PCB design skills based on GENESIS2000 software (1)

1. Shape 

There are two ways to make a shape:

1.1 By customer light painting files

steps:

a. Use the Select by net panel to select the component line border and copy it to the rout layer.

b. Delete all arcs;

c. Check the number of lines, for example, the rectangle should have four lines to remove the extra lines;

d. Check the angle of the line. The angle of the regular line should be 0°, 90° and 45°. If it is 0.1°, most of the customer's design mistakes need to be consulted;

e. Reconnect the line intersection and chamfer with the Rout→Connections function. The arc line attribute should be arc;

f. Change the line width to r10mil.

1.2 Dimensions by customer

steps:

a. Create a rout layer in Matrix;

b. Select item 5 in the Options→Line parameters function;

c. Use the Add feature function in the panel to manually draw the shape according to the customer dimension in the rout layer, and set the line width to r10mil;

d. Use the Rout→Connections function to assist in the intersection of the connecting line and the chamfer to the shape.

e. If the Rout layer has an entity such as Rect or Oval, convert it to an outline. Method: first select the entity, click Edit Reshape contourise to become Surface, execute Surface to outline, input line width value can be converted into contour.

After the shape is complete, use the Select by net command to select the shape graphic, then use the Edit→Create→Profile command to create the profile.

2. orig

Orig consists of the following three parts:

2.1 layer alignment

steps:

a. Select all layers, use the drilling as the reference layer, and use the register function to achieve automatic alignment of the line, grounding, soldering and drilling;

b. Other layers (including the character layer) need to manually move the whole layer so that the outer frame and the outer border of the component surface layer overlap, and if necessary, mirror.

Inspection Method:

a. The center of each layer of pads should be aligned with the center of the hole;

b. The outer borders of each layer shall coincide with each other;

c. The face character of the component is a positive character, and the weld face character is an inverse word.

2.2 line to pad

steps:

a. Open the features Histogram of the solder mask, select all in the Lines List, press Highlight, compare the lines and characters to determine whether the pad needs to be turned;

b. Simultaneously select and open the component surface line and component surface solder mask, press the W command to the skeleton display mode, use the panel to select the line to be converted (usually the end of the line), and then use DFM→Cleanup→Construct pads (Ref .) The function converts by class. The welding surface method is the same;

c. Check the line except the frame line and the large area tin block by the method of step a;

d. If the r-shaped line is converted to an oval-shaped pad, use the Actions→reference Selection function to select all the oval reference solder mask layers on the circuit layer, and remove the voided layer of the solder mask layer (the same as the solder mask oval). The rest of the oval interrupts the line with the Edit→Reshape→Break command, and finally moves the removed oval back to the line layer. This operation should be used with caution when there is a positive or negative superposition.

2.3 Defining SMD

Use the DFM→Cleanup→Set SMD attribute function, the parameter Types Other is set to *, and the pad that is not drilled in the outer layer is automatically set to SMD.

Delete the original edit in Matrix and copy orig to edit. The following operations are performed in edit if not specified.

3. Matrix

Take the standard 4-layer board as an example, define the attributes of each layer, and sort the layers by the X command in the order of the board.

board drill positive

board rout positive

board silk_screen positive

board solder_mask positive

board signal positive

board power_ground negative

board power_ground negative

board signal positive

board solder_mask positive

board silk_screen positive

3.1 The basis for correctly arranging the levels is as follows:

a. The customer provides a order;

b. There is a order mark outside the board;

c. There are numerical symbols in the board, such as "1, 2, 3, 4...".

3.2 The general basis for judging each layer as positive and negative is:

The center of the pad is positive for the body, and the center of the pad is hollow for negative.

4. Drilling 

4.1 drilling steps

a. Open the Drill Tools Manager and check whether the hole diameter, hole number and hole properties in the drilling file are correct according to the drill pattern provided by the customer. If there is no drilling pattern, the drilling file shall prevail;

b. Change the via property with small aperture and irregular distribution from plt to via;

c. Enter the hole diameter corresponding to each hole according to the Drilling Tool Compensation Rules.

d. Analyze the drilled layer with Analysis→Fabrication→Drill Checks function to check whether the analysis result is abnormal;

e. If there are heavy holes, use NFP Removal function, parameter Delete to select Duplicate, automatically remove the drilling hole and the heavy plate of the corresponding layer;

f. If there are intersecting holes, manually delete the smaller vias in the cross holes and the corresponding pads of each layer; if the device holes are crossed, they cannot be deleted, and two pre-drills that are tangent to the intersecting holes should be added at both ends of the intersecting holes. Hole, theoretically pre-drilled hole diameter = (cross hole center distance + cross hole hole diameter) / 2, and then use the tail method to select the hole diameter (in principle, the hole diameter is already selected in the plate).

For example, the two cross holes have a hole diameter of 2.15mm and a center distance of 1.00mm. When the hole diameter is calculated to be 1.575mm, the pre-drill hole diameter is 1.55mm.

4.2 Drilling slot

a. In the drilling layer, change the shape of the required drill slot to oval with the Edit→Reshape→Change Symbol command. The drill slot is 3.00X1.00 and the shape is oval3X1.

b. Interrupt the oval with the Edit→Reshape→Break command into line;

c. If the required length to width ratio of the drill slot is <2, add two pre-drilled holes at both ends of the slot, the same way as the cross hole.

5. Drilling outline drawing

steps:

a. Copy the rout layer to the new layer tmp with the Edit→Copy→Other Layer command, and increase the 5mil;

b. In the tmp layer, use the Add feature function to mark the complete and correct dimensions. The line width and dimension line width is r5mil, the arrow uses special symbol→jian/jian45, and the size value is Text.

The parameters are XY 80 mils and the line width is 5 mils;

c. Use the Creat Drill Map function to automatically generate the drilling pattern, the unit is set to mm, and the drilling pattern is named map;

d. Move all the graphics in the tmp layer to the map layer, and the description text in the customer drilling diagram is also moved to the map layer and merged into a drilled outline drawing;

e. Remove the tmp layer.