Hello everyone,
I am currently dealing with the issue that, under heavier loads, the screws in Malm furniture (especially those that connect the parts) tend to loosen repeatedly. I am particularly interested in understanding why this happens, even though the screws are properly tightened with the correct torque.
I have the impression that the material or the design might not be optimal, or that there are other physical reasons why the screws loosen under dynamic loads. Factors such as vibrations, material fatigue, or the type of fastening might also play a role.
Can anyone provide well-founded information on this or share proven methods to prevent loosening under heavier loads? It would also be interesting to know if this is related to the wood joints being subjected to high levels of friction and deformation, causing the screws not to hold permanently.
Thank you for your help!
I am currently dealing with the issue that, under heavier loads, the screws in Malm furniture (especially those that connect the parts) tend to loosen repeatedly. I am particularly interested in understanding why this happens, even though the screws are properly tightened with the correct torque.
I have the impression that the material or the design might not be optimal, or that there are other physical reasons why the screws loosen under dynamic loads. Factors such as vibrations, material fatigue, or the type of fastening might also play a role.
Can anyone provide well-founded information on this or share proven methods to prevent loosening under heavier loads? It would also be interesting to know if this is related to the wood joints being subjected to high levels of friction and deformation, causing the screws not to hold permanently.
Thank you for your help!
The issue with furniture made from particleboard and metal wood screws is well known. The screws do not hold in a solid, sturdy material but rather in a material that yields under stress.
These press-in nuts provide good holding strength under static loads, but they are sensitive to lateral forces and dynamic loads.
To prevent loosening in practice, the following are effective:
- Thread locking lacquer or liquid thread lockers (medium strength)
- Lock washers or spring washers
- Use of special threaded inserts (Helicoils) in high-load areas
Additionally, applying the correct torque during tightening is crucial; better holding strength is often achieved using a torque wrench.
My recommendation: If possible, retighten screws and nuts and use locking agents in critical areas.
GLATAU9 schrieb:
Metal wood screws with plastic or metal press-in nuts
These press-in nuts provide good holding strength under static loads, but they are sensitive to lateral forces and dynamic loads.
To prevent loosening in practice, the following are effective:
- Thread locking lacquer or liquid thread lockers (medium strength)
- Lock washers or spring washers
- Use of special threaded inserts (Helicoils) in high-load areas
Additionally, applying the correct torque during tightening is crucial; better holding strength is often achieved using a torque wrench.
My recommendation: If possible, retighten screws and nuts and use locking agents in critical areas.
To add: Another important factor is the surface roughness and the clearance in the drilled hole.
If the hole is slightly oversized before screwing, there is room for movement, which reduces the preload tension of the screw under load.
Sometimes small washers can help distribute the clamping force more evenly, but with particleboard panels, there is a high risk of the material cracking.
In professional settings, knock-in nuts or metal threaded inserts are often used to secure screw connections for the long term.
If the hole is slightly oversized before screwing, there is room for movement, which reduces the preload tension of the screw under load.
Sometimes small washers can help distribute the clamping force more evenly, but with particleboard panels, there is a high risk of the material cracking.
In professional settings, knock-in nuts or metal threaded inserts are often used to secure screw connections for the long term.
In addition to the causes already mentioned, it is important to consider the dynamic influences.
Vibrations or repeated load cycles cause the loss of clamping force in the bolted joint. This effect can be much stronger in fasteners used in engineered wood products than in metal or solid wood connections.
[A well-known technical aspect:] The preload force of the bolt decreases under cyclic loading due to so-called 'relaxation,' which is a gradual loosening of the bolt.
The solution therefore lies in a combination of optimized joint technology (using metal threaded inserts) and bolt locking methods.
Vibrations or repeated load cycles cause the loss of clamping force in the bolted joint. This effect can be much stronger in fasteners used in engineered wood products than in metal or solid wood connections.
[A well-known technical aspect:] The preload force of the bolt decreases under cyclic loading due to so-called 'relaxation,' which is a gradual loosening of the bolt.
The solution therefore lies in a combination of optimized joint technology (using metal threaded inserts) and bolt locking methods.
N
narDietmar15 Feb 2023 12:29It is also important to consider the entire construction. Often, pieces of furniture like Malm are designed in a way that certain areas experience higher loads, for example, when they are heavily used as a storage surface.
In such areas, it helps if the load is better distributed. Additional braces or stiffeners can ensure that the entire load does not rest solely on the screw.
I would recommend checking the structural stability in addition to optimizing the screw connection.
In such areas, it helps if the load is better distributed. Additional braces or stiffeners can ensure that the entire load does not rest solely on the screw.
I would recommend checking the structural stability in addition to optimizing the screw connection.
Thank you very much for the many helpful comments.
In summary, I find the following points particularly important:
- The material properties of particleboard/wood-based panels limit the screw holding strength.
- Dynamic loads and vibrations promote loosening due to material deformation.
- Thread-locking compounds and metal threaded inserts significantly improve the situation.
- Correct torque and load distribution are also crucial.
Next, I will try applying thread-locking fluid to some screws and ensure the proper torque when retightening.
Final question: Does anyone have experience with whether it makes sense to use wood glue or other adhesives for screw reinforcement in critical areas of MALM furniture? Or is this not recommended?
In summary, I find the following points particularly important:
- The material properties of particleboard/wood-based panels limit the screw holding strength.
- Dynamic loads and vibrations promote loosening due to material deformation.
- Thread-locking compounds and metal threaded inserts significantly improve the situation.
- Correct torque and load distribution are also crucial.
Next, I will try applying thread-locking fluid to some screws and ensure the proper torque when retightening.
Final question: Does anyone have experience with whether it makes sense to use wood glue or other adhesives for screw reinforcement in critical areas of MALM furniture? Or is this not recommended?
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