As cities, states, and countries begin to reopen in the wake of the COVID-19 pandemic, many of us will still face restrictions for some time regarding what businesses and facilities we can access and where we can travel. This “new normal” means that most of us will still spend more time at home, or nearby, […]
Motion basics: How to define roll, pitch, and yaw for linear systems
Linear guides and systems — including Cartesian robots, gantry systems, and XY tables — are typically subjected to both linear forces due to downward, upward, and side loads and rotational forces due to overhung loads. Rotational forces — also referred to as moment forces — are typically defined as roll, pitch, and yaw, based on […]
Industrial Ethernet basics for mechanical engineers
Ethernet networks are ubiquitous in our daily lives — allowing computers in office, school, and commercial environments to connect to the internet, share files, and access printers and other hardware connected to the network. And there’s a reason Ethernet is so popular — it’s a simple, flexible network protocol that facilitates high-speed data transmission. But despite […]
How to account for shock and vibration loads in ball screw drives
Calculations of ball screw service life and permissible static load take into account loads and forces that are predictable and quantifiable — thrust loads due to acceleration, process forces, and forces generated when holding a load in place, for example. But some applications are also susceptible to loads caused by shock and vibration — loads […]
When do you need to consider thermal expansion in linear guide systems?
Most materials used in linear systems have a positive coefficient of linear thermal expansion — that is, when their temperature is increased, they expand in length, and when their temperature is decreased, they contract in length. One notable exception is Kevlar, the aramid from DuPont, which is sometimes used for tensile cords in toothed belts. […]
Linear motion in medical applications: Linear systems in automated RT-PCR testing
With near-constant updates on the number of COVID-19 cases confirmed globally, you’ve probably heard about various methods to screen for the virus that causes the disease. Although several well-proven methods already exist to detect the virus, laboratories around the world are experimenting with new tests and methods to provide faster and even more reliable screening. […]
Linear motion in medical applications: Lead screw driven syringe pumps
When we think of syringes, we typically think about the single-use type that doctors and nurses use to administer vaccines or individual doses of medication. But some conditions necessitate frequent or constant doses of critical medication, making it undesirable or even unfeasible to administer via single-use syringes. And in other cases, medications that would normally […]
Linear motion in medical applications: Voice coil actuators in ventilators
More and more, medical device manufacturers are replacing traditional components with smaller, lighter-weight options that have sufficient life and reliability for “life-critical” applications. One such example comes from manufacturers of ventilators, who are using voice coil actuators to control the valves that deliver air to a patient who’s unable to breathe on their own. Ventilators are […]
What are rail brakes and when should you use them?
The servo and stepper motors that drive linear motion systems often include a braking function, or, in the case of stepper motors, detent torque that helps prevent the motor (and, therefore, the load) from moving when powered off. But in some applications, a secondary brake is required — either to provide redundancy and meet safety requirements […]
How to reduce the effects of stiction (stick-slip) in linear guides
Unless you’re playing the violin, stiction, or stick-slip, is an unwanted condition caused by the difference between static and dynamic friction between the two surfaces. When stiction occurs in linear guides, it can lead to chattering (“jerky” motion), seized motion, fluctuating torque requirements, or a loss of accuracy in the form of overshooting. What causes stiction? […]
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