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Headway Research, Inc.
Headway Research, Inc.

Modular Moving Arms

The model PWM32 Spin Controller has been upgraded and new product is now called model PWM50. We buy used equipment and factory re-furbish it at times, so the PWM32 may linger in our terminology and sales material for a considerable time. References to the PWM32 will be updated as soon as practical.

See the special page explaining the main differences in the two models.

Moving Arm

Headway's motor driven moving arm positions dispense lines on spin coaters and developers. This module may be attached to virtually any spinner and is available with a variety of options and features.

The moving arm mechanism is simple, with a minimum of parts. It is available with a 12 vdc or 24 vdc motor. Positive and adjustable limit switches determine the clockwise and counter-clockwise position limits. The module can be provided with an optional, 1024 ppr optical shaft encoder on the output shaft. Without the optical shaft encoder, the two limit switches can determine the "home" position and an adjustable stationary dispense point. With the optical shaft encoder used with external electronics, one limit switch can establish the "home" position and counter zero, and the other limit switch can act as a "crash limit" switch, as an equipment safety feature. With the optional optical shaft encoder and control electronics, dispensing can start anywhere and dispense while the arm is moving between any two points, or at any programmed stationary point between the physical limit switches. Arm speed is set by the voltage level applied to the dc drive motor.

Headway interfaces the moving arm to our spinners with appropriate dispensers as required. The microprocessor driven PWM32 Headway spinner has built-in to its program a majority of the intelligence required to control the arm, increasing the economy even further. In the past, only the more sophisticated and expensive spinners could justify the cost of an automated moving dispense line. With the introduction of this lower cost mechanism and control system, even inexpensive lab type spinners can be fitted with this feature, permitting automated pre-purge of dispense lines at the edge of the bowl before a coating cycle, and making loading and unloading the spinner easier by parking the dispense lines in a more out-of-the-way position when not in use.

On larger more sophisticated machines dispensing 3 or more fluids, it is economically feasible, and technically better to use two or more moving arm mechanisms rather than to try to position too many dispense lines on one moving arm. This reduces cross-contamination problems, and makes proper positioning of the dispense lines more feasible. The cost of two or even three mechanisms is now less than the previous cost of only one comparable mechanism.

Headway also offers this modular mechanism to other OEM's and will provide as little or as much assistance with external controls and power supplies as desired.

Model Number Derivation
Moving Arm
With Encoder/
No Encoder
Mod level
Model HRI Part Number
These standard models have a user adjustable range for the angle between the two physical limits of approximately 20 degrees to 95 degrees. Models can be provided with adjustable range to approximately 175 degrees.

Outline Dimensions: BOX: 3.5" Wide X 3.45" High X 4.7" Long

Motor Shaft: 5/16" by 15/16" long. HRI added shaft adapter: 5/8" by 2.125" long.

Weight approximately: 3 lb.

Current requirement (variable): 24 vdc up to 400 ma, surge to 800 ma, 12 vdc up to 800 ma, surge to 1.6 amp.

Useable Torque approx: 400 in-oz. Backlash is spring loaded CCW approximately 90 in-oz.

Headway recommends that not more than two fluid lines be carried by one moving arm mechanism. If needed, a nitrogen line may be carried as a third line, depending on the purpose.

Headway Research Products
Spinners | Controllers | Motors | Pumps | Chucks | Accessories

Headway Research, Inc.
3637 Marquis Dr, Ste #102
Garland, Texas 75042 U.S.A.

Phone (972) 272-5431
Fax (972) 272-7817