Advantages:
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High speed. The maximum speed of a linear motor is limited only by the bus voltage and the speed of the control electronics. Typical speeds for linear motors are 3 m/s with 1 micron resolution and over 5 m/s, with coarser resolution.
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High Precision. The accuracy, resolution, and repeatability of a linear motor driven device are controlled by the feedback device. With the wide range of linear feedback devices available, resolution and accuracy are primarily limited to budget and control system bandwidth.
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Fast Response. The response rate of a linear motor driven device can be over 100 times higher than that of a mechanical transmission. This means faster accelerations and settling times, thus higher throughput.
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Stiffness. Because there is no or simple mechanical linkage, increasing the stiffness could be simply a matter of gain and current. The spring rate of a linear motor driven system can be many times higher than that of a ball screw driven device. However it must be noted that this is limited by the motor peak force, the current available and the resolution of the feedback.
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Zero Backlash. Without or with simple mechanical transmission components, there is no backlash, except one generated by rotations around co-ordinate axes. Resolution considerations do exist. That is the linear motor must be displaced by 1 feedback count before it will begin to correct its position.
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Maintenance Free Operation – No (minimal) Friction. Nowdays linear motors have no contacting parts, so they do not wear.
Disadvantages:
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Price. Linear Motors are expensive. This is due to the relative low volume produced, and the price of magnets. Since most linear motor designs mount rare earth magnets to the length of the rail, and the cost of these magnets is high, long travel motors become expensive. However as the popularity of linear motors continues, volume will rise and cost will decline. This process has begun. Linear feedback must also be considered in the cost of using a linear motor. Most importantly, if system accuracy requires linear encoder feedback, the cost difference between linear and rotary technology is greatly reduced.
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Higher Bandwidth Drives and Controls. Since there is no or few mechanical links between the motor and the load, servo response, bandwidth, must be faster. This includes higher encoder bandwidth and servo update rates.
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Force per Package Size. Linear motors are not compact force generators compared to a rotary motor with a transmission offering mechanical advantage.
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Heating. In most linear motor applications, the forcer is attached to the load. Any Joule losses are then directly coupled to the load. If an application is sensitive to heat, thermal management techniques need to be applied. Air and water cooling options are popular and common.
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Electromagnetic safety brake required. For instance, a linear motor is traveling at 3 m/s and a power supply/drive system failure occurs. The slider moves then to a random position unless a safety brake system kicks in.
