Lead Screw Technical Basics by Moore International

Basic design

The Eichenberger high-helix lead screws are not called Speedy for nothing: never before have such high moving speeds been obtained at such low rotational speeds. The Eichenberger Speedy has made this possible by using a helix pitch unheard of before.

High-helix lead screws are made of stainless steel and are formed by the cold-rolling process. They are coupled with high wear-resistant thermoplastic nuts in simple (standard, POM-C) or preloaded (POM-C or EX 100) designs.

For higher loads or special applications, alternative plastic materials or bronze may be used for the nuts.

Materials

Screw

stainless steel X20Cr13, (material N° 1.4021 / AISI 420)
other steel qualities, i.e. · X2CrNiMo17-12-2 (material N° 1.4404 / AISI 316 L)
   or
   · X10CrNiS18-09 (material N° 1.4305 / AISI 303)
   on request
other materials, i.e. hard-anodized aluminium for fine-pitch threads on request

Nut

non-preloaded: POM-C black
preloaded:
· axial-preloaded: POM-C black
· torison-preloaded: EX100 white (if p₀ = d₀)
bronze CuSn12, material N° 2.1052
other plastics on request

Nut design

For all thread types a standard flange nut design has been defined, which is deliverable in the following types:

Of course, any other application-specific nut designs can be supplied on request including injection-molded solutions.

Lead accuracy

Standard

0,1 mm/300 mm (better than class G9 as per DIN 69051)

On request

< 0,1 mm/300 mm

Efficiency

The efficiency h depends on the helix angle and reaches values from ~0.5 to 0.75 (see chart).

Handling

High-helix lead screws are precision parts (non-hardened) and must be protected from shock, dirt or moisture when transported or stored. Please do not unpack until ready for use.

Please check for cleanness when mounting the lead screw unit. Dirt or foreign matter on the thread may cause exces-sive wear.

Please consult lubrication recommenda-tion before mounting or operating Speedy lead screws.

Radial loads and torque

Radial loads or torque brought to bear upon the nut result in overload of individual contact surfaces, thus seriously affecting the service life of the lead screw assembly. Therefore it is important to properly mount the screw and to comply with all relevant form and positional tolerances.

Lubrication

In some cases, a single lubrication with grease or oil is sufficient. However, any lubrication cycle depends on the application environment. Bronze nuts have to be lubricated regularly. Lubricant used by manufacturer:

Klüber Microlube GBU Y 131.

Applications

The Eichenberger high-helix lead screws are suitable for a variety of applications. For short strokes, they are a substitute for drive belts due to their low production cost. In addition, they are perfectly suitable as substitutes for hydraulic and pneumatic cylinders. Indeed, they allow low-friction acceleration as well as free positioning and operate without secondary energy sources. When appropriate, they are also ideal alternatives to trape-zoidal or ball screws due to high efficiency and a convincing cost-performance ratio.

Typical applications are:

Drives for doors, gates and windows
Handling systems
Graphics machinery
Drives for valves and dampers
Climate control systems
Medical devices
Textile machines
Food and packaging industries
Steering actuators
Electonics industry
etc.

Technical Basics

Basic design

Materials

Nut design

Temperature range

Lead accuracy

Duty cycle

Efficiency

Factory length

Lead screw ends

Handling

Radial loads and torque

Lubrication

Applications