How A Few Real Estate Investors Help Rebuild The Economy, One Home At A Time

We have written before on how you can find previously undiscovered deals at smaller firms, and how their buyer incentive programs can get you a good home on your terms. But, did you know that there are a few select real estate investors who rebuild the economy of an area at the same time? While the country is waiting for the economy to rebound on a larger scale, these investors are taking matters into their own hands and helping the economy along, one community at a time, one home at a time.

Step One: Purchase Unused Properties

By purchasing properties that have been abandoned or left empty for too long, these real estate investors rebuild the economy of a small town by removing potential eyesores that could essentially bring down the property values of an area. The purchase also takes these properties off the delinquent tax rolls, providing needed tax revenue for the township in which these properties lie.

Step Two: Renovation

After the homes are purchased, each one is evaluated for renovation. These few real estate investors have as part of its business model, the desire to improve the economy as well as the lives of those who would purchase these properties at a later date. Each and every home undergoes a complete renovation, not only bringing them up to code, but also to a complete green status.

Each home is improved and energy efficient systems are put into place for future owners to enjoy. This also helps to improve the future of the towns where these homes reside, by doing their part to improve the ecology of the area, lowering the drain of these homes on the power grid, and reducing their carbon footprint for future generations to come. More importantly, unemployment in the area is eased through the hiring of local, skilled contractors and employees for the duration of the renovations. They always have projects going on, so employment is assured for far longer than the short-term.

Step Three: Giving Those Who Deserve It A Break

Once the homes are ready to be resold, they are offered on the general market, and advertised on the Internet for sale. No one is turned away on the basis of bad credit, never. Everyone deserves to own their own home, and these firms go out of their way to provide that chance to every deserving applicant that they can.

Through their bad credit financing programs, as well as their rent-to-own arrangements, these real estate investors rebuild the economy by giving potential homeowners the chance to finance the home of their dreams when other institutions have turned them down. An Investor will work with them, step-by-step, helping them apply for financing through their own network of direct mortgage lenders. If they do not make the grade, it is not the end of the road. Instead, they are offered a lease-to-own package, allowing them to rebuild their credit, and save up for the down payment at the same time.


Tag:-market analysis real estat, how to find real estate investors, real estate forecasts, market research real estate, real estate growth, real estate technology, real estate market trends,leading economic indicators

Purchasing A Radar Detector

You collect a lot of speeding tickets in a month that is not only getting expensive but also increasing your insurance premium. Well, if your answer is yes then you definitely need a radar detector in your car. This product is a device that is actually a microwave radio detector. With this device you can detect the speed traps set by police and also the presence of radar guns that the police use to measure the speed of the vehicle. Hence as soon as the speed approaches you can decrease the speed of the vehicle and become a good abiding citizen.

The detector warns a driver by making a noise or by giving flash lights as soon as it senses any incoming signal within its frequency range. All radar detectors that you get in the market can detect every type of police radar. But if you are looking for a good quality product then Valentine radar detector is one good choice that you can make. However, before you purchase a detector first find out whether it is legal in the given area where you drive. Presently, in the US this product are illegal in Washington, DC and Virginia. The price of the product varies depending on the type of model you are purchasing.

There are generally three types of radar detectors. They are corded ones, remote ones and wireless ones. In the corded radar detector, the device is plugged in the cigarette lighter of the car and the detector is attached to the windshield with the help of suction cups. In the wireless model you get no annoying cords and its flexibility makes it a more popular choice.

The remote one is the costliest and requires to be installed professionally. This product is installed permanently in your car and remains inconspicuous. The easiest way to purchase radar detector is through online. Valentine model of this product is now quite popular in the market.


Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry

Radar Detectors- Help for First Time Buyers

Observing posted speed limits is obviously the most reliable method of avoiding costly speeding tickets. However, as most of us know, whether it is a lapse in attention, failure to see all posted signs, an instance of impatience, or a fear of being late, we all exceed the limit on occasion. For just these reasons, millions of drivers opt to invest in radar detectors to avoid the fines. Although radar detectors are banned in some countries and provinces, they are legal for passenger cars in all states in the US with the exception of Virginia and Washington DC.

There is a wide selection of radar detectors on the market and quite a bit of terminology to confuse first time buyers. However, the list of critical features that make a radar detector effective is rather short and once understood should make the purchasing decision a simple one.

The first choice a buyer will make is whether to purchase a corded, cordless, or remote unit radar detector. Corded radar detectors are the most common and can plug into a cigarette lighter or fuse box and are attached to the windshield. Buyers often choose corded radar detectors because they can be installed by the owner in seconds and don't require batteries. The other primary reason for choosing these particular devices is that they are capable of detecting all bands of radar signals.

Cordless radar detectors on the other hand are sometimes selected as they offer freedom from cords. Unfortunately, these devices are generally less effective however as they do not pick up all bands and have a more restricted range than corded models. Remote units are permanently mounted elsewhere on the car and are often selected as they cannot be seen by thieves or law enforcement. Remote devices are generally higher priced and require professional installation.

Since the purpose of a radar detector is to provide warning that drivers in the area are being monitored, it is important that the device pick up the bands being used and that the warning provided is sufficient. Buyers need to compare radar detectors as far as the distance at which they will sense a radar signal. Obviously, devices that sense a signal from a longer distance provide more warning and thus greater protection. To be functional, a radar detector should be able to pick up X, K, and Ka bands to assure that they will pick up the signals being used for monitoring purposes.

Another critical feature on a radar detector is how effective the alert is when a signal is picked up. The display should be easy to read, in daylight or at nighttime. Radar detectors often use LED but others use LCD displays. New buyers should determine which type of display best meets their personal needs. For instance, some prefer a text display but others feel the LCD display is difficult to see in the sunlight.

Some displays do a better job of indicating how strong a signal is so that the driver knows whether or not the threat of being detected is imminent. Obviously, having both a visual and auditory alert is important as a visual only alert could be missed.

Some radar detectors offer digital voice alerts versus an alarm only alert. Experienced radar detector owners would also recommend volume control and a mute button! Some devices will even offer an automated mute that is activated when driving in slower traffic when both speeding violations and monitoring are less likely.

Many radar detectors also offer features that allow the sensitivity to be adjusted to help reduce alerting the driver when radar signals are picked up from other sources: i.e. a "city mode" decreases sensitivity in urban areas where signals are picked up from security and other systems within buildings and equipment. The ability to filter out unrelated signals helps to reduce false warnings.

Some consumers also prefer to have a feature to shield them from having their device detected. Some devices shut down after alerting the driver and others use signals to shield them without shutting down.

Obviously, one of the newer methods of monitoring drivers are cameras at intersections with traffic lights. Beginning in 2007, some radar detectors will be offered which are capable of alerting drivers to these monitoring cameras and might be a valuable feature for some buyers.

A final, but very important feature that buyers will need to consider is whether or not the device they are considering offers laser detection. Certainly the use of laser guns by law enforcement has continued to increase and buyers have incomplete protection if their device monitors only radar signals. Laser is particularly useful to monitor drivers that are closer than what can be accurately measured by radar. This in turn means that drivers who are monitored by laser signals have even less time to react. Good laser protection requires placement of a head or sensor on the front of the car, usually in the grill, and additional sensors to provide 360 degree sensing to assure all signals can be picked up.

As with most electronics, there are radar detectors with all the bells and whistles, all of the features to assure maximum protection, and they may be well worth the investment for those drivers who hope to avoid expensive speeding tickets. For others however there are also very basic devices which provide a crucial warning but are easily affordable within almost any budget.



Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry

Interferometric Synthetic Aperture Radar

There are many methods of generating maps of the different regions having differences in terrain. Interferometric synthetic aperture radar uses the radar technique for making maps. This method is commonly used in remote sensing methods for preparing maps volcanoes, land surfaces, landslides etc.

Natural mishaps happening in different parts of the world are monitored by the experts using the techniques of remote sensing and geodesy. The concept is of allowing the waves from the objects and captured by the satellite or from an aircraft. Elevation and deformation can be easily measured with the help of Interferometric synthetic aperture radar.

Following pointers describe about Interferometric synthetic aperture radar:

1. There are two types of remote sensing techniques and this technique is the part of the active remote sensing. Instruments are moved near the surface of the earth and also near to the objects whose study is to be performed. The frequency of taking images is quite different and images can be captured even at night time. This technique has great advantage of day and night usage.

2. If the area is covered by clouds then also there is no problem in taking the images. Antenna is required to transmit the radiations which are received from the objects captured by the frequencies of electromagnetic and microwave. The phase difference is utilized in the calculation of the mapping surface features. If the vacuum is used for acquiring images then certainly the enhanced quality will be available.

3. Ground surface may change the phase of the returned frequencies. Different types of satellites are used in the process and help is taken from different satellites moving in different orbits. The images of different orbital satellites are incomparable and slight difference can cause blunders.

4. Noise is also accompanied by the signals of different frequencies. The change is the signal is measured by the Interferometric synthetic aperture radar. Sensors easily measure the changes in the angles caused by some difference in surfaces. Deformation can clearly be understood as the signals are captured by the sensors.

5. Baseline has impact on the collection of data. Different images can be obtained the latest technology and programming of Interferometric synthetic aperture radar allows the capturing of the images. There are many hindrances in the path of the signals due to atmospheric elements. Nowadays soft wares contribute in processing of the images.



Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry

Improve Your English Vocabulary Through Physics: Part B

Introduction:

Here are certain words commonly used, while teaching Physics. The same words have their literal meanings also. The undersigned author is a teacher of both Physics and English. He has listed some words which he came across while teaching both the subjects with their meanings in both the disciplines. Readers may find more words from other sources, which are commonly used, for improvement of their vocabulary.

1. Ballistics

The word Ballistics is used in various disciplines especially in Science and Technology. The dictionary meaning is science of production of projectiles such as shells, bombs, bullets etc. In Physics this word is applied in ballistic pendulum, ballistic galvanometer etc. In Space Technology it is used in ballistic missiles. So, anything which projected in a parabolic curve is known as Ballistics.

2. Barn:

The literal meaning of Barn is building in which gain, hay etc are stored. In general, a broad target. In Nuclear Physics, it represents the unit effective cross section of nucleus in the order of 10 power -24 cm.

It is a matter for our thought to ponder even Scientists think in terms of poetic language. In part A we saw the word Avalanche giving a poetic definition of raining of electrons in a diode. In this part, the word Barn may be considered a poetic description of measuring a nuclear area. How such a small area could be named with such a huge area like the storage place of paddy and rice.

For the size of electrons and protons, the cross section of nucleus is so high that for an electron, nuclear cross section is a Barn. The wisdom of our scientists in this analogy may well be appreciated.

3. Buoyancy:

A carefree, light-hearted person is generally known as Buoyant person. He is supposed to 'fly' in air. A buoyant person makes people around him carefree and joyous.

Such a meaningful word is used in Hydro- physics for the objects floating in liquids.
Buoyancy is the upward thrust on a body immersed in a liquid. This is the foundation of Archimedes principle, which is a turning point in Physics and Chemistry.

One will be stuck with wonder to understand the similarity between a care-free person flying in air along with an object floating in water.

4. Bits and Bytes: These two words are not un-common for a computer student. A Byte represents the sub-division of a word in a computer. It usually consists of 8 Bits. A kilobyte is 1024 bits and so on.

The literal meaning of Bit need not be insisted upon. whose general meaning is a small piece. Likewise, the word Byte means sequence of bits possessed as a single unit of information in Computers.

5. Camera and Cell:

The meaning of Camera is well known to us. It is an optical device for obtaining still photographs or for exposing cinematic film. The literal meaning of this word is 'a private room' especially that of a professional like a judge etc. In South India, the word is commonly used to represent a store room where personal belongings are kept.

The similarity between the structure of a camera and a small room (cabin) is to be felt and appreciated.

Likewise, we all know the uses of 'Cell' phones and battery cells. The literal meaning of Cell is also a 'small room' or an apartment.

6. Candela:

It is anybody's guess that the origin of this word is 'Candle'. It is the unit of luminous intensity formerly expressed in candle power. There is an idiom which states that 'can't hold a candle to. which means the matter under consideration does not project enough light to read.

7. Cascade:

The common dictionary meaning of this word is a 'waterfall'. It does not mean a waterfall falling continuously, but falling step after step. In Science, a 'cascade process' represents a process that takes place in a number of steps, usually because the single step is too inefficient to produce thee result. as in the case of a cascade liquefier wherein gas is liquified in various steps.

8. Causality:

Cause and effect relationship has great significance both in Science and Philosophy. In Science,the principle states that 'the effect can not precede cause'. In Philosophy the word implies 'there is no effect without cause'. In other words, this is a philosophical version of Newton's third law which states that 'Action and Reaction are equal and opposite' which, in other words means that Energy can neither be created nor be destroyed, but can only be transformed. For any change in any object or energy in the Universe, if it is considered as an effect, and the action is the cause. Hence, the word Causality has invited continuous and deep study by Philosophers and Scientists as well.

9. Chirality:

The origin of this word is Chiral. Any object which is different in its reflection is known as chiral. Otherwise it is known as Achiral. The best example of a chiral object is an arm reflected in a mirror. Left arm will appear like right arm and vice versa. Hence chirality means, the property existing in left, but belongs to right handed structural forms. The example for this is in Chemical properties in a medicine called Thalidomide.

(Example for an achiral object is a water glass reflected in a mirror which will not exchange sides)

10. Chromoticity:

This word is applied both in Optics and Sound. In Optics, it is an objective description of the colour quality of a visual stimulus and in Sound, it relates to notes in a melodic progression.TChromatic which refers to colour and music scales.

11. Cladding:

Cladding generally means 'clothes'. We could have read in stories thee phrase 'clad in white cloth' etc. The extended meanings are, to cover one material with other as in the case of a nuclear reactor, brick with another material in building construction. A modern use of this word can be found in fibre optics when optical fibres are protected by cladding.

12. Coagulation

The meaning is to clot by chemical reaction. Heating is one example of coagulating as in the case of eggs being boiled to coagulate the albumin.

13. Coefficient

A coefficient is that which acts together with another thing. In Physics, it is a constant used as a multiplier to various quantities which are multiplied.



Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry

Advances in Data Network Backup Switches

echnically Advanced Data Network Backup Switches

Abstract: Backup switches allow the users the capability of sharing devices or networks connected to the COMMON port/s among devices or networks connected to the (A, B, C, etc.) lettered or (1, 2, 3, etc.) numbered ports. Network switch designs and capabilities have changed significantly since the dawn of the computer age. This white paper delineates and clarifies some of the capabilities of the network switches on the market today.

Introduction: Network switches have come a long way since they were simply used to select either printer A or B for that report coming from a particular computer. Today's switches can still have simple designs and functions; however, new demands for high-speed capability, high reliability factors, and sophisticated control methods have developed a market for technically advanced network backup switches.

1. Today's Switch Requirements
Let's start at the beginning. The significant number of choices that need to be made to determine the exact switch to meet the user's requirements is an indication of the growing complexity of today's data network backup switches.

Switches are available with any number of positions, including secure off-line positions. The switches can have letters, A, B, C, etc., or numbered positions. Connect and Disconnect, On-Line and Off-Line, Normal and Loopback, and Normal and Crossover positions are also offered.

Switches can be designed to meet space requirements. As an example, a particular switch was developed with a small size and with mounting ears to fit a mobile/motion application. Another switch was designed to be built into a wall for a secure and handy application. Multiple modular units can fit into a rack and can be expandable as required.

Most Rackmount configured switches are designed to fit standard 19" racks. A 1U rackmount switch dimensions are 19" W x 1.75" H x 8.0" D (48.3 x 4.4 x 20.3 cm). A 2U rackmount switch dimensions are 19" W x 3.5" H x 8" D (48.3 x 8.9 x 20.3 cm).

Racks are available to house modular switches. A 19" W x 5.25" H x 7" D (48.3 x 13.3 x 17.8 cm) rack can accommodate multiple switch module chassis of various widths. Filler panels are available to cover empty slots and provide the data center with a neat appearance. Modular switches are ideal for networks that plan expansion over a period of time.

Switches can be built with any connector and with combinations of connectors. An example is a tri-channel A/B switch with both RJ45 and BNC interfaces. Channel 1 allows access to RJ45 devices 1-A or 1-B. Channel 2 allows access to BNC devices 2-A or 2-B. Channel 3 allows access to BNC devices 3-A or 3-B. Fiber optic connectors include ST, SC, LC, ESCON, FC, and others.

Switches can be selected that operate at various speeds. If the switch has RJ45 ports, CAT5, CAT5e, CAT6, CAT6a are options. CAT5 switches allow access to networks rated for 10/100Base-T (up to CAT5). CAT5e switches allow access to networks rated for 1000Base-T Gigabit Networks. CAT6 switches allow access to networks rated for Gigabit Ethernet. CAT6a switches allow access to networks rated for 10/100/1000Base-T.

Switches can be controlled via a push-button or remotely via a number of methods. Switches can switch automatically when they sense a loss of data or receive a trigger signal. Remote control types include RS232 serial, contact closure, IP addressable, and Graphical User Interface (GUI) and any combination of these controls. Automatic control is also available.

Offline switching can be accomplished where the switch can automatically switch to an offline position before switching between ports A and B. A switch can have a secure off-line position where absolutely no data passes through the switch when in the off-line position. This is the ultimate firewall.

The point is that both copper and fiber optic switches can be complex. Let's try to demystify some of the sticking points with further explanations and examples.

2. Flexibility in Switch Controls
Push-button - Many switches offer front-panel push-button for local control. Any person with access to the switch can easily change the switch position. If that's all you need, push-button control is the way to go.

Keylock - A Pass Key can ensures proper authorized usage. The advantage of the keylock is the security of knowing that only the person with the key can change the switch position. The keylock mechanism can be located on the front panel. Removing the key ensures that the switch will remain in the exact position that it was in when it was locked. Pocket the key and rest assured that the switch will continue operating exactly as it was intended.

Remote Control - Now the switching choices are a little more complex, but there are definite advantages. The switch can be controlled remotely in a number of fashions:

RS232 Serial Control - With RS232 serial control, the REMOTE connector accepts RS232 serial data ASCII commands. The remote port may be connected to any standard RS232 port on a computer. The computer, once connected to the remote port, may use any common terminal emulation software to generate RS232 serial data ASCII commands.

Contact Closure - The REMOTE connector accepts Contact Closure signaling for remote control operation. An example of the methodology for contact closure is when the switch detects a transition from open to close and remains closed across pins 2 and 3, the unit will switch to the B position. If the switch detects a transition from closed to open and remains open across pins 2 and 3, the unit will switch to the A position.

IP Addressable - An IP Addressable feature is ideal for critical network alternate-path switching. Remote control and monitoring of the switch position can be from a 10/100 Base-T LAN Ethernet environment. Users can communicate with the switch via TELNET session. The user setup can allow assignment of an IP address for the switch unit.

Graphical User Interface (GUI) - The remote GUI interface allows the user to control the switch remotely with simple point and click operation. Many switches today offer extensive GUI features. To utilize the user-friendly software, the users may simply connect to the switch from a computer with access to the LAN to which the switch port is connected. Simply launch a standard Web browser and type in the appropriate IP address.

Code-Operated - The switch position and lockout can be changed through the data stream on the COMMON port. The switch monitors its COMMON port and its A port for a specified trigger character sequence.

Auto Sensing - With automatic sensing the switch can switch itself based on sensing a loss of carrier (DCD). Some switches have multiple control methods and can also be controlled locally via a front-panel push-button, or the switch can be managed off-site with the Remote option. An Automatic Fallback A/B Switch with Optional Remote Management Port allows a device connected to the COMMON port to connect through to the A port. The unit monitors carrier presence (DCD) signal on the primary line, port A. If carrier is lost, the unit automatically switches to port B. The switch will maintain its connection to port B until carrier presence is again detected on port A. When carrier is detected on port A, the unit will automatically return to the A position. With some switches, the user can override the automatic fallback operation from the front panel and force the unit to operate as an A/B switch.

To sum up flexibility in switch control, today's switches are available with automatic, manual, and remote control systems and with any number of combinations.

3. Redundancy in Network Switches
Redundancy in network switches can mean added reliability. In the first example, the switch uses a redundant system to back itself up. In the second example the switch uses an extra remote port as an additional means of communicating with the switch and an additional power supply port to ensure power is always available to the unit.

Redundant Backup - A particular switch design of interest is a normal/redundant fallback switch that self-configures connectivity based on the devices connected to it. This type switch allows data broadcast, TD of the RS232 interface, from two data origination devices to be channeled to two devices designated as destination devices. The switch will self-configure its connectivity based on the devices connected to it, or the user can override its connection status from a front panel push-button.

This is how the Normal/Redundant switch works. During the Normal mode, the origin device connected to port D1 is connected to port COM1. The device connected to port D2 is connected to port COM2. If the RTS signal is lost from the device connected to D1, the switch changes to Redundant Fallback mode and automatically broadcasts the data from D2 device to both destination devices, COM1 and COM2. Likewise, if the RTS signal is lost from the device connected to the D2, the switch automatically broadcasts the data from the D1 device to both the devices COM1 and COM2. One of the status LED's will be lit steady ON to reflect the connectivity status and signify that the unit is in Automatic operation. To override the Automatic operation, the user simply depresses the front panel push-button and holds it down for 5 seconds and then releases.



Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry

Gating Technology

For the processing of thermoplastics the predried granulate is melted in the plasticizing unit of an injection molding machine and then conveyed by the screw to the molding via a spreader system.

This spreader system is also called a gating system. The primary requirement for the gating system is extremely careful transport of the melt to the molding. On the basis of

* the geometry of the molding,

* processing-related reasons and

* economic aspects
the gating system can be divided into the following areas:

* hot runner,

* cold runner,

* sprue and

* gate.

Strengths

* Optimal component quality
* no sequential faults
* gentle processing of the plastic melt taking into account process and component requirements Gating system of a center console

Structure of a gating system

A number of demands are placed on a gating system both by the processor and by the raw material supplier. To meet the constant cost pressure, processors attach importance to smooth and optimally automated production. Furthermore, they require a large processing window, but for reasons of economic efficiency wish to realize a short cycle and be faced with little sprue waste. From a rheological point of view, however, low shear, temperature increase and pressure loss are optimal conditions for trouble-free production. To meet these, in part, conflicting requirements, the gating system is divided into different sections.

* In the hot runner the melt is maintained at the proper temperature by means of electric heating. In this way even larger distances can be bridged over in the mold without pressure losses. The hot runner ends in a hot nozzle, which represents the boundary line between the heated and unheated zone.

* The cold runner is the link between the hot runner and sprue section and bridges the section that can no longer be reached with the hot runner. A large temperature gradient is produced between the cold mold wall and the melt in the unheated cold runner. Therefore, the melt in the cold runner is exposed to greater shear and accordingly is subjected to a greater load. Short cold runners make it possible to keep pressure loss and material load within acceptable limits.

* The sprue is the transition area between cold runner and molding. Varying sprue designs are used here, depending on the design and demands on the part.

* The gate point is the transition point from the sprue to the molding. Often rheological necessities and demands on surface quality clash at this point. Two aspects must be kept in mind:

1) A small gate is less visible and can be removed from the mold better.

2) In a gate whose size is too small the melt is exposed to an extremely high shear that may lead to surface problems, such as streaking and collapse.

Design of a gating system

The gating system guides the melt prepared in the injection molding cylinder to the molding and has direct and indirect effects on the quality of the molding. Against this background, the article designer and the tool and die maker should take these aspects into account right from the design phase in order to guarantee a trouble-free processing process and constant component quality.

In the design of a gating system the focus is on the component. Factors that influence the design of the gating system include:

* size,

* targeted surface quality,

* mechanical requirements,

* specified thermoplastic,

* complexity of the geometry and

* economic efficiency.

Runners and sprues that are dimensioned too small lead to excessive load on the melt due to high shear in the gating system. In extreme cases this may lead to chemical degradation, resulting in a drastic reduction in the mechanical capacity and streaking in the gate section or over the entire molding. To ensure optimal processing, the following points are coordinated step by step:

* gate location,

* gating technology,

* gate type and

* dimensioning of the gating system.

What used to be determined in individual steps and frequently through initial matching is now possible with the help of constantly optimized software for simulation of the molding and of the filling process prior to die making.

Gate location

When determining the gate location, the following must be given consideration:

* the flow path,

* the filling volume and

* the position of the joint lines.

The first step should be to check the filling situation on the basis of the filling pressure curves. The latter provide material-specific information on the fluidity in comparison to the pressure needs as a function of the wall thickness. With regard to the location of the gate points, the respective flowability of the material should not be exhausted so as to avoid unnecessarily restricting the processing window. If the molding is filled in several gates, it must be kept in mind with respect to the joint that

* a joint line is created that may be visible and represents

* a mechanical weak point.

Therefore, it is often necessary to select the location of the gates such that the joint line is not in optically critical exposed sections and areas subjected to mechanical load. Furthermore, the location of the sprue may depend on specific component requirements and production processes. If, for example, IMD (in-mold decoration) is used for a molding, the flow over the film has a decisive influence on the gate location.

Gating technology

After determination of the sprue location the next step is to define the gating technology. Depending on component size and requirement, a number of methods are available, from three-plate to cascade technology. Selection of the technology to be applied depends on the targeted result. The mold construction time and the costs are the primary factors in the making of prototype molds. Therefore, a simply designed cold runner system is usually used here, possibly in a three-plate mold. If runnerless injection molding is required, the appropriate hot nozzles must be selected to support such a process.

Type of gating system

The transition area between the cold runner and the molding is designated as the sprue. The point where the melt flows into the molding is called the gate. The selection of sprue and gate depends on the requirements to be met by the gate point and the filling characteristics.

* Tunnel gating system The tunnel gating system meets the requirements of automatic production and is therefore applied very often. In connection with the design, however, adequate cross-sections must be ensured in order to avoid high pressure losses and application of unnecessary shear to the melt, depending on the length of the tunnel.

* Film gating system The film gating system is especially well suited for optical components, such as headlight lenses. The arriving melt is placed across the width of the film gate via a pre-distributor and an even flow into the molding is achieved through skillful dimensioning of the pre-distributor. This type of gating enables low-stress filling, but requires mechanical removal of the sprue.


Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry