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Miniature Sensors With Monumental Capabilities

The requirement for miniature optical sensors to meet the demands of medical and semiconductor automation equipment often exceeds the capabilities of standard self-contained optical sensors. In some cases, other industry application requirements can be best solved by these same miniature optical sensors with advanced capabilities. So, what do these optical sensors offer that makes them so much better?

Applications

Let’s begin with some of the applications that require these capabilities: medical applications, such as lab-on-a-chip microfluidics, liquid presence or level in drip chambers or pipettes, turbidity, drop detection, and micro or macro bubble detection, to name a few. Semicon applications include wafer presence on end-effectors, wafer mapping, wafer centering, and wafer presence in transfer chambers. Other applications that benefit from these sensors include packaging pharmaceuticals, detecting extremely small parts, and spray detection. In addition, these sensors are frequently used in customer-specific designs because they can be customized for specific applications.

These sensors require an amplifier which sometimes is not popular with design engineers. They are associated with additional cost and extra work during installation; however, the remote amplifier offers real advantages. The optical function is separate from the control unit which allows it to be incorporated into an extremely tiny sensor head. Since the LEDs are mounted in the sensor heads, we now have a small wired connection back to the amplifier. Unlike fiber optics, this wired connection to the emitting LED and receiver allows for very minimal or no bending radius because of the cable in use.

Features

The new generation of amplifiers offers tremendous flexibility with advanced features, including:

- OLED display
- Intuitive menu structure
- LEDs for status, communication, and warnings
- Teaching/Parametrization
- Single-point, two-point, window, dynamic, and tracking operating modes
- Multiple teach modes: direct, dynamic, external, automatic and I/O-Link
- Selectable power modes
- Selectable outputs
- Selectable speed settings
- Auto-sync up to 8 amplifiers
- Configurable delays and hysteresis
- Compatible with existing all sensor heads

The sensor heads or optical heads come in a wide variety of housings, including the ability to customize them to meet specific requirements. And they are available in small precision LEDs, photodiodes, phototransistors, and complete laser modules according to a patented manufacturing process. Due to the high optical quality, additional lenses or apertures are no longer necessary.

A multitude of special characteristics completely differentiates these sensors from the products made by standard optical sensor manufacturers. The range of products includes extraordinary miniature optical sensors as standard products, optimally adapted customized solutions, and precision optoelectronic components, such as LEDs, photodiodes, and laser modules. High optical quality, and unique modular designs, in connection with the greatest possible manufacturing flexibility, guarantee solutions that are exactly adapted to the respective problems and needs of the users.

The 5 Most Common Types of Fixed Industrial Robots

The International Federation of Robotics (IFR) defines five types of fixed industrial robots: Cartesian/Gantry, SCARA, Articulated, Parallel/Delta and Cylindrical (mobile robots are not included in the “fixed” robot category). These types are generally classified by their mechanical structure, which dictates the ways they can move.

Based on the current market situation and trends, we have modified this list by removing Cylindrical robots and adding Power & Force Limited Collaborative robots. Cylindrical robots have a small, declining share of the market and some industry analysts predict that they will be completely replaced by SCARA robots, which can cover similar applications at higher speed and performance. On the other hand, use of collaborative robots has grown rapidly since their first commercial sale by Universal Robots in 2008. This is why collaborative robots are on our list and cylindrical/spherical robots are not.

Therefore, our list of the top five industrial robot types includes:

- Articulated
- Cartesian/Gantry
- Parallel/Delta
- SCARA
- Power & Force Limited Collaborative robots

These five common types of robots have emerged to address different applications, though there is now some overlap in the applications they serve. And range of industries where they are used is now very wide. The IFR’s 2021 report ranks electronics/electrical, automotive, metal & machinery, plastic and chemical products and food as the industries most commonly using fixed industrial robots. And the top applications identified in the report are material/parts handling and machine loading/unloading, welding, assembling, cleanrooms, dispensing/painting and processing/machining.

Articulated robots

Articulated robots most closely resemble a human arm and have multiple rotary joints–the most common versions have six axes. These can be large, powerful robots, capable of moving heavy loads precisely at moderate speeds. Smaller versions are available for precise movement of lighter loads. These robots have the largest market share (≈60%) and are growing between 5–10% per year.

Articulated robots are used across many industries and applications. Automotive has the biggest user base, but they are also used in other industries such as packaging, metalworking, plastics and electronics. Applications include material & parts handling (including machine loading & unloading, picking & placing and palletizing), assembling (ranging from small to large parts), welding, painting, and processing (machining, grinding, polishing).

SCARA robots

A SCARA robot is a “Selective Compliance Assembly Robot Arm,” also known as a “Selective Compliance Articulated Robot Arm.” They are compliant in the X-Y direction but rigid in the Z direction. These robots are fairly common, with around 15% market share and a 5-10% per year growth rate.

SCARA robots are most often applied in the Life Sciences, Semiconductor and Electronics industries. They are used in applications requiring high speed and high accuracy such as assembling, handling or picking & placing of lightweight parts, but also in 3D printing and dispensing.

Cartesian/Gantry robots

Cartesian robots, also known as gantry or linear robots, move along multiple linear axes. Since these axes are very rigid, they can precisely move heavy payloads, though this also means they require a lot of space. They have about 15% market share and a 5-10% per year growth rate.

Cartesian robots are often used in handling, loading/unloading, sorting & storing and picking & placing applications, but also in welding, assembling and machining. Industries using these robots include automotive, packaging, food & beverage, aerospace, heavy engineering and semiconductor.

Delta/Parallel robots

Delta robots (also known as parallel robots) are lightweight, high-speed robots, usually for fast handling of small and lightweight products or parts. They have a unique configuration with three or four lightweight arms arranged in parallelograms. These robots have 5% market share and a 3–5% growth rate.

They are often used in food or small part handling and/or packaging. Typical applications are assembling, picking & placing and packaging. Industries include food & beverage, cosmetics, packaging, electronics/ semiconductor, consumer goods, pharmaceutical and medical.

Power & Force Limiting Collaborative robots

We add the term “Power & Force Limiting” to our Collaborative robot category because the standards actually define four collaborative robot application modes, and we want to focus on this, the most well-known mode. Click here to read a blog on the different collaborative modes. Power & Force Limiting robots include models from Universal Robots, the FANUC CR green robots and the YuMi from ABB. Collaborative robots have become popular due to their ease of use, flexibility and “built-in” safety and ability to be used in close proximity to humans. They are most often an articulated robot with special features to limit power and force exerted by the axes to allow close, safe operation near humans or other machines. Larger, faster and stronger robots can also be used in collaborative applications with the addition of safety sensors and special programming.

Power & Force Limiting Collaborative robots have about 5% market share and sales are growing rapidly at 20%+ per year. They are a big success with small and mid-size enterprises, but also with more traditional robot users in a very broad range of industries including automotive and electronics. Typical applications include machine loading/unloading, assembling, handling, dispensing, picking & placing, palletizing, and welding.

Summary

The robot market is one of the most rapidly growing segments of the industrial automation industry. The need for more automation and robots is driven by factors such as supply chain issues, changing workforce, cost pressures, digitalization and mass customization (highly flexible manufacturing). A broad range of robot types, capabilities and price points have emerged to address these factors and satisfy the needs of applications and industries ranging from automotive to food & beverage to life sciences.

Note: Market share and growth rate estimates in this blog are based on public data published by the International Federation of Robotics, Loup Ventures, NIST and Interact Analysis.

Size Matters When Selecting Sensors for Semiconductor Equipment

As an industry account manager focusing on the semiconductor industry, I’ve come to realize that when it comes to sensors used in semiconductor production equipment, size definitely matters. A semiconductor manufacturing facility, better known as a fab or foundry, can cost thousands of dollars per square foot to construct, not to mention the cost to maintain the facility. Therefore, manufacturers of equipment used to produce semiconductors are under pressure to reduce the footprint of their machines. As the equipment becomes more compact, it becomes more difficult to incorporate optical sensors that are needed for precise object detection.

A self-contained optical sensor that includes the optics along with the required electronics is often much too large. There simply isn’t enough space for mounting in the area where the object is to be detected. An alternative method is to use a remote amplifier containing the electronics with a fiber optic cable leading to the point of detection where the light beam is focused on the target. However, there are some drawbacks to this method that can be difficult to overcome. There are instances where the fiber optic cable is too large and not flexible enough to be routed through the equipment. Also, a tighter beam pattern is often required in semiconductor equipment for precise positioning. To provide a tighter beam pattern with fiber optics, it is necessary to add additional lenses. These lenses increase the size, complexity and cost of the sensor.

The most effective way to overcome the limitations of fiber optic sensors is to use very small sensor heads connected to a remote amplifier by electric cables, as opposed to fiber optic cables. The photoelectric sensor heads are exceptionally small, and because the cables are extremely flexible they can easily accommodate tight bends. Therefore, these micro-optic photoelectric sensors are particularly well suited for use in semiconductor equipment. The extremely small beam angles and sharply defined light spots are ideal for the precise positioning required for producing semiconductors. No supplementary lensing is required.

An excellent example of how this micro-optic sensor technology is utilized in semiconductor equipment is for precision wafer detection needed for automated wafer handling. At the end of a robot arm used for wafer handling there is a very thin end-effector known as a blade. By utilizing a very tightly controlled and focused light spot, the sensor can detect wafers just a few μm thick with extreme precision.

The combination of extremely small optical sensor heads with an external processor unit (amplifier) connected via highly flexible cables is a configuration that is ideal for use in semiconductor production equipment.

Precision Pneumatic Cylinder Sensing

When referring to pneumatic cylinders, we are seeing a need for reduced cylinder and sensor sizes. This is becoming a requirement in many medical, semiconductor, packaging, and machine tool applications due to space constraints and where low mass is needed throughout the assembly process.

These miniature cylinder applications are typically implemented into light-to-medium duty applications with lower air pressures with the main focus being precision sensing with maximum repeatability. For example, in many semiconductor applications, the details
and tolerances are much tighter and more controlled than say, a muffler manufacturer that uses much more robust equipment with slower cycle times. In some cases, manufacturing facilities will have several smaller sub-assemblies that feed into the main assembly line. These sub-assemblies can have several miniature pneumatic cylinders as part of the process. Another key advantage miniature cylinders offer is quieter operation due to lower air pressures, making the work place much safer for the machine operators and maintenance technicians. With projected growth in medical and semiconductor markets, there will certainly be a major need for miniature assembly processes including cylinders, solenoids, and actuators used with miniature sensors.

One commonality with miniature cylinders is they require the reliable wear-free position detection available from magnetic field sensors. These sensors are miniature in size, however offer the same reliable technology as the full-size sensors commonly used in larger assemblies. Miniature magnetic field sensors play a key role as speed, precision, and weight all come into play. The sensors are integrated into these small assemblies with the same importance as the cylinder itself. Highly accurate switching points with high precision and high repeatability are mandatory requirements for such assembly processes.

To learn more about miniature magnetic field sensors visit www.balluff.com.

Sensor Technology Drivers in Semiconductor Manufacturing

As in many industries, the degree of automation in semiconductor manufacturing is increasing. The reasons for this are the same as in any industry striving to automate: increase throughput, reduce labor, and improve quality.

However, semiconductor manufacturing presents some unique technical challenges that differentiate it from conventional manufacturing in other industries. Some of the factors driving sensor technology in automated semiconductor manufacturing include:

Small size. The clean room environment, necessary for semiconductor processing, is very expensive per square foot. There is constant pressure to reduce the size of the machines, and the sensors that go into them.
- In fact, the high cost of clean room space is another motivator for reducing the role of humans in the process. Not only do humans take up a lot of physical space, they represent about 75% of the particle contaminant sources in the clean room.

Advanced Process Control (APC). APC is a method for shortening the time frame between collection of SPC (Statistical Process Control) data and the application of process corrections. This means that rather than time-consuming external metrology, there is a drive for so-called “in-situ” metrology. There is a need to measure process variables in real-time or near-real time in order to close the APC loop in a shorter time frame.

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Industrial Sensing Fundamentals – Back to the Basics: NPN vs PNP

What’s the difference and why should anyone care? If you’re confused by the terms PNP and NPN, then hopefully this post will shed some light on the differences between the two. In the context of this post, they refer to the construction of a sensor’s transistor and whether it has a p-type or n-type semiconductor.

When it comes to wiring a sensor, you can think of the “N” as standing for “Negative” and the “P” as standing for “Positive”. With respect to sensors, an NPN device is one that can switch the negative side of the circuit while a PNP device switches the positive side.