POLYLUBE^® Guide Rod bushings are designed as replacements for traditional metallic guide rod bushings materials. Replacing conventional metallic guide rod bushings with a POLYLUBE^® guide rod bushing is a straight-forward change out. Typical replacement programs where metallic guide rod bushings are replaced are driven from one or a combination of several of the following factors:

• Improved stick-slip properties
• Optimal frictional response during cycling
• Significant reduction in shaft scoring
• Extension in the bushing life
• Reduction in bushing profile
• Greatly improved side load/misalignment capacity
• Increase in load capacity of bushing
• Enhanced corrosion resistance
• Tolerance of more cost effective shaft finishes
• Lower in weight

ID seal configurations

Incorporating T-lip wiper seals, radial shaft seals, o-rings or any other similar internal sealing system is not a problem for PolyLube Guide Rod bushings. Polygon's internal fabrication capabilities allow for easy and economical incorporation of ID features required to install common sealing systems.

Two liner thicknesses are available in the standard PolyLube PTFE tape lined bushing configuration: the 0.015" thick liner being standard and a 0.030" thick liner also being available for applications where seal geometry might require the introduction of a thicker liner to accommodate a unique ID feature. The 0.030" thick liner can also be used in applications where boring the ID might be required in order to achieve tighter tolerances in an effort to address sizing and minor misalignment conditions.

Fabrication capabilities

One common fabrication detail seen on guide rod bushing applications deal with corner radiuses on internal and external grooves. Because Polygon uses a diamond wheel or groove tool to form the grooves we need to have at least a .015-.020" corner radius. When threads are used there is usually clearance involved. When assembled with the mating part the bushing could shift to one side or the other impacting the location of the bushing surface in relation to the piston shaft. This could have a negative impact on wear.

The only other fabrication issue commonly seen on incoming prints is a surface finish called out on the internal diameter. This is typically related to an OEM’s historical use of machined bronze bushings in the application. Since the bronze is machined from a solid piece or casting, the surface finish is called out since it is related to the speeds and feeds of their fabrication process. The wear surface on PolyLube bushings is not machined so the surface finish call out can be removed from fabrication requirements.

Polygon is capable of holding a TIR I.D. to O.D. within .002" and straight diameters to +/-.0005".

POLYLUBE^® Guide Rod bushings are commonly available in two configurations: a POLYLUBE^® bushing utilizing a sintered PTFE liner or a POLYLUBE^® bushing utilizing a PTFE fabric liner. The most common POLYLUBE^® guide rod bushing in use today is the sintered PTFE liner due to two primary performance enhancements over the PTFE fabric lined bushing: the frictional response under start-up conditions and the transfer of PTFE to the wear surface.

Guide rod bushing properties

Guide Rod bushings are an application for our standard product lines. Our recommended lines are as follows:

Glass Tape Bushings, recommended for non-contaminating environments.

MRP Bushings, recommended for contaminating environments.

Mechanical and physical properties

PolyLube Guide Rod bushings are manufactured by a filament winding process that results in a continuous fiberglass filament backing ensuring excellent mechanical properties (especially fatigue resistance). The filament wound fiberglass structure uses a high strength, corrosion resistant epoxy resin as the matrix material. The high strength backing permits the use of a thin wall (1/16" to 1/8") bushing which can often reduce the size and weight of the finished bushing assembly. This family of materials exhibits exceptional dimensional stability and performance predictability over wide temperature ranges (±325°F).