1. **PCB Ceramic Substrate Manufacturing Technology**
There are various ceramic manufacturing technologies used in PCB production facilities. It is estimated that more than 30 distinct processes are involved, such as dry pressing, slurry casting, extrusion, injection molding, seeding, and isostatic pressing. Since electronic ceramic substrates are typically “flat” (in the form of blocks or discs), with relatively simple shapes, dry molding and processing methods are commonly employed. These processes are straightforward and cost-effective, making them the preferred choice. The dry-pressing process for flat electronic ceramics generally includes three key stages: the formation of the green body, sintering and finishing of the body, and the creation of circuits on the substrate.
1. **Green Body Formation (Shaping)**
High-purity alumina (typically 95% Al2O3) powder is used, with varying particle sizes depending on the specific application and manufacturing method (ranging from a few microns to tens of microns). This powder is combined with additives, mainly binders and dispersants, to create a “slurry” or other processing materials for the forming stage.
1: The dry pressing method produces a green body (or “green body”).
Dry compaction is made from high-purity alumina (with alumina content over 92%, typically 99% for electronic ceramics) powder (for dry compaction, the particle size should not exceed 60 µm, and for extrusion, elongation, and use, appropriate plasticizers and binders control the powder particle size to within 1 µm). After the dry pressed billets are uniformly mixed, the pieces or fish fillets can now reach 0.50 mm or even 0.3 mm (depending on the plate size). The dry-pressed blank can be processed before sintering, such as adjusting shape and size or drilling, but it is important to consider the size compensation resulting from sintering (which causes expansion of the disc pattern).
2: The green body is manufactured through the casting method.
The liquid mixture (aluminum oxide powder, solvents, dispersants, adhesives, plasticizers, etc.) is uniformly mixed and passed through a sieve for manufacturing. The expansion flow process (the adhesive is evenly coated onto the metal or heat-resistant polyester tape on the expansion machine), followed by drying, trimming (including hole processing), skimanding, and sintering. Production can be automated, enabling large-scale PCB production.
**PCB Design Schematic Drawing Skills**
When designing a PCB drawing, ERC may show a “Multiple Net Identifiers” error message:
**Solution:** This could occur if different network labels are connected together during the PCB design, or if the same connection is assigned multiple network labels.
For a single schematic, the incorrect label can be found directly on the schematic. When using multiple schematic diagrams, especially with multi-layer editing, the error may be located in sub-diagrams.
1: Common errors in PCB schematics:
– **ERC reports no access signal for this pin.**
This can happen when I/O attributes are defined incorrectly for the pins during package creation. For example, connecting input and output ports together may trigger errors. If circuit simulation is not used in Protel, there is no need to define I/O properties for the pins.
Inconsistent grid properties during component placement can cause pins not to connect to wires. Also, if the pin direction is incorrect during component assembly, it may fail to connect at the pin name end.
2: **ERC reports duplicate network tags (error: multiple network identifiers).**
This may be due to different network labels being connected together, or assigning different labels to the same connection. It’s important to note that the error flagged by Protel may not always be a real error, or could be incorrect in other schematics (if a layered circuit diagram is used).
3: **The component runs outside the graphic boundary:**
No component should be placed outside the center of the component library sheet.
4: **The created project file netlist only partially adjusts to the PCB:**
The netlist was generated without selecting the global option.
5: **When creating custom multi-part components, avoid using comments.**
There are various ceramic manufacturing technologies used in PCB production facilities. It is estimated that more than 30 distinct processes are involved, such as dry pressing, slurry casting, extrusion, injection molding, seeding, and isostatic pressing. Since electronic ceramic substrates are typically “flat” (in the form of blocks or discs), with relatively simple shapes, dry molding and processing methods are commonly employed. These processes are straightforward and cost-effective, making them the preferred choice. The dry-pressing process for flat electronic ceramics generally includes three key stages: the formation of the green body, sintering and finishing of the body, and the creation of circuits on the substrate.
1. **Green Body Formation (Shaping)**
High-purity alumina (typically 95% Al2O3) powder is used, with varying particle sizes depending on the specific application and manufacturing method (ranging from a few microns to tens of microns). This powder is combined with additives, mainly binders and dispersants, to create a “slurry” or other processing materials for the forming stage.
1: The dry pressing method produces a green body (or “green body”).
Dry compaction is made from high-purity alumina (with alumina content over 92%, typically 99% for electronic ceramics) powder (for dry compaction, the particle size should not exceed 60 µm, and for extrusion, elongation, and use, appropriate plasticizers and binders control the powder particle size to within 1 µm). After the dry pressed billets are uniformly mixed, the pieces or fish fillets can now reach 0.50 mm or even 0.3 mm (depending on the plate size). The dry-pressed blank can be processed before sintering, such as adjusting shape and size or drilling, but it is important to consider the size compensation resulting from sintering (which causes expansion of the disc pattern).
2: The green body is manufactured through the casting method.
The liquid mixture (aluminum oxide powder, solvents, dispersants, adhesives, plasticizers, etc.) is uniformly mixed and passed through a sieve for manufacturing. The expansion flow process (the adhesive is evenly coated onto the metal or heat-resistant polyester tape on the expansion machine), followed by drying, trimming (including hole processing), skimanding, and sintering. Production can be automated, enabling large-scale PCB production.
**PCB Design Schematic Drawing Skills**
When designing a PCB drawing, ERC may show a “Multiple Net Identifiers” error message:
**Solution:** This could occur if different network labels are connected together during the PCB design, or if the same connection is assigned multiple network labels.
For a single schematic, the incorrect label can be found directly on the schematic. When using multiple schematic diagrams, especially with multi-layer editing, the error may be located in sub-diagrams.
1: Common errors in PCB schematics:
– **ERC reports no access signal for this pin.**
This can happen when I/O attributes are defined incorrectly for the pins during package creation. For example, connecting input and output ports together may trigger errors. If circuit simulation is not used in Protel, there is no need to define I/O properties for the pins.
Inconsistent grid properties during component placement can cause pins not to connect to wires. Also, if the pin direction is incorrect during component assembly, it may fail to connect at the pin name end.
2: **ERC reports duplicate network tags (error: multiple network identifiers).**
This may be due to different network labels being connected together, or assigning different labels to the same connection. It’s important to note that the error flagged by Protel may not always be a real error, or could be incorrect in other schematics (if a layered circuit diagram is used).
3: **The component runs outside the graphic boundary:**
No component should be placed outside the center of the component library sheet.
4: **The created project file netlist only partially adjusts to the PCB:**
The netlist was generated without selecting the global option.
5: **When creating custom multi-part components, avoid using comments.**
