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What Is an Injection Molding Machine?

An injection molding machine is a machine that performs injection molding of plastic and other resins. The manufacturing process of injection molding begins by pouring heated, softened resin into a mold. The mold is then subjected to high pressure, and the cooled product is removed.

Injection molding is the most commonly used method of molding plastics and other resins. Many familiar products, such as stationery and cell phone parts, as well as automotive and home appliance parts, are produced by injection molding.

Uses of Injection Molding Machines

Injection molding machines are used to produce many household items. This is because injection molding machines specialize in the molding of resins. Injection molding machines can mold a wide range of resin materials, including thermosets, thermoplastics, and elastomers.

Products manufactured by injection molding machines include automotive interior and exterior parts. Most automotive interior and exterior parts are molded on injection molding machines. In addition, most exteriors of everyday products such as electric fans, microwave ovens, televisions, and washing machines are also produced by injection molding machines.

Injection molding machines are indispensable in the manufacture of familiar products, from small parts to large products.

Structure of Injection Molding Machines

The structure of an injection molding machine is divided into an “injection section,” which injects resin, and a “mold clamping section”, which molds the product. In the injection section, the resin is melted at a high temperature of approximately 200°C and poured into the mold. The flow is automated by simply setting the amount and temperature to be poured into the machine.

The mold is installed in the mold clamping section. The mold must be moistened with a mold release agent and warmed up to prevent resin from sticking to it. Resin is poured into the mold from the injection section, and the mold is clamped under high pressure for molding.

After molding, the resin is cooled to completion. The removed resin has burrs, which are removed and inspected before it is made into a product.

Types of Injection Molding Machines

Injection molding machine types are classified according to the materials to be molded and the structure of the injection molding machines. There are two main types of materials used by injection molding machines: thermoplastics and thermosetting plastics. 

• Thermoplastics deform when heat is applied.
• Thermosetting plastics harden when heat is applied.

The most common injection molding machines are for thermoplastics. There are also three types of injection equipment: plunger type, pre-plunger type, and screw type.

• Plunger Type
  Material is injected using a piston-type plunger. This method was common until the 1960s but is now used only for special applications.
• Pre-Plunger Type
  This method combines two cylinders. Since two cylinders are used, a high cycle time is possible.
• Screw Type
  A single screw is used to measure and inject material. Also called the screw-in-line method, this is the most common method used today.

In selecting an injection molding machine, it is necessary to have a good understanding of the type of material and structure used. This is because if the combination is not right, there is a possibility that the product will not be molded well.

In addition, care must be taken because failure to mold the product will further result in huge costs.

Other Information on Injection Molding Machines

Advantages and Disadvantages of Injection Molding Machines

The advantage of injection molding machines is their extremely high production efficiency. When manufacturing small parts, injection molding machines are designed to produce as many products as possible with a single mold to achieve high production efficiency.

Injection molding methods are simple, and injection molding machines are highly automated. The major advantage of injection molding machines is their extremely high productivity.

The disadvantage of injection molding machines is that they are costly. Injection molding machines must be strong enough to withstand the high pressure of the injection section. In addition, the mold clamping section requires the production of high-precision molds.

To meet the requirements of high strength of the injection section and high precision of the mold, development and processing costs are incurred. Since individual molds are manufactured for each desired product, a large initial cost is required.

What Is an Isolated Gate Driver?

An isolated gate driver is a circuit used to drive and control the gate terminals of a voltage-driven type of MOSFET or IGBT.

Currently, the most general-purpose isolated gate driver is a circuit that drives and controls the gate of a MOSFET, but there are analog circuit technologies that use resistors, diodes, bipolar, and other transistors. Recently, isolated gate driver peripheral circuit components themselves have also evolved.

Although there are many types and combinations of them, learning gate voltage drive control circuits using MOSFETs is the most practical.

Uses of Isolated Gate Drivers

Isolated gate drivers are used to drive power transistors with a simple drive circuit consisting only of MOSFETs and gate resistors.

The advantage of isolated gate drivers is the small number of components. The disadvantage is that switching speed and loss vary greatly depending on the resistance value, and it is difficult to set an appropriate resistance value. As a circuit that improves this problem of adjusting the resistance value, it is also used in circuits where the gate of a MOSFET is turned on and off separately driven by a diode.

The voltage for the diode remains, so it cannot be completely zero, but a circuit called a push-pull, in which the Pch and Nch of the MOSFET are connected up and down solves this problem. This is currently the most common use of isolated gate drivers.

Principle of Isolated Gate Drivers

Isolated gate drivers consist of a push-pull circuit of transistors.

A push-pull circuit is a circuit that performs switching or amplification by using two transistors to operate alternately. There are two types of push-pull circuits: “emitter follower type” and “emitter grounded type,” but the latter is used in most cases.

The isolated gate drivers consist of a circuit that acts as a middleman between the power element, which is the powerhouse that does the heavy lifting at the transistor site, and the microcontroller, which is the brain that commands the control policy and plays the role of president.

Power MOSFETs and IGBTs are examples of power elements that can carry large currents. The voltages and currents that directly drive these devices are in most cases insufficient for the currents and voltages that a normal microcontroller can output.

Therefore, isolated gate drivers are needed between the power devices and the microcontroller to drive them.

Other Information on Isolated Gate Drivers

1. Ultra-High-Speed Isolated Gate Drivers

Ultra-high-speed isolated gate drivers are isolated gate drivers that specialize in high-speed switching. The ultrahigh-speed category is generally defined as a device with a switching speed of several tens of ps (pico-seconds) or less.

Pico is 10 to the minus 12th power, so the switching speed is less than one trillionth of a second. This evolution can be said to have occurred due to recent technological innovations in semiconductor devices. 

2. Practical Application of Ultra High-Speed Gate Drivers

The following ultra-fast device isolated gate drivers are in practical use.

The first is a transistor using silicon, the most commonly used semiconductor. The bipolar type is fast, and capable of switching in tens of picoseconds, while the MOS type has delayed operation but is suitable for high-density circuit integration.

The second type is the compound semiconductor type transistor. These include the MESFET, a Schottky gate-type field-effect transistor, the HBT, a hetero-bipolar transistor, and the HEMT, a high-mobility field-effect transistor. The semiconductor used is a gallium arsenide compound. This device is capable of switching operations of a few picoseconds, making it the fastest semiconductor available today for ultrahigh speeds.

The third, although still in the research stage, is the Josephson device, which utilizes the tunneling effect between two types of superconductors; it has half the switching speed of the second device and uses metallic materials such as niobium. However, it requires cryogenic temperatures for operation, and there are still challenges to be overcome before it can be put into practical use.

3. SiC Isolated Gate Drivers

SiC isolated gate drivers are semiconductor devices that have been attracting attention in the recent power electronics world because of their superior breakdown voltage performance and improved switching speed. The isolated gate drivers are composed of a semiconductor called silicon carbide (commonly known as SiC), the use of which has become a trend in the industry.

In particular, MOSFETs using SiC have contributed to a significant improvement in switching performance, which has been an issue in high-power inverters and have improved heat dissipation while achieving high breakdown field strength and carrier drift speed.

However, SiC has the challenge of resolving voltage differences in various SiC composition configurations.

4. Current Mainstay Devices in Isolated Gate Drivers

Currently, the main devices that we want to operate with isolated gate drivers are voltage-driven devices called MOSFETs and IGBTs. Although isolated gate drivers do not require a constant flow of current, they do require a short pulse current during switching operations, so the rated current and voltage values as power devices must be carefully considered.

In particular, in the case of IGBTs, compared to MOSFETs, their characteristics are best demonstrated at high voltages of several 10 V. Therefore, it is safer to select bias characteristics for the isolated gate drivers that match the voltage range and application as much as possible.

5. Modularization and Future Trends

IGBTs are characterized by their tendency to operate at high voltages and to break down instantly when their maximum ratings are exceeded. For this reason, IGBT modules, which combine IGBTs with isolated gate drivers ICs and protection circuits, are easier to use than IGBTs alone (discrete) and are now widely accepted in the market.

Future trends in isolated gate drivers technology development will include not only more compact, high-performance, and easy-to-use products but also application-specific ICs such as Class-D amplifiers and motor drive ICs. These isolated gate drivers will be differentiated from the isolated gate drivers for SiC semiconductors and GaN devices mentioned earlier.

What Is a Brush Motor?

A brush motor is a motor with sliding contacts called brushes to conduct current to the rotating shaft. They are characterized by simple and inexpensive construction and easy torque control. However, brushes are worn by rotation and require periodic maintenance. The disadvantage of brush motors is that they are noisy when driven.

Although wound AC motors and other types of motors also use brushes, the term “brush motor” generally refers to DC brush motor.

Uses of Brush Motors

Brush motors are used in a wide range of applications, from consumer products to industrial applications. Typical examples are as follows

• Small office fans and PC cooling fans
• Industrial equipment such as boiler exhaust fans
• Running motors for commuter trains
• Elevator lifting motors

Because they are inexpensive among DC motors, they are used in cooling fans for DC office equipment. They have also long been used in moving equipment such as trains and elevators because of their easy torque and rotation speed control.

In recent years, inverter control, which requires no brushes and is easy to maintain, has become the mainstream for torque control in mobile equipment. Brushless motors are also becoming popular.

Principle of Brush Motors

Brush motors consist of a rotor, stator, and commutator. The stator may use a coil or a permanent magnet.  

The stator generates a magnetic field at all times, and the current flowing in the coil wound around the rotor, and the stator’s magnetic field generates electromagnetic force to rotate the motor. It is important that the brushes are in contact with the commutator and that the direction of the coil current is in one direction.

Torque and speed can be controlled by changing the magnitude of the current.

Other Information on Brush Motors

1. Brush Motors Life

The brush life of brush motors is generally several hundred to several thousand hours. On the other hand, the life of the brush motors itself is determined by the life of the bearings and is generally tens of thousands to hundreds of thousands of hours.

Brush motors rotate by switching between repelling and attracting forces between the stator and rotor. For the rotor to rotate, the polarity of the magnetic force must be switched according to the angle of rotation, and the commutator plays this role.

While the drive is simple and easy to use by simply applying DC voltage, the brushes are mechanical contacts that wear out due to rotation, so if the brushes cannot be replaced, the life of the motor depends on the life of the brushes.

2. Difference from Brushless Motors

Brush motors are also called DC motors because they can be easily driven by a DC power supply. Brushless motors, on the other hand, are also called permanent magnet synchronous motors. Brush motors are easier to drive and less expensive than brushless motors, making them suitable for a wide range of applications.

Brush motors are used in many applications, but their short life span due to brush wear is a drawback. Brush replacement is necessary for long-term use. Brush motors can be controlled not only by DC voltage but also by PWM pulses.

Brushless motors, on the other hand, eliminate the commutator and brushes and use permanent magnets in the rotor. The absence of brushes gives brushless motors a longer life, and bearing life is the life of a brushless motor.

The brushless motor drive is classified into “square wave drive” (a method of driving with square wave voltage) and “sine wave drive” (driving with sine wave voltage). While square wave drive has a relatively simple drive circuit, it generates noise and vibration during rotation. Sine wave drive, on the other hand, has a more complex drive circuit but features lower noise and vibration during rotation.

What Is a Slide Potentiometer?

A slide potentiometer is a type of variable resistor with a knob that slides horizontally to move the contactor.

It is one of the variable resistors whose resistance value is changed by physically moving the contactor. Variable resistors also include rotary types called rotary volumes and potentiometers. The main difference is that the slide potentiometer moves horizontally in one direction, whereas these move the contactor in the rotational direction.

Slide potentiometers can also be structurally designed to handle more power than rotary ones.

Uses of Slide Potentiometers

Typical applications for slide potentiometers include audio mixers and graphic equalizers in PA (public address) equipment, and dimmers to control room lighting. Whether a slide potentiometer or a rotary type, the function as a variable resistor is the same, but the appearance and the user’s sense of operation are very different.

Therefore, they are selected according to the usage and outfit (design) envisioned when developing devices and products. In particular, by adding a memory next to the slide pick, the amount of setting can be visually grasped, so it is often utilized for applications such as adjusting volume or light intensity.

Principle of Slide Potentiometers

When the position of the slide potentiometer pick is moved, the resistance value between the terminal connected to one end of the resistive element and the terminal connected to the conductor connected by the contactor changes according to the distance from the end of the resistive element to the contactor. This allows the resistance value to be changed according to the position of the plucking.

Structure of Slide Potentiometers

A slide potentiometer has a resistive element of a certain length, covered by a body case, with terminals at both ends of the resistive element for connection. There is a slit in the body case where a plucking tool can slide, and a plucking tool with a contactor attached is placed there.

In parallel with the resistive element, there is a conductor in the case, and the contactor is in contact with both the resistive element and the conductor. The conductor is also equipped with terminals, and together with the terminals on both ends of the resistor, it has a structure with three terminals.

Other Information on Slide Potentiometers 

1. Characteristics of Slide Potentiometer

A slide potentiometer changes its resistance according to the position of the pick, and the degree of change in resistance relative to that distance can be expressed as one of the three curves shown in ABC. When a voltage is applied to both ends of the resistive element and the position of the contactor is varied, a voltage appears between the terminal on one side of the resistive element and the terminal connected to the conductor connected by the contactor.

• In the Case of Curve A
  The above voltage varies logarithmically with the distance of the pick.
• In the Case of  Curve B
  The above voltage varies proportionally to the distance of the pick.
• In the Case of Curve C
  The above voltage varies inversely logarithmically with the distance of the pick.

Therefore, it is important to decide in advance at the design stage which characteristic to use. 

2. Resistance of Slide Potentiometer

Among slide potentiometers, those used for small signals often have carbon or metal film resistive elements and are not suitable for high power applications. Rotating resistors, in particular, are structurally disadvantageous for using large resistive elements because the length of the resistive element is limited by its diameter.

Slide potentiometers, however, are less restricted in terms of resistive element length. Some product groups use enameled resistors for resistive elements or wire-wound resistors with resistive wires wound on rods, and these are available in power ratings from tens to hundreds of watts.

What Is a Laser Marker?

A laser marker is a device that marks or processes objects by irradiating them with a laser beam. This technology allows for high-precision printing and produces marks that are more resistant to fading than those made by inkjet printers and other printing methods. Laser markers can print on a variety of materials, including metals, resins, glass, and wood.

Uses of Laser Markers

Laser markers are employed across various industries, such as automotive, food, and semiconductor fields, for tasks like:

• Printing 2D codes for tracking the manufacturing history of automotive parts
• Applying lot numbers on electronic components
• Marking serial numbers and expiration dates on beverage cans
• Microfabrication of metal parts

With their capability for precision processing, laser markers are increasingly preferred over traditional engraving methods like drilling.

Principle of Laser Markers

Laser markers operate primarily through two methods: masking and scanning.

Masking Laser Marker

This method involves irradiating a laser beam through a patterned mask to print. While it allows for detailed marking, it requires a unique mask for each pattern, making it time-consuming and costly.

Scanning Laser Marker

Here, a laser beam is scanned over the material according to the desired pattern using a galvanometer mirror. This technique allows for precise control and is adaptable for curved surfaces. The scanning method is widely used due to its efficiency and flexibility.

Types of Laser Markers

The choice of laser for a marker depends on the material and the specific processing requirements. Common types include:

YAG Laser

Utilizing YAG crystal, these lasers are versatile, suitable for marking on aluminum cans and plastic surfaces without damaging the materials.

Fiber Lasers

Fiber lasers, using optical fiber as the medium, provide high output power for deep marking into metals.

CO2 Laser

CO2 lasers, ideal for processing transparent materials, are commonly used for marking and processing glass.

Other Information on Laser Markers

Laser Markers for Home Use

Home-use laser markers are available for personal projects, like engraving names on wood or resin plates, and include safety covers to prevent dust scattering and accidental laser exposure.

Handheld Laser Markers

Compact laser markers, similar in size to a digital camera, offer portability for on-the-go marking, though they require a stable platform like a tripod for precise work.

Price of Laser Markers

Prices range widely from affordable options for hobbyists, costing about 50,000 yen, to industrial models priced between 1,000,000 yen and 5,000,000 yen, with high-power versions for metal processing reaching around 10,000,000 yen.

What Are Check Terminals?

Check terminals are terminal components processed to facilitate temporary wiring connections.

They are used for checking the operation of electronic components in circuit design or to check electrical characteristics in manufacturing processes. Probe-type terminals are commonly used for measuring instruments, such as oscilloscopes.

Since it is difficult to always hold a probe in one’s hand while conducting inspections, measurements are made by connecting it to a check terminal. Check terminals are also available in many shapes that are easy to apply probes to, reducing errors caused by human restraint.

They are sometimes referred to as checker chips or test terminals. In recent years, many RoHS-compliant products have also been sold.

Uses of Check Terminals

Check terminals are used to check board operation and electrical characteristics. The following is an example of where check terminals are used.

• Mounting on evaluation boards
• Signal extraction from logic circuits

Check terminals are used as a mounting base for direct connection to the board and are often mounted on the finished product.

Principle of Check Terminals

Check terminals are components that are placed in a circuit to expand the conduction area and facilitate measurement. Stainless steel or brass is used as the material, and the outside is plated with gold or brass over nickel. Operating temperatures range from -40°C to 150°C.

In many cases, colored beads are attached so that the color of the beads can be distinguished. The beads are made of glass or resin.

Types of Check Terminals

There is a wide range of types of check terminals, depending on the application. Shapes include the type that the probe is pressed against, the type that is hooked onto a loop, and the type that is fastened with an alligator clip.

Check terminals for logic circuits, which are suitable for logic circuits, can be attached to through-hole lands for top and bottom continuity. Check terminals for panels and signal checks are also available.

How to Select Check Terminals

Check terminals are sold by manufacturers specializing in peripheral accessories required when checking board operation, such as Mac-Eight. Check terminals are available for board mounting or surface mounting, and it is important to select the right one for your application.

Also, since there is a wide lineup of sizes and shapes, check terminals are selected according to the board space and the shape of the probe. Products that are not plated on the inside can be used for flow soldering, and the color of the beads can be differentiated for each signal line.

Other Information on Check Terminals

1. Check Terminal Blocks

Check Terminal Blocks are products with check terminals on the board as terminal blocks. Common parts, such as ground terminals and power supply terminals, are replaced with short bars, thus saving space and cost.

If check terminal blocks are not used, it takes time and effort to arrange multiple check terminals in a row, etc. Multiple tester terminals and alligator clips must also be used. By using check terminal blocks, work during inspections such as continuity and withstand voltage tests can be reduced.

Time can also be saved by using check terminal blocks during breakdowns and maintenance. It drastically reduces labour-hours spent on fabrication of electrical inspection jigs and inspection work.

2. How to Use a Check Terminal

Use a check terminal at the point where you want to check the voltage, etc., with a tester or oscilloscope. The check terminal should be soldered directly to the circuit, and a probe can be used to measure the voltage directly.

Generally, the check terminals are installed in the shortest distance from the point where you want to measure and in a position where they will not be affected by other circuits. Decide on the location of the check terminal at the time of circuit design. It is a good idea to avoid placing tall electronic components around check terminals, taking into account that probes may be applied to them.

Incorrect selection or placement of check terminals may have adverse effects such as increased wiring capacitance and influence of wiring impedance due to increased wiring length and wiring area. Reflected noise due to unnecessary radiation noise, etc., can result in erroneous measurements due to so-called wiring impedance matching or unbalanced shielding lines.

What Is an Arbitrary Waveform Generator?

An arbitrary waveform generator is a signal generator that can generate signals with arbitrary frequencies and waveforms.

Function generators of the past could only output signals with a fixed pattern.

In contrast, waveform generators have increased functionality and are characterized by the ability to generate arbitrary signals that can be set by the user, even when complex waveforms are required. The most common method of generating arbitrary waveforms is to store digital waveforms in semiconductor memory and output them by D/A conversion.

Uses of Waveform Generators

Waveform generators are often used in the development and testing of electronic equipment. Systems and individual components are repeatedly tested using waveform generators for design, testing, and manufacturing.

For example, they are used in wireless communication applications involving intermediate frequency (IF) and radio frequency (RF) signals, as well as testing in physics fields such as quantum computing and spintronics.

Some waveform generators can generate waveforms at high speed, while others allow the user to freely define and output sequence, modulated, or pulse waveforms.

Principle of Waveform Generators

The most mainstream waveform generator used in the past was called a function generator (FG). In addition to sine and pulse waves, these waveform generators can also generate triangle, ramp, and noise waves. Although function generators can also generate simple arbitrary waveforms, they cannot sufficiently generate complex waveforms.

Waveform generators generally consist of a large waveform memory, a clock signal source, and a D/A converter. This allows the sample frequency in the clock signal source to be set arbitrarily so that all waveform data recorded in the waveform scale can be output without interruption.

Specifically, by replacing the waveform ROM portion with rewritable RAM in the digital direct synthesizer DDS method oscillator, the user can freely write waveforms. The DDS method consists of an accumulator with an adder and a latch, and accumulates the frequency setting value N in synchronization with the clock to obtain digital data in the form of sawtooth waveforms.

Other Information on Waveform Generators

1. Functions of Waveform Generators

Arbitrary waveforms include sine, square, triangular, and sawtooth waveforms, as well as waveforms with a time component such as continuous, single-shot, and intermittent waves.

Frequency is not only constant, but also has a function called sweep, which continuously changes the frequency. In addition, the amplitude can be generated arbitrarily from 10 mVp-p to 30 Vp-p.

2. How to Use Waveform Generators

Waveform generators have multiple output terminals, which are BNC terminals, making them resistant to noise and minimizing signal transmission loss.

The output impedance is 50 Ω, so care must be taken to attenuate the signal if the input impedance of the circuit to which it is connected is low. Each output terminal can output waveforms as desired.

They are also used for driving signals for various test equipment, such as changing the rotation speed of a motor or arbitrarily changing the vibration frequency of a vibration tester.

3. Waveform Generators With USB Connections

Recently, an increasing number of arbitrary waveform generators have USB ports. Waveform generators can be controlled via USB by setting arbitrary waveforms with a PC application.

USB is also used as a communication port for ON/OFF or frequency sweep by an automatic control program. Extensive control is possible, such as switching between sine, square, sawtooth, and burst waveforms, changing amplitude and duty, and frequency sweeping.

What Is a Drop Tester?

A drop tester is a device that allows a test object to be dropped spontaneously while repeatedly maintaining a specified height and other conditions in order to determine the impact and effects of dropping the object.

In particular, easily portable and compact smartphones and mobile devices require countermeasures against the impact caused by drops in their operating environment. In order to improve the shock resistance of equipment due to drops, which are relatively easy to occur in the operating environment, it is very important to conduct highly reproducible drop tests.

Drop testers are also used to test the impact resistance of heavy cargo and packaging materials.

Uses of Drop Testers

Drop testers are used in the development of a wide variety of products. The main application is for industrial products. Drop tests are conducted under two main conditions: one assuming the logistics process and the other assuming the product’s usage environment.

1. Drop Test Assuming Logistics Process

Drop tests are mainly used for the development of products that are to be placed in a specific location. Examples are large home appliances such as televisions and refrigerators. These products are very unlikely to be dropped in our daily lives.

Large home appliances may accidentally fall during shipping, distribution, and transfer to stores or purchaser’s installation location. 

2. Drop Test Assuming the Product’s Usage Environment

Products that may be dropped depending on the environment in which they are used include mobile devices. Small electronic devices such as smartphones and digital cameras are carried around and used, so it is not uncommon for them to experience drops. Drop test are used to verify the durability and reliability of products subjected to such drops.

Principle of Drop Tester

The principle of drop tester can be divided into the following types: Holding-Fall Type, Rotating Drum Type, Rotating Arm Type, and Electromagnetic Hook Type.

1. Holding-Fall Type

The holding-fall type has a simple structure. The object is clamped and secured horizontally using a pneumatic pen cylinder. When the object is dropped naturally from a set height, the cylinder separates from the object in the middle of the fall, allowing only the object to fall. This method is effective when you want to drop the object at the same angle.

2. Rotating Drum Type

In the rotating drum type, the object is placed in the drum and the drum rotates at a constant speed. The object can be repeatedly dropped in the drum at random.

3. Rotating Arm Type

The rotating arm type has a drop test mechanism using an air-driven cylinder and a spring. After the table on which the object is placed is moved at high speed by the air cylinder, the table is rotated by the tension of a strong spring and the object is dropped vertically in a natural manner.

4. Electromagnetic Hook Type

The electromagnetic hook type is a device in which cargo suspended by electromagnetic hooks falls naturally when the hooks are released.

In either case, the height at which the cargo is dropped can be set freely. In addition, the drop operation can be set either by remote control or by a control panel. In addition, some of them are equipped with a high-speed camera and can analyze the state of falling.

Other Information on Drop Testers

Drop Test Applications

In drop impact testing, tests are conducted assuming a situation in which a fall actually occurs. If the product to be used is a medium or large-sized household appliance, it is assumed to be used in a stationary position, but for a cell phone, it is desirable to test for a drop from a position half the height of the user.

If the product is expected to be used in a stationary position, a drop test from the height of a truck when loading cargo is conducted to examine the possibility of dropping the product during the distribution process. In addition, the test should not be limited to simple height, but should also include loading by hand, using a forklift, or using a crane to hang the truck if the load is too heavy to be loaded under special conditions.

For example, it is necessary to drop the load while turning. For example, a cell phone can be assumed to be accelerated, not just dropped, so an impact test is also conducted to physically apply velocity to the object.

What Is a Probe Card?

A probe card is an instrument required for wafer-level inspection in the semiconductor manufacturing process.

They are used by attaching them to wafer inspection equipment. Most of the cost of semiconductors is determined by the manufacturing equipment, but the cost of the package itself and packaging also has a large impact during the manufacturing stage. Therefore, it is possible to reduce costs by determining whether a product is good or bad at the wafer level after the semiconductor manufacturing process is complete, and sending only the good products to subsequent processes.

A wafer consists of several hundred to several thousand chips on a single wafer, and wafer inspection is the process of sorting these chips by determining whether they are good or bad before cutting them into individual pieces and packaging them.

Use of Probe Cards

Wafer inspection consists of an LSI tester that inputs electrical signals called test patterns to a chip and determines the output signal pattern by comparing it with expected values, a wafer prober that performs chip-level positioning control to connect signals accurately to the electrode terminals of each chip, and a probe card that performs positioning control to hit hundreds to tens of thousands of electrode terminals accurately, within a chip. Probe Cards with an equal number of needles (probes) positioned to precisely hit the hundreds of thousands of electrode terminals on the chip are used.

Probe cards must be made specifically for each chip design, which is costly in itself and requires re-creation due to wear from use, but is essential to overall manufacturing costs. Semiconductor chips are used in countless products, not only in computers, but in almost every product in our lives, and probe cards are one of the supports of these products.

Probe Card Principle

A probe card is mounted on the wafer prober and acts as a connector between the electrode terminals of the chip and the LSI tester through the wafer prober.

The LSI test head has spilling contact pins and high-density pins mounted for connection, but the placement pitch of the electrode terminals of a semiconductor chip is narrower than the pin placement density of the test head, at several tens of microns, so it is necessary to connect the two through the probe card.

Probe Card Structure

The upper side of the probe card has the connection pins to the test head, and the lower side has the needles to connect with the electrode pins of the semiconductor chip.

By connecting the test head and the probe card’s connection terminal, and then connecting the semiconductor chip’s electrode terminal and the probe card’s needle, an electrical connection is formed, and each semiconductor chip on the silicon wafer is tested by judging whether it is good or bad based on electrical signals from the LSI tester.

Probe cards are available in advanced and cantilever types. In the advanced type, a block with vertical terminals is attached to the board, and the probes can be freely arranged for easy maintenance. In the cantilever type, probes are directly attached to the board without any blocks, which makes it easy to accommodate narrow-pitch terminals.

Other Information on Probe Cards

Probe cards are often made of ceramic substrates, due to the fine and high level of reliability required in wafer inspection. For example, Kyocera uses thin-film single-layer and thin-film multilayer ceramic substrates with metallization for probe cards for DRAM, flash memory, and logic devices.

Generally, spring connectors or high-density connectors are used for the signal connections of large-scale integrated semiconductor circuits called LSIs or system LSIs. Probe cards also serve as an intermediary between the test head and the wafer to be inspected, and since they are required to have a high level of connection reliability and electrical inspection performance functions, their mechanisms and materials are delicate. Materials, such as ceramics are used.

However, the durability of probe cards is limited, and even the slightest distortion due to physical shock will prevent them from fulfilling their intended use. They are also consumable parts that are difficult to repair and must be replaced on a regular basis.

What Is a Programmable Controller?

A programmable controller is a control device with a built-in microprocessor.

Normally, inputs from sensors and switches in equipment are output to motors, displays, and other devices via mechanical relays, timers, and other control mechanisms. In contrast, a programmable controller controls the operation of a device using an internal program, without the need for mechanical relays or other control mechanisms.

Since there are fewer mechanical contacts, the device can be controlled without contact wear and defects between electronic components, cumbersome input/output devices, and wiring between mechanical relays for control. In addition, electrical wiring can be simplified, facilitating downsizing and mass production of devices.

Figure 1 shows a simple example of a control panel that uses mechanical relays, timers, etc. to control lamps.

Uses of Programmable Controllers

Programmable controllers are used in a wide range of fields, including factory automation systems, automobiles, home appliances, and industrial equipment. They are mainly used in industrial and commercial equipment.

Examples of commercial applications include their use in large washers and dryers with sequence control because they are cheaper and more robust than using a PC. Another factor is that they usually do not require cooling systems because there is no graphics board and the microprocessor generates little heat.

Programmable controllers can be either all-in-one, in which all the electronic components necessary for operation are built in, or modular, in which you select each functional component yourself.

It is important to select the memory, processor, and output/input terminal specifications according to the electronic device to be used.

Principle of Programmable Controller

A programmable controller consists of an input module, an output module, a processor, and memory. The input module is connected to sensors and switches. The processor processes that input data based on the internal program stored in the memory and outputs it to motors, displays, communication devices, etc.

If you wish to change the operation of an electronic device equipment controlled by the programmable controller, you do not need to make any changes to the wiring or other components. You only need to change the program code, which saves time and labor costs.

Programs used in programmable controllers include the ladder method, SFC method, flowchart method, and stepladder method, with the ladder method being the most common. In the ladder method, programs are written on a PC by connecting symbols such as relays, switches, and timers between two parallel lines like a ladder.

This method is easy to learn because the program code can be created using a graphical user interface.

Other Information on Programmable Controllers

1. The Difference Between a Programmable Controller and a Sequencer

If you work in production, you may have heard the term “sequencer.” As it turns out, there is no difference between a programmable controller and a sequencer.

Sequencer refers to the trade name of Mitsubishi Electric’s programmable controller. It was marketed under the name Sequencer as a mechanical device that enabled sequence control and remains in use today as another name for programmable controllers.

2. Connection Between Programmable Controllers and PCs

Generally, a PC is used to store a program in a programmable controller. Each company that sells controllers sells PC software for editing the programs stored on them.

Serial signals have long been used for connection to PCs. In the past, many PCs had serial ports permanently installed, but these days serial ports are rare.

Also, serial signals required matching COM ports or installing special drivers. In recent years, sequence editing is often performed using USB ports, which do not require COM port matching and are familiar to general users.

It is also now possible to edit multiple controllers from an Ethernet port when available.