An SFU1605 ball screw does not have one universal operating-noise value in decibels. The measured sound depends on screw speed, unsupported length, load, lubrication, support bearings, installation alignment, machine structure, microphone distance and background noise.
For this reason, noise should be evaluated under defined and repeatable test conditions. A change from the machine's normal baseline is usually more useful than comparing one dB reading with an unrelated ball screw tested on another machine.
What Does SFU1605 Mean?
SFU1605 normally refers to a flanged single-nut ball screw with a nominal screw diameter of 16 mm and a lead of 5 mm. The nut moves approximately 5 mm for each complete screw revolution.
The SFU1605 designation does not define:
- Total screw length
- Accuracy grade
- Preload or axial clearance
- End-support arrangement
- Operating speed and load
- Lubricant type and quantity
- Machine-frame vibration
These factors can all change the measured noise. Two SFU1605 assemblies may therefore produce different sound-pressure levels even when both are operating normally.
Why There Is No Standard SFU1605 dB Value
A sound-pressure reading is meaningful only when the complete test method is recorded. Moving the sound meter closer to the nut, increasing the RPM or testing the screw on a resonant metal frame can change the result significantly.
A useful noise record should include:
| Test item | Why it matters |
|---|---|
| Screw RPM | Ball circulation frequency and structural vibration change with speed |
| Linear speed | For a 5 mm lead, linear speed is directly related to screw RPM |
| Applied load | Load changes contact force between the balls and raceways |
| Screw length | A longer unsupported shaft may be more sensitive to vibration |
| Support arrangement | Bearing rigidity and alignment affect vibration and noise |
| Meter distance | Sound-pressure readings change with measurement position |
| Background noise | Motor, fan, guideway and surrounding machinery may dominate the reading |
Without these details, stating that an SFU1605 "should operate at a specific dB level" may be misleading.
What Does a Normal SFU1605 Sound Like?
A correctly installed and lubricated SFU1605 generally produces a continuous rolling or circulating sound. The sound may become more noticeable as speed increases because the balls pass through the loaded raceways and return system more frequently.
Normal sound should usually remain relatively consistent at the same speed and load. It should not suddenly become rough, metallic or strongly repetitive at one position along the stroke.
Some difference between forward and reverse movement may occur because of load direction, gravity, bearing condition or machine structure. A large or newly developed difference should be investigated.
How to Measure SFU1605 Operating Noise
1. Establish a Repeatable Test Position
Place the sound-level meter at a fixed distance and angle from the nut or selected machine reference point. Record the position so that later measurements can be repeated.
Do not compare one measurement taken close to the ball nut with another measurement taken beside the operator or outside the machine enclosure.
2. Record the Background Noise
Measure the surrounding sound with the ball screw axis stopped. Fans, pumps, nearby machines and motor noise may affect the final reading.
If the operating reading is only slightly higher than the background level, the result may not represent the ball screw accurately.
3. Test at Defined Speeds
Run the axis at several controlled speeds and record the screw RPM, linear speed and sound level. Avoid testing only at maximum speed.
For an SFU1605 with a 5 mm lead:
Linear speed (mm/min) = Screw speed (rpm) × 5 mm
For example, 1,000 rpm corresponds to a theoretical linear speed of approximately 5,000 mm/min, or 5 m/min. This relationship helps keep later tests comparable.
4. Check the Full Stroke
Measure or listen near the fixed end, middle and supported end of the stroke. A repetitive sound at only one location may indicate local contamination, raceway damage, shaft deformation or installation stress.
5. Repeat Under the Same Load
Do not compare an unloaded test with a later test performed under production load. Record the moving mass, acceleration and direction because they can change both vibration and sound.
Which Noise Changes Require Attention?
| Noise pattern | Possible area to inspect |
|---|---|
| Continuous dry or rough sound | Lubrication condition or contamination |
| Regular clicking at the same screw position | Local raceway damage, debris or a damaged return component |
| Noise only at high RPM | Critical-speed margin, shaft vibration, lubrication or support rigidity |
| Knocking during reversal | Backlash, loose coupling, support-bearing movement or mounting bolts |
| Noise together with rising temperature | Excessive preload, bearing preload, misalignment or inadequate lubrication |
| Noise changes through the stroke | Parallelism, nut-housing alignment, local wear or screw straightness |
A sound recording can be useful during diagnosis, but it should be accompanied by the corresponding speed, load and axis position.
Main Factors Affecting SFU1605 Noise
Lubrication
Insufficient, contaminated or unsuitable lubricant can increase friction and make ball circulation sound rougher. Excessive grease can also increase resistance temporarily, particularly immediately after relubrication.
Installation Alignment
If the screw axis, ball nut housing, support units and linear guideways are not properly aligned, the nut may operate under unwanted side load. This can cause uneven torque, heat and noise.
Support Bearings and Coupling
Noise near the screw does not necessarily originate inside the ball nut. Loose or damaged support bearings, an incorrectly tightened locknut and coupling misalignment can transmit sound through the screw shaft.
Operating Speed and Screw Length
The safe operating RPM depends on screw length, root diameter and end-support arrangement. A 16 mm screw that operates smoothly at a shorter length may become more sensitive to vibration when used over a longer unsupported span.
For additional speed considerations, see Can an SFU1605 Ball Screw Be Used for High-Speed Motion?.
Wear or Raceway Damage
If noise increases gradually together with backlash, rough motion or metal particles in the lubricant, inspect the screw raceway, balls and return system. Continuing operation after local damage appears can worsen the affected surfaces.
How to Reduce Unnecessary Noise
- Confirm that the ball screw is suitable for the required speed and unsupported length.
- Align the screw, nut housing, support bearings and guideway travel correctly.
- Use suitable lubricant and maintain an appropriate relubrication interval.
- Keep metal chips, dust and coolant away from the raceways.
- Check support-bearing locknuts, coupling screws and mounting bolts.
- Avoid excessive preload that raises torque and temperature unnecessarily.
- Record a baseline after installation for future comparison.
If the SFU1605 develops abnormal noise, follow the inspection sequence in Why Is the Ball Screw Making Noise?.
DLY SFU1605 Selection and Inspection
DLY supplies SFU1605 ball screws with a 16 mm nominal diameter and 5 mm lead. C7 rolled accuracy is commonly used for general automation, while the required screw length, end machining, support units, nut structure and operating conditions should be confirmed for each application.
During product and assembly checks, running smoothness should be evaluated together with appearance, screw-and-nut matching and the required clearance or preload. A sound reading by itself cannot replace mechanical inspection.
Available ball screw models and assembly options can be viewed on the DLY ball screw page.
Is your SFU1605 producing abnormal noise?
Send DLY the screw length, operating RPM, load, support arrangement and a video showing where the sound occurs.
Email: export@dlybearing.com
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