Roller screws make high force linear actuators possible

Posted by Aaron Dietrich on
Screw cut-away.jpgWhen you’re specifying a high force linear actuator, your application’s requirements call the shots. It used to be that hydraulic cylinders were your only recourse when high force was needed.  Now there are electric linear actuators with roller screws that rival the high force, high thrust, high torque capabilities of hydraulics.  Plus, these electric actuators deliver high speed, great accuracy and repeatability and long life. Electric roller screw actuators are definitely an alternative to consider.

Our new line of RSX extreme force, hydraulic class electric linear rod actuators are designed to meet the growing need for high force in linear motion. The first product in this line, the RSX096, is available now and can deliver 30,000 lbf (133 kN) of thrust. 

As the component responsible for converting rotary into linear motion, the power screw is critical in any electric linear actuator. As a machine designer you’ll want to understand the advantages of the three screw types: acme, ball and roller. Tolomatic’s guide is a great resource to download and have at hand.

GUIDE Which screw? Picking the right technology

How roller screws work

The screw’s thread form is generally triangular. In the screw, multiple threadedScrew illustration.jpg helical rollers are assembled in a planetary arrangement around the shaft. The rollers rotate within the nut while contacting the thread form of the shaft. This converts the motor’s rotary motion into linear movement of the screw shaft.

Screw components are usually ground to provide continuous contact area, smooth motion, and high thrust outputs. However, in some screws components are rolled rather than ground. This saves cost but sacrifices performance.

Roller screws have a large surface area of rollers in contact with the threads so they have higher load carrying capacities than ball screws of the same diameter. This screw technology is well suited for applications where extremely high force is required or if an application requires extended life, high degrees of precision and programmability.

Electric high force linear actuator advantages

high force linear actuator chart.jpgIt used to be that if you had a high force or heavy load application, a hydraulic cylinder was your only option. Initial cost for the cylinder was low, but along with it you got a high risk of hydraulic fluid leaks plus a space- and energy-consuming hydraulic power unit (HPU).

Now there are electric actuators powered by roller screws capable of delivering forces equal to hydraulic cylinders. These actuators are compact and offer very high levels of accuracy and repeatability, making them excellent choices for highly precise applications.  They can operate at high speeds with good acceleration, as well.

Being electric, these actuators are easily programmable and able to execute even the most complex linear motion profiles. They are pollution-free, long-lasting and need minimal maintenance.

Tolomatic high force linear actuators

We offer a range of high force actuators, all with long-lasting standard roller screws:

 Learn more

Download our guide: Which Screw? Picking the right technology.

GUIDE Which screw? Picking the right technology

Topics: High force linear actuators

High force linear actuator: electric replaces hydraulic

Posted by Nick Holmgard on
LUMBER_MILLIt used to be that when a machine designer was confronted with a high force linear actuator application, the only solution was a hydraulic cylinder.  That meant the designer had to factor in the bulky hydraulic power unit (HPU), the inevitable leaks of hydraulic fluid and the downtime produced by frequent maintenance.

Now there’s another option when a high force linear actuator is needed. There are electric linear actuator products that can meet demanding specifications with ease. 

Often, high force performance starts with the selection of the correct power screw/nut combination. Roller screws offer the best performance in both high force and long life, although ball screws deliver higher thrust than acme screws. Download our guide to screw selection for more information.

GUIDE Which screw? Picking the right technology

Sawmill needs a change

A sawmill needed a new linear actuator solution for moving a heavy saw blade used to cut logs. They had been using hydraulic cylinders because it took a lot of force to move the saw; however, the cylinders leaked fluid and contaminated the surrounding environment. The sawmill is located on a protected body of water, and contamination can incur hefty government fines.

Production is wet and dusty due to wood particles generated by sawing and water used to cool saw blades. Also logs often strike equipment, and there are extreme temperature fluctuations.

The hydraulic cylinders stood up to the dirty environment and impacts but had trouble with temperature changes. Cold temperatures resulted in sluggish and inconsistent performance. Heat caused oil to degrade and seals to fail. The cylinders had significant maintenance requirements that causeRSA electric linear actuator in sawmilld equipment downtime, plus they had low accuracy and were difficult to adjust or change.

New high force linear actuator solution

The company wanted accuracy, repeatability and programmability as well as the high force, environmentally-friendly, heavy duty attributes noted above. Their best solution was electric linear actuators.

The sawmill settled on the recommended IP67-rated RSA high force linear actuator because it could:

  • Deliver the accuracy, speed and force required
  • Eliminate hydraulic fluid as a source of environmental contamination
  • Withstand dust, water spray and impacts
  • Increase the reliability of the sawing equipment and reduce maintenance
  • Operate in low and high temperatures
  • Be re-programmed quickly and easily for multiple motion profiles

The RSA64 high force actuator’s heavy duty design can survive the sawmill’s rigors, even shocks and impacts. The IP67 selection seals the actuator against spraying water and wood dust. Special grease means the actuator can perform well in all temperatures.  The RSA64 selected used a roller screw to deliver the required thrust.

RSA electric rod actuators

rsa heavy duty actuatorRSA/RSM heavy duty linear actuators offer an extensive selection of sizes, options and system components. RSA-HT models are capable of force up to 13,039 lbf or 58 kN. Designed with high force, heavy duty performance, and long-term reliability in mind, RSA/RSM high force linear actuators are a cost-competitive solution for many applications.

Click here for a catalog of the RSA/RSM family 

RSA brochure

Learn more

Download our guide: Which Screw? Picking the right technology.

GUIDE Which screw? Picking the right technology

Topics: High force linear actuators

Electric linear actuator accuracy and repeatability webinar

Posted by Gary Rosengren on

accuracy_and_repeatability_in_linear_actuators.jpgWhen an engineer is developing a machine design, accuracy is often top-of-mind.  So is machine cost. But these two considerations can be at odds since the usual scenario is that the higher the accuracy of a device, the higher the cost. This certainly holds true for electric linear actuators and linear motion systems.

Engineers often ask us about the accuracy of our different products. They’d like a simple answer, but there really isn’t one. Accuracy is dependent on many factors, so you have to look at the application itself to know how an actuator will perform.

Don’t throw your hands up in frustration, though. Talk to Tolomatic first when your design calls for linear motion. It might be that what your application really needs is repeatability rather than accuracy. Or you may be able to adjust mounting and other parameters so you can use a lower cost actuator.

To learn about accuracy and repeatability in electric linear motion systems, download our white paper. 

  White paper:  accuracy & repeatability

Or view our webinar



Here are two definitions you need to know.

  •  Accuracy means hitting the bullseye every time. In linear actuator terms that means consistently reaching an assigned position.
  • Repeatability means reaching the same position time after time. That position may or may not be the assigned position. So you may not be hitting the bullseye but you’re hitting the same point on the target every time.

Match the actuator to the application

electric linear actuators from TolomaticAs we mentioned above, accuracy is affected by many factors. Along with the potential for inaccuracy in the motor, controller and encoder, every elecric linear motion system has the potential for position errors around the X, Y and Z axes of the actuator itself. Back and forth. Side to side. Up and down. Linear actuators are mechanical devices with built-in tolerances along these planes and, of course, there’s rotation around each axis to keep in mind.

Let’s consider the housing of an actuator. Maybe the housing allows some bow and twist which would lead to position errors on the X and Y axes. This might make the actuator inappropriate for some high-precision applications and cause a machine designer to look at more accurate alternatives.

That same actuator could perform very well in another application, though. Consider an application where the actuator can be secured to a known flat surface. That would eliminate the bow and twist problems, allowing the machine designer to use a lower cost actuator that’s theoretically less accurate but repeatable and performs well in practice.

Learn more

Download our white paper: Introduction to accuracy and repeatability in linear motion systems

White paper:  accuracy & repeatability

Topics: Actuator selection

Electric linear actuators meet the challenge of FSMA

Posted by Aaron Dietrich on

clean-in-place (CIP)The federal Food Safety Modernization Act (FSMA) that was enacted in 2011 has energized the food industry around food safety and the prevention of food-borne illnesses. Most of the major producers and food equipment manufacturers have kept ahead of FSMA requirements successfully since food safety and prevention have always been among their top priorities.

As a supplier of electric linear actuators for food processing, we were very interested in this recent article in Packaging + Processing OEM that details the current state of the industry and FSMA compliance.

Read it here.

Easy-to-clean electric actuators keep food safe

FSMA has had a significant impact on food industry cleaning processes. Food producers agree that equipment needs to be thoroughly cleaned, regularly and often. The emphasis now is on reducing the time cleaning procedures take while maintaining effectiveness and reducing cost.

Because electric actuators are important components in food manufacturing, they either have to withstand washdowns [and be clean-in-place (CIP) compliant], or they have to be shielded from food particles and moisture. Shielding adds cost and complexity to a machine’s design so it’s not the optimal solution. Easy-to-clean actutators make better sense in terms of both foodsafety and economics.

When they’re selecting linear actuators for food processing washdown environments, machine designers look for key cleaning-related features like

  • stainless steel housings, fasteners and motor enclosures
  • corrosion-resistant seals
  • water-shedding designs
  • IP69K rating (no need for shielding)

Tolomatic has easy-to-clean ERD IP69K electric cylinders that are well-suited to CIP electric linear actuators for food processingfood processing demands. The ERD electric rod actuator series includes SS2 (15 and 20) and USDA approved (22, 25 and 30) models that are CIP compliant. Because these electric cylinders don’t have to be shielded, machine design is streamlined and costs are kept down.

Download our catalog. 

ERD Catalog

Learn more

Download our white paper: Evaluating actuators for washdown in food and beverage applications.

Evaluating linear actuators  for food and beverage  processing

And contact Tolomatic. We’re here to help.

Topics: Actuators in Food and Beverage Processing

High force linear actuators: hydraulic vs roller screw actuators

Posted by Aaron Dietrich on

How to select the best high force linear actuator for your application

paper_mill needs high force linear actuators.jpgHydraulic cylinders have long been a leading choice for factory automation equipment needing a high force linear actuator. However, there have been advances in electric actuation  (for example, the availability of roller screw actuators) which make these electric actuators suitable now for many high force applications.

Industrial machine designers faced with choosing between hydraulic and electric actuation need an understanding of how each can benefit their application. This blog will review both types of high force linear actuators, hydraulic cylinders and electric linear actuators (roller screw actuators, in particular), on a variety of parameters. For a more in-depth comparison of these actuation technologies, download our white paper. 

White Paper: Hydraulic versus Electric Linear Actuators


Hydraulic cylinder systems produce high forces because of their high operating pressures [1800 to 3000 psi (124.1 to 206.8 bar)]. Because Force = Pressure x Area, even a 3-inch cylinder at 2200 psi can achieve 15,000 lbf (66,723.3 kN). However, hydraulic cylinders often are oversized to improve control and may not operate at full force.

Roller screw-powered electric linear actuators can deliver forces of13,039 lbf (58,023 N) and higher and can be used in many applications that call for a high force linear actuator. A major advantage of electrical actuators is that force is instantaneous. Current passing through the servo motor produces torque that drives the roller screw and generates force. A hydraulic actuator must wait for pressure to build until force is achieved.


A hydraulic actuator works well in simple, end-to-end position applications. However, applications that call for mid-stroke positioning require a more complicated set-up that includes a control valve and operator assistance.

An electric linear actuator with roller screw and servo drive/motor offers infinite control over position, velocity, acceleration/deceleration, output force and more. Adjustments can be made on the fly, plus accuracy and repeatability levels are far better than those of a hydraulic system.

System footprinthydraulic_actuator-system_components.jpg

A hydraulic system often includes a cylinder, power unit, control and accessory valves, filters, hoses and additional components. The cylinder itself offers a compact footprint at the work point, but the hydraulic power unit (HPU), which regulates oil pressure and flow, can require a lot of floor space.

An electric actuator has a smaller overall footprint with its combination of actuator, motor, and cables. The drive/amplifier is usually mounted in a control cabinet. Size requirements for an electric servo actuator system are normally a fraction of those of a hydraulic cylinder plus HPU.


It can be difficult for both hydraulic and electric actuators to achieve high velocities at high forces.

For a hydraulic cylinder to achieve high speeds at higher forces, there must be enough pressurized oil in the system to push the specified volume of oil in the cylinder in the required amount of time. There often must be an accumulation system to hold the pressurized volume.

The force capabilities of an electric actuation system depend on the right combination of motor RPM, motor torque and screw characteristics. As servo motors increase in size, torque increases significantly but RPMs decrease. This limits speed. However, an electric actuator has control over the motion profile and doesn’t have to stroke the entire length of each cycle. Also, an electric roller screw linear actuator may be able to deliver the peak velocities required since it can execute shorter, more intelligent moves.

Sensitivity to temperature

Hydraulic systems are sensitive to temperature. The oil in these systems gets thicker and slower-moving in the cold resulting in sluggish and inconsistent actuator performance. In hiindustrial thermometer.jpggher temperatures caused by overheating or the environment, oil may degrade and seals fail. Both conditions may require additional system components and additional cost. A tank heater can maintain operating temperature in the cold. A heat exchanger can mitigate overheating.

Electrical actuation systems are much less temperature-sensitive. Due to higher efficiency, electric systems can be selected to run at a desired temperature for the given amount of work required. Accurately predicting temperature allows the electric actuation system to perform consistently without affecting the life of the device. Electric devices can be specified with optional extreme temperature grease for fast response in the cold.

Life and maintenance

Hydraulic cylinders are rugged devices that offer long service life when maintained properly. However, maintenance requirements (new seals, oil and filters) can mean machine downtime and added cost.

If the electric linear actuator is sized correctly for the application, there is no maintenance required so there is no downtime. Proper roller screw actuator selection starts with accurate calculation of actuator life. For correct sizing, rely on our sizing software.

Data collection

Manufacturing management is very interested in monitoring and measuring all Data_visualization_process_v1.pngaspects of production performance. This has given rise to the need for data collection at the work point.

When it comes to hydraulic actuation, only expensive, complex servo-hydraulic systems with additional sensors can track and monitor position, velocity, force, etc. at the work point. Standard hydraulic actuation systems don’t have data collection capabilities.

Sensing capability is built into an electric actuator’s servo system. Motor current monitoring tracks force and repeatability. The motor’s feedback device registers position and velocity.

Electricity costs

Hydraulic systems are typically 40-55% efficient in converting electrical power to motion. The HPU needs to be powered up to keep the hydraulic system energy costs by actuatortechnology.jpgpressurized whenever the system is on. The result is inefficient use of power.

Electric linear actuator systems typically operate in the 75-80% efficiency range. The actuator at rest requires no current or very low amounts of current to hold its position.

Environmental risks

Hydraulic actuation systems are prone to oil leaks that can create safety hazards, contaminate products and pollute the environment. Clean-up can be costly and time-consuming.

Electric actuation is one of the cleanest linear motion technologies. Grease on the roller screw is the only potential contaminant, and special greases (food grade, clean room, etc.) can be specified. Seals keep grease inside the actuator, virtually eliminating contamination issues

To summarize

When you need a high force linear actuator, consider all these factors carefully. While hydraulic actuation systems may be appropriate for simple motion profiles with high force requirements, an electric actuation system can offer many advantages for complex linear motion. As a machine designer you’ll want to look beyond force capabilities to consider relevant factors like footprint size, control capabilities, velocity, data collection, efficiency, maintenance, temperature sensitivity and the hazards of leaks.

For more information on electric and hydraulic actuators as they relate to these factors, see our white paper: Electric rod actuators vs. hydraulic cylinders: A comparison of the pros and cons of each technology. Download it here. 

White Paper: Hydraulic versus Electric Linear Actuators

And contact an expert like Tolomatic. We’re here to help.

Topics: High force linear actuators

Electric actuator life in units of time: ball & roller screw actuators

Posted by Aaron Dietrich on
A machine’s useful life depends on the life of its critical components. And machine Ball screw Actuators_in_machine.jpgdesigners  frequently hear the question, “How long can I expect this machine to keep working?”

When electric linear actuators are used, calculating life can be straight-forward for ball screw and roller screw actuators.  Since these screw types incorporate rolling elements as essential parts, you can use the L10 life formula for ball bearings.

For a thorough explanation of how to use the L10 life formula when estimating electric actuator screw life, see our newest guide, Actuator Life: How to estimate for ball and roller screw actuators. Get your copy here. 

Actuator Life Guide

Distance versus time

The result of an L10 life calculation is in inches or milllimeters of travel. This is useful information; however, the individuals asking you how long your machine will last probably want the information in units of time, like days, months or years.

(Of course, L10 is a theoretical calculation of life based on load. As a seasoned designer, you’ll also consider the many other factors that can affect actuator life like the environment and alignment.)

This blog will show you how to convert an L10 result to units of time. But first a quick review.

Linear actuator Lead-ScrewsImportant terms

Dynamic Load Rating (DLR): Provided by the manufacturer and represented by the letter C. DLR is a constant load under which a ball bearing device will achieve 1 million revolutions (rotations) .

Constant load:  A load that doesn’t change during the working cycle.

Varying Load:  A load that changes during the working cycle.

Equivalent Dynamic Load:  Must be calculated when an application has a varying load. It’s a dynamic load which, if applied constantly, would have the same effect on screw life as the combined actual loads. Represented by the symbol, Pe.L10_life for electric actuators

L10 (or B10) Life: L10 life for a group of identical screw actuators operating under the same conditions is the number of revolutions which 90% of these actuators have the statistical probability to achieve (or at which 10% can be expected to fail).

Here are the basic formulas.

L10 life with a constant load

L10 = (C/Pe)3 x l

C = Dynamic load rating (lbf) or (N)

Pe = Equivalent load (lbf) or (N) = constant load

l = Screw lead (in/rev) or (mm/rev)

L10 life with a varying load

First, calculate the Equivalent Load, Pe:

Pe = 3 √{ [L1(P1)3+L2(P2 )3+L3(P3 )3+Ln(Pn )3]/L}

Pe = Equivalent load (lbs) or (N)

Pn = Each increment at different load (lbs) or (N)

L = Total distance traveled per cycle (extend + retract stroke) (L = L1 + L2 + L3 + Ln)

Ln = Each increment of stroke (in) or (mm) at different load

Then use the calculated Pe in the life calculation formula: L10 = (C/Pe)3 x l

estimating ball screw and roller screw actuator life in timeHow to estimate actuator life in time

Here’s what you need to know for this calculation:

L10 life calculation in distance  

L          total distance traveled per cycle (extend + retract stroke)

CpM   Number of cycles per minute  

HpD    Number of hours operated per day

DpY    Number of days of operation per year

Put that information into one of these formulas:

Life Estimate in Years =

(L10 / L) / [(CpM) X 60 min/hr X (HpD) X (DpY)]


Life Estimate in Days

(L10 / L) / [(CpM) X 60 min/hr X (HpD)]

This gives you the estimated life of the ball screw or roller screw actuator in units of time.

Now you can begin to answer the question “How long can I expect this machine to keep working?”  In an upcoming blog we’ll consider comparing actuators for an application.

To learn more

Download our new guide, Actuator Life: How to estimate for ball and roller screw actuators.

Actuator Life Guide

Topics: Actuator selection

Solid-bearing, belt-driven linear actuator handles harsh environment

Posted by Nick Holmgard on

PulpAndPaperMill.jpgMany applications call for the carrying action of a rodless electromechanical actuator. And many of these need the high speed and long stroke capabilities of a belt-driven linear actuator. But what do you do when your application is in a dusty, harsh environment? Many rodless electromechanical actuators can’t handle these conditions. Their roller bearings get clogged with dust and stop working. Could a solid bearing be the solution?

When you need general advice on specifying rodless electromechanical linear actuators, look to Tolomatic.  Our 10 tips white paper provides the information you need.     Download it here.

  Selection Tips White Paper Rodless Electric Actuators

Read further to learn how one user solved the problem of handling a harsh environment with a rodless actuator.

Harsh environment causes problems

Paper making creates tough environmental conditions for automation equipment. Water, chemicals and wood dust combine to challenge machinery. Designers who work for this industry have to take these factors into account in order to develop long-lasting, hard-working production systems.

We recently worked with the designer of a paper processing machine to develop a new roller-cleaning mechanism. In earlier machines, pneumatic rodless actuators powered the brushes that cleaned pulp from the paper-making machine’s rollers. These actuators failed frequently because pulp particles caused seal failures. The on-going maintenance the pneumatic actuators needed was very costly.MXB-S_in_pulp_and_paper.jpg

The machine designer wanted to use an electromechanical actuator to avoid the problem of seal failures in pneumatic actuators. The application had a stroke length of over 100 inches (2540mm), making a belt-driven actuator the best choice. However, many of the belt-driven electromechanical actuators that were considered had roller bearings on their carriers. Pulp particles got into the roller bearings, clogging them and leading to actuator failure.

Solid bearing is the solution

MXB-S solid bearingThe machine designer worked with Tolomatic to find a solution – our new MXB-S electric belt-driven linear actuator. The MXB-S with its unique solid bearing replaces the previously-used pneumatic actuator that was causing failures and high maintenance costs. This new rodless actuator’s solid bearing is self-cleaning. It easily pushes pulp away as it moves the carrier back and forth on the actuator body. The end of the actuator is left open so moisture and pulp particles can be pushed out. A stainless steel gearbox and motor power the actuator. Stainless steel was selected to withstand the wet environment.

The MXB-S delivers reliable performance and increased actuator life in this application. Plus, there’s less down time, and maintenance costs are lower.

Introducing the new MXB-S

MXB-S_Features.jpgThe MXB-S belt-driven linear actuator is the newest member of the MXB rodless electromechanical actuator series. The series includes the MXB-U unguided belt-driven linear actuator and the MXB-P heavy duty linear actuator with profiled rail carrier bearings. The MXB-S features a trapezoidal, self-cleaning solid bearing system for the carrier, a bearing system that is field-replaceable.

The MXB-S is a good choice for applications in harsh environments like paper production or sawmills because of its long-lasting, self-cleaning bearing. It is also well-suited to applications requiring light to moderate load carrying and guidance. long-stroke linear actuator MXB-S.jpgThis low-cost linear actuator offers speeds of up to 100 in/sec (2540 mm/sec) and thrusts of up to 418 lbf (1860 N). The MXB-S is a long stroke linear actuator that is available in stroke lengths of up to 200 inches (5080 mm).

Download the MXB catalog here.

MXB Catalog

For more information

To learn about specifying rodless electromechanical linear actuators, download our 10 tips white paper.

  Selection Tips White Paper Rodless Electric Actuators

When the choice between screw-driven and belt-driven linear actuators isn’t obvious, see our white paper for helpful information: Screw-driven vs. belt-driven rodless actuators: How to select drive trains for reliability, efficiency and long service life. Download it here.

White Paper: Belt Driven vs Screw Driven Rodless Electromechanical Actuators

Topics: Linear Actuator Application Tips

Selecting a rodless electromechanical actuator: belt- vs. screw-driven

Posted by Igor Glikin on
Screw-Driven and Belt Driven ActuatorsLet’s say you’ve decided you need a rodless electromechanical actuator to carry a load in your application. Now you have to select a linear drive system. The two most common choices are screw drives and belt drives. Both drive types offer long life, low maintenance and efficiency in converting the motor’s rotary motion to the carrier’s linear motion. However, each drive type is more suited to particular applications than others, depending on a few key factors.

This blog will review the advantages and disadvantages of these linear drive systems. For a detailed explanation, download our white paper.

White Paper: Belt Driven vs Screw Driven Rodless Electromechanical Actuators

The key factors you’ll need to consider in your drive train choice are:

Let’s take a closer look at each of them.


Accuracy is the ability of an actuator to achieve a specified position. Repeatability is the ability of an actuator to achieve a position time after time. Each application will have its own requirements for accuracy and repeatability.

A screw-driven linear actuator’s accuracy/repeatability performance depends on ball_screw-1.jpgthe screw type and the method in which the screw and nut were manufactured. For example, actuators with precision-rolled ball screws can combine very good accuracy and repeatability with an affordable price. Acme (lead) screws often offer a lower level of accuracy at a lower cost while roller screws (uncommon in rodless electromechanical actuators) offer the highest accuracy with an accompanying high price

A belt-driven linear actuator will deliver lower levels of accuracy due to the variations in the belt material.

Length of stroke

The length of the stroke of a screw-driven linear actuator is often limited by the available length of the screw stock. Screw-driven actuators are most often used in stroke lengths of less than 120 inches.

Screw length and speed are related. Critical speed (see below) decreases as screw length increases.

Belt drives, on the other hand, can reach very long lengths without affecting speed. In fact, the length of a belt drive is limited only by the ability to tension a long belt. Belt-driven linear actuators can achieve stroke lengths of over 200 inches (5080 millimeters).


screw_whip.jpgThe speed at which a screw-driven linear actuator travels is limited by the critical speed value of the screw. The critical speed is a rotational speed that approaches the system’s natural frequency, leading to resonance and vibration (also known as “screw whip”). Screw whip can lead to actuator malfunction and catastrophic failures. Screw-driven linear actuators typically operate at no more than 60 inches per second (about 1500 mm/second).

Belt.jpgBelt-driven linear actuators are not limited in this way and can achieve speeds of 200 inches/second (5080 mm/second).


There are several ways a linear actuator can be mounted depending on the orientation of the required move:Lead-Screws_lo_res.jpg

  • horizontal
  • side
  • incline
  • vertical

Of these, vertical orientation and some incline orientations can present problems resulting from back driving (the tendency of an actuator carrier plus load to free fall due to gravity). Actuators with Acme screws of certain leads are resistant to back driving because of a higher coefficient of friction between the nut and screw threads, but a ball screw actuator will require a brake to prevent back driving in the event of a power loss.

Belt-driven linear actuators are susceptible to back driving as well and must have emergency brakes for the same reasons.

In summary

Some applications make it easy to choose a linear drive system. Belt-driven linear actuators are ideal for long-stroke applications requiring high velocity and acceleration. If the application’s stroke length and speed requirements are moderate but the accuracy level required is high, then a screw-driven actuator is best.

When the choice isn’t obvious, see our white paper for helpful information: Screw-driven vs. belt-driven rodless actuators: How to select drive trains for reliability, efficiency and long service life. Download it here. 

White Paper: Belt Driven vs Screw Driven Rodless Electromechanical Actuators

And contact an expert like Tolomatic. We’re here to help.

Topics: Actuator selection

Electric linear actuator is clean-in-place, washdown ready

Posted by Nick Holmgard on
cleaning.jpgStringent regulations govern the food processing industry. Food processing equipment and components, like electric linear actuators, must meet food safety regulations and stand up to clean-in-place (CIP) procedures. Food industry cleaning procedures may include regular washdown with hot water, steam, high pressures and caustic chemicals. Corrosion resistant materials and a water-shedding design are musts.

Need to know more about how to select an electric linear actuator for a food and beverage industry application? Get our whitepaper.

Evaluating linear actuators  for food and beverage  processing

CIP or COP: Clean is critical

clean_in_place.jpgFood processing equipment can be cleaned-in-place (CIP) and cleaned-out-of-place (COP). CIP systems can clean even interior surfaces of difficult-to-move equipment. COP methods clean equipment or components that cannot be cleaned where they’re used. Either method lets food producers keep production equipment clean and sanitized. The type of cleaning method used has to take both the equipment and the food product into account. The goals are to maximize cleaning/sanitizing effectiveness while minimizing the amount of time cleaning procedures take.

With the advent of the Food Safety Modernization Act (FSMA), there is more emphasis on sanitary design in food plants. Equipment manufacturers are focusing design efforts on making food processing equipment easier to clean and sanitize and better able to stand up to CIP and COP processes. Linear actuators used in food processing equipment need to handle the rigors of regular cleaning and sanitizing procedures without diminished performance, effectiveness or life expectancy.

Wanted: Electric actuator to stand up to washdowns

As part of the dairy industry, cheese production has some of the strictest regulations for cleanliness and food safety. When a cheesemaker was looking for a linear actuator to push cheese blocks out of molds, they needed an actuator that would not introduce any contaminants into the food and could withstand high pressure, high temperature washdowns. The producer knew a hydraulic cylinder wasn’t appropriate because of the high probability of leaks. A pneumatic cylinder was rejected since there wasn’t an existing pneumatic power system in the plant. An electric linear actuator seemed the best solution.cheesefactory-floor.gif

Electric actuator solution found

The cheesemaker asked Tolomatic for assistance. We recommended the USDA-approved ERD25 electric rod actuator. This electric linear actuator is constructed of stainless steel and is IP69K rated to stand up to the harshest conditions. Its hygienic design is approved by the USDA for use in dairy, meat (livestock) and poultry processing. The ERD25 actuator for this application has a longer than standard stroke to release cheese blocks from larger molds.

The ERD25 delivers the hygienic design the producer needs, plus it handles washdown procedures without the need for expensive shielding. Because it is fully programmable, the ERD25 offers greater control over position and speed.ERD_SS2_and_USDA

USDA ERD electric cylinders

ERD electric cylinders are well-suited to food processing industry requirements. The ERD product family includes the IP69K, USDA-approved design in three sizes (22, 25 and 30). These models feature stainless steel housings and fasteners, a water-shedding design, corrosion resistant seals and gaskets and food grade lubricants. They are washdown ready and clean-in-place compatible. No shielding is needed, so machine design’s streamlined and costs are reduced.

ERD actuators can be paired with many stepper or servo motors to create flexible, powerful, cost-effective electric actuator systems. See our video for ideas on how these actuators can be used. 

Download our ERD series catalog here.

ERD Catalog

Learn more

Download our white paper on selecting electric linear actuators for the food processing industry. 

Evaluating linear actuators  for food and beverage  processing

Topics: Actuator selection, Actuators in Food and Beverage Processing

Linear actuator helps convert conveyor to electric

Posted by Nick Holmgard on
conveying.jpgEvery factory relies on some kind of conveying system to take components, work pieces or finished goods from one place to another. In fact, most factories have several conveying systems, each tailored to a specific need. Conveying equipment is varied and essential. Components in these systems, like linear actuators, must be able to meet these varied needs and provide reliable performance.

We’ve worked with many manufacturers of conveying equipment, matching linear actuator solutions to each application. Read a case study about how we worked with a global conveyor manufacturer to meet their need to develop an electric option for their product.

Conveying equipment case study

But that’s not the whole story of our involvement in this industry. Here’s how we solved another manufacturer’s challenge.

The need: Convert to electric

A conveying machinery builder was using pneumatic actuators in diverting systems. However, the manufacturer wanted to offer an electric conveying system to meet conv-002_erd-1.giftheir customers’ requests for greater control and programming flexibility. That new electric system required an electric actuator solution.

The existing machine design had proprietary controls that operated the pneumatic cylinder. These controls couldn’t be redesigned, and the manufacturer wanted a solution that could be retrofitted in the field. That meant a new actuator control system was needed in addition to an electric actuator. The controller needed to work with both electric and pneumatic models to allow for retrofitting.

The answer

The ERD electric cylinder with ACS stepper drive was chosen as the answer to this challenge.  The ERD is a low-cost actuator for pneumatic replacement. Its compact design fits the available space in this conveying equipment so no redesigning has been necessary. Its stainless steel construction means the ERD is sturdy and reliable. Fully programmable, the ERD can be tailored to changing application needs.

The ACS is a driver/controller specially designed for linear actuators. For this ERD-features.jpgconveying system, a new Pneumatic Mode was added to the ACS software. It allows the ERD electric cylinder to mimic the operation of a pneumatic cylinder.  With the combination of the ERD electric linear actuator and the ACS, this conveying equipment builder can now market an all-electric machine. Future expansion is also possible since the ACS offers infinite positioning through its Ethernet/IP option.


Our ERD electric actuators offer a range of body sizes, screw options and stroke lengths. They create flexible, powerful, cost-effective linear motion solutions and can be paired with stepper or servo motors. ERD electric cylinders are appropriate for sorting, diverting and product change-over applications.

Download our ERD series catalog here. ACS_features.jpg

ERD Catalog

Our ACS driver/controllers are available for both servo motors and stepper motors. They are often paired with ERD electric linear actuators to create straight-forward, cost-efficient linear motion systems.

Get our ACS catalog here.

Download the brochure

Learn more

Download our conveying equipment case study.

Conveying equipment case study

Topics: Actuator selection, Actuators in material Handling