Solve! How do You Make and Change A Footprint in PCB?

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Tues, Mar 09, 2021

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How to design PCB?

How to make a footprint in PCB? How to change your footprint in the PCB editor? This blog will tell you how to create a PCB footprint using the CADSTAR program, and you can also learn how to change the footprint in a PCB editor.


1. How do You Make A Footprint in PCB?

In this lesson, we will look at the various functions of finalizing the board drawing: add dimension symbols and a textual description of the project, and also learn how to use the mechanism for making changes to the ECO (Engineering Change Order) project.

PC board.jpg

Dimensioning legend

To work, we need a special example Chapter8.PCB, which is included in the standard delivery of the CADSTAR program.

1. Execute the menu command File | Open and in the window that appears, select the file Chapter8.PCB.

2. Execute the menu command View | View All or click the button  icon1.png  on the toolbar.

The PCB editor window will open with the selected project. 

Color palettes for displaying graphic primitives here are configured in such a way that only the outline of the board and the frame with the signature are visible on the screen. 

At the end of this exercise, we should get the drawing shown in Figure 1.

figure 1.jpg

When working with the size legend, we need to lock the graphic object scaling handles.

3. Execute the menu command Tools | Options, in the Options window that appears, go to the Interaction tab and here in the Interaction field, turn off the Enable Resize Markers option, and then close the window by clicking OK.

Before proceeding to add dimensions to the project, we need to configure their default parameters: the appearance of lines and arrows, the units of measurement displayed in the project, as well as the size and appearance of text values.

4. Let's execute the menu command Setting | Defaults and in the appeared Defaults dialog box go to the Dimension tab (Fig. 2).

figure 2.jpg

First of all, let's customize the appearance of the arrow.

5. In the Arrow Heads field in the Style drop-down list, select the arrow display style shown in Figure 2.

6. Set the Length of the arrow to 90 thousandths of an inch.

7. Set the slope angles of the upper and lower arrow lines (Upper Angle and Lower Angle) equal to 20 degrees.

Let's configure the display of linear units of measurement.

8. In the Units drop-down list, select Thousandths of an Inch as units of measurement, and set the Precision parameter to 0, which will correspond to integer values.

Likewise, configure the display of angular units.

9. In the Angular Units drop-down list, select Degrees as the unit of measurement and set the Angular Precision parameter to 0, which will correspond to integer values.

10. In the Layer drop-down list, select a layer called Documentation, on which the dimension symbols will be placed. Set up the styles of the lines that make up the dimension legend.

11. In the Defaults dialog box, go to the Dimension Line tab (Fig. 3).

figure 3.jpg

12. In the Dimension Line field in the Line Code drop-down list, select the Line 5 line style for displaying dimension lines (with arrows at the end).

13. In the Style drop-down list, select the Internal value.

Note: The differences between the Internal and External linear dimension styles are shown in Figure 4. If the dimension text does not fit inside the dimension lines when the Internal style is selected, the system will automatically switch the style to External.

figure 4.jpg

Let's configure the parameters of the Leader Line objects - "shelves" intended for designating the sizes of radii, diameters, etc. (Fig. 5).

figure 5.jpg

14. In the Leader Line field, set the Angle parameter to 45 degrees, the Length parameter to 300 mils, and the Extension Line parameter to 394 mils. Let's configure the parameters of the extension lines Extension Line (Fig. 6).

figure 6.jpg

15. In the Extension Line field in the Line Code drop-down list, select the Line 5 line style for displaying extension lines.

16. For the Offset and Overshot parameters, set the values equal to 30 and 50 mils, respectively. 17. Turn off the Suppress First Extension Line option.

This option is used when several measurement lines start from the same point and stop the extension line beyond the previously drawn dimension.

Let's set up the display styles of text size symbols.

18. In the Defaults dialog box, go to the Dimension Text tab (Fig. 7).

figure 7.jpg

19. In the Text Code drop-down list, select the Text Size 75/75/12 text style.

20. In the Position field, select the Style (Style) Inside and set the value of the Gap parameter to 50.

If we had chosen the Outside style, then the second parameter would automatically change to Offset. The meaning of these parameters is shown in Figure 8.

figure8.jpg

We just need to customize the format of the text size designation. The format can contain an arbitrary set of characters and four standard variables: DISTANCE, UNITS, UNITS SHORT, and UNITS ABBREVIATED. Figure 9 shows several examples of the format for describing the textual designation of dimensions. Variables are selected from the context menu invoked by clicking the> button located next to the corresponding text field.

figure 9.jpg

Note: For our exercise, we chose the Internal style for displaying dimensions. However, we need to adjust the format for the outer style as well, since the system will automatically use the outer layout style of the size text if there is not enough space for its inner layout.

21. Let's check that the settings of the formats of text symbols in the Format field are made, as shown in Figure 7.

22. Click OK and close the Defaults window.

Note: If the appearance of any designation of the size does not suit us, we can change it individually, using the editing of the object properties (Item Properties).

Let's start adding dimensions to the drawing.

23. Let's execute the menu command View | Toolbars | Dimension to enable the display of the Dimension toolbar.

24. Let's execute the menu command View | Toolbars | Snap to enable the display of the Snap toolbar.

25. On the Snap toolbar, click the Snap-on Endpoint and Snap to Perpendicular buttons, as shown above in Figure 10.

figure10.jpg

26. Let's execute the menu command Add | Dimension | Direct or click the button icon2.png on the Dimension toolbar and switch to the mode of setting linear dimensions.

The status bar will prompt Select start point for dimension.

27. Move the mouse pointer over the left end of the horizontal segment of the board outline and, as soon as the cursor turns into a square (the system will capture the end of the line), click the left mouse button.

The Select endpoint for dimension prompt appears on the status bar.

28. Move the mouse pointer to the right, grab the right end of the horizontal segment, and perform another left-click.

Notice that as you move the cursor, the linear dimension symbol begins to follow. The Place dimension line prompt appears on the status bar.

29. Move the mouse pointer down approximately 250 thousandths of an inch and click the left mouse button a third time.

The system will finish drawing the conventional designation of the linear dimension, which after all the performed operations will look like it is shown in Figure 11. Let's continue drawing the linear dimensions, especially since the system is in the mode we need.

figure 11.jpg

30. Move the mouse pointer over the lower-left corner of the board and click the left mouse button to set the first point.

31. Move the mouse pointer to the right and set the second point at the end of the horizontal segment of the contour by clicking the left mouse button.

32. Move the mouse pointer up a bit so that the size takes the form shown in Figure 12, and by clicking the left mouse button, finish drawing it.

figure 12.jpg

Since the text part did not fit between the size arrows, the system automatically changed the designation style from Internal to External.

Notice that both of the dimensions we drew were defined by starting points that were vertically aligned. In case the points are at different levels, linear orthogonal dimensions are usually used.

33. Let's execute the menu command Add | Dimension | Orthogonal or click the button  icon3.png  on the Dimension toolbar and switch to the mode of creating a linear orthogonal dimension.

34. By sequential clicks of the left mouse button, set points 1 and 2, as shown in Figure 13.

figure 13.jpg

35. Move the mouse pointer to the left of the board.

The system will prompt you to draw an orthogonal vertical dimension in the External style.

36. Move the mouse pointer down.

The system will prompt you to draw an orthogonal horizontal dimension in the Internal style.

37. Let's left-click and finish drawing the dimension.

Add an angular dimension symbol to the drawing. Usually, to measure the value of an angle, it is necessary to set two lines, and these lines may not have an intersection point, which is very common in practice.

38. Let's execute the menu command Add | Dimension | Angular or click the button  icon38.png  on the Dimension toolbar and switch to the angular dimensioning mode.

39. Without changing the snapping mode, by clicking the left mouse button successively set points 1 and 2 in the upper right corner of the board outline, as shown in Figure 14.

figure 14.jpg

40. Move the mouse pointer up a little.

The system prompts you to draw a concave angle symbol with a value of 225 degrees, that is, greater than 180 degrees.

41. Move the mouse pointer down a little.

The system prompts you to draw a convex angle symbol with a value of 135 degrees.

42. Let's click the left mouse button and finish drawing the dimension.

Let's add a circle diameter symbol to the drawing.

43. Click the button  icon43.png on the Snap toolbar and turn on the Snap to Quadrant mode, which selects the quarters of the circle.

44. Let's execute the menu command Add | Dimension | Diameter or click the button  icon44.png  on the Dimension toolbar and switch to the mode of setting the designation for the diameter of the circle.

45. Move the mouse pointer over the circular cutout in the board and left-click on one of the anchor points.

The designation of the diameter of the circle will appear on the drawing (Fig. 15). Since the text will be large enough, the system will automatically style it to External.

figure 15.jpg

As an independent exercise, we propose to add to the drawing all the other dimension designations shown in Figure 1.

Creating Topological Footprint Libraries

Now that we have learned the basic techniques of working in the PCB editor.

We need to close another blind spot - learn how to create topological component footprints and save them in a special library for later use in our projects. 

Recall that earlier in one of the lessons, we learned how to draw element symbols for the schematic editor and package them into component libraries.

It includes references to symbols and footprints, as well as information about the equivalence of sections and pins. 

2.How do You Make an Altium Footprint?

You can create an Altium footprint by following 4 steps:

  • Creating the pads
  • Defining component height and area
  • Adding silkscreen information
  • Saving the footprint

Let’s discuss these steps of the process in detail.

  • Step 1: Creating the Pads

The first requirement is the landing pattern for the electronic component or part.

This pattern is available in the PCB library or the component datasheet.

If you have to add a new footprint to the library you should follow File → New → Library → PCB Library.

Along with this footprint, you will also add the new components to the library.

However, if you create a new library for the PCB footprint, this will produce a blank footprint for your electronic component by default.

  • Step 2: Defining Component Height and Area

This step will help you to estimate the height and area of the component.

The type of the component is also important in this step.

For this purpose, find out the footprint of the component from the list of footprints.

Then click the edit option from there. It will show you the three types of information here.

It will set the type of the component to the standard one.

The other components will not be the standard components and will show up as the appropriate type of component.

  • Step 3: Adding Silk Screen Information

The layer image of the silkscreen and the pin 1 indication is important for the accomplishment of this step.

The datasheet of the component will help us to indicate the corners.

For the creation of the corner, you have to select the line icon and create a line of 0.08 mm.

In the final step, you save the project files and library of your PCB footprint.

  • Step 4: Saving the Footprint

In the final step, you have to create a name for your footprint and save it.

The name of the footprint can also contain the symbols.

You can easily find and search the name of your footprint later.

3. How do You Create the Footprint in the OrCAD PCB Editor

The OrCAD PCB editor is very helpful for the creation of the footprint of any electrical component.

For this, choose a file and go into library manager.

There are 2 fundamental options while creating a new footprint for any component.

You can take the existing footprint and edit it to your requirement.

Or you can start from scratch with nothing.

If you want to choose the existing footprint, you can select it from the list.

You can find the existing footprint from the left side of the screen.

Once, you have selected the footprint, it will appear to the right in the work area.

4. How to Change Your Footprint in the PCB Editor

You can also change the footprint in the PCB editor.

For this, firstly, you have to edit the footprint properties present in the schematic.

Then you can recreate the netlist of the PCB and import it.

The PCB editor also provides an Alt-symbols property for your footprint.

This property can create an alternative to the footprint if we add it to the schematic.

Conclusion

This blog is going to end at here, about what is the footprint in PCB you can read our last article or please click: https://www.pcbonline.com/blog/what-is-the-pcb-footprint.html

And for any PCB design questions, you can also register on our website PCBONLINE, after the register, if you have a PCB project you can quote online by yourself. If you just need to ask design questions, after registering, there also will be a staff of PCBONLINE write an email to you to provide you with the one by one service!