A Sawyer motor or planar motor (also called area drive) is a multi-coordinate drive that can perform several independent movements in one plane. Goods can be transported along any path to any location. In the industrial environment, the planar motor replaces cross tables in machine tools, for example. This class of motors is named for Bruce Sawyer, who invented it in 1968.

Operating principles

The planar motor is a driver/guideless drive system. The planar motor consists of a flat base element ("stator") made of tiles and carriages ("movers") arranged on it. The latter are equipped with mostly cuboid

magnets A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...

whose magnetization is perpendicular to the plane and which are controlled in the X and Y directions with alternating

polarity Polarity may refer to: Science *Electrical polarity, direction of electrical current *Polarity (mutual inductance), the relationship between components such as transformer windings * Polarity (projective geometry), in mathematics, a duality of ord ...

. The movement of the slides themselves is achieved by further magnets arranged parallel to the plane, thus allowing the slides to move in the X and Z directions. The number and arrangement of magnets perpendicular and parallel to the base determines the

degrees of freedom Degrees of freedom (often abbreviated df or DOF) refers to the number of independent variables or parameters of a thermodynamic system. In various scientific fields, the word "freedom" is used to describe the limits to which physical movement or ...

and positioning accuracy. The operating principle of the planar motor can be traced back to Bruce Sawyer, which is why it is also known as the ''Sawyer motor''. The U.S. engineer applied for a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...

for a "Magnetic Positioning Device" in 1966, which was confirmed in 1968.

Application area

Planar motors are mainly used for handling products in individual machines or in machine lines. They combine the dynamics of conventional linear transport systems with magnetic fabric technology, which enables individual and decoupled product transport. In addition, there is the traceability. Since there is no mechanical connection between the base surface and the carriage, planar motors are characterized by minimal

maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doctrine ...

and cleaning requirements. The cover of the base surface can also be made of

stainless steel Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...

glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

, or

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

, for example, to protect it from leakage of liquids or cleaning processes.

References

{{Reflist Electric motors Linear motion

Operating principles

Application area

See also

References