A few days ago, the Chinese cabbage recommended VSON LCD tablet, which is the following goods.
VSON wrote LCD slate 5 inch 19.8 yuan value of friends broke the original: 5 inch handwriting 19.9 yuan shipping, 9 inch can receive coupons, 59.9 yuan free shipping. High cost performance. 10 cheaper coupons than before: 10 yuan imsatan | Value 16 Comments 64 Favourite 97 Direct View Details Has been full of curiosity on similar handwriting, however, foreign brands frequently cost two or three hundred oceans, it is really difficult to get started, after all, the days are still flowing, a sudden impulse to consume and then eat gray like tragedy, or try to avoid . How can we not care about the cabbage flicker, meet the curiosity moment is still coming. Taking into account the 5-inch screen is also a mobile phone size, it is not tossing, decisive into the 9-inch, with tickets down less than sixty oceans. Courier wobbled on the road for three days and succeeded.
The packaging of the handwriting board is very simple, and there is no trace of texture in an ordinary, wrinkled, broken paper box. Take the packaging and go to the gift and that is nothing more than a full-fledged support. The front and back of the box are full of prints and the functions of the goods are clear at a glance.
Open the carton, and it is the handwriting board wrapped in a plastic bag, a thin layer of plastic bags, no protection, cheap sense of blowing.
There is another page of product manual, certificate, and warranty card inside the box. When you look closely, there are still typos, and obsessive-compulsive disorder can't stand it. Did you find it? Note 3 "Do not put the tablet into the water" This "into" problem...
When the plastic bag is peeled off, it is a handwriting board. This product is really worthless, and holding it in your hand is like holding a piece of hard plastic. The shape is very simple. In addition to the huge handwriting area, the front side has a square clear screen button and an anti-erroneous protection button on the side. The function is quite simple.
A nameplate was attached to the back, and there was a battery back cover.
Unscrew the battery cover, you can see this is a common button battery.
Stylus pen inserted in the top of the tablet, take down, it is like this...
In order to explain how big the 9-inch, take the antique 9.7-inch IPAD to make a comparison, 9-inch is actually quite small...
Originally intended to use this draft paper as a paper, however, this slap in the ground is really silent. After several calculations, it will not move.
When it's not scratch paper, it's more than enough to be a graffiti board. The landlord has not kept his pen for years, and he is very rusty.
Careful observation can be found, this tablet has a certain degree of perception of the pressure of different severity, it is said that the distinction between high-end strokes is obvious, but there is no harm without comparison, the landlord felt quite satisfied. The feeling of a nib writing on a handwriting board is almost the same as the feeling of a pencil writing on a piece of paper. In the ointment, the stylus is too short and too thin, and the grip is not very good. Anti-delete function is very intimate, after the opening, the clear screen button is invalid, which can effectively prevent accidental deletion.
The product does not have data storage and export capabilities, the official provides an APP, is a photo tool, adjust the contrast only, no meaning, no sun.
Finally, summarize the advantages and disadvantages.
advantage:
1. The price is cheap, the cost performance is high 2. The writing feel is close to the pencil, very kind 3. A key to clear the screen, simple and practical 4. Prevent accidental deletion function safe and intimate
Disadvantages:
1. The screen is too small, not enough to use the draft 2. The stylus grip is normal and needs to be improved 3. The screen display is general, the reflection is heavy, and the light is particularly noticeable. 4. The durability is doubtful, write for a while, on the tablet Already full of scratches 5. Rough workmanship, clear seams, and poor packaging
In the end, take a couplet townhouse.
Just like that, thanks for watching.
High TG PCB - High Temerature Circuit Board for PCB applications that requires high temperature.
In recent years, there are more and more customers request to manufacture PCB with high Tg.
If you work with printed circuit boards in your industry, you may or may not be familiar with the high-TG PCBs. Since the effective operation of your printed circuit boards is so important to your business, it may be in your best interest to understand a little bit more about high-TG printed circuit boards.
What Is High-TG printed circuit board?
Tg means Glass Transition Temperature. As flammability of printed circuit board (PCB) is V-0 (UL 94-V0), so if the temperature exceeds designated Tg value, the board will changed from glassy state to rubbery state and then the function of PCB will be affected.
If working temperature of your product is higher than normal (130-140C), then have to use high Tg material which is > 170C. and popular PCB high value are 170C, 175C, and 180C. Normally the PCB Tg value should be at least 10-20C higher than working temperature of product. If you 130TG board, working temperature will be lower than 110C; if use 170 high TG board, then maximum working temperature should be lower than 150C.
When Do You Need a High-Temperature Circuit Board?
You need a high-temperature circuit board for your applications if your PCB will be experiencing a thermal load no greater than 25 degrees Celsius below the TG. If your product will be operating in the 130-degree Celsius range or higher, you will want to use a high-TG PCB to be safe. The main reason for the Hi TG PCB is because of the movement to RoHS pcb`s. It is causing most of the pcb industry to move toward Hi-TG materials because of the higher temperatures needed for the lead-free solder to flow.
Applications for High-Temp PCBs
If you are working with high power density designs whose heat generation is likely to overwhelm your heat sinks or other heat management methods, a high-TG PCB is really the only answer. Trying to reduce the heat generation of your PCB may affect the weight, cost, power requirements or size of your application, and it is usually much more cost-effective and practical to simply start with a high-temperature heat-resistant PCB.
High temperatures can be disastrous for unprotected PCBs, damaging dielectrics and conductors, creating mechanical stresses due to differences in thermal expansion rates and ultimately causing everything from inconsistent performance to total failure. 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 PCBs.
- Multilayer PCB boards with many layers
- Industrial electronics
- Automobile electronics
- Fineline trace structures
- High-temperature electronics
Considerations for Heat Dissipation
High-TG PCBs will be very important when you are looking to protect your printed circuit boards from the high temperatures of your application`s process or during the extreme temperatures of lead free assembly, but you will naturally want to consider multiple methods of drawing the extreme heat generated by electronic applications away from your board.
There are three considerations for dissipating the high heat generated by the action of electronics with printed circuit boards: convection, conduction and radiation.
Convection heat transfer is the process of transferring heat to air or water to allow it to flow away from an area - for example, when fluid absorbs heat and flows to a heat sink where it cools. Convection can also refer to the use of a fan or pump to force air over the surface, drawing heat away with it.
In most printed circuit boards, you will find a convection system where convection, usually including a cooling air fan, bears the heat through thermal vias to large, emissive heat sinks connected to conductive backings.
Conduction heat cools by putting the heat sink in direct contact with the heat source, allowing the heat to flow away from the source much like an electrical current flows through a system.
Designers dissipate radiation heat by making sure to design a direct path for electromagnetic waves to flow away from the source. Although electromagnetic wave radiation does not generate a tremendous amount of heat, if the board is designed to put reflective surfaces in the path of these waves, it can cause a rebound effect and significantly magnify the amount of heat that radiation generates on the board.
You can see that the more heat you need to deal with, the more it affects the design of the board. Reducing power density can limit the effectiveness of your product while adding heat sinks and fans can increase size, weight and cost. This is why, even if you are aware of other effective methods of heat management, it can be a very good idea to look into high-TG materials as part of your overall heat control solution.
High TG PCB Materials
At JHYPCB, we offer Complete PCB Assembly solutions for all types of High-Quality PCB Fabrication and High-Quality PCB Assembly requirements. Among the most common special requirements for PCB Fabrication is the need for high-temperature tolerance to withstand demanding operating conditions and/or environments.
We often encounter questions from our clients about the temperature requirements for the PCB Assembly Process itself, and whether or not a specific material selection will be required for Lead-Free PCB Assembly. Since our facilities are all fully RoHS Compliant, all of our default materials are suited to the higher Reflow Soldering temperatures of lead-free processes. You never have to worry about selecting a more robust heat profile for the production process itself, but in some cases, the finished boards must operate at high-temperature levels for prolonged periods. In this case, we provide a selection of PCB Materials that can meet your specific needs.
Temperature profiles for PCB material are generally expressed through the Tg (Glass Transition Temperature) of the material. This metric notes the temperature at which the stiff, glass-like polymer softens and is subject to warping or other physical defects. If you do not specify a minimum Tg level for your boards in your PCB Design Files, we will normally use our default Tg 140 FR4 material, which is sufficient to withstand the reflow soldering process and the majority of standard operating conditions.
We also offer higher Tg materials for your convenience, such as Tg 170 FR4 material, and IT180A with a characteristic Tg 180. We still offer all of our Standard PCB Options with high-Tg boards, so you will not have to worry about changing your design as a result of this material selection. The chart below shows a selection of PCB materials and their characteristics for your reference.
What Is FR-4?
FR-4 is a grade designation for flame-retardant fiberglass reinforced epoxy material. Thus, FR-4 PCB offers a much greater level of resistance to heat than a standard PCB. FR-4 circuit boards are divided into four classifications that are determined by the number of copper trace layers found in the material:
• Single-sided PCB / Single-layer PCB
• Double-sided PCB / Double-layer PCB
• Four or more than 10 layers PCB / Multilayer PCB
The characteristics of High Tg materials are listed below:
- Higher heat resistance
- Lower Z-axis CTE
- Excellent thermal stress resistance
- High thermal shock resistance
- Excellent PTH reliability
- Pcbway offers some popular High Tg materials
- S1000-2 & S1170: Shengyi materials
- IT-180A: ITEQ material
- TU768: TUC material
Technical options for High-Tg circuit boards
CTE-z
The CTE value shows the thermal expansion of the base material. CTE-z represents the z-axis and is e.g. due to the stability of the vias, of high importance. A higher Tg value favors a low CTE-z value which represents the absolute expansion in the z-axis. Errors like pad lifting, corner cracks and cracks within the via can be prevented through a low CTE-z value.
T260 - T288 value, Td
The decomposition temperature Td of a resin system depends on the binding energies within the polymers, and not on the glass transition temperature Tg. A good indicator for this characteristic is the T260 or T288 value, which specifies the time until delamination at 260°C or 288°C, respectively.
A very important indicator of the heat resistance is the time-to-delamination at a certain temperature. This test is preferably performed at 260 °C or 288 °C. The T260- or T288-value is the time to delamination of the tested material at 260 °C or 288 °C, repectively.
Td: Temperature-of-decomposition indicates the temperature at which the base material has lost 5% by weight and is an important parameter for the thermal stability of a base material. Through exceeding this temperature an irreversible degradation and damage to the material by the decomposition occurs.
High TG PCB Advantages
- High glass flow temperature value (TG)
- High-temperature durability
- Long delamination durability
- Low Z-axis expansion (CTE)
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High TG PCB manufacturer and manufacturing capability
JHYPCB can manufacture High-Tg Circuit Boards with a Tg value of up to 180°C.
We used below High Tg materials usually, if you need Data Sheet, please contact us directly.
|
Material |
TG |
Td |
CTE-z |
Td260 |
Td288 |
|
(DSC, °C) |
(Wt, °C) |
(ppm/°C) |
(min) |
(min) |
|
|
S1141 (FR4) |
175 |
300 |
55 |
8 |
/ |
|
S1000-2M (FR4) |
180 |
345 |
45 |
60 |
20 |
|
IT180A |
180 |
345 |
45 |
60 |
20 |
|
Rogers 4350B |
280 |
390 |
50 |
/ |
|
Blank PCB,High TG PCB,High TG Circuit Board,High TG Printed Circuit Board
JingHongYi PCB (HK) Co., Limited , https://www.pcbjhy.com