segments
Selection of objects is possible either one by one or through a rectangular area, and if you place the cursor on the left and top of the drawing, then for selection it is necessary that the objects completely fall into the area. If we select from the bottom right (that is, from the bottom right corner), then it is enough to capture only some areas of the selected objects, and they will be selected completely.
2. To cancel the action, click the right mouse button, and in the drop-down window select the “cancel selection” command
Zooming – zooming in and out of a drawing
For visualization, you can use the magnifying glass icon. Click on this icon and when the icon (magnifying glass + -) appears, moving the mouse while holding the left button will remove the drawing away from you, and moving it towards you will bring the drawing closer.
Select the icon with - drop-down list, select the object that we want to zoom in on and press the space bar.
If you select the last icon “Show to borders” in the drop-down list, then the elements of the drawing will be displayed on the screen.
III. The way to enlarge an image is to quickly double-click on the mouse wheel.
And the third icon “show previous” by clicking on this button we return the previous zoom.
Panning is moving around the drawing (also possible in 2 ways) either by pressing the foot and holding the right mouse button, or by holding the mouse wheel.
Absolute and relative coordinate system.
When entering coordinates (20,20), an indentation along axesX by 20mm. And by axesYby 20mm., relative to absolute zero.
By entering then the coordinates (50,50), we get the coordinates of the 2nd point still relative to the origin (that is, absolute zero).
However, sometimes it becomes necessary to enter coordinates relative to an arbitrary point. To do this, call the “segment” command and set the beginning of the segment at any point on the screen (in order for tooltips to be visible, dynamic input must be active) and then the specified coordinates will be given relative to an arbitrarily selected origin.
To make sure of this, go to the “Dimensions” and “Linear Dimensions” menus.
And having set these dimensions, we notice that along the “Y” axis - 50mm, Esc, (space) and along the “x” axis -50mm.
To construct a square with a side of 10 mm, enter an arbitrary point and specify the coordinates of the points.
Origin (-10;0) – lower left point,
(0; -10) – lower right point.
(10; 0) – upper right point,
(0;10) – top left point.
The origin of coordinates occurs counterclockwise, sequentially.
Construct the following figure using the coordinate system.
| X | Y |
| 60 – lower horizontal straight line | 0 - bottom horizontal line |
| 20 |
|
| 120 - intersection of the lower (rhombus) | |
| -60 | 0 |
| 40 – right and left line of the rectangle (vertical) |
|
| 30- left top line | |
| 20 – top right line |
|
Polar relative coordinate system
In the case when we want to set the length of the segment and the angle (alpha) to the horizontal, we must first set an arbitrary point (or the coordinates of a given point relative to absolute zero), after which we enter the length of the segment prev., 60 mm, and then by successively pressing the Shift+ keys
To display the size horizontally or vertically, use the “Dimensions” menu ͢
"Linear size"
To display absolute length
Use the menu “Dimensions” > Parallel size”
Toolbars
The AutoCad workspace starts from the main menu
On the side of the worksheet there may be toolbars that display not the full range of main menu commands, but the most frequently used commands.
You can add or remove toolbars from the workspace; in order to add a toolbar, right-click on any of the icons on the top toolbar and check the box next to the name of the menu whose toolbar we would like to display.
The very first top toolbar is called "STANDARD"
The transition from ribbon to classic AutoCad is carried out using the “Workspace” toolbar
The profile is saved through the command “service” > “settings” > (scroll arrows to the end) > “profiles” > “add” > “Name”; and if you want to insert a “description” > OK
Drawing 2D shapes (Ray, straight line, segment)
Drawing such primitives as a straight line, a ray and a segment is carried out using the “Drawing” menu or the drawing panel with the “straight”, “ray”, “segment” icons.
In order to draw a straight line in AutoCad, you need to click on the drawing icon
The starting point can be set either arbitrarily or by specifying coordinates (x;y). Note that the straight line rotates freely relative to a given point; to fix the straight line, you must specify either the coordinates of the 2nd point, or the length of the segment and the angle (shift +
To draw a ray, you must use the “drawing” menu, because There is no such icon in the drawing panel.
By clicking anywhere on the screen, we note that the beam also rotates freely relative to the starting point.
Let's set the coordinates of the second point and fix a beam of a certain length. To exit drawing mode, press Esc, spacebar or Enter. And the segment, which is constructed from two points, is also called “segment” at the beginning of the tools.
AutoCad offers us the drawing of several segments to the given coordinates of the second point, taking the end of the already drawn segment as the first point,
If any prompts pop up while moving around the screen, this function can be disabled by pressing the “BS” button - Quick Properties
Circle and arc
In the Drawing panel, a circle is represented by an icon, an arc. However, let’s use the “Drawing” menu from the drop-down list, select the “Circle” command - and by clicking on the arrow, we notice several ways to define a circle:
Center and radius
Center and diameter
2 points
3 points
2 touch points, radius
3 touch points
When selecting the “circle” icon, we are prompted to select the default radius; if you need to select a diameter, you need to right-click and select the command diameter, then enter the linear dimension of the diameter from the keyboard.
If we choose to draw a circle using three points or two points, then by clicking on the “circle” icon, right-click and select 3t or 2t from the list.
The method is to construct a circle using two points of contact and a radius.
This method of constructing a circle provides for the presence of two more segments, which the constructed circle must touch.
Therefore, first we build 2 segments, after which we enter the “Drawing” menu and select the “KKR” command, the tooltip requires “Specify a point on the object that defines the first tangent” - move the cursor over the first segment and click the left mouse button in an arbitrary point lying on the segment, we do the same when choosing the second point of contact, only this time we select on the second segment.
The radius of the circle can be taken by default or set independently by entering its value from the keyboard.
The method is to construct a circle along 3 tangents. This method is used when it is necessary to inscribe a triangle in a circle.
In this case, first we build a triangle from segments, then go to the “drawing” menu, select the “three touch points” command and select all three segments one by one.
If we draw a closed contour from segments, then we can use the context menu command (right mouse button) “close”.
Arc.
To depict an arc (part of a circle), we will also use the “draw” menu > “Arc”
Let's consider the method of drawing an arc through the task “center, start, end” in the tooltip you need to indicate the center of the arc, which can be entered from the keyboard in the form of a point coordinate (X; Y). Then enter the coordinates of the beginning of the arc (you must remember that the arc is always drawn counterclockwise) and enter the coordinates of the end of the arc.
2 ways to draw an arc, the center is the beginning of the angle.
In the tooltip, you need to enter the center of the arc, which can be set either by arbitrarily clicking on any point in the workspace or by entering the coordinates of the point (20;20), then enter the coordinates of the starting point of the arc (X;Y) and then the angle of rotation, taking into account drawing the arc against clockwise (45 degrees; 90 degrees – 270 degrees).
And the last way is to specify an arc using “center, origin, length”
In an arbitrary place we indicate the center and beginning of the arc. By long arc we mean the length of the chord.
No less frequently used is the command in the menu “Drawing” > “Arc” > “Continue”
In order to use the continue command, you must first draw that primitive whose last point will be the beginning of the arc.
The path will be a segment, after drawing which we enter the drawing menu “Drawing” > “Arc” > “Continue”.
We notice that the depicted arc is tied to the end of the segment, i.e. to its end point, then, depending on our task, we can extend the arc in any direction and to any length.
This command is most often used when two segments are adjacent.
Contour and area.
The “area” icon is located in the drawing panel, while the outline icon is called up only from the “Drawing” menu. The “area” command is used to add or subtract primitives when, having several simple primitives available, it is necessary to create a more complex figure. Let's draw a rectangle and a circle on the working space, so that the radius of the circle is equal to the side of the rectangle.
E 
If we need to get a figure depicted on the workspace, then this is possible by adding a circle and a rectangle.
However, by its type, a circle is all around and the rectangle is polyline , as we know, only homogeneous quantities can be subtracted and added. To make the type of both primitives the same, we will use the “area” command; after clicking on the “area” icon, we select all those objects with which we will subsequently add or subtract.
Computer graphics
Tutorial
Saint Petersburg
1.1. Basics of working in the AutoCAD environment.. 4
1.2. Drawing using 3D technology. 10
1.3. Laboratory work No. 1. 15
1.4. Typical connections of parts. 19
1.5. Types of products and design documents. 27
1.6. Laboratory work No. 2. 32
2.1. Objects in 3ds Max. 39
2.2. Methods for transforming geometric objects. 45
2.3. Laboratory work No. 3. 48
2.4. Lofting modeling. 50
2.5. Deformation of models built using the lofting method. 53
2.6. Laboratory work No. 4. 56
2.7. Mesh shells. 58
2.8. Editing mesh shells. 61
2.9. Laboratory work No. 5. 66
2.10. Sources of light. 67
2.11. Filming Cameras.. 70
2.12. Materials.. 75
2.13. Laboratory work No. 6. 80
2.14. Animation. 82
2.15. Movement of objects along a given path. 86
2.16. Laboratory work No. 7. 88
3. Graphic programming. 90
3.1. Description of the DirectX driver set.. 90
3.2. Description of the OpenGL graphics system. 93
3.3. OpenGL Basics. 96
3.4. Drawing geometric objects. 102
3.5. Laboratory work No. 8. 107
References.. 110
AutoCAD is the world's most widespread computer-aided design and production system for working design and design documentation. With its help, two-dimensional and three-dimensional projects of varying degrees of complexity are created in the field of architecture and construction, mechanical engineering, geodesy, etc. The AutoCAD data storage format is de facto recognized as the international standard for storing and transmitting design documentation.
The main advantage of AutoCAD is the availability for creating powerful specialized calculation and graphic packages on its basis. Autodesk produces two main product lines designed for architects (Autodesk Architectural Desktop) and mechanical engineers (Autodesk Mechanical Desktop). All of these products use AutoCAD as a base.
The first version of MicroCAD (the prototype of AutoCAD) was released on August 25, 1982. This day is considered the date of release of the first Autodesk product.
Basics of working in the AutoCAD environment
Status bar
The status bar (Fig. 1.1) displays the current coordinates of the cursor and contains buttons for turning on/off drawing modes:
· SNAP - Snap Mode (Step snapping) - turn on and off the step snapping of the cursor;
· GRID - Grid Display - turns the grid on and off;
· ORTHO - Ortho Mode - turn on and off the orthogonal mode;
· POLAR - Polar Tracking - enable or disable polar tracking mode;
· OSNAP - Object Snap - enable and disable object snap modes;
· OTRACK - Object Snap Tracking - turns on and off the tracking mode for object snapping;
· MODEL/PAPER - Model or Paper space - switches from model space to paper space;
· LWT - Show/Hide Lineweight (Display of lines in accordance with weights) - enable or disable the mode of displaying lines in accordance with weights (thicknesses).
Rice. 1.1. Status bar
Using object snapping allows you to reduce the time spent working on a drawing, since in some cases there is no need to manually enter coordinates; you just need to point the cursor at an existing point that belongs to an object.
Command Prompt Window
The “Command Line” window (Fig. 1.2) is usually located above the status bar and is used to enter commands and display AutoCAD prompts and messages. In Fig. 1.2 shows an example of creating a wedge (the “Wedge” tool of the “Solids” toolbar) using the command line. It can be specified by specifying two opposite vertices of the base and height, or one vertex, length, height and width (for a wedge inscribed in a cube, the vertex and side values). When enumerating, parameters are specified separated by commas. The separator between the integer and fractional parts is a dot.
Rice. 1.2. Command Prompt Window
Coordinate systems
There are two coordinate systems in AutoCAD: the World Coordinate System (WCS) and the User Coordinate System (UCS). Only one coordinate system is active, which is usually called the current one. In it, the coordinates are determined in any available way.
The main difference between the world coordinate system and the user one is that there can only be one world coordinate system (for each model space and sheet), and it is fixed. The use of a custom coordinate system has virtually no restrictions. It can be located at any point in space at any angle to the world coordinate system. This is because it is easier to align a coordinate system with an existing geometric object than to determine the exact location of a point in 3D space.
To work with coordinate systems, use the “UCS” panel (Fig. 1.3). With its help, you can, for example, switch from the user coordinate system to the world one (the “World UCS” button) or align the coordinate system with an arbitrary object (the “Object UCS” button).
Rice. 1.3. UCS Toolbar
Absolute and relative coordinates
In three-dimensional and two-dimensional space, both absolute coordinates (measured from the origin) and relative coordinates (measured from the last specified point) are widely used. A sign of relative coordinates is the @ symbol before the coordinates of the specified point: “@<число 1>,<число 2>,<число 3>».
Typical views of objects
To present the model in various views, use the “View” toolbar (View, Fig. 1.4). It allows you to present the model in both six standard views and four isometric ones.
Rice. 1.4. View Toolbar
RELATIVE COORDINATE SYSTEM
When using flat processing, the technologist-programmer has the opportunity to set a relative coordinate system. The need for this very often arises, for example, in the case of mismatch between design and technological bases. To create a relative coordinate system, the user must use the command:
After calling the command, the following options will be available in the automenu:
Coordinate system parameters
Options with coordinate axes (, and) on their icons allow you to specify the center and corresponding axes of the coordinate system. As a rule, to specify each of these elements, a node is indicated in the part drawing.
The default parameter entry option allows the user to set all of the listed parameters with specific digital values in the “Coordinate System Parameters” dialog box.
To specify a relative coordinate system, it is enough to specify the center and one of the axes of the created coordinate system. After this, just use the button
The CNC will independently calculate the missing axis of the created coordinate system.
In order for the processing trajectory to be calculated in accordance with the created relative coordinate system, this coordinate system in the list of trajectories must be placed before the processing trajectory.
PROJECT SETUP
When using the T-FLEX CNC 2D version, the user can create processing paths and control programs based on them for different types of processing (from electrical discharge to milling) on one drawing of the workpiece. For example, first the technologist-programmer does all the machining, and then the electrical erosion. The technologist-programmer makes all the necessary settings in the working project settings window that appears when calling the command:
In the example in the figure, there are two positions in the list of compound trajectories. “Machining 1” includes all drilling and milling of the workpiece. “Processing 2” is empty, but may include, for example, processing the part from the other side (for a different setup) or processing from the same side, but of a different type (electrical discharge or laser), or some other option.
[Add] and [Delete] keys
serve respectively to enter a new position into the list of composite trajectories or delete an old position.
It should be noted that for each position in the list of composite trajectories, its own control program is created in accordance with the postprocessor selected by the user.
Additionally, the constituent parts of an active compound toolpath are displayed in one color, while existing toolpaths are displayed in a different color.
Creating a control program
CREATION OF A CONTROL PROGRAM
After the technologist-programmer prepares a processing path in the system, he also needs to generate a control program for the machine used, with the postprocessor with which this machine works. To do this, in the case of 2D, 2.5D and 4D processing, use the command:
"CNC|Save G program"
For 3D and 5D processing paths:
When you call any of these commands, the “Save G Program” dialog box appears on the screen.
In the window that appears on the screen, you must
press , after which the “Parameters for saving a composite trajectory” dialog box will appear on the screen.
In this window, the names of the postprocessors required for the selected type of processing, the name of the control program and the location of its saving are sequentially specified.
It should be noted that the user can select postprocessors supplied with the system or those that were developed by him in the system using the postprocessor generator. The control program for the same part and for the same type of processing can be saved in different files with different post-processors. This makes it possible to optimally use equipment of the same type, but with different CNC stands.
If all the steps listed above were carried out correctly, the user will see a window on the screen that should contain all the entered data.
It should be especially noted that it is possible to remove a specific selected control program from the list. To do this, you need to specify it in the list using the or keys< >And< ↓ >, and then click the [Delete] button. It is also possible to save all control programs present in the list into separate files, for which you need to use the [Save] button.
Martynyuk V.A.
Second Workshop – Supporting Elements 1
Coordinate systems in NX 7.5 1
Working coordinate system 2
Orientation of RSK 3
When else do you need to remember about RSK 4?
Basic coordinate systems 4
How to recover a lost reference coordinate system 5
Concept of associativity 6
Auxiliary coordinate planes 8
Associated and fixed coordinate planes 9
Methods for constructing a coordinate plane 10
Auxiliary coordinate axes 11
Construction of perpendicular coordinate axes 12
Construction of points 14
The first method of constructing points is precise input 14
Constructing a point with an offset relative to another point 15
Constructing a point on face 15
Constructing a point on an auxiliary plane 16
Constructing point sets 17
Coordinate systems in Nx7.5
At the first seminar, we already mentioned that the NX7.5 system contains three coordinate systems:
Working coordinate system – (RSK).
Basic coordinate systems(there may be several of them).
Absolute coordinate system, which never changes its position. At the initial moment of working with a new project, all of the above coordinate systems coincide in place and in the orientation of the axes with the absolute coordinate system .
Fig.1 Fig.2
The very first thing you see on the screen in the workspace when you start a new project with the “Model” template- This:
Triad of vectors with a cube in the lower left corner of the screen (Fig. 1). It always shows the orientation of the axes absolute coordinate system in case your model rotates.
Two combined coordinate systems in the center (Fig. 2): RSK(colored arrows) and Basic coordinate system(brown arrows), which coincide with the absolute coordinate system. In Fig. 2 these two coordinate systems are combined. And herself absolute coordinate system considered invisible.
Working coordinate system
The working coordinate system (WCS) in the project is always the only one. But it can be arbitrarily moved in space. For what? The fact is that in NX7.5 there is a very important concept - working plane. This planeXOYworking coordinate system.
Why do we need the concept of a work plane? The fact is that in NX7.5, like in any other graphics system, there is flat construction apparatus. But if in other systems such a tool for flat constructions is only flatsketching , then in NX7.5, in addition to constructing flat sketches in the drop-down menu Insert\Curves There is a whole range of tools that can be used to direct drawing of flat primitives without any mention of any sketches at all (Fig. 3).
But these are flat primitives. This means they must be drawn in a plane! In what plane? Exactly in the working plane!
Thus, if you want to somehow arbitrarily orient a flat ellipse in space, you will first have to orient the DCS and its working plane accordingly. And only then, in this working plane, build, for example, an ellipse (Fig. 4).
