Drill, Lamination, And Plating Of PCB Design

1. PNC INC. DRILL, LAMINATION, AND PLATING OF PCB DESIGN www.pnconline.com

2. About A PCB with more than one layer consist of drilled vias and plating, and lamination. You can laminate layers before or after making vias. Holes need plating after drilling, which is known as PTH plated- through holes. The plating helps in the current flow through PCB layers. In this article, we will discuss three processes in detail, such as drilling, plating, and lamination. WWW.PNCONLINE.COM

3. Understanding Drilling PC Board drilling involves different drilling machines which can make more than 30,000 holes in an hour. The machines have built-in systems for making precise holes and consist of spindles that can drill at a high speed of up to 110,000 RPM. An automated system and laser help manage drill bits to provide high-quality vias. WWW.PNCONLINE.COM

4. BLIND AND BURIED VIA DRILLING Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. www.pnconline.com

5. MICRO-VIAS DRILLING The drilling of micro-vias involves a laser machine because their size has to be small which is not easy to create through mechanical drilling. Micro- vias are ideal for thick PCBs, and you can connect them vertically by stacking them in layer pairs. Such as, in a traditional buried via, you can sequentially fabricate micro-vias whereas the buried vias need copper plating to connect the stacked vias. www.pnconline.com

6. HOW TO SELECT A DRILL Though drilling is a basic function for a PCB Manufacturer, engineers use certain techniques to have precise drilling. Sometimes a board needs lots of drills of the same size, which can cause changes in the bit during drilling. Such a change creates errors in terms of tolerance between hole diameters. So, engineers use drills of different sizes to avoid the quantity of the same-size drills. Drilling diameter should be minimum, like in mechanical drilling, a six to eight mils drill is ideal for a 62-mils thick board. Whereas it is hard to use the small drill sizes in mechanical drilling, and its aspect ratio also makes plating difficult. So, engineers have to use laser drilling which is more expensive than normal drilling techniques. You have to use large drills for thick PCBs which are more than 62mils thick. Use blind and buried vias when they are necessary otherwise avoid them. As their fabrication involves a sequential buildup method that increases the manufacturing cost of a raw board.

7. PCB PLATING OR METALLIZATION AND SOLDERING You need metal pads or lands to help components in mounting or soldering. You can’t solder the bare copper and have to plate it with an easy-to-solder material. In the past, lead-based tin was a common plating material. But, these days the environmental changes call for advanced materials like gold and nickel. Unsoldered parts of the board need materials to resist soldering, such as polymer coating that prevents the bridging of traces. Moreover, it creates short circuits in the adjacent part leads. www.pnconline.com

8. FABRICATING THE EXTERNAL LAYERS The above etching is ideal for circuits of external layers and the process includes drilling, metallization, and photoengraving. The final finishing happens after the external layers’ metallization. In general, the process includes soldering, silk screen application, testing, as well as packaging. www.pnconline.com

9. PCB LAMINATION PCB lamination is crucial in terms of accuracy and creating a well-finished board. The process involves lots of stress, as you have to take care of the properties of PCB materials in terms of performance and production. PCB engineers and manufacturers have to work together to develop a functional product without sacrificing production. www.pnconline.com

10. UNDERSTANDING THE LAMINATION PROCESS The lamination of individual layers involves two main steps, such as: Laying up: It involves the stack-up of multiple layers. The manufacturer starts it from the bottom of the base substrate. Then comes the prepreg and internal etched layers. Then all layers are pinned together to make a final board without any disturbance. Laying up prepares the PCB before pressing. Pressing of layers: Pressing involves heat and pressure that melts prepreg to finish the etched copper layer, making the insulation layers essential for electronic layers which can work closely. Prepreg bonds the layers, getting hard after curing, and makes a PCB mold. You need to consider different factors during pressing. Like, many PCBs can be pressed together to save time and production costs. However, manufacturers have to place a separator between the individual layers to bear high pressure and heat without changing the PCB shape. The laminating press also needs a vacuum to prevent the PCB voids to hinder the dielectric property, affecting its structural strength. The environment after pressing also needs consideration to prevent the STP quenching due to weather conditions. Manufacturers should store the pressed circuit boards in a press to cool them down. Cooling of the boards prevents the thermal contraction of the board.

11. LAMINATION STYLES Two styles are common in this case, such as: ·Foil lamination ·Cap lamination PCB Lamination with A Foil: the foil lamination is simple and involves less hassle, as you have to foil the base and top layer. After lamination, the layers go through etching just like internal layers. Foil lamination is more advanced than cap lamination, but you have to select the foil layer with care to remove them easily later on. The technician should work in alliance with the designer and material manufacturers to ensure precise production. Copper Clad or Cap Lamination: It is an original method that PCB manufacturers have been using for years. There is a layer clad with copper between the base layer, top layer, and first and last inner layer. Such lamination is suitable for blind vias, however, you need a special laminate between the external and nearby layers to enhance a PCB function.

12. PURPOSE OF SEQUENTIAL LAMINATION You can use sequential lamination for advanced vias where drilling and plating come after lamination. However, vias other than through holes should be made before lamination, leading to sequential lamination. Such a technique involves many precautions in terms of materials and design to have a successful lamination. For like, you have to consider the z-axis CTE, Tg or glass transition temperature, and copper retention. A copper filling helps reduce copper accumulation to have a well- managed uniform CTE expansion. The selection of the materials for PCB lamination involves great care. Besides, you should use the latest design software. www.pnconline.com

13. TESTING A FINAL PRODUCT You can use sequential lamination for advanced vias where drilling and plating come after lamination. However, vias other than through holes should be made before lamination, leading to sequential lamination. Such a technique involves many precautions in terms of materials and design to have a successful lamination. For like, you have to consider the z-axis CTE, Tg or glass transition temperature, and copper retention. A copper filling helps reduce copper accumulation to have a well-managed uniform CTE expansion. The selection of the materials for PCB lamination involves great care. Besides, you should use the latest design software. www.pnconline.com

14. FINAL THOUGHTS Drilling, plating, and lamination are important processes of PCB construction. PCB drilling involves machines that can make more than 30,000 holes in an hour. The machines have built-in systems for making precise holes and consist of spindles that can drill at a high speed of up to 110,000 RPM. An automated system and laser help manage drill bits to provide high-quality vias. The two-layered PCB goes through lamination after drilling. Whereas a multi-layer PCB is stacked and laminated after which it needs drilling and plating. The drilling of micro-vias involves a laser machine because their size has to be small which is not easy to create through mechanical drilling. Micro-vias are ideal for thick PCBs. Plating of the holes is also essential to provide electrical connections. PCB laminating press needs a vacuum to prevent PCB voids to hinder the dielectric property, affecting its structural strength. The environment after pressing also needs to be considered to prevent any damage due to weather conditions. Would like to know more about the Drilling, Lamination, & Plating or smt assembly? Email us at sales@pnconline.com

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