SMT Technology « PCB & MCPCB

Archive for the ‘SMT Technology’ Category

What Should be Prepared Before Starting the SMT Process?

Tuesday, February 15th, 2022

SMT, whose full name is Surface Mounted Technology, is the most popular technology in electronic assembly industry. It refers to process on PCB (Printed Circuit Board), putting various electronic components on PCB, such as resistors, capacitors, inductors, and so forth. Also, there are some dos and don’ts in the whole process of PCBA.

As noted previously, there are all sorts of electronic components that will be used in the assembly process of Printed Circuit Board. Therefore, it is extremely important to take some measures to keep a check on static. Here are three steps before entering the SMT workshop.

First, put on anti-static clothes and hats. It is to prevent static existing in clothes and hair from influencing the board, for static has a potential and tremendous destructive power.

Second, what we have to do is to put just one hand on static elimination instrument, and do not leave our hand from it until the red light turns to green, which aims to eliminate the static existing in our body.

Third, across the air shower door. In this way, dust that is invisible on our body can be blown off in about 5 seconds.

Only finishing the three steps above can we enter the PCB assembly workshop. And after entering the workshop, there are also something needed to be prepared.

Solder paste. The storage temperature of solder paste is 2-10 degrees Celcius, hence it has a period of regaining temperature, which conducts in the rewarming machine for 4 hours. Then the solder paste should be rabbled in a blender for 5 mins in order to help three ingredients in it to be fully integrated, which can help to achieve a better printing and back-flow soldering effect.

Oven. This machine is used to get rid of the moisture from materials or boards, ensuring that PCB will not be defective due to moisture during the subsequent assembly process. Moreover, different boards have different requirements. But generally, the baking parameter is 105 degrees Celcius, lasting 1.5 hours.

Dryer. It is used to maintain a set temperature and humility of materials and boards that needs to be processed that day, which is also to avoid that moisture does harm to materials and boards after removing the moisture by oven.

Tension test of stencils. Before manufacturing, the stencils’ uniformity should be tested by tensiometer, which mainly tests the four corners and the center part of the stencil, guaranteeing the solder paste printing quality. And the parameter should be between 30 and 45.

To sum up, although there are lots of preparations should be done before starting the formal assembly process, each of them is significant, for they will probably influence the quality of boards directly. Besides, only a good preparation can make a certain that the follow-up process can keep going. Thus, it is a must to prepare well in advance.

And Best Technology is an experienced electronic company. It not only can provide PCB A service, but can provide other services, such as FPC, FR4 PCB, Rigid-flex PCB and so on. And if you have any questions about SMT, or any other questions about assembly, you are welcome to contact us.

The SMT production progressing

Thursday, November 18th, 2021

SMT (Surface Mounted Technology) is the most popular Technology and process in electronic assembly industry. SMT refers to a series of process processes based on PCB. Due to the better outcome and higher efficiency, SMT has become the primary approach used in the process of PCB assembly. In some extent, the turn-key service is a way to reduce the cost.

There are the SMT progressing in the following.

1. Solder paste printing: The function is to print the solder paste to the PCB pad to prepare for the welding of components. The screen-printing machine is located at the front end of SMT production line.

2. Part mounting: The function is to accurately install surface assembly components into fixed positions on the PCB. The equipment is the SMT machine, located behind the screen-printing machine in the SMT production line.

3. Furnace curing: its function is to melt the patch adhesive, so that the surface assembly components and PCB board firmly stick together. The equipment used is the curing furnace, located behind the SMT machine in the SMT line.

4. Reflow welding: The function is to melt the solder paste, so that the surface assembly components and PCB board firmly stick together. The reflow furnace is located behind the SMT machine in the SMT line.

5. AOI optical detection: its function is to detect the welding quality and assembly quality of assembled PCB board. The equipment used is automatic optical detection (AOI)

6. Maintenance: its function is to detect the failure of the PCB board for repair. The tools used are soldering iron, repair workstation and so on. Configured after AOI optical detection.

7.Dividing board: its function is to cut PCBA of multiple connecting boards, so that they are separated to form a single individual, generally using V-cut and machine cutting.

8. Grinding plate: its role is to scrub the burr parts to make them smooth and flat.

9. Washing plate: its function is to remove welding residues such as flux and other harmful to human body on assembled PCB board and manually clean it.

Turnkey service reduces customersâ€™ time in contacting with multiple suppliers for separate steps in PCB assembly manufacturing. And the scientific order arrangement system allows customers to get PCB assembly products with higher quality and less cost in a shorter time than the traditional way of PCB assembly.

How to make Panel for MCPCB?

Friday, July 16th, 2021

Regarding all Metal core PCB required panelization, which needs to take into account how the boards are connected. There are two main connectionÂ methods for panel: Double face carved V-shaped groove (V-CUT), and the long slot plus a small circular hole (commonly known as stamp hole), depending on the shape of the PCB.

V-CUT

V-CUT is to draw a slot at the junction of two boards, where the connection of the boards is relatively thin and easy to break. Currently SMT Board is widely used, characterized with neat and level edges after separation, which is recommended as priority.

V-cuts are generally straight lines, and there will be no complicated traces such as curved arcs, so pay attention to be in a straight line when making the panelization. Please also note the following two points.

â‘ The two sides of V-CUT line (top side and bottom side) require a no circuits area that is not smaller than 1mm, to avoid the damage circuits when separating.

â‘¡Â After cutting the V-shaped groove, the remaining thicknessÂ should be 1/4 to 1/3 of the total board thickness , which is not smaller than 0.4mm.

Stamp Holes/Mouse Bite

For irregular PCB boards, the shape of the board has curved corners, there will be many burrsÂ if useÂ V-cut.Â In this case the stamp hole connection would be the better choice.

Panelization Rules:

The spacing between the panel and the board is 1.2mm or 1.6mm.

The diameter of hole is 0.55mm, generally a row of 8 holes (Hole count depends on the design requirements, more holes can enhance the stability), the spacing of the two holes is 0.2mm.

The distance between the upper and lower rows of holes is 2mm, and 1/3 of the stamp holes enter the board. Pay attention to avoid the circuit on the edge of the board.

After adding the stamp holes, the shape of both sides of the hole need to be connected to facilitate the subsequent routing manufacturing.

The part picture after panelization.(Using the connection bridge in the middle, which can minimize the residual.)

The effect picture after panelization.

If you want to learn more about MCPCB design, welcome contact us.

Common Problems in SinkPAD Board Design

Thursday, June 17th, 2021

1.Â What is the SinkPADÂ Board?

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

The thermal conductive PADÂ 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.

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.

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 weÂ use SinkPADÂ technology for any LED packages?

No, itâ€™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 ManufacturingÂ Process for the SinkPAD Board?

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

6. How does SinkPADÂ BoardÂ 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, itâ€™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, thereâ€™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,Â so copper is generally used as the substrate for Heat SinkÂ in our company.

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.

How to do SMT for ceramic PCB

Wednesday, May 19th, 2021

As we all know if ceramic PCB is very fragile, so it is not easy to do SMT for them.

But we can do the SMT for ceramic PCB easily because we do it every day and we have more than 15 years experiences for doing that.

For the almost SMD components (such as SMD rsistors, capacitors, diode etc), normally we will add the solder paste by using SMT stencil, then put the components by machine, finally do the oven reflow.

For some special components, we will need to solder it by hand, such as through connectors, but it canâ€™t be soldered by hand directly, it need to be put on the heating table to keep the temperature is high enough to make the solder past at melt state. Because the ceramic material with very good heat dissipation, the solder paste will be solidification very easily if donâ€™t put the ceramic PCB on heating table

For some small LED, it canâ€™t be put by SMT machine, because no such small feeder to pick it up, then need to put it on board by hand.

We can do very well for the small BGA components too.

Below some photos of ceramic PCB.

If you would like to know more about ceramic and ceramic PCB SMT, please feel free to email me

The Advantages of Surface Mount Technology of a printed circuit board

Friday, March 19th, 2021

Surface-Mount TechnologyÂ has been the industry standard for assembling printed circuit board. It has maintained its popular due its wide array of advantages and relatively few drawbacks. For more than 15 yearsâ€™ experience,Â Best TechnologyÂ has been offering surface-mount service for worldwide customers, and SMT service become a great part of our business.

See some photo which we are do assembly for our customer this month.

Top Advantages of Surface-Mount Technology

Smaller size and reduced weight are the two main advantages to SMT. Components can be aligned closer together and end products will be more compact and light weight.

Here are additional benefits of SMT:

1.Component placement auto correctly â€“ there is no alignment between the PCB solder pads and components pads to avoid placement errors.

2.Low cost:

The advantage of small size up to 0201. One set, SMT typically requires lower production costs than through-hole placement. The size of the board is reduced, the number of drilled holes is reduced, and routing of traces is reduced. So bring down the cost of the whole project.

3.Design flexibility â€“ You can combine through-hole technology and SMT manufacturing on the same board for greater functionality.

4. Printed circuit boards created with the SMT process are more compact, providing higher circuit speeds. (This is the main reasons most manufacturers choose for this method.)

5.Higher circuit speeds â€“ Most manufacturers rate this the number-one benefit.

Lower resistance/induction â€“ High-frequency performance reduces unwanted consequences of RF signals.

6. Quick Turn Around

Using Surface-Mount Technology, it can save lots of time, SMT is a much more streamlined manufacturing process compared to through-hole. Time is saved because components are applied using a solder paste instead of drilling holes in the PCB

7. Quantity â€“ More components can be positioned using both sides of the circuit board, creating more connections for each component. Fewer circuit boards are needed for devices.

8. Stability â€“ Better performance delivery is realized with vibration mechanical conditions. SMT connections are more reliable, it can reduce the dis connection risks during the final test.

Best TechnologyÂ offers expertÂ surface-mount technologyÂ services in China, along with manufacturing bare printed circuit board, flexible circuits,Â and MCPCBÂ fabrication. With more than 15 years rigid PCB board experience, Best Technology has the resources, equipment, and know-how to produce your PCBs quickly and reliably.

Call Best Technology nowÂ and let us become your partner of PCB assembly service.

High-TG FR4 Printed Circuit Board

Thursday, December 31st, 2020

If you work in Printed Circuit Board industry, you may know a normal PCB FR4-Tg is 130-140 degrees, the medium Tg is greater than 150-160 degrees, and High-TG FR4 Printed Circuit Board is greater than 170 degrees.
And what is a High-TG FR4 Printed Circuit Board? High-TG PCB is another name for a high-temperature FR4 PCB, it means the printed wiring boards designed to endure for extremely high-temperature. A Printed Circuit Board is defined as high-TG FR4 PCB if its glass transition temperature (TG) is higher than 170 degrees Celsius. High-TG FR4 will have better mechanical and chemical resistance to heat and moisture than standard FR4. The higher the TG value, the better the temperature resistance of the material, so High-TG FR4 is more and more popular particularly working in high power industry.
Best Technology can provide many different High-TG FR4 material for Rigid Circuit board, Typical High-TG FR4 PCB material including: ITEQ-IT-180A, ISOLA 370HR, ShengYi S1000-2 and etc.

From the following PCB picture, you can see the normal TG130 FR4 PCB substrate is not only softening, deformation, melting, as well as other phenomenon working under high temperatures, but also there is a sharp decline in electrical properties, which will effect on product life.

If your FR4 Printed Circuit Board or PCBA board appear to above problems, then you should consider to use a High-TG FR4 Rigid Circuit Board. it may be catching your interest willing to understand a little bit more about High-TG FR4 printed circuit boards. Because High Tg Rigid Circuit board have a better stability at high temperatures, the substrate provides better heat resistance, mechanical and chemical stability for the circuit board.

Properties/ Applications of high Tg PCB
With the rapid development of electronics industry, High-TG FR4 PCB is widely used in Uninterrupted Power Supply, precise instrument as well as industry. High-TG FR4 PCB material probably designed for the high functionality, high multi-layer development high-density circuit; higher heat resistance and high-density surface mounting technology (SMT). So, the demand on High-TG FR4 PCB material become more widely used PCB manufacturing.
Whatâ€™s more, High TG material is also popular in LED lighting industry, because heat dissipation of LED is higher than normal electronic components, but same structure of FR-4 board is much cheaper than metal core PCB, such as aluminum PCB.
High-TG FR4 PCB materials have the following properties:
Â Resistance to high temperatures
Â LongÂ delamination durabilityÂ (aging of materials to consider for safety reasons)
Â Low thermal expansion
Excellent PTH reliability
Good mechanical properties
High temperature durability
High value of thermal stress resistance
high temperature durability
long delamination durability
Low Z axis expansion (CTE)

Advantages of High-TG FR4 PCB
Higher stability:Â it will automatically improve the heat resistance, chemical resistance, moisture resistance, as well as stability of the device if increasing the TG of a printed circuit board substrate.
Bear high power density designs:Â high TG PCB will be a good solution for heat management if the device has high power density with quite high heat generation rate.
It can achieve with using a larger printed circuit board to change the design and power requirements of a device when reducing the heat generation of ordinary board, whatâ€™s more, it also can use the high TG PCB.
Ideal for multilayer & HDI PCBs:Â there will lead to high levels of heat dissipation because multilayer & HDI PCBs are more compact and have dense circuits. So high TG PCBs are often used for the multilayer & HDI PCBs so that it can make sure reliability in Printed circuit board fabrication.

If your applications are in any danger of subjecting your PCBs to extreme temperatures or the PCB is required to be RoHS Compliant, it will be in your best interest to look into high-TG FR4 PCBs.
Come to contact Best Technology Co., Limited. for High-TG PCB assistance. we can help you determine if you need high-temperature printed circuit boards and direct you to which specific boards are likely to be useful for your design and application. If you are transitioning to RoHS or just need more information about the High TG laminates, just give us a call and weâ€™ll be happy to accommodate you. contact us online right now.

Main types surface finish of FR4 Printed wiring board

Wednesday, November 4th, 2020

Printed Circuit Board surface finish is a coating between bare FR4 board and components. The main function for surface finish is to protect the exposed copper circuitry and provide a solderable surface when assemblingï¼ˆsoldering) the components to a copper clad PCB board.

Most of the Rigid Circuit board company can make several different types of surface finish. Best Technology as a leading custom FR4 printed circuit board manufacturer since year 2006, it could provide following different finish.
HASL
Lead-free HASL
Immersion Tin/Immersion Silver
OSP (organic Solderability Preservative)
Gold
ENIG (Electroless Nickel Immersion)
Hard Gold
Wire bonding Gold

As the surface mounts assembly service became more complex and needs to conform to new regulations like RoHS and WEEE. People maybe face the question how to choose a suitable surface finish for your FR4 Copper board?

Before decide to choose suitable surface of copper conductors circuit board, you may need to take the cost, RoHS, your components type, PCB assembly method, factory circuit fabrication capability, and rigid board circuit testability into consideration.
Basis on above information of copper foil PCB, we would like to make a explain PCB finish in detail, wish this may help when you make decision at circuit board design and manufacturing.

HASL/Lead Free HASL
It is a most popular surface finish, and the cost is low and easy to repairable, it is acceptable for simple SMT. But the surface is uneven, it is not suitable for fine pitch components and not good for plated through-hole(PTH). In other way, it is poor wetting.
Material different with same finish
HASL(standard):Typically Tin-Lead
HASL(Lead Free):Typically Tin-copper, Tin-Nickel, without lead
The thickness will conform to IPC 6012 class 2 standard

Advantages of HASL-LF
Excellent solderability
Inexpensive / Low cost
Widely Available and used
Easy reworkable
Allows large processing window
Long industry experience / well known finish

Disadvantages of HASL-LF
Uneven surfaces for printed circuit board
No good for fine pitch components from Samtec/Hirose/Molex
Thermal shock
Solder Bride for circuit board assembly
Plugged or reduced PTHâ€™s
Not suited for < 20mil pitch SMD & BGA
Bridging on fine pitch
Not ideal for HDI products

Immersion Tin

Advantages
Flat surface
No Pb
Good for fine pitch / BGA / smaller components
Mid range cost for lead free finish
Press fit suitable finish
Good solderability after multiple thermal excursions
Easy reworkable

Disadvantages
Very sensitive to handling â€“ gloves must be used
Tin whisker concerns
Aggressive to solder mask â€“ solder mask dam shall be â‰¥ 5 mil
Not recommended to use peelable masks
Exposed tin on final assembly can corrode
Not good for multiple reflow/assembly process
Difficult to measure thickness

OSP (organic Solderability Preservative)
OSP(organic Solderability Preservative) same with HASL, lower cost but the OSP have flat surface, and it is not good for PTH components, sensitive and short shelf life, it is very easy come to oxidation.

Advantages
Flat surface
No Pb
Good for fine pitch / BGA / smaller components
Inexpensive / Low cost
Easy reworkable
Simple Process
Disadvantages
Not easy to measure thickness
Not good for circuit copper board plated through-hole(PTH)
Short Shelf Life
Maybe cause ICT issue
Exposed Cu on Final assembly
Handling sensitiveâ€“ gloves must be used and scratches avoided

The above surface finish of Printed Wiring Board compared with Gold finish, the cost is corresponding cheaper, but in my coming blog, I would like mainly to explain Gold finish for printed circuit board fabricator with 13 years rich-experienced in FR4 PCB custom contract manufacturer.

If you have any question about the printed circuit boards (PCBs). Warmly welcome to send mail or call Best Tech.

How to avoid circuits issue while the production process ?

Monday, July 13th, 2020

As we all know,Â the short & open circuits is a very common issues for the Printed Circuits Board, especially for the extra thin PCB, because its substrates thickness are very thin, generally from 0.4mm-0.15mm, so the circuits will be easy to be broken if we didnâ€™t control the production process well.

So, you may want to know, as an experienced PCB manufacturer, what we will do to avoid the circuits issues?

Here let me show you what we do:

Firstly, after the process of copper plating, we will put the boards into our washing line to remove those drilling burr, surface oxide layer, etc. To make sure the boards are fully clean before start the traces making process.

Actually, most of the open and short circuits problem are caused by the film scratching, so each operation while the pattern transfer process is very important.

Thatâ€™s also why the exposure and developing need to be processed in the dust-free workshop. We will use the rack to place each PCB board separately, to avoid the touching between PCB.

After the circuits etching out, we will take the boards to do the AOI testing, to check if there are any broken circuits, short gaps, protrusions, copper surface garbage and other problems. If there is, our machine will alert the problem, and we will fix the problem or scrap the defectives boards, with this process to prevent the defective boards move to the next step.

Most importantly is that we will do the first article inspection for all the boards, as long as we found the circuits issues while the AOI process, we will not take the whole batch boards go ahead.

Besides, the operation standard while the etching process is also very important for how the traces being. So, our production team will control the running speed of the etching machine very strictly. If it is a PCB with o.5oz bottom copper , only allow walk 1.4 meters at per minute, if 2oz, walk 0.8m one minute.

Except above process, all the boards will be required to do a final electrical testing before move to the packing. For prototypes, we will use flying probe testing. For volume, we will open the E-testing fixture to do the testing.

In our company, for the extra thin PCB, if the boards thickness lower than 0.2mm to do the flying probe testing, it needs to be tested before the outline process, because the boards are too thin to support the boards well while the flying probe, it will fall down easily.

flying probe testing and electric testing

Of course, our QC people will do the double visual inspection to make sure all the boards are being well made.

We always try our best effort to prevent any defective boards send to customers.

Quality and Customers Scarification, it is always our companyâ€™s pursuit.

We will be exhibiting at electronica Munich 2020

Monday, June 8th, 2020

Best Technology, a China- based assembly manufacturer will be exhibiting at electronica Munich 2020 in Bavaria, Germany at booth No. 623(Hall B1) from November 10, 2020 to November 13, 2020(Western Time). Actually, we have participated in this exhibition for continuous 2 years. Here are some pictures for your reference.

At our exhibition booth, attendees will be able to learn more about our company for PCB manufacturingÂ and PCB assemblyÂ technology.

For interested professionals, Best Technology had on hand experts to offer detailed insights and experience on PCB assembly, covering PCB prototype and low/high-volume production. For more information on PCB assembly and fabrication, welcome to visit our booth.

You will see 10mm to 1,500 mm flexible circuit board, from 2 layer rigid-flex circuit to 50 layers, 1/2 OZ copper to 3 OZ, 0.15mm extra thin FR4 PCB to 30 OZ heavy copper, turn-key service from components sourcing,board fabrication(FPC, PCB, MCPCB, Ceramic PCB) and final assembly with programming and testing and metal dome that is used in conjunction with a printed circuit board, flex circuit, or membrane, become normally-open tactile switches. we have four types of metal domes: four legs with size from 5mm-20mm; triangle with size 4mm-12mm; round dome with size 4-16mm, oblong dome with size 3.7mm-58.1mm, and we also make dome with adhesive, named dome array.

You are warmly welcome to see how we can manage the components wastage and efficiency to help save your time, money and energy.

About electronica Munich:

Electronica is the international trade show for electronic components, systems and applications and shows the full range in all its diversity in width and depth as the world’s leading trade fair. It reflects the high degree of innovation throughout the industry. Exhibitors and users in the areas of systems, applications and technologies of electronics can receive the information of the latest innovations and developments in the fields of system peripherals, power engineering to printed circuit boards or EMS.

Welcome to visitÂ us at Booth 623 from November 10, 2020 to November 13, 2020(Western Time).

PCB & MCPCB – Best Technology

Archive for the ‘SMT Technology’ Category

What Should be Prepared Before Starting the SMT Process?

You may also like

The SMT production progressing

You may also like

How to make Panel for MCPCB?

You may also like

Common Problems in SinkPAD Board Design

1.Â What is the SinkPADÂ Board?

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

3. What is the thermal conductivity of a SinkPAD ?

4. Can weÂ use SinkPADÂ technology for any LED packages?

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

6. How does SinkPADÂ BoardÂ compare to Conventional MCPCB?

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

8. Does SinkPAD Board require special PCB design?

You may also like

How to do SMT for ceramic PCB

You may also like

The Advantages of Surface Mount Technology of a printed circuit board

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High-TG FR4 Printed Circuit Board

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Main types surface finish of FR4 Printed wiring board

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How to avoid circuits issue while the production process ?

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We will be exhibiting at electronica Munich 2020

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