Surface Engineering Spindles


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Surface Engineering brings to the market over 30 years of custom design, extremely close tolerance grinding and assembly experience on precision rotary spindles. Our products incorporate ball and/or air bearing structures with DC and AC brushless servo motors. The typical speeds range from 10 to 10,000 RPM with speeds of over 30,000 RPM possible.

Surface Engineering can provide DSP based motor control & drive systems for speed control of +/- 1 RPM at 5,000 RPM.

State of the art design, manufacturing and inspection capabilities allow spindle errors of 0.5 microns and asynchronous errors of 0.25 microns.

All spindle assemblies undergo 2 plane balancing corresponding to G-0.4 (as per ISO 1940 and ANSI S2.19-1975). Vibration levels of <0.1 mm/s RMS are provided.

Water cooling and axial vacuum and/or pressure passages are just some of the possible design options.

Surface Engineering has, among other machining centers, the following machines that are ideally suited to the manufacture of precision spindles:

1)	Long Bed (1000 mm) Voumard ID grinder with spindle speeds in the range of 8,000 to 12,000 rpm Also two other Voumards including one CNC turret machine.
2)	The Kellenberger (1000 mm) CNC OD grinder with a B-axis and Movomatic Gauging. Two OD wheels and ID grinding facility.
3)	CNC Studer with left/right wheels and a full B-axis.
4)	3 balancing machines, 1 Hofmann and 2 Heinz two-plane balancers
5)	The Charmilles Technology CNC Wire EDM.
6)	Thread grinding capability.
7)	Hembrug Super Precision Lathe with 0.00005 mm accuracy.

Speeds up to 30,000 rpm and average speed stability of +/- 1 rpm over the entire speed range are characteristic of our custom designed precision spindles. Average spindle error motions of the order of 0.5 microns and asynchronous error motions of the order of 0.25 microns are also characteristic features of these spindles. Water cooling and vacuum connections are also provided with each spindle.

All spindle assemblies undergo 2 plane balance corresponding to G-0.4 Quality Grade (as per ISO1940 and ANSI S2.19-1975) and vibration levels of 0.1 mm/s (rms.) are attained. Materials used in the assembly include Stainless Steel, Anodized Aluminum, Electroless Nickel coating, etc. Surface Engineering is also involved in the supply of high speed air bearing spindles to the disk drive industry.

Terminology

1)	RunoutThe total displacement measured by an instrument sensing against a moving surface or moved with respect to a fixed surface. The term T.I.R (total indicator reading) is equivalent to runout.
2)	Amount of UnbalanceThe quantitative measure of unbalance in a rotor (referred to a plane) without referring to its angular position. It is obtained by taking the product of the unbalance mass and the distance of its center of gravity from the shaft axis.
3)	Mean-Time-Between-Failures (MTBF)Mean Life or Mean-time-between-failures, is the total operating time of the entire system divided by the total number of equipment failures.
4)	Bearing PreloadPreload refers to the initial thrust load placed on a set of bearings during installation. Preload allows precise control over the operating geometry of the mating parts to the bearing and is applicable where axial and radial motions must be held within critical limits.
5)	Rating LifeThe rating (L10) life of a group of apparently identical bearings is the life in millions of revolutions that 90% of the group will meet or exceed.
6)	Basic Dynamic Load RatingThe basic load rating C, for a radial or angular contact ball bearing is a calculated constant radial load which a bearing with a stationary outer ring can theoretically endure for a rating life of 1,000,000 revolutions of the inner ring. These ratings are based on ANSI/ABMA STD-9 and STD-11.
7)	Static Load RatingsA static load is a load acting on a non-rotating bearing. Experience shows that a total permanent deformation of 0.0001 of the rolling element diameter, at the center of the most heavily loaded rolling element/raceway contact, can be tolerated in most bearing applications without the bearing operation being impaired. The basic load rating, is therefore, that load that produces the above deformation. These ratings are based on ANSI/ABMA STD-9 and STD-11.
8)	Brushless MotorA brushless motor is a rotating self-synchronous machine with a permanent magnet rotor and with known rotor shaft positions for electronic commutation. A motor meets this definition whether the drive electronics are integral with the motor or separate from it. Brushless motors are sometimes referred to as Brushless DC or AC Servo.
9)	Peak TorquePeak torque is the maximum torque that can be generated by a motor under specified conditions.
10)	Continuous Stall TorqueContinuous stall torque is the maximum continuous output torque that a stalled motor can develop under specified conditions.
11)	Torque Constant (Kt)Torque Constant is the torque developed internally in a motor per ampere of input current and is temperature dependent. The available shaft output torque is the developed torque reduced by frictional and rotational losses.
12)	Back Emf Constant (Ke)Counter electromotive force EMF constant is the voltage generated by an electromagnetic machine per unit speed at a specific motor temperature.