Industrial Automation: The Machine Parts Behind the Motion
Are you looking for guidance on machine parts used in manufacturing automation? Automation technology is fascinating to watch but perplexing to ponder. If you work in a manufacturing environment, you may be required to know what creates those mesmerizing automated movements in a well-running machine. Without a background in the principles behind mechanical, electrical, and electronic power distribution, it is hard to envision how machine parts work together to move work along without human intervention.
An example of fun-to-watch flexible automation, this automated machine is capable of producing intricate work over and over again:
Workers in manufacturing environments wear many hats these days. Your duties are broad and varied. With automation installations increasing and artificial intelligence (AI) gaining a foothold, the manufacturing floor is becoming much more complex. While you may not be responsible for automated machine maintenance, you may need knowledge of machine parts for a variety of reasons.
Depending on the type of manufacturing and the size of the business, automation technology questions may spill over onto floor managers and purchasing agents. For business owners and finance managers, it is imperative to understand the advantages of newer automation control technologies. There can be no future vision or plans of action without an understanding of technology and how it impacts competitive advantages.
The principles behind automation are not hard to grasp. Learning the fundamentals behind automation technology is a benefit for all living in this age of connectivity.
This fundamental overview is for those who need to improve their aptitude regarding automated machine components. By dividing the machine into categories, you will gain a basic understanding of how components work individually and together in systems. Luckily, even unique machines share similar components. Understanding components and how they work within the machine system will make forecasting, purchasing, maintenance, parts orders, troubleshooting, and repairs easier, faster, and more productive.
Table of Contents:
Introduction to Automated Machine Parts
Structural Machine Parts
Fluid Power Components
Industrial Safety Products
Connector Cables and Wire Harnesses
Introduction to Automated Machine Parts
Welcome to Industrial Automation: The Machine Parts Behind the Motion. You're about to get a basic overview of automation technology on the component level through the lens of simple science concepts.
What is automation?Automated machines are designed to complete specific work tasks without human intervention. This is accomplished by utilizing energy, power, and force to influence and control movement.
- Energy is the potential to create movement across a distance. In automation, machine designers are concerned with the amount of energy needed to complete work from the front of the process to the back. Machine components are the means to transfer energy throughout the machine to complete work. Some components are tasked with preserving energy through a mechanical advantage, while others convert mechanical, electrical, chemical, and solar energy as needed.
- Power is the rate of energy moved or expended in a specific amount of time.
- Force is a push or pull interaction between objects. Force can be used in machine components to control motion, direction, and shape
- Motion is to be both created and limited in automated machinery. An automated task can’t be completed without components that initiate movement and those that limit or dampen it such as a dampening device.
How is motion controlled?
Inducing and controlling motion is at the core of the automated machine. Controlling machine movement involves individual components and subsystems of components that interact together to move a load and complete work. Typically, motion control is classified as a sub-field of automation.
Key motion control components:
motion controller (drive- or controller-based)
As today’s machines advance with precision servo systems, programmable automation controllers (PACs) and robotics, there are experts that declare all machine components within a system are important to motion control. To achieve optimal performance, all the machine’s components must interact with accuracy and precision to control movement.
Using the above machine as an example, machine design will incorporate components that manage energy, power, force, and motion to move the work from station to station. Motion control is spread throughout the machine.
Machine automation components:
- field level
Today's automation consists of a combination of structural, mechanical, control, field level and communication components. We will take a look at each of these and their corresponding machine parts. Let's start with the most basic concepts and work our way through to the most challenging.
Structural Machine Parts
Structural components are the metaphorical bones of the automated machine. The structure provides the support framework for all the machine’s components. A key function of a machine's structural design is to minimize vibration, so production or tooling precision is maximized. A well-designed machine structure controls vibration by balancing a machine’s stiffness to its load mass. This balance keeps the non-tooling portion of the machine rigid and lightweight.
A machine's structure is designed to enhance productivity, accuracy and eco-efficiency. Structural components achieve this by supporting machine parts and transferring the load to the frame, decreasing unnecessary motion and reducing friction between mechanical parts.
In this video, notice how each machine requires precise movements to complete the machining task. If unacceptable vibration is present, tooling movements would be negatively impacted and structural parts may fail due to uneven loads and shear.
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Additional considerations for frame design include:
- a skeleton for parts mounting
- access to control panel
- safety from moving parts
- easy to clean walls
Watch this video for an example of a machine frame that supports tooling:
Tip — Predictive and preventative maintenance measures include:
- monitoring for unnecessary vibrations
- visual inspection of associated components
- performance testing
- avoiding stress risers when mounting new devices or accessories, such as mounting kits or cable management system components
Reduce fastener failures by:
- ensuring that the fastener quality matches expected performance for form and function
- avoiding over- or under-tightening
Examples of fastening parts:
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Welded joints vs. fasteners:
- A welded joint will be comparatively stronger yet lighter than a fastened joint.
- Creating or repairing a welded joint takes skilled labor or a professional welding service.
Tip — Don’t try to add or stabilize a component, nor make a repair, if you are not familiar with the design of the machine structure or components involved. Call a professional.
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Moving along, we will next look at mechanical machine parts. With mechanical power distribution, mechanical parts may be fastened or welded directly to the frame to reduce instability and take advantage of the additional support.
No matter how complex the automation technology, the fundamentals of one or more simple mechanical designs will be present. In a typical automated machine, working in combination with and within electrical and electronic devices, are mechanical components designed from simple machine concepts.
The Six Simple Machines:
- A lever is a rigid bar that pivots and balances on a fulcrum (joint or hinge). The placement of the fulcrum relative to the ends of the bar will impact the mechanical advantage of the leverage.
- The wheel and axle are closely related to simple levers and to today’s gear systems. With this tool, a larger wheel circumference is locked to a smaller axle circumference, so both rotate together with the fulcrum at the center of the wheel. You have the mechanical advantage plus the ability to complete a full rotation of the axis.
- An inclined plane saves energy by allowing an object to be raised or lowered with less force than physically lifting and lowering. The mechanical advantage is determined by the angle of the incline. This is key when using automation to move items on a conveyor from one level to the next.
- A wedge can separate two surfaces as with a doorstop, split two surfaces as an ax, or connect and secure as with a nail or screw. The mechanical advantage is achieved by the length to the slope of width.
- The pulley is an extension of the wheel and axle. By adding a belt, rope, chain, or cord to a wheel, an object can be moved up, down, back or forth. The mechanical advantage is achieved by adding additional pulleys, known as block and tackle. Additional pulleys and belts increase the amount lifted with no additional physical effort needed.
- The screw is a rotational torque turned into a linear action that adjusts height or depth—picture a screw-on lid or valve (faucet). The mechanical advantage of a screw depends on the circumference of the screw and pitch of the threads. The tighter the pitch between screw threads, the greater the mechanical advantage.
Mechanical machine parts interact together as a complex machine to:
- Control motion
- Transmit power
Here is an example of mechanical parts working in conjunction with a motor to achieve a mechanical power advantage. The motor is spinning one shaft, but the shaft, with the aid of bearings, can transfer power to multiple devices through pulleys and gears.
Two or more bars are linked (with pin joints, sliding joints, or ball and socket joints) with one having a fixed point. When one link moves the other(s) follow relative to the fixed link. The four-bar linkage is most often used in machine construction. Robotic grippers can be designed from linkages, gears, and pins.
The simple definition of a shaft is a stem or pole. Many tools include the shaft, such as a screwdriver. A shaft has a circular cross-section, which may be solid or hollow depending on the application. In a machine, a shaft can be as simple as an extension within a door-coupling handle or a complex rotating component that receives and/or transmits power. In heavy-duty applications, the rotating shaft will be supported by bearings on either end and an oil film lubrication will be applied between the shaft and bearings to further reduce friction.
With a variety of options available, bearings are designed to reduce friction between moving parts and control unwanted motion without disrupting the desired motion. For radial rotation, as in shafts, bearings have a circular cross-section and are sandwiched between a rotating inner ring and a stationary outer ring. Other motions achieved with bearings include a linear motion for drawers, spherical rotation for ball and socket joints, and hinge movements for doors.
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Gear systems transfer motion and power to and between other mechanical machine components. Gear systems vary greatly and are labeled according to shape, tooth design, and axes configurations.
Couplings are devices that connect machinery parts and allow for the free flow of movement from one part to the next. A properly mated coupling will last for years and won't transfer stress or failure issues to mated components. When replacing a coupling it is important to choose the right size. Either over- or under-sizing will create an inefficient design. To determine the correct coupling for the job thoughtful consideration is needed to determine the role of the specific coupling. There are a great many options with different attributes from which to choose including torque transmission, application speed, and alignment.
A conveyor is a mechanical material handling device that transports products with minimal effort between points. The conveyor consists of a frame, support, driving unit, bearings, and a conveying surface that may consist of either a belt, rollers or wheels. Powered by a motor, gravity, or manually, the conveyor’s type, frame, and components can be configured in a variety of shapes and outfitted with components for feedback. Care should be taken in assuring the conveyor surface remains clear of material carryover, so working components remain clear and clean.
This video is a great example of modern-day mechanical and structural components combined with electrical and electronic controls.
Machine motion within an automated system utilizes a variety of electrical means and mediums to provide and aid power transmission. A typical automated machine uses a combination of electrical, electronic, and electromechanical technologies to move a load.
These technologies serve specific roles within the automated machine and are represented by a variety of field devices. Some devices are designed to provide an electrical or electromechanical push while others provide electronic signaling. The differences between the devices lie in the circuits and additional components within.
Electrical devices are designed to channel electricity for energy and power distribution. These devices convert electrical current to light, heat, or motion. If a device is strictly utilizing electricity for energy and power distribution, it is considered electrical.
You will typically find these devices in your machine control cabinet. Alternating current (AC) flows from the building’s main electrical feed into the machine’s panel box. The electrical devices are designed to control the current channeling into the machine via circuits. An electrical circuit is a loop, which conducts the flow of energy to the load and back again.
There are four basics parts to an electrical circuit:
- A power source provides the energy to a load and is comprised of the following—
- Voltage — It provides the push behind electrical charges. It is the pressure that moves the electric charge.
- Current — The push from voltage creates a current of electrons. There would be no current without voltage.
- Resistance — The conductivity of the substrate will impact resistance. The amount of resistance is dependent on the size and composition of the substrate.
- A conductor provides the pathway. Electrical energy is conducted along metal wires such as copper and aluminum.
- A switch controls the circuit by adding a method to toggle between opened or closed, hence on or off.
- A load device is part of the circuit loop. Power flows through the device, activating it.
The highly consistent relationship between voltage, current, and resistance allows for even greater control of circuits and the ability to produce more meaningful outcomes.
Ohm’s Law states [V (Voltage) = I (Current) x R (Resistance)]
We control any one of these variables by controlling the other two. That brings us to electronic components.
Electronic components are the tools used to control these variables and thus the circuit. By adding an active and passive electronic component to a typical electrical circuit, we manipulate electric current to create signals which impart communications between electronic machine devices. Depending on the electronic component, signal amplification, calculation, and data transfer capabilities are harnessed.
Key components of an electronic circuit design:
- Capacitor — A two-terminal component that stores energy in an electric field electrostatically.
- Resistor — A passive two-terminal component that provides electrical resistance within a circuit. Reduces voltage and current.
- Diode — A two terminal device that limits the flow of current to one direction, like a check valve. Once it primarily consisted of a vacuum tube of gas, but now it has almost completely been replaced by semiconductor material and is considered a solid-state component.
- Transistor — A three terminal device that performs two functions. Made of semiconductor material, it acts as a switch or amplifier for electronic signals, controlling the flow of voltage and current. It is considered a solid-state component.
- Transducer — Transducers are devices that convert energy from one form to another. Actuators are one form of transducer. Transducers act as sensor in that they receive and respond, and forward system signals as when used as a thermocouple.
In today’s automation, electronic devices contain duty-specific integrated electronic circuits which form a circuit system. The circuits are dispersed onto semiconductive wafer material and packaged within a chip. Semiconductor materials are not conductors or insulators. The semiconductor lies between the two. This technology is popular because its charge carriers (electrons and holes) are easily manipulated with internal (doping with boron or phosphorus) and external (temperature, light, etc.) factors.
Devices that rely entirely on semiconductor components are considered solid-state. Contemporary transistors and diodes, integrated circuits, light-emitting diodes (LED), and liquid-crystal displays (LCD), are all solid-state components. In the marketplace, two examples of solid-state devices used in automation include relays and sensors. These devices were originally and still are sold in an electromechanical version. Solid-state devices provide the same function as their electromechanical counterpart minus the moving parts.
A device with both a mechanical and an electrical component is considered electromechanical. These devices convert electrical energy into a mechanical movement. Mechanical movement can also be harnessed to create an electrical output exampled by piezoelectric technology.
Electromechanical components are widely used in today’s automation but are endangered due to technologies that offer actuation without moving parts such as solid state. For now, electromechanical-electromagnetic actuating parts are still in demand due to lower price points and other pros. An advantage to using an electromechanical component is its ability to switch higher load currents without the aid of additional parts for circuit cooling. Solid state components often require additional heatsinks to avoid overheating the circuit
Circuit protection devices protect industrial equipment from an excess amount of energy that could cause damage and/or safety issues. This is a critical part of any automated system.
Circuit breakers automatically prevent short circuits as well as dangerous or excess amounts of temperature and current in electrical systems. They interrupt the flow of power to the malfunctioning equipment, which protects components and wiring from damage.
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Disconnect switches provide maximum safety for personnel by ensuring that a circuit is completely de-energized for service.
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Electrical control is required for all motors, from simple on/off to complex variable speed applications.
Line reactors are electromagnetic devices used as inductors to protect variable frequency drives (VFDs) and other devices from electrical disturbances such as voltage spikes, surges and transients. Line reactors can limit your current flow and harmful harmonics from the drive.
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Variable Frequency Drives (VFD)
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Power components provide stable, safe and efficient power services for your electrical devices.
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Power Supply Units
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A relay is a electrical or electronic switch that opens and closes circuits. Circuits are controlled by opening and closing contacts in a different circuit. Relays are typically used to switch smaller currents and are not used with power consuming devices.
Electromechanical Vs. Solid State Relays (SSRs)
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Time Delay Relays
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A sensor switch is a device that converts a physical value (input) to an electrical signal (output). The active element in a sensor is the transducer. Sensors are a vital part of automation. A control system depends on sensors for raw data to open and close a circuit.
Sensors are chosen based on environmental and economic factors and the characteristics of the sensor. Within automation, you can expect to find a wide variety of sensors that access and report on machine functions including motion, pressure, temperature, light,
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Fluid Power Devices
Hydraulic and pneumatic technologies fall under the heading of fluid power. Fluid power is a power transmission method. Since no one method is all around best for all automation activities, fluid power typically works in conjunction with electrical and mechanical power transmission.
Fluid power advantages over electrical and mechanical power transmission:
- Produces linear motion without mechanical aid of a rotational device
- Provides high torque with smaller space requirements
- Control valves are an economical control option
- Can be configured to be safer in ignitable environments
As subsets of fluid power, hydraulic and pneumatic technologies are similar but have significant differences.They both channel a fluid for power transmission, and share terminology and component categories, but that is where the similarities end. The difference between pneumatics and hydraulics lies in the fluid type. For power transmission, pneumatics channel gases while hydraulics channel liquids. The differences in mediums creates major differences in outcomes and applications.
Pneumatics can provide the gentler, cushioned pressure required for many automated tasks. Pneumatic technology utilizes compressed air or another inert gas for power transmission in actuating. For machine actions that require a fast response time and power transmission within close quarters, pneumatic systems are a simple solution.
When comparing pneumatic systems to other power transmission models, advantages include access to affordable components, ease of installation, and unlimited access to atmospheric gases (air). While air is free, there are some added expenses with this technology. The air within the system will need to be compressed and cleaned.
It takes an abundant amount of energy to compress the gas, so long-term operating costs can be higher than with other power transmission models. Compressed air also needs to be prepped to keep water and contaminants out of your system. You will need to apply filters and air dryers to keep the system clean and dry.
Valves help stop and start the flow of air in a pneumatic system. These can be manual like a foot valve or they can be electrical like a solenoid valve.
Air preparation components ensure the maximum performance and health of a pneumatic system by providing clean and dry air with regulated pressure. Air filters protect machine function by cleaning incoming air. Air regulators ensure consistent pressure for the optimum performance of pneumatic devices. Air lubricators allow for reduced leakage, slower wear and increased speed of pneumatic parts. FRL (filter / regulator / lubricator) combination units combine these functions into a single unit.
Cylinders move a load in a straight line using a piston rod. Compressed air either pushes or pulls the piston rod in and out of the cylinder barrel. Two key parameters for air cylinders include stroke and bore size. Stroke refers the distance the cylinder piston or rod extends when it is actuated. Bore refers to the diameter of the pneumatic cylinder. The larger the bore size, the more pressure or force the cylinder can exert.
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Hydraulic systems provide constant force and torque in applications that require higher forces than pneumatic or electromechanical systems can generate. Hydraulic systems use a compressed liquid, typically oil (hydraulic fluid), for power transmission. This liquid power is a force multiplier and easily manipulated with simple pushbutton and lever controls.
With few moving parts and ease of control, hydraulics can be safe, simple and economical. Do to the use of oils, liquid power has its drawbacks. Before selecting a hydraulic system, it is important to understand the dangers and overall messiness of hydraulic fluids within your manufacturing environment. Hydraulic lines leak and can burst to cause injuries to workers. There is also a possibility of combustion in hazardous environments.
Hydraulic fluid, beyond the power transmission medium, has four functions. Those functions are to transfer heat for cooling, remove contaminants, seal and lubricate.
Hydraulic valves direct the flow of fluid through the system and are activated either electronically or mechanically. These valves control the flow of fluid from the pump to other hydraulic components and are typically used to control the direction of a hydraulic cylinder or motor.
Hydraulic cylinders are mechanical actuators that provide unidirectional force though a unidirectional stroke. The two primary type of cylinders are welded and tie-rod.
Hydraulic PumpsHydraulic pumps induce liquid movement and flow and convert mechanical energy into fluid power energy.
Complex automation systems are easier to understand when broken into parts. To better communicate on the plant floor, plant personnel refer to machine parts by level. In automation, control components and systems are those that signal data to field-level devices, which in turn complete an action or return information. The logic component or software in control systems, or a PLC component is designed to scan inputs, scan code, and set outputs to the field devices based on pre-programmed instructions.
Industrial controllers are designed to receive inputs and communicate pre-programmed instructions to field level devices There are two types of control - continuous and discrete.
With continuous control, parameters and variables are analog and continuous. Analog signals are variable and have more than one state, not just 'on' and 'off', but also in between. With discrete control, binary digital signals are utilized. Digital signals are either 'on' (binary 1) or 'off' (binary 2).
Since both continuous and discrete I/O controls are utilized in today's automation to control a multitude of machine functions, many control systems are designed to communicate in both signal types with the aid of conversion circuits or components.
Human Machine Interface (HMI)
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Programmable Logic Controller (PLC)
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Fieldbus consists of a series of networked field devices which communicate serially over a 31.25kHz bus. On a fieldbus system, devices can communicate data between each other and the host control system using a single pair of wires. With fieldbus, your data is not limited to a measurement variable, but also includes diagnostics data, status information, and alarms.
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Industrial Safety Products
The increase in automation on the factory floor has brought new safety challenges and opportunities. Challenges include keeping the worker away from moving parts, and in case of emergency, being able to immediately stop the machine. Using the same components found in automation, manufacturers have designed high tech safety equipment to fill the needs and gaps.
Safety Light Curtains
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Connector Cables and Wire Harnesses
Machines components rely on cables for power distribution and communication transfers. A cable is designed to connect devices and conduct without radio frequency interference (RFI) and electromagnetic interference (EMI). The connectors are the plugs at either end of the cable. The conductor is the enclosed wire. The shield layer(s) prevents interference. Cables can be custom-designed to the geometric and electrical specifications of the machine. The number of cables needed to complete all the jobs within a machine can create an often calls for a configured as assemblies or in wire harnesses. There are a variety of cable management systems available to tame unruly cable tangles.
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Today automated machines are being built with a vast assortment of components capable of inter-connectivity. Connectivity has become a first priority consideration when designing a machine. Network communications are carried from component to component or system to system through analog and/or digital signals, or other industrial communication protocols. Wirelessly or traveling along wired connections, machine communications follow standardized communication protocols.
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Just as you have a street address, machine PCs, PLC, and other smart control devices have a Network Interface Card (NIC) and an internet protocol (IP) address with a unique machine access code (MAC).There are two main communication protocols available to build upon:
- User Datagram Protocol (UDP)
- Transmission Control Protocol (TCP)
The keywords here are “build upon.” Devices have different protocol additions based on specific functions. Network protocols make it possible for devices to identify, connect, and share information.
Key Industrial Communication Network Protocols include:
As American manufacturers increase their automation efforts, connectivity issues will continue to be raised and solutions weeded out. Industry trends show acceptance and aversion to both older and newer communication technologies.
The newer technologies that required expensive proprietary interfaces and equipment are falling to open standards, the Internet Protocol Model (IP), and Ethernet connectivity. For those manufacturers with a blend of older analog equipment and newer digital equipment, there is a move to create technologies to bridge those gaps. Interoperability is the keyword for now and into the future.
Machine components, though independent, all work together as a system to influence movement. Today’s automated machine components and system designs include aspects of the earliest mechanical devices up to the complex communications and logic control devices of today. Machine design engineers have a multitude of options when choosing the building blocks of their machines, but the end goal of the design is to complete work as efficiently as possible. If you understand the work or load that is to be moved through the system and have a basic comprehension of what creates your machine’s movement, it is easier to inductively conclude your next steps. We hope this overview was helpful and has given you a bigger picture of the machine automation components. As an industrial parts supplier and custom automation expert, we can assist you with questions concerning machine components and automation design. Please let us know how we can help you.