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Product List for PTFE Components

SELF LUBRICATING PLANE BEARINGS

Crossflon Bearings overcome problems of poor lubrication, excessive heat and cold, friction, wear and corrosion. The Crossflon range of bearings simplify design problems and ensure greater reliability, efficiency, self-lubrication and improved performance. In general all of the variations of Crossflon materials are designed to operate dry, and offer self-lubrication with high performance.

APPLICATIONS
Beldam Crossley has been at the leading edge of development of compounded PTFE materials since the mid 1950's. By staying close to the rapidly changing requirements of the design engineer's world we are able to meet the demands of today's technology. If problems with lubrication, heat, cold, friction, wear or corrosion are blocking the way to a design solution, Crossflon bearings can generally solve the problem of reliability and efficiency. In general, all of the diverse Crossflon bearings are designed to run dry. They offer self-lubrication with high performance.

BEARING MATERIALS

Crossflon LRD5
General purpose, hard wearing all-round bearing. Eliminates the need for lubrication in almost any operating area. Crossflon LRD5 operated at PV values up to 0.70.
Crossflon 1403
Operates at PV values up to 0.9 dry. Ideal for rotary, linear & reciprocating bearings, Crossflon 1403 is suitable for running against soft mating surfaces such as 316 Stainless Steel and aluminium without excessive wear to the counter surface.
Crossflon FG
Specially formulated from PTFE and fillers designed for excellent load and wear characteristics in food and drug contact bearing applications. All of the constituent elements of Crossflon FG are FDA cleared and non-toxic.
Crossflon J
Because its fillers are all polymeric, Crossflon J runs against soft mating surfaces such as mild steel, aluminium and 316/304 Stainless Steel without the mating surface wear found with other filled PTFE compounds.
Crossflon 905
General purpose bearing material operating at PV values up to 0.78, ideal for rotary and liner applications. Crossflon 905 is suitable for all shaft surfaces, i.e. Stainless Steel, mild steel, aluminium.

Design Criteria
In choosing the appropriate Crossflon bearing, the critical parameters of the application must first be determined. Bearing load, speed, PV, environment, mating surface, duty cycle, etc. all play an integral part in this choice. The more important criteria are described here, and their values listed in the "Design Criteria".

Bearing Pressure
Bearing Pressure is measured in Newtons per square millimetres (N/mm²) or Megapascals (Mpa). It is calculated by distributing the total load in Newtons that the bearing is carrying by the projected area (I.D x length in mm) of the bearing. This gives the avearge pressure, MPa, that the bearing must support. The criteria chart lists the maximum recommended ambient temperature and static pressures. Elevated temperatures generally reduce static load capacity, lower temperatures generally increase load capacity.

Bearing Speed
Bearing Speed is determined by fiest calculating the circumference of the shaft I metres, then multiplying by the revolutions per second of the shaft. This gives the sliding, or surface velocity of the bearing in metres per second (ms-1). The chart lists the maximum recommended dry sliding speed at very light loads. Lubrication or liquid cooling can greatly extend these limits.

Bearing PV
The third parameter is the product of operating pressure and surface velocity, defined as PV. (PxV = PV) It is in effect a measure of the work the bearing is doing. While it is not the final answer, PV is an invaluable general guide in matching bearing to application.

Shaft Hardness and Finish
The various Crossflon materials are designed to operate against surfaces that have minimum hardness and surface finish requriements. These mnimum values should be followed since each bearing's published dynamic properties and predicted wear rate are based on this system.

Friction and Wear
Crossflon Bearings utilise custom-compounded PTFE. Like PTFE they exhibit very low friction at very low speeds, and very low friction at high loads. These properties are diametrically opposed to most other materials and give Crossflon bearings their smooth start/stop characateristics. They eliminate most stick-slip problems.

Start-up Phase
In the start-up phase, a transfer takes place between the bearing material and the shaft or counter-face. This initial transfer is essential in order to ensure that the bearing runs at its optimum friction and life expectancy. After initial break-in, the wear rate levels out, and the coefficients of friction continue to change through this phase, until finally attaining a value that is for the most part, constant.

WHY USE CROSSFLON PLANE BEARINGS

Wherever low-cost high-performance dry bearings are desired for service up to 2.0 PV.
Where bearing lubrication is undesirable or impossible.
Where high temperature up to 250ºC or low temperatures down to -200ºC occur and oil and grease are unsuitable.
In corrosive environments, with non-lubricating liquids, or under conditions of high or low humidity, or where high vacuums are present.
In lubricated applications where friction and wear rates are unacceptable during starting and stopping, or where stick-slip is a problem.
Where the electrical and insulating properies are important.
Where space and weight must be saved.
Where other bearings, metal or polymer, are causing problems.

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