Open the project (.epb /.epx), for example Counter.epb and invoke the PCB layout Editor.
• Select a layer on which copper pour area is to be created from Layers toolbar. (If all the layers are not visible, select ViewLayout Active layers. Click Set to Used and Accept.)
• Select the required Net from toolbar.
• Select Copper
from Tools menu
• Select Create Copper graphics item function tool (second function tool), and then select Create copper pour area option tool (fifth option tool). And draw copper pour area.
• Open Fabrication Manager
• Select ToolsArtwork/Power & Gnd planesSet used toAccept
• Meshed copper pour area can be viewed by enabling Meshed Copper Pour Area from Preference menu.
• PreferenceMeshed Copper Pour Areas Display
It is necessary to check the isolated pockets of copper, cut offs in the pads, routing within copper pour etc after creating copper pour areas. This can be done using copper pour flood tests available in EDWinXP.
Invoke Tools Connections Connection property tool Copper pour flood test. Activate this option and then click on the copper pour area. A new window appears as shown in figure below.
You can select the test from the drop down menu of Select Test. The test starts by pointing flooding point within boundaries of copper pour polygon. The display presenting flooded areas (red), isolated (black) and air gaps (white) with superimposed layer over it, stays put until ‘Esc’ or until next polygon selection. (The same Copper pour flood test has been added as option to Copper Copper item property tool)
Copper pour areas tested depends on flood point position. Program establishes all other parameters automatically. In cases when few polygons on different layers overlap at flooding point, there is a possibility provided to select net and flooding layer. Flooding may be applied to current layer where selected polygon resides or to all layers where there are connections for tested net. The test checks always for bottlenecks in the same way as in Fabrication manager. However, it takes always currently set value of trace width as minimal allowed bottleneck.
Principles of copper removal
Copper pour areas on given layer are defined as polygons assigned to selected nets. Polygonal definition allows creation of complicated shapes. Nevertheless, it may be simpler in certain instances to adjust shape of copper pour areas by removing copper within roughly drawn polygon. This task may be performed while editing layer artworks in preparation for generating Gerber ASCII output.
Copper may be removed by placing so called copper relieve items within boundaries of copper pour area polygons. These copper relieve items are basic EDWinXP graphic elements, like lines, circles, rectangles and arcs. Circles and rectangles may be either open or filled. By placing such elements at desired position and adjusting their size (and rotation), the user removes equivalent shape of copper. This effect is achieved through drawing / printing copper relieve items in white over black background and in cases of photo plotter output, by plotting these elements in reversed polarity after first plotting copper pour areas in positive polarity. In other words, it is done in similar way as when air gaps for pads and traces are drawn or plotted.
Functions for manual creation and edition of copper relieve items are available in Fabrication Manager. The toolbox appears when editing artwork containing copper pour areas and when user clicks View->Artwork->Copper Relieve Edit View. The repertoire of available copper relieve items have been recently enhanced by polygons
As mentioned before, copper relieve may be used to adjust shape of copper pour areas. For example, it may be necessary to cut out copper free window within copper pour polygon or isolate two parts of the same polygon from each other (analog and digital ground). Additional problems usually arise in situations when copper pour area polygons are placed on layers where there are also trace connections. Traces running within air gaps and air gaps around pads may create isolated pockets of copper. These may lead to loss of connectivity if pads that should be connected by copper are inside those isolated areas. In order to detect this kind of errors, the user should run copper pour connectivity test.
Even if copper pour connectivity test does not find any errors, the isolated pockets usually still exist on the layer. Isolated copper is usually not needed and in many cases undesirable. Tiny pieces of copper or “slivers” between parallel traces may curl and created shortcuts. Isolated copper may be removed by placing copper relieve items over it, but because of their number and irregular shapes it is a tedious task even with recently introduced copper relieving polygons.
Automatic copper cleanup
The results of copper pour connectivity test are presented graphically. Copper areas that are connected are drawn in red color. Those isolated are drawn in black. Providing that the test did not detect unconnected pads, the user may subsequently invoke automatic copper cleanup function to remove all “black” copper areas from the artwork. The program analyzes display of the artwork after test and generates copper relieve items (filled rectangles) in number and sizes necessary to cover all detected black spots. This solution has this advantage that results of automatic copper cleanup are fully editable. The user may fine tune copper relieve by removing or adjusting items that cleaned “too much” of the copper. The existing copper pour polygons are not affected by automatic copper cleanup.
Semi-automatic copper trimming
This function reminds of erasing with help of movable “rubber”. The user can define shape (rectangle or square) and size of trimming tool. Removing copper works in similar way as in automatic copper cleanup, with this distinction that copper relieve items are generated only within boundaries of trimming tool. User may also select (while in trimming mode), whether to trim isolated (“black”) copper or connected (“red “) copper. Trimming is necessary complement to automatic cleanup, especially when there are areas of connected (“red”) copper that are superfluous and should be removed. It is advisable to re-test copper pour connectivity in cases where connected copper has been trimmed.
i) Automatic Removal of Isolated Copper
• Load the project in Fabrication Manger
• Select Artwork Tool
• Select layers for preview window appears, Select the layer or click on Set to used and then click on Accept button.
• Select the layer, which has the copper pour area plotted.
• Select Net Info function tool and then select check reference nets option tool and click on the copper pour area.
• Select Reference Net window appears, Select the reference net and click on Accept button. Again click on the copper pour area to view the possible unconnects in net. The unconnected nets are displayed in the resulting window.
• To clean up isolated copper, click on Automatic copper cleanup option tool. Click on Yes button of the warning window.
• Select copper relieve type (rectangle or polygon) in Auto clean up window and click on Accept button.
Note: Automatic cleanup applies only to the net selected for test and only to currently edited layer. Procedure has to be repeated for each net that has copper pour polygon on currently edited layer and for each layer that contains copper pour polygons. This approach is necessary because copper pour (flood) point has to be defined by the user to obtain correct test results.
ii) Manual Removal of Isolated Copper
• Load the project in Fabrication Manger
• Select Copper Relief from Tools
• Select create graphic item to relieve copper function tool and then select for example relieve copper in polygon option tool and mark the area to be relieved.