Looking back at Altium Roadshow 2022

PCB via filling and countersinking holes were among the practical topics covered during the Altium Roadshow 2022. The event took place at the beginning of February. Due to the unfavorable COVID situation, the originally planned in-person meeting in Brno was cancelled and moved to an online format.

On February 2, participants interested in the latest developments in Altium Designer, as well as practical solutions related to PCB manufacturing, met via a ZOOM video conference. Brno-based company RETRY, the event organizer, also invited Gatema PCB to give a presentation. Gatema PCB answered questions about PCB manufacturing technologies and processes and introduced participants to the practical aspects of PCB via filling and countersunk holes in PCBs.

These technologies can now be addressed directly in Altium Designer. Understanding the manufacturing process made it easier for participants to see what needs to be configured when creating the design documentation. This helps ensure that the manufacturer receives all the necessary information for flawless PCB manufacturing, including the requirements for PCB via filling and hole countersinking.

HDI PCB via filling

PCB via filling helps prevent solder residues and other contaminants from entering or remaining in holes. This is particularly important for critical interconnects, typically located underneath BGA components. PCB via filling is also a common process in the production of HDI boards.

• Space saving: PCB via filling enables the use of via-in-pad technology, helping save valuable space on the PCB and supporting more compact designs.
• Improved vacuum compatibility: One advantage of PCB via filling is that it allows vacuum processes to be used more effectively during the assembly of electronic devices.
• Better heat dissipation: Using copper or thermally conductive paste as the filling material can improve heat dissipation from the PCB.
• Increased PCB durability: Filling the holes helps protect the PCB from damage, making the board more durable and capable of withstanding higher voltages.

Pic. Visible subsurface moisture expansion including PCB deformation

Then we explained to the customers the PCB via filling process and showed them why it can be more advantageous to choose Type VII over other filling options, such as Type V and Type IV via filling.

Type VII PCB Via Filling at Gatema PCB

Type VII PCB via filling, which is the most commonly used filling method at Gatema PCB, received the most attention. A simple animated model was used to explain the individual production steps and the advantages of this process. With Type VII PCB via filling, the plated holes are filled from both sides simultaneously before the actual PCB fabrication process.

1. drilling

2. forging

3. PCB via filling

4. grinding

5. drilling

6. punching

7. etching + non-soldering mask

Pic. Type VII PCB via filling

The advantage of filling the plate with Type VII, compared to filling the plates with Type V and VI, lies in the price. Both types V and VI with completely filled holes are, especially in prototyping, incomparably more expensive, because producer has to change standardized processes. As a result, they require more manufacturing steps, plus lighting and etching. There are also more problems with surface flatness. Therefore, a PCB with Type VII fill is in all respects of higher quality and more reliable.

In order to give the participants comprehensive information, the practical part of the production presentation was followed by a demonstration of the via filling setup in Altium.

Countersink

The next input was a presentation and practical information on PCB embedding, given by Radim Vitek on behalf of Gatema. He presented the tools used not only for countersinking, but also for chamfering of connectors. The 6 mm diameter countersink tool has three variants of drill tip chamfers, standard 90°, 120° and 140°.

Pic. Countersink ø 6 mm

He also introduced the counterbore options (for flat head screws). For this technology, we use a tipless milling tool, which we call a 3D/recessed milling tool, as shown in the B model below.

Pic.     A – countersink hole       B – counterbore hole

Data preparation

The manufacturer must obtain precise information from the contracting authority on the requirement for recessing. Ideally, all recorded in the data. When creating a backfill design, the best way is to have filled vias in a special layer. Alternatively, the specification can state what diameter of drill bit the holes are to be filled to. If the customer asks for filled holes and does not specify them in any way, then we will automatically fill all holes up to a drill diameter of 0,45 mm.

When preparing data in ODB++, the countersinks have their own layer. In the PCB drawing, you need to show the dimensions of the countersunk hole, including the side view. Finally on fabrication, it was noted that both the countersinking and milling can be plated (3D plated mill).

To make the fabrication seamless, it is very much dependent on the supplied PCB fabrication documents. More and more parameters are entering into the specification, so for anyone who is unsure how to prepare the data for flawless PCB manufacturing, we have a technical sheet available on our website, while our PCB Designer’s Guide is available upon request from our sales team.