2017年11月12日星期日

Sensors on the car

Sensors on the car

Now the car is more and more intelligent, many functions on the car are controlled by the computer to complete, such as engine systems, transmission systems, suspension systems, brake systems, air conditioning systems, body control systems and so on. The computer has to control the system, must obtain the correct information to confirm the state of the system, and then issue the correct instructions to control the system action, so the implementation of the driver's intention, the correct control of the car. The information on these reaction system states is done by a component called a sensor. Even a very common car, up to dozens of sensors, and up to hundreds of cars. So what are the effects of these sensors?

What is a car sensor?
We are in the daily maintenance of the car, often hear a variety of sensors, then in the end what is the car sensor?
In the operation of the car, the system will be in different working conditions, such as water temperature, oil temperature, intake pressure, speed, throttle position, stalls, etc., these information car computers can not read directly, must be translated into the computer can recognize the electrical signal. Car sensor is the implementation of this task, it is running the car light, electricity, temperature, pressure, time and other information into electrical signals, and then enter the car the computer system, and then by the computer in advance of the stored procedures for the calculation and analysis, thus Determine the running status of the car. Now the car on the sensor is very much, here we talk about the car system in the name of the sensor and the role.

Injection molding is equally important for medical products

1, the intake pressure sensor
Intake manifold pressure sensor (MAP)
The function of the intake manifold pressure sensor (MAP) is to detect the degree of vacuum of the intake manifold and to convert the pressure signal into an electronic signal to the engine control computer. It is the main reference signal for controlling the pulse width and ignition timing
Divided into two types of semiconductor varistor and capacitive intake manifold pressure sensor.
Ingress manifold pressure sensor failure, the engine will start difficult, performance disorders, acceleration deterioration, idle instability, fuel consumption, accelerated instability, accelerated tempering, blasting, fuel consumption, deflagration and other failures.

2, the crankshaft position sensor

Crankshaft position sensor (CKP)
Crankshaft position sensor (CKP) is one of the most important sensors in the engine centralized control system. It is an indispensable source for confirming the crank angle position and the engine speed. The engine control module (ECU) uses this signal to control the fuel injection quantity, Timing, ignition timing (ignition advance angle), ignition coil charging closure angle, idling speed and electric gasoline pump operation.

3, the camshaft position sensor (CMP)

The camshaft position sensor is used to detect the angular position of the camshaft. The engine control module (ECU) uses this signal to determine the cylinder sequence of the engine to control the injection sequence, the ignition sequence
When the camshaft position sensor fails, the engine output power will be reduced.

4, the engine coolant temperature sensor (ECT)
The engine coolant temperature sensor is used to detect the temperature of the engine coolant and convert the temperature signal into an electrical signal to the engine control module (ECU) as the primary correction signal for gasoline injection, ignition timing, idling and exhaust emission control.

5, piezoelectric knock sensor

The knock sensor is used to detect the knocking of the engine during combustion and to send the knock signal to the engine control computer as an important reference signal for correcting the ignition advance angle
Knock sensor with non-resonant and resonant type of two, generally installed in the 2-cylinder and 3-cylinder, or 1, 2 the cylinder in the middle of a 3,4-cylinder in the middle one. The connection of the general knock sensor is wrapped with shielded wire.

When the knock sensor failure, the engine will deflagration, ignition timing inaccurate, high fuel consumption, power reduction, the engine work rough

2017年8月9日星期三

Trump to impose a tariff of 45% on China! What is the impact?

The Trump team is releasing news that the new US president may honor his campaign pledge to include China as a currency manipulator,But may not fulfill another promise: the Federal Reserve Chairman Janet Yelen pull down.

In a Bloomberg TV interview Friday, Trump's economic adviser Judy Shelton replied, "When he was asked whether Trump would really include China as a currency manipulator, he said, "He said, and Trump argued against currency manipulation by trade opponents.

Shelton also said that the Fed will remain independent in the future, he could not imagine why Yellen will not complete the current term. However, he revealed Trump's low interest rate on the Fed to maintain dissatisfaction, said Trump does not support the establishment of a low interest rate based on the "false economy."

Trump economic adviser Judy Shelton on Friday hinted that China will determine the exchange rate of the country, he also said Trump is a "say to do" people. Trump has pledged to declare China the currency manipulator on the first day of his presidency, threatening to impose a high tariff of 45% on Chinese imports. Once it is determined that there is exchange rate manipulation in a country, the United States will not only exert pressure on the government to adjust its exchange rate policy through the IMF, it is more likely to retaliate by means of trade. Trump after the election may exacerbate the outflow of capital in China, thereby increasing the pressure on the RMB depreciation in the medium term. 45% of the tariff!! At this time a lot of partners to panic. However, a careful analysis, even though the United States is China's largest export target, but China is actually on the US trade exposure is shrinking, according to Morgan Stanley estimates, even with 45% punitive tariffs, China's total exports Will only drop 13%. The United States accounted for 17 percent of China's total exports, up from 21 percent five years ago, but contributed 43 percent of China's trade surplus.


In the first nine months of 2016, China's exports to the United States were in the form of telecommunications equipment ($ 56 billion), office facilities ($ 47 billion), electronics ($ 33 ​​billion), clothing ($ 24 billion) ($ 16 billion). China's exports to the United States accounted for 39% of furniture exports, followed by metal ores and scrap metal (33%), footwear (33%), telecommunications and recording equipment (29%), Handbags (26%).


If the United States to raise tariffs on China Chinese exporters because of their profits are not high (5%), so the ability to absorb US tariffs to improve the impact of limited capacity. The increase in tariffs will be fully spread to the prices of Chinese exports. Suppose that US tariffs on China increased from the current 2.8% to 15%, 30% and 45% (see the Republican March debate: edition.cnn.com/2016/03/10/politics/republican-debate-tran-full China's exports to the United States will be more hit, will decline 21%, 46%, 72%; However, China's total exports in the medium term corresponding to the decline in the rate of much smaller, respectively, 4% 8%, 13%.


The United States a substantial increase in tariffs may not occur immediately Trump government to raise tariffs on the matter before the first communication with the domestic and foreign, Congress passed, but also through the domestic long judicial review. In addition, WTO is a series of mechanisms to resolve trade disputes, the United States as a WTO member should give priority to choose WTO to resolve trade disputes. So the United States is unlikely to really in the short term to China to implement a more tightening of trade policy. But if China's export growth falls drastically, a fall in trade surpluses will deter yuan demand, which could accelerate the devaluation of the renminbi, especially in the face of speculative sentiment and the effects of cross-infection. Of the bad big.

2017年1月2日星期一

Injection mold principle

Plastic injection mold is given to the shape and size of the molding member. Although the structure of the mold and performance of varieties of plastic, shape, and configuration and the type of plastics injection molding machine may be different and changing, but the basic structure is the same. Die mainly by gating system, molded parts and structural parts of three parts. Gating system and molded parts which are in direct contact with the plastic part, and with the plastics and products change, the mold is the most complex and the biggest change, the most demanding part of the process finish and accuracy.

Gating system refers to the plastic from the nozzle portion of the cavity before entering the flow path, including the main channel, cold-slug, diversion channel and the gate and so on. Forming part refers to the shape of the various parts constituting products, including dynamic simulation, the fixed mold and cavity, core,  air popper forming rod and exhaust ports and so on. 

Sprue
   
  It is mold injection machine nozzle connected to a shunt or cavity section channel. Sprue concave top to the nozzle convergence. Sprue inlet diameter should be slightly larger than the diameter of the nozzle (O.8mm) to avoid overflow and prevent the interception of convergence between the two are not allowed to occur due. Imported products according to the size of the diameter, usually 4-8mm. Expanding the diameter of the main channel at an angle of 3 ° to 5 ° should be within in order to release the flow channel thereof is superfluous.

Cold slug
    
It is located in the main channel at the end of a hole to trap shoot between the ends of two injections of mouth generated by cold material, thereby preventing the diversion channel or gate blocked. If cold material once mixed with the cavity, then the system is easy to produce products in the internal stress. Cold slug diameter of about eight a lOmm, depth of 6mm. In order to facilitate mold release, normally borne by the bottom of the release lever. Top release lever should be designed to zigzag trench subsidence hook or set up in order to successfully pull the sprue superfluous matter when stripping.

Shunt

It is a multi-slot die cavity connecting the main channel and each channel. In order to melt each cavity is filled with equal speed, diversion channel on the mold arrangement should be symmetrical and equidistant distribution. Runner-sectional shape and size of the plastic melt flow, and ease of mold release products has an impact. If the feeding amount in equal flow, it places the smallest cross-section of the flow path resistance. But because of the cylindrical flow channel surface area is small, the cooling of the shunt superfluous material adverse, and this shunt must be opened on the two halves of the mold, both labor-and easy alignment. Therefore, regular use of the trapezoidal or semi-circular cross-section of the runner, and the opening on one half of the mold with a release lever. Channel surface polished to reduce flow resistance must provide faster filling speeds. Depends on the size of the plastic flow channel variety, size and thickness of the article. For most thermoplastics, the shunt section width does not exceed 8m, up to 10 a large 12m, special small 2-3m. Under the premise of meeting the needs of the cross-sectional area should be minimized to avoid increasing the shunt Warts and extend the cooling time.

Gate

It is on the main road (or shunt) and the cavity of the channel. Sectional area of ​​the channel can be with the mainstream channel (or shunt) are equal, but are usually reduced. So it is the smallest part of the whole system, the cross-sectional area of ​​the flow path. The shape and size of the gate great impact on product quality. The role of the gate is: A, control the material flow velocity: B, due to the injection can be stored in this part of the condensate and prevent melt back earlier: C, so that the melt by strong shear by increasing the temperature , thereby reducing the apparent viscosity to increase flowability: D, easy separation of products, and the flow channel system. Gate design shape, size and position depend on the nature, size and structure of the article of plastics. The gate of the cross-sectional shape is generally rectangular or circular cross-sectional area should be small and the length should be short, not only based on the above effects, but also because larger than the small gate easy, and it is very difficult to reduce the large gate. Gate location should generally be selected in the products do not affect the appearance of the thick places. Gate size should be designed to take into account the nature of the plastic melt.

Cavity

It is the mold space molded plastic products. Component as constituting the cavity collectively referred to as molded parts. Various molded parts are often specific names. The molded article constituting the shape of the concave part called a die (also known as the female mold) to form the internal shape of the article (such as holes, slots, etc.) is referred to as core or convex mold (also known as the male mold). First, the overall structure of the cavity to be determined according to performance, the geometry of products, dimensional tolerances and use requirements designed plastic molded part time. Second, to select sub-surface, the gate and the vent mode position, and release according to the determined structure. Finally, press the control product dimensions of each part of the design and determine the combinations between the various components. Plastic melt with high pressure into the cavity, so the molded parts to be reasonable selection and check the strength and stiffness. To ensure the smooth plastic surface appearance and easy stripping, where contact with the plastic surface roughness Ra> 0.32um, but also resistant to corrosion. Molded parts are generally by heat treatment to improve the hardness and corrosion-resistant steel manufacturing.

Vent

A groove which is open in a mold outlet, and for discharging the original gas into the melt. When the molten material into the cavity, the original is stored in the cavity from the melt into the air and gas must be discharged through the exhaust port to die at the end of the stream outside, otherwise it will make products with holes, bad splices, filling dissatisfaction, even accumulated compressed air due to high temperature and the product burns. In general, both exhaust holes provided in the cavity of the melt flow at the end, may be provided on the mold parting surface. The latter was set up at the side of the die deep 0.03-0.2mm, wide shallow groove 1.5-6mm's. Injection, the vent does not have a lot of melt leakage, because the melt is cooled and solidified in where the channel blocked. Never open position toward the exhaust port operator, to prevent accidental discharge wounding melt. It will also use the top of the bar with the gap with the top of the hole, the top block and the stripper plate and with the gap cores like exhaust.

Structural parts
  
  It refers to the various parts constituting the mold structure, including: orientation, ejection, core pulling and genotyping of various parts. As the front and rear plates, after deduction templates, pressure plate, bearing columns, guide posts, stripper, stripping pole and the return pole and so on.
Heating or cooling means
   

  This is to make the melt solidified in the mold shape of the device for thermoplastic male and female mold is typically a cooling medium passage, and by circulating cooling medium to the cooling purposes. Pass into the cooling medium and the structure of an article with the type of plastic and the like, cold water, hot water, hot oil and steam. The key is uniform cooling high efficiency, uneven cooling products will directly affect the quality and size. Should be based on the thermal properties of the melt (including crystallization), the shape of the article and the mold structure, consider selecting the arrangement of the cooling passage and the cooling medium.