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1. PLANE BEARING DESIGN AND MATERIALSWhere and When to Use Plastics As A Bearingpresented by David Biering Technical Director
3. PLANE BEARING PRODUCTS
4. PLANE BEARING PRODUCTS
5. What is a Plane Bearing?
A plane bearing is any non-rolling element
Sleeve or flange bushings
Slide plates
Friction Bearings
Any situation where two surfaces rub together is a plane bearing
6. Plane bearings offer several advantages when properly applied SIMPLE COMPONENTS
SELF-LUBRICATING
WIDE RANGE OF ENVIRONMENTS SERVED
EASY INSTALLATION AND REMOVAL
LOWER COST
7. All plane bearing designs are material selection problems!
All designs must include a review of the following:
BEARING LOAD – P
BEARING SPEED – V
COMBINED P-V
TEMPERATURE
TEMPERATURE VARIATIONS
ENVIRONMENT
8. Bearing Loads are often the most difficult attribute to define PRESSURE (P) = Load/Projected Area
P=LBS/ID X LENGTH
P IS EXPRESSED IN PSI
Each material is rated for a maximum static load (P)?
9. The Relative Speed between the shaft and the bearing is usually easier to define. VELOCITY (V) =Circumference x RPM
Circumference (C) = TTD/12 in feet
V is expressed in Surface Feet per Minute
(SFPM)?
Every material is rated for a maximum velocity (V) at no load
10. Pressure (P) and Velocity (V) do not occur independently and must always be dealt with in tandem! The combination of load and speed generates frictional heat
AS A RESULT WE MUST ALWAYS REVIEW P X V or PV
Every material has a maximum PV Rating
11. Material Rating Overview Material Max. PV Max. P Max. V
Graphite PI 300,000 6,000 1000
Carbon/PTFE PEEK 100,000 6,000 600
Tri Steel PE (lubed) 100,000 40,000 2,000
Tri Steel PI 50,000 36,000 1000
Oilite Bronze 50,000 2,000 1200
Carbon PEEK 50,000 6,000 600
FCJ 20,000 20,000 500
Ultracomp UC200 20,000 54,500 15
Ultracomp UC300 20,000 45,000 30
Rulon 10,000 1,000 400
CJ 10,000 35,000 150
Delrin AF 3,000 1,000 100
Nylon 6/6 1,000 300 360
UHMW 1,000 800 50
12. Other Factors Can Affect The Ability of Plane Bearing Systems to Handle the P, V and PV AMBIENT TEMPERATURE - HIGHER AMBIENT TEMPERATURES REDUCE ALL CAPACITIES
INTERMITTENT OPERATION – OSCILLATING AND RECIPROCATING MOTION ALLOW HIGHER P, V, AND PV VALUES
SHAFT MATERIALS – MATERIALS THAT ARE GOOD THERMAL CONDUCTORS ALLOW INCREASED VALUES
SURFACE FINISH – TOO SMOOTH A SURFACE FINISH WILL GENERATE HIGHER FRICTION, THUS MORE HEAT, AND WILL LOWER VALUES
13. MANY PLANE MATERIALS ARE PLASTIC OR PLASTIC LIKE MATERIALS
THESE MATERIALS ARE AFFECTED BY HEAT AND ALL HAVE A MAXIMUM CONTINUOUS OPERATING TEMPERATURE
14. Maximum Operating Temperature of Plastics MATERIAL MAX. OPERATING TEMPERATURE °F
Graphite Polyimide 650
Rulon 550
TriSteel PI 500
Carbon/PTFE PEEK 480
Carbon PEEK 480
FCJ/CJ 320
Ultracomp 266
Nylon 6/6 210
Delrin 180
UHMW 180
15. Plane Bearing materials have coefficients of thermal expansion that differ from surrounding hardware!
As a result, bearings that operate at elevated or extreme low temperatures or function in hot/cold cyclic environments must be given special design attention.
Lack of attention to the thermal expansion rates of the bearing material will cause seizure or bearing drop out
16. Plane Bearing Coefficients of Thermal Expansion MATERIALS EXPANSION IN/IN°F x 10E-6
Tri Steel PT 6.0
1040 Carbon Steel 6.0
FCJ 7.0
CJ 7.0
Carbon Fiber PEEK 7.0
660 Bronze 10.0
Aluminum 12.4
Carbon/PTFE PEEK 17.0
Graphite PI 27.0
Ultracomp 33.0
Rulon 35-49.0
Nylon 6/6 55.0
Delrin AF 63.0
UHMW 130.0
17. A major strength of plane bearings is their ability to function in a wide range of environments
Wet – fresh, salt, DI, slurry
Dirty – coal, quartz, sand, road ballast
Chemicals – full pH range
Clean rooms – minimal debris production
FDA/USDA/3A/NSF approvals
AND ALL THIS WITHOUT LUBRICATION!
18. How do self lubricating plastics bearings lubricate? There are two types of lubrication methods in plastic plane bearings:
Smearing systems – small amounts of lubricating additives such as PTFE, silicone, graphite or MOS2 are wiped into the microfinish
Debris systems – small particles of the polymer are removed during normal operations and develop plastic “ball bearings”
19. Smearing Systems Smearing systems are typical of PTFE and PTFE filled polymers
As the shaft makes initial contact with the mating contact surface, softer lubricating material is wiped into the microfinish of that surface building a thin film of lubricant
Lubricant remains in place and will not migrate out thus reducing the friction and wear on both the shaft and the bearing.
20. Smearing System Materials Best know materials utilizing this type of self lubricating process:
Rulon
Fluorosint
PTFE Blends
Delrin AF
Ertalyte TX
BG PEEK
Graphite PI
TriSteel PT/PI
Ultracomp
21. Debris Systems Debris systems are found in harder thermoplastic or thermoset polymers that deposit particles of the actual resin between the shaft and bearing.
These types of materials tend to be less efficient since the debris remains on the surface area between the dynamic faces rather than embedding.
Over time the debris is “cast off” as residue and the wear process tends to be on a slow but continuous basis.
22. Debris Systems Materials Nylon 6/6, 6/12
Acetal/Delrin 100/500
Cast Nylons
UHMW
It should be noted that debris materials have inherently low friction but not as low as smearing systems with migratory lubricants.
It should also be noted that debris materials tend to be lower cost than the smear materials but they also have lower P,V,PV ratings and limited temperature ranges.
23. Materials Review By far, the largest family of self lubricating plane bearings are the filled PTFE materials.
The best known of these is Rulon, a family of blended PTFE materials designed for bearings, seals and structural components.
Fluorosint family of mica filled PTFE for low thermal expansion applications
24. Rulon Bearings
25. Rulon Bearings Rulon™ is a product from Saint Gobain Performance Plastics – Formerly Dixon-Furon
Family of products has over 300 blends
Tri Star Plastics is the Master Distributor for Rulon products in North America
26. Rulon Bearings All Rulon materials have similar properties:
Temp. Range - -400 to +550/600F
Inert to all chemistry
Zero moisture absorption
Self Lubricating
Variable thermal expansion properties
Outstanding wear life and strength
27. Most Common Rulon Bearing Materials Rulon LR – maroon color, ceramic fiber filled, excellent creep and wear resistance, low friction – best used against 35RC hardness or better
Rulon J – gold color, lowest friction of any plastic, non abrasive so will run against soft shaft materials
Rulon 641 – white color, FDA grade for food processing and packaging applications
Rulon 142 – blue/grey color – bronze filled for extremely low deformation, excellent sliding bearing for machine tools, motor mounts, slide pads
28. Rulon Availability All Rulon materials are available in standard sleeve, flange and thrust sizes to match bronze standards
Rulon is also available in rod, sheet, tape or tube for in house machining
Rulon is very easy to machine and Tri Star can assist with techniques.
29. Bearing Grade Composite Materials The newest generation of self lubricating plane bearings are composites
Ultracomp – family of very high load, low speed bearing materials for high impact and vibration applications on oscillating pin bushings
CJ – filament wound rigid epoxy bearing for extreme loads in oscillating or rotary applications. PTFE/Nomex liner on ID for low friction and long wear life
FCJ – filament wound rigid epoxy bearing for extreme loads in full rotary or linear applications. Alloyed PTFE liner for increased speed ratings. Lower load rating than CJ and Ultracomp
30. Ultracomp Ultracomp is a made using synthetic fibers and impact resistant thermoset resins for extreme loads.
Ultracomp bearings have static load ratings of 54,500 psi to break and 18,500 psi to yield.
Ultracomp is primarily a high load, low speed oscillating material.
All Ultracomp materials have less than 0.1% swell in water
All Ultracomp materials have migratory lubricants such as PTFE, graphite or MOS2
31. Ultracomp
32. Ultracomp Ultracomp materials are used in construction, agriculture, material handling, railway, and general industries for pin bushings, slide pads, spherical inserts, trunnion support bearings, etc.
Ultracomp is easy to machine
Ultracomp is an excellent replacement material for lubricated steel or bronze bushings
33. CJ Bearings CJ bearings are off the shelf replacement bearings to bronze standards
CJ bearings use filament winding techniques at different helix configurations to improve strength through the wall.
Nomex/TFE blended liner gives excellent wear life and lubricity
CJ bearings have very low swell in water and are thermally stable for tight tolerance designs
34. FCJ Bearings FCJ bearing is similar to the CJ but the Nomex/TFE liner is substituted with a alloyed PTFE tape liner
Lower load limits than CJ but higher speed rating for full rotary applications without lubrication
Excellent wear and friction properties
35. TriSteel® Metal Backed Bearings TriSteel bearings are metal bearings with various self lubricating liner materials sintered into the substrate
Liner materials vary depending on loads and speeds
Liner materials include PTFE, Acetal, PEEK, PI/PTFE blends, PTFE/PVDF blends
All TriSteel bearings have very high P, V and PV ratings and have extremely low deformation
36. TriSteel Bearings
37. Tri Steel Bearings Tri Steel bearings are available with tin or copper plated steel, 316 stainless or bronze.
Liner materials will vary in thickness from .002” to .020”
Wall thicknesses are .060 and .090 nominal
38. TriSteel Bearings TriSteel bearings are capable of PV ratings up to 80,000 without lubrication and 2 million with lubrication
Temperature ratings vary from -400F to +500F
PEEK/SS grade excellent substitute for rolling element bearings in chemical pumps and other rotary equipment
40. High Performance Materials An additional group of plane bearing materials are the HPM grades:
PI – polyimide with graphite additives can operate at 700F without lubrication and with extremely low wear. PV ratings as high as 300,000 in some conditions without lube
Trade names - Meldin®, Vespel®, Duratron®
41. High Performance Materials
42. High Performance Materials High Performance Materials are catagorized as imidized materials and advanced hybrid polymers.
Imidized materials include:
Celazole PBI
Polyimide – Vespel, Meldin, Duratron
Polyamide-imide – Torlon
Kapton – polyimide film
43. High Performance Materials PBI – Highest temperature polymer on the market
HDT of over 800F with continuous service over 750F and short term excursions to 1100F
Ionic impurities very low
Very strong material without any fillers
Lowest coefficient of thermal expansion of any unfilled plastic
Highest compressive strength of any unfilled plastic
Excellent thermal insulator
Inherently good wear properties without PTFE
44. High Performance Materials Polyimides
True condensation polymer with excellent wear and thermal properties
Vespel best known trade name. Meldin family is 8 different versions of polyimide
Compression, isostatic or injection moldable. Also available in thin cast films known as Kapton
Unfilled and filled versions available for different bearing or structural needs
45. High Performance Materials Another family of HPM products is Torlon® which is a PAI.
Excellent wear life at extreme speeds without lubrication
PV values up to 3 million with lube
Used as sleeve or thrust bearing in transmissions, gear boxes, final drives, etc.
Thermally stable, coefficient of thermal expansion close to steel
46. High Performance Materials PEEK – available with carbon fiber, graphite powder and PTFE fillers for outstanding high load, high speed rotary applications
Inert to most chemistry, able to work in steam or high temperature liquids
Very low thermal expansion, excellent wear life and low friction
47. Other Bearing Grade Materials There are many more engineering grade plastics used in bearing applications
PET – Ertalyte, Ertalyte TX
PBT - Hydex
PPS – Ryton, Techtron – Poor Mans PEEK
Cast Nylons (Nylatron)?
48. Final Comments Tri Star Plastics specializes in material development, design and fabrication of self lubricating plastic bearings.
Our interest is in assisting customers with product selection, component development and successful production.
Our website www.tstar.com is interactive and you can use our online design assistance to determine potential materials for your application.
49. Final Comments Tri Star looks forward to working with you as you investigate improved performance, longer life and more cost effective bearing systems for your equipment.
Remember – No lube/No maintenance!
50. Supplier Recognition Ultracomp – Tri Star Plastics Hydex – Ensinger/Hyde
TriSteel – Tri Star Plastics Ertalyte - Quadrant
Delrin – E.I. DuPont Ryton - Phillips
Celazole – Quadrant Torlon – Solvay Chemical
PEEK – Victrex CJ/FCJ – Saint Gobain EPP
Teflon – E.I. Dupont Duratron - Quadrant
Rulon – Saint Gobain EPP Techtron - Quadrant
Nylatron – Quadrant Fluorosint - Quadrant
Nylon – E.I. DuPont
Meldin – Saint Gobain EPP
Vespel – E.I. DuPont Some names are registered tradenames of various companies.
Values indicated are typical. Tri Star recommends testing in your particular application to insure performance expectations are met.