Oil-Rite Designs Lubrication System for CNC Machinery

Oil-Rite Corporation has designed a compact and efficient lubrication system specifically suited to CNC machinery. Utilizing only essential components, the system is economical, simple to operate, and highly reliable.

There is a continuous bath of lubricant on the cutting surfaces during CNC operations. Less visible – but as important – is the lubricant applied behind the scenes on moving parts that are part of the internal machinery. Most CNC machines come equipped with a lubrication system of some sort for these internal mechanisms. Users sometimes report problems with lines clogging, entrapped air, faulty pressure switches, maintaining reservoir pressure, and making basic adjustments.

Discussions with industry experts led to the idea that more could be done to improve lubrication for new machinery as well as upgrade lubrication for CNCs that are already in service. Oil-Rite Corporation addressed the challenge with a design that is both pragmatic and affordable.

The core component of the lubrication system is PurgeX, the patented dispensing technology of Oil-Rite Corporation. Contained within the 4-inch aluminum PurgeX body are the mechanics necessary for precise, repeatable lubrication cycles. The pump uses a burst of compressed air to move a stainless steel piston. That movement clears the internal chamber of its contents while achieving a 9:1 ratio of force. Basic shop air supplied at 40 to 120 psi transfers to a force of 360 to 1,080 psi at the outlet.

The piston during its downward motion occupies the space that contained the fluid, thus achieving positive displacement. This is the basis for the precision inherent to PurgeX. An adjustment screw controls the length of the piston stroke and determines the volume of fluid dispensed with each cycle.

There are considerable benefits to this technology:

·        There is no need to maintain a high level of pressure at a central reservoir, since the mechanics of the PurgeX pump convert low air pressure into much higher outlet pressure.

·        The system is not susceptible to plugging. Fluid, air, and impurities are purged with each piston stroke, essentially eliminating the possibility of contaminant build-up and air lock.

·        Since PurgeX generates additional pressure during cycling, high-pressure supply lines are not necessary. Flexible polyurathane tubing may be used to simplify installation and contain costs.

The components of the lubrication system in addition to PurgeX are:

·        3-way air solenoid

·        Polypropylene ½ gallon reservoir with low level switch

·        Aluminum mounting bracket

The 3-way solenoid controls the flow of air to the PurgeX pump and is attached directly to it. The introduction of air pressure through the solenoid forces the pump piston down. The subsequent cessation and exhausting of the supply line allows the piston to return under spring compression and complete the cycle. (The 3-way solenoid is different from a more typical 2-way solenoid in that it not only shuts off the air supply but also vents the supply line.)

The polypropylene reservoir is shatter and impact resistant. It has liquid contact clarity, which means the level of the fluid can be detected with a glance. A low level switch is housed within the reservoir. That switch can be integrated into the machine’s logic to alert an operator or shut-off the machine should the fluid reach a critical level. A vented cap ensures that gravity enables the flow of the fluid. The reservoir is mounted to the bracket by a 5/8”-18 threaded stem and plumbed directly to the PurgeX pump.

The aluminum bracket is compact and includes pre-drilled mounting holes. The installation of the unit requires:

·        Securing the bracket

·        Connecting compressed air

·        Supplying on/off power to the solenoid that is controlled by the CNC’s logic

·        Creating a circuit with the low level switch

·        Routing flexible tubing to the output point

When lubrication is dispensed with this level of accuracy, only small amounts are typically required. For instance, a half gallon supply can last 8 months if .065 milliliters are dispensed 5 times per hour for 24 hours a day. PurgeX can dispense as much as .200 milliliters with each stroke and can be adjusted down to less than .030 milliliters.

CNC repairs are costly and a reliable lubrication system is a first defense against premature wear. PurgeX tested to 360,000,000 cycles in the laboratory without appreciable wear. In the lubrication scenario mentioned above, 5 cycles per hour would require 8,219 years to reach the 360 million mark.

The CNC lubrication system is one of multiple products designed by Oil-Rite to specific industry requirements. Oil-Rite Corporation has designed and manufactured lubrication equipment in its U.S. plant since 1933. For more information, contact Technical Sales at 920-682-6173 or sales@oilrite.com.