General Presentation
All the load is applied on the 4 external miniature linear guides.
The inner linear guide and the self-adjusting bearing are translating rotation into reciprocating motion but are not subjected to vertical load.
The inner linear guide and the self-adjusting bearing are translating rotation into reciprocating motion but are not subjected to vertical load.
Miniature Linear Guides
Specifications
Default Reciprocating:
Part Number | Misumi PN | Dynamic Load Rating (N) | Static Load Rating (N) | Temperature Range (°C) |
BM126049 | SSEBV10-55 | 1500 | 2500 | -20 ⇒ 80°C |
BM126051 | SSE2B10-155-WC | 1500 | 2500 | -20 ⇒ 80°C |
Load Rating & Rated Life
The linear guide load calculation sheet available in the customer manual was calculated using the following parameters and formulas:
- P1(max) = 1500N (as per misumi Dynamic Load rating)
- X = 50mm (Center of the 4 screws holding the carriages)
- Y = 36mm (Center of the 4 screws holding the carriages)
- W (Max applied load for that position to be within the Load rating):
Reciprocating extreme use case limits
- X0 = 15mm (max stroke length: 30mm, X.Position=0)
- Y0 = 18mm
X0 (Max position in X, mm) | Y0 (Max position in Y, mm) | W (Max applied load for that position to be within the Load rating) |
15 | 18 | 2308 |
Centered in X, Y at the extremity, the maximum load is 2300N
Rated Life
The linear guide rated life calculation sheet available in the customer manual was calculated using the following parameters and formulas:
- L : Rated Life (km)
- C : Basic Dynamic Load Rating (N)
- Dependent on the linear guide used
- P : Applied Load (N)
- Using the Pmax calculated previously to determine the maximum rated life of the guide under the highest load.
Self-Adjusting Ball Bearing
Rtec: BM121020
McM: 6660K11
Manufacturer: FAG
Item Number: 108-TVH
- Type of lubrication:
- Grease
- Oil
- Radial Load Capacity:
- Static: 560N
- Dynamic: 2750N
- Axial Load Capacity:
- Calculation needed
- Rated life:
- Calculation needed
- Rotational speed:
- Reference: 27.000RPM
- Limit: 39.000RPM
- Temperature Range:
- Min: -30°C
- Max: +120°C
Needle Roller Bearing
Rtec Part Number: BM121128
SKF: RNA 69/32
Schaeffler: RNA69/32-ZW-XL
Basic dynamic load rating, radial: 53kN
Basic static load rating, radial: 82kN
Limiting speed: 6700 rpm / 111.6Hz.
Reference speed: 6500 rpm / 108.3Hz
Min temperature: -30°C
Max temperature: +120°C
Production
Mounting
Linear Guides
Refer to the specific assembly drawing for the module to identify the correct Linear Guide part number. Always order replacement components using the exact part number listed on the drawing or bill of materials (BOM) to ensure compatibility and maintain alignment accuracy.
- Install the new rail
- Place the rail gently on the installation side of the base.
- Align the rail precisely against the alignment pins.
- Insert and lightly tighten (0.2 N.m) all screws while maintaining rail contact with both pins.
- Final tightening
- Using a calibrated torque wrench, tighten the screws to 0.6 N.m in a center-out pattern to distribute load evenly.
- Start by tightening the center screws first.
- Then alternate outward toward both ends (left–right–left–right).
- Confirm that the rail sits flush across its full length before completing the tightening sequence.
LVDT
- Install the board into the DAQ box
- Secure it using a screw.
- Plug in the RJ14 connector into the board.
- Get the cable through the left side of the MFT-5000 and secure it in position.
- Install the 4 standoffs onto the side of the reciprocating.
- Place the amplifier board onto the standoffs and secure it will the longer standoffs.
- Place the black cover on top and tighten the 4 screws.
- Place the lvdt and the 2 arms on the reciprocating and secure the lvdt by tightening the arms using 2 screws.
- Get the rod through the lvdt and secure it into the reciprocating LVDT L shapes.
- Secure the L shapes to the reciprocating drive using 2 screws on each.
- Connect the LVDT cable to the LVDT board (ensure that the cables are facing backwards)
- Connect the LVDT DAQ board cable to the amplifier board.
Unmounting
Linear Guides
- Remove the old bearing assembly
- Slide the carriage off the rail carefully to avoid scratching the raceways.
- Remove all rail mounting screws and lift the rail vertically from the base.
- Clean the mounting surfaces
- Moisten a lint-free wipe with isopropanol (IPA) — do not soak.
- Wipe the mounting surfaces in one direction (not circular) to remove oil, dust, or debris.
- Verify that both the mounting face and the pins are free of burrs, scratches, or residues.
- Blow off any remaining solvent with clean, dry compressed air.
Calibration/Verification
Reciprocating
To verify the reciprocating drive you can follow the checklist procedure. It is recommended to proceed through the verifications within Rtec MFT software.
- To control the gear ratio, you will need to use a laser tachymeter and place a reflective tape on the reciprocating shaft. Then, set a specific frequency (ex: 10Hz) and verify that the value measured is within tolerance (rpm: Hz*60).
- To control the maximum speed, ensure that no load and no additional components are attached to the reciprocating module.
LVDT
An LVDT sensor needs to be calibrated on its reciprocating drive.
- Place a dial gauge on the side of the reciprocating to record the true displacement.
- Go to Data Logging, record “Lvdt”
- Go to the run tab
- Manually rotate the reciprocating (drive off) or rotate it at 1 Hz (drive on) and record the total amplitude of the lvdt recording in the software and on the dial gauge.
- Go to Configuration > Sensors > LVDT > CONFIG.
- Modify the Unit Range value by using the following formula:
- If the Unit Range is not within 12 to 13 after modifying it and a verification, you will need to adjust the potentiometer.
- To adjust the potentiometer, remove the black cover and turn the small white potentiometer on the amplifier board until you obtain a Unit Range between 12 and 13.
- Once you have found a satisfactory unit range, you will need to change the bias of the LVDT. To do so, go to Configuration > Sensors > LVDT > CONFIG and ensure that “Unit Offset” is set to 0.
- Then, manually find the center of the reciprocating (half of the amplitude) and adjust the potentiometer on the DAQ board (the furthest potentiometer if there are 2 on your board) until the center of the reciprocating is at 0. Then, you can turn on the reciprocating drive and it should oscillate around 0 and have a displacement position equal to the one on the dial gauge.
Maintenance
Lubricate the Linear guides
Grease type
The guides are filled with Lithium soap based grease (Multemp Grease PS2 by Kyodo Yushi Co., Ltd.).
Property | Typical Value / Feature |
Thickener | Lithium soap |
NLGI Grade | 2 |
Base oil type | Synthetic + mineral blend |
Base oil viscosity (40 °C) | ≈ 15 mm²/s |
Operating temperature range | −50 °C → +130 °C |
Application focus | High-speed precision bearings, linear carriages |
Characteristics | Low torque, low noise, oxidation stability, good water resistance |
Preferably use this grease reference or search for a compatible Lithium soap based grease replacement available (EMEA: SKF LGLT2).
Grease application
- Wipe off all old grease and debris from the carriage and rail using a clean, lint-free cloth.
- If you’re changing grease type (e.g., from MULTEMP to SKF LGLT 2), flush out as much of the old grease as possible with a mild solvent (isopropyl alcohol or mineral spirit), then dry completely.
- Place a small amount of grease at one of the sides of the carriage
- Place the carriage back onto the rail.
- Move the carriage slowly back and forth along its full stroke several times to distribute grease evenly across the ball raceways.
Lubricate the roller bearing
- Prepare the grease gun
Replace the grease cartridge with a lithium high-load grease
(EMEA reference: SKF LGMT 2).
- Connect the grease gun
Connect the grease gun to the reciprocating grease inlet.
- Relubricate the bearing
Apply grease slowly and progressively until the old grease begins to purge from the rotary exit.
Do not continue greasing once fresh grease appears — avoid over-greasing.
- Clean the grease exit
Dry-clean the rotary grease exit to remove expelled grease.
- Run-in test
Run a test at maximum operating frequency, without load or components, to allow excess grease to purge.
- Final cleaning
Stop the system and thoroughly dry-clean the grease exit.