Introduction

In the past few decades, there has been a tremendous expansion of the wireless industry, which transformed itself from being predominantly military-driven to a consumer-driven, cost-conscious commercial market. Simultaneously, wireless applications are venturing further into the frequency spectrum. For instance, personal communications systems that earlier operated on 1.9 GHz, are being replaced by newer designs operating on 5.8 GHz.

Applications

With applications moving up in the frequency scale, there is renewed interest in high frequency, high performance, but low-cost substrates. Earlier, only military applications considered polytetrafluoroethylene (PTFE) as a substrate that satisfied the above technical requirements. PTFE is also commonly known as Teflon.

Why Use PTFE?

With a melting point of 327°C, Teflon has high temperature resistance, negligible water absorption, good resistance to processing chemicals, and a very low loss tangent. That makes the PTFE substrate suitable for all the technical requirements of RF/Wireless designs. However, commercial applications also demand low costs along with high performance, but the conventional PTFE substrates were eight to ten times more expensive than regular FR-4 epoxy glass laminates are. In addition, processing of PTFE substrates was difficult because of the inert and soft nature of PTFE.

Ceramic Filled PTFE Substrates

New research has established ceramic filled PTFE substrate, such as RF-35, as not only satisfying the commercial price requirements, but also exceeding all electrical and mechanical property that manufacturers seek in a PCB substrate for high frequency applications. The dielectric constant of RF-35 has a value of 3.5±0.1, and the material is available in thicknesses of 10, 20, 30, and 60 mil.

Substrates such as RF-35 are unique as the variation in their thickness and dielectric constant within a sheet are minimal. For instance, a sheet of RF-35 shows a standard deviation for dielectric constant as 0.01, while that for thickness as only 0.00023” within the sheet. Within a range of 500 MHz to 11.2 

PCB Global manufacture 1 layer, 2 layer and the high tech 4 layer Aluminium PCB’s for the worldwide electronics manufacturing industry.  A standard Aluminium Printed Circuit Board stack up for 1, 2 and 4 -Layer PCB’s is shown below:

Base Metal Layer:  Aluminium – generally 1.0 to 4.0mm thickness, 1.5mm being the standard.

Dielectric Layer:  Not only to bond the copper circuit layer to the aluminium but more importantly offer the required electrical isolation with minimal thermal resistance; 1W/m-k and 2W/m-k being the standard.

Copper Foil:  The copper foil will be processed and etched to the required circuit layer design.

PCB Global offer these technologies for Aluminium Printed Circuit Boards on our easy to use online portal  at: http://www.pcbglobal.com/quote/aluminium-pcbs/

It is common for PCB Global’s Computer Aided manufacturing (CAM) Engineering department to have Engineering Questions, also known as, EQ’s to confirm with our customers, dependant on the quality of the design file provided. One example of a typical EQ is shown below:

Mechanical Layers in Altium/Protel File

EQ from CAM:

Are the mechanical layers from GM2, GM4, GM7 and GM8 relevant for PCB fabrication?

Explanation:

Most Altium/Protel files we receive tend to have mechanical layers which are not required for the actual bare printed circuit board fabrication. These are usually part of the product design and have no relevance to our bare PCB fabrication processes.

 Resolution:

Our customer in this case, confirmed to ignore these 4 mechanical layers.

For further tips and information when designing and laying out your printed circuit board design file please do not hesitate to contact our PCB Global team at sales@pcbglobal.com

EQ’s or Engineering Questions are common for many PCB design file packages received.  PCB Global’s Computer Aided manufacturing (CAM) Engineering department will invariably have a few EQ’s to confirm before proceeding with the customer’s PCB order. One common example of a typical EQ regarding Tooling and V-Grooving is shown below:

Tooling Hole Cut by V-Grooving

EQ from CAM:

Tooling hole on the tooling strips too close to the V-groove.

Explanation:

The V-grooving can easily damage the tooling hole and cause poor registration through the SMT process on both solder paste application as well as SAMT component placement.

 Resolution:

Our customer confirmed to move the tooling hole 2mm to the right to ensure the V-grooving will not affect the integrity of the non-plated through tooling hole.

For further tips and information when designing and laying out your printed circuit board design file please do not hesitate to contact our PCB Global team at sales@pcbglobal.com

When ordering your prototype printed circuit board, there is a tooling charge associated with the creation of your new PCB. When re-ordering your existing PCB’s, it is important to consider and understand the minimum order quantity (MOQ) associated with the minimum order value (MOV).

MOQ’s and MOV’s are important as this is associated with the economic viability of producing your PCB’s. For example: It is commercially viable for the factory to run the production for 3pcs at US$3.00 with a tooling charge of US$198.00 (Total of US$207.00 plus shipping) however, it is not commercially realistic to fabricate 3pcs with a total cost of US$9.00.  The cost of all the set ups required and running the production line machines is accounted in the MOQ.

Here is the matrix below:

2 layer – US$125.00

4 layer – US$225.00

6 layer – US$275.00

8 layer – US$375.00

10 layer – US$395.00

12 layer – US$495.00

14 layer – US$545.00

16 layer – US$620.00

18 layer – US$695.00

20 layer – US$750.00

Note: These MOV’s do not include the price of shipping.

Example using matrix: If you initially ordered 5pcs of a 6- layer PCB at US$12.50 each and you require another batch of the same revision PCB again, for US$275.00 you will receive 22pcs or be charged the equivalent of 22pcs if you do not wish to obtain 22pcs.

For further explanations, or more information on this, please don’t hesitate to contact us at sales@pcbglobal.com