1 Special Environmental Specifications of Linear Motion Systems The linear motion systems used in special environments such as semiconductor production systems, liquid crystal production systems, health care equipment and food processing machinery are the product of roughly 30 years of technology and a vast amount of experience. This brochure provides an introduction to the special environmental specifications products created by taking full advantages of ’s proprietary Caged Ball Technology, materials technology, lubrication technology and surface treatment technology in order to effectively respond to the increasingly diversified needs of today. Clean Rooms High Speed Corrosion Resistance Vacuum High Temperatures Low Temperatures Fine Movement
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1
Special EnvironmentalSpecifications of
Linear Motion Systems
The linear motion systems used in special environments such as
semiconductor production systems, liquid crystal production systems, health
care equipment and food processing machinery are the product of roughly
30 years of technology and a vast amount of experience.
This brochure provides an introduction to the special environmentalspecifications products created by taking full advantages of ’s
technology and surface treatment technology in order to effectively respond
to the increasingly diversified needs of today.
CleanRooms
HighSpeed
Corrosion
Resistance
Vacuum
High
Temperatures
LowTemperatures
FineMovement
CleanRooms
In clean environments such as the environments found inclean rooms, it is necessary to reduce the generation of dustby linear motion systems as well as enhance rust preventiveperformance since rust preventive films cannot be used. Inaddition, depending on the degree of cleanliness of the cleanroom, it is also necessary to use a dust collector.
AFE Grease and AFF GreaseGrease resulting in low generation of dust is used and is suitablefor clean environments.
LM Guide with Ball CageThe use of the LM Guide with Ball Cage reduces the level of metalwear fragments produced by eliminating friction between the balls,thereby making it possible to suppress the generation of dust.
Stainless Steel LM GuideThis LM Guide uses martensite stainless steel that is effective inprohibiting rust.
High Corrosion Resistance LM GuideThe LM Rail uses austenite stainless steel resulting in a highdegree of rust preventive effects.
AP-C Treatment, AP-CF Treatment and AP-HC TreatmentSurface treatment (plating) of linear motion systems results inimproved rust prevention capabilities.
1
VacuumIn vacuum environments, it is necessary to selectproducts having excellent rust preventioncapabilities as countermeasures against dispersionof gases released from resins and splattering ofgrease since rust preventive oil cannot be used.
Measures against gasreleased from resins:
Measures againstgrease splattering:
Rust preventativecountermeasures:
Stainless Steel LM GuideStainless steel is used for the material of the end plates of the LM block(through which plastic balls circulate) to reduce the levels of released gas.
Vacuum GreaseWhen general-purpose grease is used in a vacuum environment,the oil component of the grease ends up dispersing resulting in aloss of lubricity. Consequently, vacuum grease is used that uses afluorine-based oil having a low vapor pressure for the base oil.
Stainless Steel LM GuideThe stainless steel LM Guide is used in vacuum environments dueto its excellent rust preventative effects.
High-Temperature LM GuideThe high-temperature LM Guide is used in cases of being subjectedto high temperatures such as during baking, etc. because of itsexcellent heat resistance and corrosion resistance.
2
Measures against dustgeneration caused bysplattering of grease:
Measures against dustgeneration caused byproduction of metalwear fragments:
Materialcountermeasures:
Surface treatmentcountermeasures:
Generation of Dust from Linear Motion Systems
Rust Prevention
2
Similar to the case of use in clean rooms,corrosion resistance is enhanced byselecting appropriate materials and surfacetreatment.
Materialcountermeasures:
Surface treatmentcountermeasures:
Stainless Steel LM GuideThis LM Guide uses martensite stainless steel that is effective inprohibiting rust.
High Corrosion Resistance LM GuideThe LM Rail uses austenite stainless steel resulting in a highdegree of rust preventative effects.
AP-C Treatment, AP-CF Treatment and AP-HC TreatmentSurface treatment (plating) of linear motion systems results inimproved rust prevention capabilities.
3
4 In high-speed environments, an optimum lubricationmethod is required that suppresses the generation ofheat during high-speed motion and improves theretention capabilities of the grease.
Measures againstheat generation:
Lubricationcountermeasures:
LM Guide with Ball CageHeat generation is reduced as a result of the ball cageeliminating friction between the balls. Moreover, since theretention capabilities of the grease are improved, a long servicelife and outstanding high-speed performance are achieved.
High-Speed Ball Screw with Ball Cage(DN value = 130,000)The use of a ball cage realizes the ideal ball circulationstructure, enabling high-speed feeding unable to be realized withconventional products.
AFG GreaseThe use of grease capable of suppressing heat generationduring high-speed use while also offering excellent lubricitymakes it possible to achieve high-speed feeding.
Lubricator QZLubricator QZ makes it possible to significantly extendlubrication maintenance intervals by compensating for lost oil.Since only the minimal amount of lubricating oil is applied to therolling surface, the surroundings are not soiled resulting in alubrication system that is environmentally friendly.
CorrosionResistance
HighSpeed
3
6Under low-temperature conditions, grease is usedthat results in minimal effects on plastic partscaused by low temperatures while also minimizingfluctuations in rust preventative countermeasurescaused by temperature changes from normal tolow temperatures as well as fluctuations in rollingresistance even at low temperatures.
Effects of lowtemperatures onplastic parts:
Rust preventativecountermeasures:
Grease:
Stainless Steel LM GuideStainless steel is used for the material of the end plates ofthe LM block (through which plastic balls circulate).
Surface treatment of the linear motion system results inenhanced rust preventative capabilities.
AFC Grease is used that exhibits only minorfluctuations in rolling resistance even at low temperatures.
In high-temperature environments, the effectsof dimensional changes caused by heat canbecome a problem. The High-Temperature LMGuide and High-Temperature Grease are usedbecause they offer outstanding heat resistanceand are subjected to minimal dimensionalchanges following heating and cooling.
Heat resistance:
Grease:
High-Temperature LM GuideThis LM Guide offers outstanding heat resistance and issubjected to only minimal dimensional changes followingheating and cooling.
High-Temperature GreaseHigh-temperature grease is used because it causes only minorfluctuations in rolling resistance even during temperaturechanges from normal temperature to high temperatures.
5
7Extremely short strokes can cause oil films to bedepleted and ineffective lubrication eventuallyleading to rapid wear. In cases such as this, agrease is selected that has excellent oil filmstrength and enables the oil film to be formedeasily.
Grease: AFC GreaseThis urea-based grease offers excellent oil film strength andwear resistance.
LowTemperatures
HighTemperatures
Finemovement
4
Special Environmental Specifications of Linear Motion Systems
Special Environmental Specifications of Linear Motion Systems
Clean RoomsHSRHRHRW
HSR-M2
SRRSRRSH
SSRSHWSRS
LM Guide with Caged Ball Technology
High Corrosion Resistance LM Guide
Surface Treatment
Grease
Applicable types
SRS
Applicable type
Applicable types
• Measures against dust generation
• Rust preventative countermeasures
Stainless Steel LM Guide
SHSSSR
SNR/SNSSHW
5
P.15~
P.19~
P.19~
P.21~
P.23~
P.24~
Clean
Rooms
SHS
AP-HC Treatment
AFF Grease
AFE Grease
SHW SRS
SSR
HSR-M2
SNR/SNS
6
Vacuum
High-Temperature LM Guide
High Corrosion Resistance LM Guide
Stainless Steel LM Guide
Applicable type
HSR-M1SR-M1
RSR-M1Applicable types
Applicable types
Vacuum Grease
• Measures against released gases
• Measures against grease splattering
• Rust preventative countermeasures
HSR-M2
HSRHRHRW
SRRSRRSH
SSRSHWSRS
7
Special Environmental Specifications of Linear Motion Systems
P.19~
P.20~
P.19~
HSR-M2
HSR-M1SR-M1RSR-M1
Vacuum
8
CorrosionResistance
HSR-M2
High Corrosion Resistance LM Guide
Applicable type
HSRHRHRW
SRRSRRSH
SSRSHWSRS
Stainless Steel LM Guide
Applicable types
Surface Treatment
• Material countermeasures
• Surface treatment countermeasures
9
Special Environmental Specifications of Linear Motion Systems
P.19~
P.19~
P.21~
P.22~
P.22~
Corrosion
Resistance
AP-CF Treatment
AP-HC Treatment
HSR-M2
AP-C Treatment
10
High Speed
SBN
LM Guide with Caged Ball Technology
High-Speed Ball Screw with Caged Ball Technology
Lubricator QZ
Grease
SHSSSR
SNR/SNSSHW SRS
Applicable types
Applicable type
• Measures against heat generation
• Grease retention
11
Special Environmental Specifications of Linear Motion Systems
P.15~
P.17~
P.18~
P.18~
P.25~
HighSpeed
Lubricator QZ forLM Guide
Lubricator QZ forBall Screw
AFG Grease
SBN
SHS
SHW
SSR SNR/SNS
SRS
12
High Temperatures
Fine Movement
High-Temperature Grease
Sruface Treatment
Grease
Grease
High-Temperature LM Guide
HSR-M1SR-M1
Applicable types
• Grease retention
• Effects on plastic parts
• Rust preventative countermeasures
• Grease
• Heat resistance• Grease
Low TemperaturesHSRHRHRW
SRRSRRSH
SSRSHWSRS
Stainless Steel LM Guide
Applicable types
RSR-M1
13
Special Environmental Specifications of Linear Motion Systems
P.19~
P.20~
P.22~
P.26~
P.26~
Fine
MovementLow
TemperaturesHigh
Temperatures
AFC Grease
AP-CF Treatment
AFC Grease
HSR-M1SR-M1RSR-M1
14
15
■Low Dust Generation Data
■Friction Between Balls
Time (hours)
Am
ount
of d
ust g
ener
ated
(par
ticle
s/2
min
-lite
r)
00
100
200
300
5 10 15 20
Am
ount
of d
ust g
ener
ated
(par
ticle
s/2
min
-lite
r)
Time (hours)
00
100
200
300
5 10 15 20
Contact between balls is eliminated for reduced ball wear
The LM Guide with Ball Cage is able to demonstrate outstanding low dust generation performancedue to the low level of production of metal wear fragments as a result of the ball cage eliminatingfriction between the balls.
LM Guide with Caged Ball Technology HighSpeedClean
Rooms
Contact state between balls and cage
Particle size(µm)
0.3 – 0.50.5 – 1.01.0 – 2.0
2.0 – 5.05.0 –
16
The use of ball cages reduces the generation of heat caused by friction between the balls, therebyimproving grease retention capabilities and resulting in outstanding high-speed performance.
Grease remains on theballs and there are noabnormalities observedin the balls or grease.
Detailed illustration of ball cage
Calculated service life
23000km
8618km
0 5000 10000 15000 20000 25000
Distance traveled (km)
Distance traveled
■High-Speed Durability Test ResultsSample : SHS65LVSSSpeed : 200 m/minStroke : 2500 mmLubrication : Initial sealing of
grease onlyActing load : 34.5 kNAcceleration : 1.5 G
Grease retention status after travel(SHS45LV: load durability test)
Grease pockets are formed around the entire circumference of the ball cage.
17
Ball guidance in ball rolling direction
Ball guidance in lead angle
Lead angle
Return pipe
Screw shaft
Pick up angle
Nut
Tangential direction
Return pipe
Screw shaft
Nut
SBN Type
Conventional Type
The use of ball cages in the SBN type results in smooth ball circulation and is the ideal form of ballcirculation for accommodating high speeds, resulting in outstanding high-speed performance and loaddurability.
■High-Speed Durability Test ■Load Durability Test
Sample
Speed
Stroke
Lubricant
Amount applied
Load
Acceleration
SNB3210-7
3900 (min-1) (DN value: 130,000)
400 mm
AFG grease
12 cm3 (applied every 1000 km)
1.73 kN
1 G
Conditions
Results
No abnormalities after 3000 km of travel(still running)
Sample
Speed
Stroke
Lubricant
Amount applied
Load
Acceleration
SBN3210-7
1500 (min-1)
300 mm
AFG grease
12 cm3 (applied every 1000 km)
17.3 kN
0.5 G
Conditions
Results
Traveled 2.5 times the estimated service life
Since the return pipe of the SBN type does not have a lip so that the balls are picked up in thetangential direction, a flexible ball track is maintained resulting in the ideal form of circulation. Inaddition, since the design of the return pipe and ball cage enables these parts to have adequatestrength, they can be used at a DN value of 130,000.
High-Speed Ball Screw with Caged Ball Technology HighSpeed
18
LM Guide Lubricator QZ
The LM Guide and Ball Screw lose a small amount of grease during the course of travel.The Lubricator QZ is a revolutionary new lubrication system that supplies an appropriate amount oflubricating oil at the appropriate locations, thereby enabling it to compensate for any oil lost over along period of time. Installation of the Lubricator QZ on the LM Guide with Ball Cage or High-SpeedBall Screw with Ball Cage, demonstrating excellent grease retention capabilities, results in evenfurther enhanced lubrication performance.
Significant Extension ofMaintenance IntervalsSince lubricating oil is continued to besupplied for a long time, maintenanceintervals can be extended considerably.
Since the Lubricator QZ supplies an optimal amount of lubricating oilat appropriate locations, lubricating oil can be used without waste.
Lubricator QZ oil content:0.166 cm3/sheet x 2 sheets
= 0.332 cm3
Forced lubrication:0.03 cm3/6 min x 16667 min
= 83.3 cm3
Amount of lubricating oil used is 1/250that of forced lubrication.
Comparison
Ball Screw Lubricator QZ
Comparison of Amount of LubricatingOil Used After Travelling 5000 km
19
Stainless Steel LM Guide delivers outstanding corrosion resistance as a result of using martensitestainless steel. In addition, heat treatment to a level of HRC58 or higher results in a long service life,enabling it to withstand high loads.
Although plastic end plates are used in ordinary environments, when used in a vacuum environment,SUS304 (austenite stainless steel) is used for the end plates to reduce the level of released gases.SUS304 materials are characterized by low oxidation and low levels of released gases.
Stainless Steel LM Guide Low
TemperaturesCorrosion
ResistanceVacuumClean
Rooms
(SUS304)
(THK-EX50)
(SUS440C)
(THK-EX50)
End plate
Ball
LM rail
LM block
End plate(synthetic plastic)
Side seal(synthetic rubber)
Ball(SUS431)
LM rail(SUS304)
Retaining plate(SUS304)
Retaining plate(SUS304)
Grease nipple(SUS304)
End seal(synthetic rubber)
LM block(SUS431)
45
45
Structure of the Type HSR-M2A High Corrosion Resistance LM Guide
Austenite stainless steel SUS304, offering excellentcorrosion resistance, is used for the LM rail, wile SUS431,offering the highest level of corrosion resistance amongmartensite stainless steel materials, is used for the LM blockand balls. The result is a significant improvement in corrosionresistance over conventional stainless steel (SUS440C).
High Corrosion Resistance LM Guide Corrosion
ResistanceVacuumClean
Rooms
High Corrosion Resistance LM Guide
Standard Stainless Steel Guide
20
14
12
10
8
6
4
2
0Normal
temperature150°C
Measurement temperature
Flu
ctu
ation v
alu
e (
N) —THK high-temperature grease
...Competitor’s high-temperature grease
End plate(SUS304)
Side seal(high-temperature rubber)
Ball(SUS44C)
LM rail(THK-EX50)
End seal(high-temperature rubber)
LM block(THK-EX50)
45
45
Structure and Materials of High-Temperature LM Guide (Type HSR)
• Total length and curvature dataindicate the amount of change whenfrom normal temperature to 150°C for100 hours followed by cooling tonormal temperature.
• HSR25 + 580L high-temperature,standard and stainless steel productswere used for the samples.
Dimension stabilizationtreatment makes it possible toreduce dimensional changesfollowing heating and coolingto extremely low levels.
High-temperature grease isused that minimizes changesand fluctuations (catching) inrolling resistance caused bythe grease even when thetemperature changes fromnormal temperature to hightemperature.
HSR25M1R1C1 is used as the samplefor the above data.
The LM block and LM rail are made of -EX50 martensite stainless steel additionally treatedfor dimensional stability to minimize the effects of heat on dimensional changes.
SUS304 austenite stainless steel is used for the end plates for enhanced heat resistance.
High-Temperature LM Guide High
TemperaturesVacuum
■Dimensional Stability Data
Fluctuation value
Spceific heat capacity : 0.481J/(g • K)
Coefficient of thermal conductivity: 20.67W/(m • K)
Mean coefficient of linear expansion : 11.8 x 10-6/°C
Thermal Characteristics ofLM Rail and LM Block Materials
21
AP-HC treatment results in high surface hardness and offers excellentwear resistance. The large amount of wear occurring in the initial portion of thegraph is considered to be attributed to initial wear of the end seals.
Note: THK AP-HC treatment (equivalent to hard chrome plating)THK AP-CF treatment (equivalent to black chrome plating + fluororesin coating)
■Characteristics of AP-HC Treatment
■ AP-HC TreatmentTHK AP-HC treatment is equivalent to hard chrome plating, and allows for corrosion resistance
nearly equivalent to that of martensite stainless steel.In addition, since surface treatment is performed that results in the formation of a film having ahardness of 700 HV or more, dust generation is reduced while offering outstanding wear resistance.
Surface Treatment Low
TemperaturesCorrosion
ResistanceClean
Rooms
00
20
40
60
80
10 20 30 40 50
Time (hours)
AP-CF (without seal)
AP-CF (with seal)
AP-HC (with seal)
Dus
t cou
nt P
(p/
1-m
in)
Test ConditionsLM guide model numbers :SSR20WF + 280LF (AP-CF with seal)SSR20UUF + 280LF (AP-CF without seal)SSR20UUF + 280LF (AP-HC with seal)Injected grease : AFE GreaseAmount applied : 1 cc (1 block)
Cycled saltwater spraying testSprayed solution : 1% NaCl solutionCycle : Spraying for 6 hours followed by drying for 6 hoursTemperature conditions : During spraying : 35°C
During drying : 60°C
■ AP-C TreatmentTHK AP-C treatment consists of black film treatment for the purpose of improving corrosion resistance.
It is used in applications requiring rust prevention since it is priced lower than stainless steel LM guides.
■ AP-CF TreatmentTHK AP-CF treatment consists of compound surface treatment in which a special fluororesin is coated
into a black film. Since this treatment results in complete coverage of metal surfaces, it offers a high degreeof rust prevention and is suitable in cases requiring a high level of corrosion resistance. Moreover, since thefluororesin constitutes a chemically stable film, it also offers outstanding contamination resistance.
Before testing
After 6 hours
After 24 hours
After 96 hours
Austenitestainless steel
Martensitestainless steel AP-HC AP-C AP-CF
Test material
Time
23
Test itemWorking temperature range (°C)Mixing consistency (25°C, 60 W)Dropping point : °CCopper plate corrosion (100°C, 24h)Evaporation : mass% (99°C, 22h)Oil separation : mass% (100°C, 24h)Oxidation stability : kPa (99°C, 100h)Impurities : quantity/cm2 25 µm or larger 75 µm or larger 125 µm or largerMixture stability (100,000 W)Low-temperature torque : StartingN-m (–20°C) RunningApparent viscosity : Pa-s (–10°C, 10S-1)Timken load resistance performance : NFour-ball test (fused load) : NAnti-fletching performance : mg
4 cm3/1 LM block (initial injection only)1 mm/s3 mm
Test Conditions
Low-Speed Rolling Resistance ValuesGrease Viscous Resistance Values
AFF Grease is a high-grade syntheticoil that uses a lithium-based thickener andspecial additives to realize the perfect balance ofstable rolling resistance, low dust generation andflaking resistance not possible with conventionalvacuum grease and low dust generation grease.
The use of THK AFF Grease results inimproved uniform velocity characteristics of theprecision positioning units used in semiconductorand liquid crystal production systems as well asimproved response during micro-step feeding.Moreover, due to its excellent flaking resistanceto minute vibrations (f ine movement wearperformance), the intervals between lubricationtimes can be extended resulting in a reduction inmaintenance costs.
AFE Grease uses for its base oil ahigh-grade synthetic oil along with a urea-based thickener for outstanding low dustgeneration characteristics.
Since THK AFE Grease is able toaccommodate a wide temperature range fromlow temperatures to high temperatures, andgenerates lower levels of dust than vacuumgrease and typical low dust generation greaseconventionally used for low dust generation, itis optimal for the LM guide, ball screws andvarious other units of semiconductor and liquiddisplay production systems. In addition, it alsocontributes to reduced maintenance costs bybeing able to significantly extend the servicelife of LM systems.
AFE Grease Clean
Rooms
Typical Properties of AFE Grease
25
Test item
Mixing consistency (25°C, 60 times)
Dropping point : °C
Copper plate corrosion (Method B, 100°C, 24h)
Evaporation : mass% (99°C, 22h)
Oil separation : mass% (100°C, 24h)
Oxidation stability : Mpa (99°C, 100h)
Mixture stability (100,000 times)
Rinsing resistance : mass% (38°C, 1 h)
Low-temperature torque : Starting
N-m (–54°C) Running
Rust prevention test : (52°C, 48h)
Testing method
JIS K2220 5.3
JIS K2220 5.4
JIS K2220 5.5
JIS K2220 5.6
JIS K2220 5.7
JIS K2220 5.8
JIS K2220 5.11
JIS K2220 5.12
JIS K2220 5.14
ASTM D1743
Typical values
285
261
Passing
0.20
0.50
0.029
329
0.6
0.439
0.049
1,1,1
Typical Properties of AFG Grease
0 500 1000 1500
Shaft rotating speed (min-1)
2000 2500 3000 3500
60
50
40
30
20
AFG Grease
Typical grease
Sat
urat
ion
tem
pera
ture
of
nut e
xter
ior
(°C
)
Item
Shaft diameter/lead
Speed
Shaft rotating speed
Stroke
Amount of grease injected
Temperature measurementlocation
Description
32/10mm
67 - 500mm/s
400 - 3000min 1
400mm
12cm3
Nut exterior
Appearance of shaft traveled region after traveling for 1000 km Appearance of balls after traveling for 1000 km
There are no abnormalities observed.
Unused
Aftertravel
Item
Shaft diameter/lead
Max. rotating speed
Stroke
Acceleration
Description
32/10mm
3900 min-1 (DN value: 130,000)
400 mm
9.8 m/s2
[Lubrication Conditions]
Lubricant : AFG GreaseInjection volume : 12 cm3
(initial injection only)
AFG Grease uses for its base oil ahigh-grade synthetic oil along with a urea-based thickener for outstanding low dustgeneration characteristics. It also reducesheat generation during high-speed use whileoffering excellent oxidation stability.
AFG GreaseHigh
Temperatures
■Low Heat Generation Characteristics
■Ball Screw High-Speed Durability Test Combining with a ball screw with ballcage enabled use at ultra-highspeeds at a DN value of 130,000.
Test Conditions
Test Conditions
26
Test item
Mixing consistency (25°C, 60 W)
Dropping point : °C
Copper plate corrosion (Method B, 100°C, 24h)
Evaporation : (Method B, 177°C, 22h)
Oil separation : (177°C, 30h)
Oxidation stability : (99°C, 100h) MPa
Impurities : quantity/cm2 25-75 µm
75 µm or larger
Mixture stability (100,000 times)
Rinsing resistance : (38°C, 1 h) %
Low-temperature torque : Starting
N-m (–54°C) Running
Bearing rust prevention : (52°C, 48h)
Vibration test : (200 hr)
Working temperature range (°C)
Typical values
288
269
Passing
7.9
2.0
0.031
370
0
3.41
0.6
0.439
0.049
1,1,1
Passing
–52°C - +177°C
AFC Grease uses a high-gradesynthetic oil for its base oil along with a urea-based thickener and special additives torealize extremely outstanding flaking andcorrosion resistance.
Since AFC Grease also offers excellentoxidation stability, the intervals betweenlubrication times can be extended resulting ina reduction in maintenance costs ascompared with typical metallic soap-basedgrease.
AFC Grease
Item
Stroke
Strokes/min
Total strokes
Bearing pressure
Amount of grease injected
Description
3 mm
200 min-1
2.88 x 105 (24 hours)
1118MPa
12 g/unit (supplied every 8 hours)
■Flaking and Corrosion Resistance Test Data
Typical Properties of AFC Grease
1mm
1µm
1mm
2µm
Before travel
After travel
1mm
1µm
1mm
2µm
Before travel
After travel
AFC Grease General-purpose grease
Test Conditions
Fine
MovementLow
Temperatures
• “LM Guide” is the registered trademark of the THK Co., Ltd.• Appearance and specifications are subject to change without notice. Please inquire in advance at the time of use. • Although the utmost precautions have been taken in the production of this catalog, the manufacturer cannot take responsibility for
damages resulting from misprints or other clerical errors. Unauthorized reproduction prohibited