On Line Controls, Inc.

Who we are

Manufacturer of two product lines:

MICROAIR---The MicroAir line of ultra low air pressure regulator and controllers which controls air pressure to a set point during tubing extrusion. Our MicroAir units are used on extrusion lines making catheters, profiles, taper, bubble, multi-lumen, medical and automotive.  It maintains air pressure for widely varying flow rates during variation in the process such as when a cut is made.  The outside diameter and structure of the tubing is conrolled by the precision and accuracy of the air regulator.  As medical tubing producers have continually decreased their OD, ID and wall dimensions, we have improved our design to provide more accurate and precise air pressure regulation. Ranges as low as 0-3" of water can easily regulate below 1" of water. Maximum range is 0-5 psi. Meters are available in "inches of water"; "psi", "mbar"; kpa, etc. All units are CE certified.

MOTORIZED POTENTIOMETER/RHEOSTAT--- line of products was purchased in 1999. A high precision proportional controls fro automating analog driven devices. Each model contains a slip clutch to protect the potentiometers end stops, prevents gear train breakage, and allows for manual adjustment when motor is off. Our motor pots combine pot, gear and motor in a small efficient package. Available with either AC or DC motors in .5, 1, 2 or 5 watts, and ohmages (100 ohms to 200K).  We can replace old units built in the 1980 and 1990's or can help you design them into your new equipment.  Also available are Motorized Rheostats for higher wattages.

On Line Controls, Inc. is a small privately held corporation selling worldwide from our new facility in Shrewsbury, Massachusetts U.S.A.  For over 40 years, OLC has manufactured products for the plastic tubing industry.  

Our values

We are committed to manufacturing high quality, dependable products for tubing manufacturers and providing the best customer service.  Our MicroAir units have been known to work for over 15 - 20 years without a problem.   Spare parts are not required nor is recalibration.  

Our motorized potentiometer and motorized rheostats are built with high quality potentiometers, motors and geartrains.  They have a extremely long life span and we can repair or replace models made by ETI Systems in the 1980 and 1990's.


         MicroAir units are the standard in the industry for control air pressure in a tubing extrusion line.

          We are constantly looking for ways to improve our products.

           We stand behind the quality of our work and will always work to correct any problems immediately and limit any line shutdown time.