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Heavy Copper PCB

Up to 20 oz PCB Manufacturing, Rich experience to print solder mask, High quality guarantee for extreme copper PCB. 

What is Heavy Copper PCB ?

heavy copper pcb

Heavy Copper PCB are fabricated with 4 or more ounces of copper on each layer. 4 oz Copper PCBs are most commonly used in commercial products. The copper concentration can be as high as 200 ounces per square foot. Heavy Copper PCBs are widely used in electronics and electrical circuitry where high power transmission is needed. Furthermore, the thermal strength offered by these PCBs is impeccable. In many applications, especially electronics, the thermal range is of vital importance since high temperature is devastating for sensitive electronic components and badly affects circuit performance.

The heat sinking capacity of Heavy Copper PCBs is much higher as compared to casual PCBs. Heat sinking is vitally essential for the development of a robust and durable circuit. Poor handling of heat signals not only affects electronics performance but also shortens the life of circuitry.

High power circuit wirings can be developed using Heavy Copper PCBs. Such a wiring mechanism offers more reliable thermal stress handling and offers fine finishing while incorporating multiple channels on a single layer of a compact board.

Heavy Copper PCBs are widely used in various products as they provide multiple features for improving circuit performance. These PCBs are widely used in high power equipment such as transformers, heat sinking, power inverters, military equipment, solar panels, automotive products, welding plants, and power distribution systems.

Heavy Copper PCB generally need to adopt a special pressing procedure. It involves the use of multiple PP fillings to meet the required filling during the pressing process. The pressing involves high pressure and a large flow of glue. There are empty areas in the heavy copper PCB in each layer of the inner layer pattern; there is no copper in the open area. Also, the edge of the plate is designed with a single air guide groove.

Due to the high pressure, the amount of PP glue passes very easily, and the air guide grooves are lost. This causes the thickness of the board in the open area to be too thin. The board’s overall thickness is extremely large, which causes the film to be not tight during the subsequent processing of the outer layer, ultimately causes the product to be not useable.

The priority is to reduce the flow of glue in the open area and prevent the open area’s thickness from being too thin. This is an urgent problem to be solved in the production process for such heavy copper PCB .

How to solve issue of the uniform thickness in the production of Heavy Coppy PCB

extreme copper pcb

1. This is amethod for manufacturing a heavy copper PCB with uniform thickness.Each inner core plate of the heavy copper PCB is provided with a copper-free open area at the same position, which includes the following steps:

  •          Cut the material to obtain the inner core board. Through the inner layer pattern and etching process, the inner layer lines are made on each inner core board, and some copper PADs are staggered on the edge of the open area of each inner core board.  Made each inner layer board.
  •          The inner layer board and the outer layer copper foil are pressed together by the prepreg to make a multi-layer production board.
  •          Post-processing the multi-layer production board according to the existing technology to obtain a thick copper board.

2. The method for manufacturing a heavy copper PCB with uniform thickness according to claim 1, wherein the copper PAD in step S1 has the same shape and size, all of which are round, oval, diamond, or square.

3. This is a method for manufacturing thick copper plates with uniform thickness according to claim 2. The radius of each copper PAD is R, and at least two rows of circular shapes are provided on the edge of the open area of the inner core plate. The copper PADs in each row are arranged equidistantly along the long edge of the board. The center distance between two adjacent copper PADs is any two adjacent copper PADs in each row. 

The bottom copper PAD is called the bottom copper PAD. The copper PAD between the bottom copper PAD is the corresponding vertex copper PAD. The center of each bottom copper PAD and the corresponding vertex copper PAD are connected to form an isosceles right triangle.

4. A thick copper plate with uniform thicknessiscomprised of at least one inner layer core plate. Each inner layer core plate is provided with a copper-free open area and at the same position, characterized in the open area of the inner layer core plate. Several copper PADs are staggered on the edge of the board.

5.The heavy copper PCB with uniform thickness according to claim 4, wherein the shape of the copper PAD is a circle, an oval, a diamond, or a square.

6.The heavy copper PCB with uniform thickness according to  5, each copper PAD has a radius R, and at least two rows of circular copper PAD are provided on the edge of the inner core plate’s open area. The copper PADs in each row are arranged equidistantly along the long edge of the board. The center distance between two adjacent copper PADs is any two adjacent copper PADs in each row; 

they are called bottom copper PADs. Adjacent rows are located on the bottom side. The copper PAD between the copper PADs is the corresponding vertex copper PAD. The center of the two base copper PADs and the corresponding vertex copper PAD centers form an isosceles right triangle.

How thick is the copper on a PCB?

copper thickness

RayMing can produce more than 20oz of heavy copper PCB. However, special attention should be paid to the inner layer’s width and line spacing if the copper thickness exceeds 3 ounces considering the side corrosion factor.

Inner layer 3oz:line width/space 8/10milOut Layer 3oz:line width/space 8/12mil
Inner layer 4oz:line width/space 8/12mil

Out Layer 4oz:line width/space 9/13mil

Inner layer 5oz:line width/space 10/12milOut Layer 5oz:line width/space 10/14mil
Inner layer 6 oz:line width/space 12/14milOut Layer 6oz:line width/space 12/16mil
Inner layer 7oz:line width/space 14/16milOut Layer 7oz:line width/space 14/18mil
Inner layer 8 oz:line width/space 14/18milOut Layer 8oz:line width/space 16/18mil

Heavy copper PCB Design for Manufacturing (DFM)

  1. The diameter of the plugged via hole requires Φ≤0.5m.
  2. The difference should not exceed 0.1mm, for no more than two types.
  3. Minimize the types of vias.
  4. The copper hole minimum requirementis 20um. The averagerecommended size is 25um.
  5. The metalized groove on the side of the board must extend into the board by more than 4mil.

Profile Tolerance:

L<100 mm100 ≤L<300mm300≤L
Tolerance±0.15mm±0.2mm±0.25
  1. The minimum milling groove width between veneers and process edgesis ≥ 1.6mm.
  2. The minimum internal angle R≥0.8mm,  if 0.5mm internal angle needs to be marked,
  3. External angle R ≥ 1.0 mm.
  4. V-CUT tolerance ≥±0.15mm, angle: 30°.
  5. V-CUT knife jump distance: 8mm.

Delivery Panel Design

  1. The orientation is stated in the drawing.
  2. The connection is a V-carved connectionor physical connection;a stamped hole is not recommended.
  3. It is recommended to provide CAD drawings for easy reading.

Circuit Layout Design

  1. The orientation is stated in the drawing.
  2. The connection is a V-carved connectionor physical connection;a stamped hole is not recommended.
  3. It is recommended to provide CAD drawings for easy reading.
Copper Thick(oz)3oz4oz5oz
Inner line space/width6/8(mil)9/10(mil)10/10(mil)
Out layer line space/width7/8(mil)9/10(mil)10/10(mil)
Vias ring width6(mil)8(mil)8(mil)
Parts vias ring width8(mil)9(mil)10(mil)
SMD Distance10(mil)12(mil)12(mil)
Min copper Legend line8(mil)10(mil) 

 

12(mil)

Circuit Layer Display

Circuit Layer Display

It is recommended that copper should be laid in blank areas as much as possible in the design. The design of plan A schematic is far superior to the design of plan B.

  1. Avoid opening the window with solder mask to expose lines.
  2. When SMD and MD need to make a green oil bridge, they must meet a certain distance.
  3. Avoid opening half a window in the hole position.
  4. For the sprayed tin plate, the plugged vias should be designed to be covered with solder mask on both sides.The plugged vias of the non-sprayed board should be designed for single-sided solder mask coverage.

Silkscreen Layer Design

Basic requirements for characters:

 

Legend line widthLegend widthLegend heightSilk 2 SMDSilk 2 PTHSilk 2 RoutSilk 2

 

V-CUT

≥5mil≥7time line width≥7time line width≥8mil≥8mil10mil≥16mil

Note: Try to avoid placing characters between the substrate and the copper skin.

Withstand Voltage Drawing

Thick copper plates need to withstand voltage and inductance test drawings. Provide test equipment and magnetic cores when necessary.

Thick Copper Circuit Board Production Process of Double-Sided 450um Ultra

pcb copper thickness

Heavy Copper PCB Instruction

Heavy Copper PCB Instruction
 Specification requirements
AThe copper thickness requirement of the circuit is ≥450UM
BThe copper plating thickness in the hole is required to be ≥150UM
CFR-4 inner core board does not contain copper; the requirement is 1.4MM
DThe Resin hole plug must be flat with the surface of the circuit without voids or bubble

2. Cutting Laminate

Cutting Laminate
Specification requirementsOperating conditions
ACopper Foil Thickness 2oz=70umChoose 1.4mm base fr4 core,2oz copper lam
BFr4 core 1.4mm without copper
CCutting Tolerance ±1.0mmNormal production with roller cutting machine

3. First Copper Plate Thickening

First Copper Plate Thickening
 Specification requirementsOperating conditions
ASurface copper plating thickness ≥150UM18ASF current density plating time is 80MIN plating six times
BThe deviation of copper thickness uniformity on board surface is within 20UMThe electroplating of the rotating transposition pinch point is divided six times to evenly distribute the current trend and the thickness of the coating

4.Outer Layer Drilling

Outer Layer Drilling
Specification requirementsOperating conditions
AAccurate positioning is requiredStack: 1PNL/1 stack
Drill life: Φ 3.2mm diameter 100 holes, Φ 1.0mm diameter 500 holes/tool
Drilling speed: 3.2mm Φ 0.4m/min, 1.0mm, Φ 0.8m/min
Spindle speed: 3.2mm Φ 23krpm, 1.0mm Φ 55krpm
Tool return speed: 3.2mm Φ 12m/min, 1.0mm, Φ 15m/min

5.First Circuit Etching

First Circuit Etching

 

 Specification requirementsOperating conditions
ANo OS (open and short circuit), line width tolerance is controlled within ±15%

Film pressing speed: 1m/min

Film pressing temperature: 105℃

Film compensation: the original film is not compensated
Alignment accuracy: CCD automatic alignment accuracy 3mil
Exposure energy: 8 grids = 40mj
Etching speed: 1m/min once +2.5m/min once, the machine has been etched twice

 

6.One-Time Resin Printing Plugging

 

One-Time Resin Printing Plugging

 

 Specification requirementsOperating conditions
AThe resin ink filling must be flat with the circuit surface without voids, bubbles, or copper on the ink surfaceNet yarn T number: 35T
Screen open compensation: unilateral compensation 15mil
Scraper angle: 21 degrees
Printing speed: 1.2m/min
Printing speed: front scraper 1.2m/min, oil return knife 1.0m/min
Squeegee pressure: 7.5kg/cm2
Number of printing knives: 8 knives repeatedly

Baking parameters: 75℃ for 30 minutes

150℃ 60 minutes

 

7.Grinding Board

 

Grinding Board

 Specification requirementsOperating conditions
ANo resin ink residue is allowed on the circuit surfaceUse 320 grit sandpaper for uniform sanding, and sand all the resin ink remaining on the surface of the circuit.

8. One-Time Immersion Copper

One-Time Immersion Copper

 

 Specification requirementsOperating conditions
AA layer of copper metal is evenly deposited and distributed on the surface of the circuit copper layer and filling resinIn heavy copper production, the glue is not removed, and the others are made according to normal production conditions.

 

9.Second Copper Thickening

 

Second Copper Thickening

 Specification requirementsOperating conditions
aSurface copper plating thickness ≥100um18ASF current density plating time is 80min plating four times
 The deviation of copper thickness uniformity on the board surface is within 15umPlating with four rotating transposition grips to evenly distribute current trend and coating thickness

 

10.Second Circuit

 

Second Circuit

 Specification requirementsOperating conditions
ANo OS (open and short circuit), line width tolerance is controlled within ±15%

Film pressing speed: 1m/min

Film pressing temperature: 105℃

Film compensation: the original film is not compensated
Alignment accuracy: CCD automatic alignment accuracy 3mil
Exposure energy: 8 grids = 40mj
Etching speed: 1m/min once +3.5m/min once; the machine has been etched twice in total

 

11.Secondary Resin Plugging

 

Secondary Resin Plugging

 Specification requirementsOperating conditions
AThe resin ink filling must be flat with the circuit surface without voids, bubbles, or copper on the ink surfaceNet yarn T number: 35T
Screen open compensation: unilateral compensation 15mil
Scraper angle: 21 degrees
Printing speed: 1.2m/min
Printing speed: front scraper 1.2m/min, oil return knife 1.0m/min
Scraper pressure: 7.5kg/cm2
Number of printing knives: 8 knives repeatedly

Baking parameters: 75℃  for 30 minutes

150℃  60 minutes

 

12.Second Drilling

 

Second Drilling

 Specification requirementsOperating conditions
ARequires precise positioning and unbiased holesStack: 1PNL/1 stack
Drill life: Φ 3.2mm diameter 100 holes, Φ 1.0mm diameter 500 holes/tool
Drilling speed: 3.2mm Φ 0.4m/min, 1.0mm, Φ 0.8m/min
Spindle speed: 3.2mm Φ 23krpm, 1.0mm Φ 55krpm
Tool return speed: 3.2mm Φ 12m/min, 1.0mm, Φ 15m/min

13.Secondary Grinding Treatment

Secondary Grinding Treatment

 Specification requirementsOperating conditions
ANo resin ink residue is allowed on the circuit’s surfaceUse 320 grit sandpaper for uniform sanding, and sand all the resin ink remaining on the surface of the circuit.

 

14.Second Immersion Copper

 

Second Immersion Copper

 

 Specification requirementsOperating conditions
ANon-metallic hole wall, circuit copper layer and filling resin surface, uniformly deposit and distribute a layer of metallic copperDuring the production of heavy copper, the glue is not removed, and the others are made according to normal production conditions.

 

15.Third Copper Plating

 

Third Copper Plating

 Specification requirementsOperating conditions
AThe electroplated copper thickness on the surface and the hole is more than 180um, and the cumulative surface copper thickness is more than 500um18ASF current density plating time is 80min plating six times
BThe deviation of copper thickness uniformity on the board surface is within 15umThe electroplating of the rotating transposition pinch point is divided six times to evenly distribute the current trend and the thickness of the coating

16.Third Circuit

Third Circuit

 Specification requirementsOperating conditions
ANo OS (open and short circuit), line width tolerance is controlled within ±15%

Film pressing speed: 1m/min

Film pressing temperature: 105℃

Film compensation: the original film is not compensated
Alignment accuracy: CCD automatic alignment accuracy 3mil
Exposure energy: 8 grids = 40mj
Etching speed: 1m/min once +2.5m/min once. The machine has been etched twice in total

 

17.ThirdResin Plugging

Third Resin Plugging

 Specification requirementsOperating conditions
AThe resin ink filling must be flat with the circuit surface without voids, bubbles or copper on the ink surfaceNet yarn T number: 35T
Screen open compensation: unilateral compensation 15mil
Scraper angle: 21 degrees
Printing speed: 1.2m/min
Printing speed: front scraper 1.2m/min, oil return knife 1.0m/min
Scraper pressure: 7.5kg/cm2
Number of printing knives: 8 knives repeatedly

Baking parameters: 75℃  for 30 minutes

150℃  60 minutes

   

The subsequent processes are the same as the normal PCB board production parameters. You can review the PCB manufacturing process for further steps.

 

Heavy Copper PCB manufacturing demands proper care, and inappropriate handling during manufacturing process can lead to poor performance, always consider services of an experienced manufacturer.

 

high current pcb

RAYMING offers executive PCB manufacturing facilities for various types of PCBs. RAYMING has specialized in Heavy Copper PCB manufacturing over the last 10 years and developed an image for high-quality production.

If you are looking for a Heavy Copper PCB manufacturer, RAYMING offers complete solutions that you need for your PCB development.