SMAC Moving Coil Actuators today introduced its LDR16 Series electric linear rotary actuator designed for electronic assembly applications.

The LDR16-035 is the first of a new series with 35mm stroke and features an HT12 motor for industry-leading precision control needed for pick-and-place machines used to surface-mount devices onto a printed circuit board (PCB). Pick-and-place machines require extreme precision when placing a range of electronic components such as capacitors, resistors and integrated circuits onto PCBs used in computers and consumer electronics.

The LDR16-035 offers the highest precision available for electronic assembly,” said SMAC Founder and CEO Ed Neff. “There is demand for narrow pitch actuator with very low rotary runout, which is the wobble of the rotating shaft. Precise control of component placement and force is extremely critical in circuit board assembly, especially as electronic parts continue to get smaller.”

Designed and manufactured by SMAC, the LDR rod runout is less than 10 microns. Inline rotary bearing location, combined with adjustable raceway preload, results in this industry-leading performance, with 75% lower runout than competitors. Additionally, the HT 12 direct drive brushless servo motor uses precise printed coil technology to eliminate motor cogging, a series of jumps in friction caused by varying electromagnetic coupling that can affect the rotational positioning of a part. The standard 13mm rotary motor has 24,000 or 48,000 counts per revolution (CPR).

When a part is placed on a circuit board it must be orientated so that its contact points match those on the board. The margin for error introduced by rod runout of greater than 10 microns makes it difficult to align the part with the contacts.

SMAC manufactures the rotary motor, including its printed coil technology, laser-machines the components and assembles the LDR16-035 in its Carlsbad, Calif. facility.

SMAC’s LDR 16-035 also costs 7.5% less than the SMAC model it replaces, which Neff notes has been “inexpertly copied by competitors.” A combination of improved design, the rotary motor’s laser manufacturing and printed coil technology, SMAC in-house manufactured encoders and U.S. manufacturing contribute to the lower price.

Keeping the manufacturing and assembly in-house provides the highest quality control and allows us to keep costs down,” Neff said. “That aligns with SMAC’s long-term cost-down strategy of 25% reduction every five years.”

The LDR16-035 is designed with linear guide built-in lubrication for extended life. The electronic actuators also have programmable force and “soft-land” capabilities for absolute control of force and torque, position, acceleration and velocity. SMAC’s LDR actuators are energy-efficient and dependable, tested to last more than 200 million cycles, even at fast cycle rates.

The LDR16-035 also has other applications such as silicon wafer brushing, small-cap assembly and small-screw assembly.

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