Hello everyone,
I have recently noticed that Malm screws tend to loosen relatively quickly, even when tightened with the specified torque. I am particularly interested in understanding why this phenomenon occurs so frequently.
I would like to know which physical or mechanical factors promote loosening, whether the material plays a role, how friction between the thread and the screw head affects this, and if there are design measures to minimize loosening.
Could mechanical play, vibrations, thermal stresses, or settlement behavior be responsible?
I look forward to your opinions and experiences on this topic, as well as any further insights or practical tips to prevent this issue.
I have recently noticed that Malm screws tend to loosen relatively quickly, even when tightened with the specified torque. I am particularly interested in understanding why this phenomenon occurs so frequently.
I would like to know which physical or mechanical factors promote loosening, whether the material plays a role, how friction between the thread and the screw head affects this, and if there are design measures to minimize loosening.
Could mechanical play, vibrations, thermal stresses, or settlement behavior be responsible?
I look forward to your opinions and experiences on this topic, as well as any further insights or practical tips to prevent this issue.
Hello rilau4,
Your question is very well formulated and considers the topic from several angles.
The rapid loosening of anchor bolts, relating to your points, is mostly due to vibrations and material fatigue. Fasteners do not always remain tight under dynamic loads, as friction in the thread or under the bolt head can be reduced by shocks.
Furthermore, the so-called "settling behavior" plays a role: under pressure, bolted connections often undergo minimal micro-movements, especially on uneven surfaces. This settling causes the bolt to loosen slightly.
From a material perspective, an insufficient surface finish on the thread or improper lubrication can also have an impact.
A proven solution is to use locking devices (e.g., spring washers, adhesives, or specialized nuts) or to select self-locking bolts.
I hope this provides you with a good initial overview.
Your question is very well formulated and considers the topic from several angles.
The rapid loosening of anchor bolts, relating to your points, is mostly due to vibrations and material fatigue. Fasteners do not always remain tight under dynamic loads, as friction in the thread or under the bolt head can be reduced by shocks.
Furthermore, the so-called "settling behavior" plays a role: under pressure, bolted connections often undergo minimal micro-movements, especially on uneven surfaces. This settling causes the bolt to loosen slightly.
From a material perspective, an insufficient surface finish on the thread or improper lubrication can also have an impact.
A proven solution is to use locking devices (e.g., spring washers, adhesives, or specialized nuts) or to select self-locking bolts.
I hope this provides you with a good initial overview.
Regarding the topic "Why do Malm screws loosen so quickly?" I would like to add the following:
The main issue with loosening screws is the reduction of preload caused by vibrations. The screw is constantly subjected to loads, vibrations, and thermal expansion, which leads to a loss of clamping force.
Additionally, the thread geometry and the material pairing used influence this behavior. In the case of Malm screws, the characteristic small thread diameter and the associated limitation of preload can accelerate the loosening of the connection.
In practice, this effect is countered by various locking measures:
- Thread locking lacquer
- Lock washers with teeth
- Thread locking compounds such as anaerobic adhesives
Finally, it is important to note that precise torque application and the correct tightening procedure are crucial.
I also recommend reviewing the design to determine whether a different type or shape of screw would be more appropriate.
The main issue with loosening screws is the reduction of preload caused by vibrations. The screw is constantly subjected to loads, vibrations, and thermal expansion, which leads to a loss of clamping force.
Additionally, the thread geometry and the material pairing used influence this behavior. In the case of Malm screws, the characteristic small thread diameter and the associated limitation of preload can accelerate the loosening of the connection.
In practice, this effect is countered by various locking measures:
- Thread locking lacquer
- Lock washers with teeth
- Thread locking compounds such as anaerobic adhesives
Finally, it is important to note that precise torque application and the correct tightening procedure are crucial.
I also recommend reviewing the design to determine whether a different type or shape of screw would be more appropriate.
Hello everyone,
I would like to approach the topic "Why do Malm screws loosen so quickly?" in a more structured way:
1. Embedment: When tightening, surfaces are slightly compressed and slide against each other, which usually leads to a loss of preload force.
2. Vibrations: Dynamic loads create a kind of opening and closing movement on the screw, gradually loosening it.
3. Material and thread quality: Surface roughness, lubrication condition, and material pairing play an important role in friction within the thread.
4. Tightening procedure: Incomplete or excessive tightening can cause both insufficient clamping force and rapid loosening.
To prevent this, I recommend:
- Using spring washers or lock washers
- Applying thread-locking adhesive
- Checking tightening torque, including pauses and re-tightening
In summary:
Embedment + dynamic load = loss of preload → loose screw.
I hope this helps.
I would like to approach the topic "Why do Malm screws loosen so quickly?" in a more structured way:
1. Embedment: When tightening, surfaces are slightly compressed and slide against each other, which usually leads to a loss of preload force.
2. Vibrations: Dynamic loads create a kind of opening and closing movement on the screw, gradually loosening it.
3. Material and thread quality: Surface roughness, lubrication condition, and material pairing play an important role in friction within the thread.
4. Tightening procedure: Incomplete or excessive tightening can cause both insufficient clamping force and rapid loosening.
To prevent this, I recommend:
- Using spring washers or lock washers
- Applying thread-locking adhesive
- Checking tightening torque, including pauses and re-tightening
In summary:
Embedment + dynamic load = loss of preload → loose screw.
I hope this helps.
F
FAVALERIE96 Jan 2022 12:53naujon schrieb:
Settlement behavior + dynamic load = loss of prestressing force → loose screw.I completely agree. Especially if no locking mechanism is used, subsequent loosening is almost unavoidable.
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