Archive for the ‘mcpcb’ Category

About the “heat” problem in PCB & MCPCB

Monday, October 18th, 2021

For high-power products, the concept of “heat” is often mentioned, which is especially important in high-power products. It not only determines the service life of the product, but also relates to whether the product can work properly.

We will explain the “heat” problem in circuit board design from three aspects: the generation of heat, the impact of heat on the product and the “heat” in the system layout.

1. Heat generation:

Heat generation in a system takes several paths:

1) Power consumption of the component itself

2) Efficiency of power conversion devices

3) High frequency signal conversion heating

4) Power consumption of contact resistance and wire resistance during signal transmission

2. Impact of fever on products

The operating temperature of components is generally below 80℃, and the operating temperature of commonly used capacitors and resistors is generally controlled below 50℃.If the temperature of the system is not controlled, the following conditions may occur:

1) The temperature rise will cause the working parameters of components to change, resulting in the unstable working performance of the whole system.

2) Temperature rise will accelerate the aging of components, affecting the accuracy and life of components.

3) Temperature rise will cause circuit board deformation and poor contact of components.

General heat dissipation components arrangement

3. “Hot” considerations in system layout

1) Selection and layout of the chassis: choose materials with good thermal conductivity, such as aluminum alloy

2) Black heat absorbing material is coated inside the shell to enhance the function of radiation heat absorption

3) The shell is closely combined with the components with high calorific value to conduct heat dissipation

4) A large number of heating components should be placed at the edge of the plate to shorten the heat transfer path. Heat-resistant components should be kept away from light sources.

5) In the design process, the appropriate wire width and copper thickness should be selected, and the influence of wiring density on the current-carrying capacity should also be considered. Copper foil should be filled in the gap of the board surface as far as possible for heat conduction. The heat conduction hole can help effectively heat dissipation and reduce local temperature.

In the design of circuit board, how to effectively control the temperature of the system is a problem that must be considered.

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Why choose MCPCB rather than FR4 PCB for high power LED?

Monday, September 20th, 2021

Compared to conventional LED, high-power LED consume more electricity and require higher currents, but the heat generated in the end cannot be dissipated in time through the ordinary FR4 CPB. And there will be some failures when the heat from a LED is not properly removed, the LED’s light output is reduced as well as degradation when the heat remains stagnant in the LED package.

So if the PCB requires fast cooling, it’s better to use a metal base rather than a traditional FR-4 substrate. The typical LED MCPCB is a single circuitry layer copper foil which is bonded to a layer of thermally conductive dielectric material which is bonded to a thicker layer of metal like Aluminium or Copper base, the purpose of a MCPCB is to efficiently remove the heat from all topical IC’s (not just LEDs). Following are the comparison between FR4 PCB and MCPCB for your reference.

 

1 – Thermal Dissipation

FR4 has low thermal conductivity, typically around 0.3W/m.K, while MCPCB has higher thermal conductivity, ranging from 1.0-7.0W/m.K. MCPCB transfer heat 8 to 9 times faster than FR4 PCB, the dielectric layer must be very thin to create the shortest path from the heat source to the supporting metal plate, its thickness is normally between 0.003 and 0.006 inches.

As an example, consider that a test conducted on an MCPCB with integrated 1W LED showed how its temperature remained pretty close to the ambient temperature of 25°C, while the same power LED mounted on a FR-4 board reached a temperature 12°C higher than the ambient one.

2 – Better Strength and Stability

Since high power LED chips are usually assembled directly on the PCB, these LEDs can create stability and reliability problems for the circuit. Without adopting the right technique, heat dissipation can hinder the performance of electronic devices that operate at high power. The use of metal PCBs in these applications effectively solves this problem. In addition to ensuring a high durability, aluminum is very light, and adds strength and resilience to the printed circuit board without causing an increase in weight.

3 – Dimensional Stability

The size of a metallic printed circuit board remain more stable, as environmental conditions vary, than that of a PCB made with traditional materials, such as FR-4. Subjected to a heating process from 30°C to about 150°C, PCBs with metal layers (such as aluminum) have undergone a very small variation in size, ranging from 2.5% to 3.0%.

If you have other questions about MCPCB, welcome to contact us.

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Baking Time & Temperature Standard of MCPCB

Tuesday, August 17th, 2021

After manufacturing the Metal Core PCB, there is a shelf life, once the shelf life has passed, we need to bake the bare board before assembling the components, otherwise the MCPCB is prone to burst when the SMT line is produced. There are industry specifications for both how long MCPCB can be stored and how long they can be baked.

MCPCB Control Standard

  1. Unpacking & Storage
  2. If the packing bag is sealed, and the manufacturing date is within 2 months, it can be directly used before assembly.
  3. The manufacturing date is within 2 months, and the unpacking date must be marked after unpacking.
  4. The manufacturing date is within 2 months, and it must be assembled and used within 5 days after unpacking.
  • Baking Time
  • If unpacked for more than 5 days within 2 months of the manufacturing date, bake at 120±5°C for 1 hour
  • Two months after the manufacturing date, baking at 120±5℃ for 1 hour before assembly.
  • Two to Six months after the manufacturing date, baking at 120±5℃ for 2 hours before assembly.
  • Six to Twelve months after the manufacturing date, baking at 120±5℃ for 4 hours before assembly.
  • The MCPCB after baking must be used up within 5 days (put into IR REFLOW), and unused board must be baked for another hour before assembly.
  • Over half one year after the manufacturing date, bake at 120±5℃ for 4 hours before assembly, and then send it to the production line to do HASL_LF before using.
Baking Machine

Preservation & Baking Standard for in different regions

The specific storage time and baking temperature of MCPCB are not only related to the production capacity and production process of manufacturer, but also have a great relationship with the region.

  1. For areas with heavier humidity, the MCPCB must be used up within 24 hours when exposed to the air, otherwise it is easy to oxidize. After normal opening, it is best to use it up in 8 hours.
  • For areas with a relatively dry climate, the preservation time of PCB will be longer, and the baking time can also be shorter. The baking temperature is generally 120±5℃, and the baking time is determined according to the specific situation.

The MCPCB with OSP or Gold Immersion has a shelf life of 6 months after packaging, and it is generally not recommended to bake for MCPCB with OSP.

PCB board with SMT

If you have other questions about MCPCB, welcome to contact us.

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Common Problems in SinkPAD Board Design

Thursday, June 17th, 2021

1. What is the SinkPAD Board?

Sink Pad Board, also called Heat Sink or DTP (direct thermal path), it’s an alternative PCB technology to the conventional metal core PCB providing direct thermal path solutions for high power LED. 

The thermal conductive PAD is convexity area of copper core/pedestal, so that the thermal PAD of LED can touch the convexity area of metal core directly, and then the heat of LED will be dissipated into the air much faster and more efficient than conventional MCPCB.

Heat Sink

2. If only the LED pad can be made as SinkPAD?

Of course no, the pads of other chips or components also can be designed as Sink PAD, one of the most common is the IC pad. In some designs, IC needs to pass through the large current and it will emit a lot of heat, it would be best to design its pad as a thermal conductive pad at this time.

SinkPad Board after SMT

3. What is the thermal conductivity of a SinkPAD ?

The thermal conductivity could be 235 W/m.k to 400 W/m.k.

4. Can we use SinkPAD technology for any LED packages?

No, it’s designed to be used with the LEDs which has electrically neutral thermal pad. Such as Cree XPL/XML/XHP/XPG/XPE/XPC/XTE/XBD, Luxeon Rebel & Luxeon M from Philips Lumiled, Oslon SSL & Oslon square from Osram, Nichia N219, Seoul Semiconductor Z5P / Z5M, Samsung 3535, Bridgelux SM4, etc.

5. What is the Manufacturing Process for the SinkPAD Board?

Manufacturing process is the same as conventional MCPCB, please click here to see the manufacturing process status.

Shinkpad

6. How does SinkPAD Board compare to Conventional MCPCB?

Conventional MCPCB uses a thermally conductive dielectric layer to bond circuit layer with base metal (Aluminum or Copper) layer. The key to thermal performance of MCPCB lies in its dielectric layer. Even though thermally conductive dielectric has higher thermal performance compared to normal FR4, it’s still a weakest link in the conduction thermal path.

SinkPAD Board approach overcomes this limitation, which provides “Direct thermal path”, the LED Chip can directly contact the copper substrate, there’s no dielectric between LED thermal pads and the metal base, then the thermal resistance is very small.

7. Can the aluminum be made as the base of Heat Sink?

Actually yes, however, regarding of current technical conditions, since aluminum or aluminum alloy cannot directly react with acid, the reaction process is too complex and difficult to control, which will increase the difficulty of etching the LED pad platform.

Considering the scrap rate, the process of etching LED pad platform with aluminum is more complex and the overall cost is higher, and the copper also dissipates heat much better than aluminum, so copper is generally used as the substrate for Heat Sink in our company.

Copper Substrate

8. Does SinkPAD Board require special PCB design?

No, we can use your existing MCPCB Gerber data.

Welcome to contact us if you have other questions about Sink Pad Board. 

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Aluminum vs Copper Core PCB

Wednesday, May 19th, 2021

In Best Technology, currently the most common metal used for Metal Core PCB manufacturer are Aluminum, Copper. Today let’s talk about the main differences between aluminum substrate and copper substrate, hoping to help you choose the right substrate in future design projects.

Although they both share similar properties and functions, there are still a few variations between the two kinds of metals. Some of the key differences between aluminium and copper core PCBs are explained in the points below.

1. Thermal Conductivity

The thermal conductivity of copper substrate is up to about 400(W/mK) and the thermal conductivity of aluminum substrate is generally about 200W(W/mK). The thermal conductivity is higher, the transfer efficiency will be better, and the heat dissipation will be better, then the working life will be longer.

 Thermal Conductivity

2. Electrical Conductivity

Both aluminum and copper, being metals, are electrical conductors of electricity, although the exact degree of this varies between the two metals. When it comes to electrical conductivity, copper has a clear advantage over aluminum. In other words, in applications where there is a need for efficient electrical conductivity, copper makes for an ideal pick.

 Electrical Conductivity

3. Electrical Resistance

Resistance is very important when it comes to PCB design, as it can have an effect on the overall function and stability of the component. Given that copper has a higher density than aluminum, it tends to have a lower resistance than aluminum, so copper is an better choice where there’s a requirement for thinner circuits and faster electricity transfer.

Electrical Resistance

4. Weight

Since copper has the higher density for per unit area, the weight of copper PCB is much heavier than aluminum PCB for the same design.

In applications where light-weight construction is required more than anything else, aluminum is the preferred material of choice. On the other hand, applications where weight is not much of an issue, tends to be the ones where copper is widely used.

Weight

5. Application

Copper core PCB is the best heat dissipation among all MCPCB, so it’s mostly used in automobile headlights, taillights and some high-tech electronic products (unmanned aircraft, mining machine) high-power lighting equipment. The aluminum core PCB is mostly used in indoor lighting, energy saving lighting, street lighting and other energy-saving lighting electronic products.

Application
Application

In conclusion, due to the above different parameters and performance, the cost of copper is generally more expensive than aluminum. If you have other questions about MCPCB, welcome to contact us .

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Why do MCPCB board have holes? What is PTH/NPTH?

Thursday, April 15th, 2021

If you look closely at a MCPCB board, you will see holes of different sizes in the board, each hole was designed for a purpose. These holes can be divided into PTH (Plating Through holes) and NPTH (Non-Plating Through holes). Best Technology’s smallest drill tool is 0.5mm, so generally we require customers to design the minimum hole size of 0.5mm or more.

How to distinguish PTH and NPTH through holes?

In fact, it is very simple. Just look at the hole wall to see if there are bright plating traces (Copper). The holes with copper are PTH, and the holes without copper are NPTH.

PTH & NPTH

What is the NPTH used for?

If you pay a little attention, you will find that the size of NPTH is usually larger than the PTH, because most of NPTH are for positioning purposes, it can be divided into the following four types.

  1. 1) Countersink: It’s a cone-shaped hole that is cut into the PCB to allow the flat head of a socket cap screw to fit flush with the surface of the board.
  2. Counterbore: It’s a cylindrical flat-bottomed hole that is designed to house a hex head or socket head cap screw to be used to secure a PCB board.
Countersink & Counterbore
  • Screw hole: As shown below.
As shown below
  • Slot hole: Some components of the installation and positioning of the foot is rectangular or oval, we called this kind of irregular drilling as slot hole. During PCB machining, there are two types of drilling tools for plugins, one is called a drill cutter, which is used to drill round holes, and the other is called a routing bit, which is used to drill slot hole.
Slot hole

What is the PTH used for?

In order to connect the circuits between two or more layers, we need to design the PTH, which have following three main purposes.

  1. Used for conducting electricity.
  • Used for heat dissipation.
  • Used for plug-in components.

If you have other questions about MCPCB, welcome to contact us

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The main factor affect the heat dissipation of Metal Core PCB

Tuesday, December 1st, 2020

various LED applications due to its good heat dissipation, do you know what factors can affect the heat dissipation?
As we all known, MCPCB(Aluminum/Copper/Stainless steel) is widely used in
One of the reasons is that Metal base board use special substrate material which is specifically formulated to improve the reliability of designs that run at higher than normal temperatures. Instead of serving strictly as a mounting surface for the various components, the substrate actively draws heat from the locations of hot-running components through to the opposite layer of the board where it can dissipate efficiently and safely, it’s the Dielectric Layer, which is the main factor affect the heat dissipation.

Some people may also mistakenly believe that the dielectric layer is thicker, the heat dissipation will be better. Actually the thickness of Dielectric Layer depends on the customer’s design requirements, it will not effect on heat dissipation. What affects heat dissipation is the material of the dielectric layer, also known as thermal conductivity.

Compare to Metal base board, FR4 PCB has low thermal conductivity, typically around 0.3W, while MCPCB has higher thermal conductivity, which include 1.0W, 2.0W, 3.0W, 7.0W, 8.0W.

In order to save the cost, not all boards need to use 3W dielectric layer. 1W is enough for 2835 or 3030 LED. High power LED like Cree need to use 3W.

If you have other questions about MCPCB, welcome to contact Tammy (Email:sales@bestpcbs.com), she will prove you professional suggestions and solutions.

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What are the commonly used aluminum base materials? What’s the difference?

Wednesday, November 11th, 2020

Best Technology has more than 14 year experience for producing Metal core PCB, we have our own raw materials factory for MCPCB and we fabricate MCPCB in Shenzhen, so that customer various special requirements can be meet here.

Compared to copper and stainless steel, aluminum is the most economic option considering thermal conductivity, rigidness, and cost. And many of these aluminum alloys base have been divided into classes, the commonly used on MCPCB are AL1060, AL3003, AL5052 and AL6061.

Do you know the differences between these substrates? This blog will give a brief introduction for you.

1060 alloys
AL1060 are commercially pure, unalloyed aluminum, it’s soft, ductile, workability and exceptional corrosion resistance, making it suitable for hard-forming applications. It can be welded with any method, but it cannot be heat-treated. Its cost is the lowest of the four types.

3003 alloys
AL3003 use silicon, copper, and magnesium as the main alloying elements, oftentimes with supplemental nickel and beryllium. They are heat treatable, have high strength, good resistance to cracking and wear, and have good machinability.

Mechanical PropertiesMetricEnglish
Ultimate Tensile Strength200 MPa29000 psi
Tensile Yield Strength186MPac
Shear Strength 110 MPa16000 psi
Modulus of Elasticity68.9GPa10000 ksi
Shear Modulus25 GPa3630 ksi

5052 alloys
AL5052 use magnesium as their primary alloying element and are not heat-treatable, but it’s the highest strength alloy of the more non-heat-treatable grades. Its resistance to fatigue is better than most grades of aluminum and have a great surface aesthetic when anodized.
In our company, if not special request or notes, the default material we use is AL5052 after considering all the performance and cost.

Mechanical PropertiesMetricEnglish
Ultimate Tensile Strength228 MPa33000 psipsi
Tensile Yield Strength193 MPa28000psi
Shear Strength138 MPa20000 psi
Modulus of Elasticity70.3GPa10200 ksi
GPaShear Modulus 25.9 GPa25.9 760 ksi


6061 alloys

Mechanical PropertiesMetricEnglish
Ultimate Tensile Strength310 MPa45000 psi
Tensile Yield Strength276 MPa40000 psi
Fatigue Strength207MPa30000 psi
Shear Strength96.5MPa14000 ksi
Modulus of Elasticity68.9 GPa10000 ksi
Shear Modulus26 GPa770 ksi

AL6061 implement magnesium with silicon as their principal alloying elements. Their strength is improved with heat treatment. AL6061 is one of the most widely used aluminum alloys, it has high strength and superior corrosion resistance. Its weld-ability and formability make it suitable for many general-purpose applications.

Cost Comparison: AL1060 < AL3003 < AL5052 < AL6061

If you have other questions about MCPCB, welcome to contact Tammy (Email:sales@bestpcbs.com), she will prove you professional suggestions and solutions.

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What are the factors affecting cost of the MCPCB?

Tuesday, September 29th, 2020

Best Technology considers all the factors affecting the cost of MCPCB production while formulating final cost structure. Many customers contact us to know the factors which affecting the price. The factors are Size & Thickness, Number of layers, Cu Thickness, Thermal Conductivity, Surface Finishing etc.

Size & Thickness: Since larger boards require more material.

As you know, 1.6mm is the standard thickness, if you choose non-standar thickness (Thicker or thinner than 1.6mm), sometimes the price will need to increase, it depend on the layers of your MCPCB.

The different number of layers and manufacturer technology:It’s the main factor for affecting the manufacturing price, therefore the circuit board designing is done in such a manner that it comprises a minimum number of circuit layers. 

Thermal Conductivityis one of the most important performances of MCPCB, the higher the thermal conductivity is, the more expensive the price is. At present, the highest thermal conductivity we can provide is 8W/m.K, the commonly used thermal conductivity is 1-3W/m.K

Cu Thickness: The cost will be more expensive if the copper is thicker. We can provide 0.5 OZ, 1.0 OZ, 2.0 OZ, 3.0 OZ, up to 10 OZ.

Surface Finishing: The common Surface Finishing for MCPCB is HASL_LF, OSP  ENIG (The normal thickness of gold is 1u’’). ENIG is more expensive since the gold is expensive and it with good performance for protecting the surface from oxidized.

ENIEPIG is good for wire bonding (the normal thickness of gold is 3u”).

We always strive to formulate a competitive price structure for our customers, this enables to have a considerable reduction in the total prices and deliver superior quality services to them. If you would like to know more about MCPCB, please directly contact our sales Tammy

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