FREQUENTLY ASKED QUESTIONS

Q: Can I get away with just knowing the maximum force required for my actuator?

 

A: To properly size such a linear actuator, the average dynamic load and duty cycle must be calculated, as well as knowing the maximum force.  Without this information, it's easy to under- or over-estimate actuator size.  Underestimating thrust can cause an actuator not to perform at all.  Over-estimating can lead to incorrect motor and drive selections, unnecessarily increasing system costs.

 

Q: Why is it important to calculate the screw life of an actuator and how do you do it?

 

A: The drive screw is often a limiting factor in the performance and service life of an actuator, and is therefore a key element in selecting the proper actuator.

 

We calculate the L10 of a ballscrew or rollerscrew as part of our actuator sizing process, considering acceleration forces as well as basic thrust requirements in the determination of average dynamic load.   L10 calculations are a statistical estimation of performance life (in travel millimeters or inches) at a given average dynamic load;  This is akin to a B10 calculation for a rolling bearing mechanism.  The L10 life rating states that 90% of a similar group of screws will achieve this life.  Although 10% will not achieve the life, 50% could exceed life by 5 times.

 

The statistical wear life of lead (acme/trapezoidal) screws are difficult to predict due to surface finishes, lubrication, operating temperature, and environmental consideration.  We rely on pressure vs. velocity evaluation to determine limitations on use.

 

Q: Why select an electro-mechanical actuator over a hydraulic or pneumatic cylinder?

 

A: Electro-mechanical actuators can be cleaner, safer, and energy saving alternative to fluid power cylinders.  For more information, click here.

 

Q: Can your actuators be used in Food Grade applications?

 

A: Yes and we have standard offerings developed specifically for food industry equipment.  With our Victory Series ram-style actuators we have versions with both epoxy painted (“FG1” version) and full stainless steel exteriors (“FG2”), both of which have an IP67 ingress protection rating.  For rodless actuator and screw jack based solutions, we have incorporated special finishes and materials.

 

Q: How do I lubricate my actuator?

 

A: Most of our actuators have single-point lubrication, and can have new grease added without disconnecting the unit from the payload.  Consult the specific product manual.

 

Q: Do you design custom actuators to fit my specific needs?

 

A: We recognize that each application is unique, and welcome opportunities that require modifications to our standard products, or in some cases, complete custom designs.  Allow us to evaluate your specific needs.  We thrive on actuator opportunities that others consider too tough to solve.

 

Q: Why do you keep asking more questions around the duty cycle?

 

A: Because the more we know, the better job we can do in properly sizing the actuator without over-sizing or under-sizing it.  What we care about in this regard is how much of the time the actuator is in motion.  The conversation often starts with, “The machine runs 100% of the time.”  But in reality, that does not usually translate directly to a 100% duty cycle for the actuator.  Overlooking some of the finite details could end up in a solution that breaks the budget, which we like to avoid.

 

Q: Do you offer actuators with enhanced corrosion resistance?

 

A: Indeed, we do.  See the FAQ in regards to Food Grade environments.  We also have extensive experience with actuators used in marine, mining, and other arduous environments – indoors and out.

CONTACT/FOLLOW US

 

Precision Technology USA, Inc.

225 Glade View Drive

Roanoke, VA 24012

 

P: 540-857-9871

E: PTsales@pt-usa.net