There are a lot of factors that go into the surface pressure under the screw head in soft materials. Some of these do effect the production process, the alignment of fibers in the material and the surface finishing and temperature changes.
Because there are a lot of factors, it is not possible to precisely define the permissible surface pressure for a particular type of material used to make a component, but there are some things that you can do to the screw design to help reduce the surface pressure.
The following can be used to reduce the surface pressure:
- Use of flange screws and flange nuts
- Chamfered holes (field investigations have shown up to a 20% increase in permissible surface pressure)
- Select a fine hole-through hole to ISO 273
Flange nuts and flange screws have been shown to reduce the surface pressure. Check out some of the advantages below!
Advantages of flange screws and flange nuts:
- Less intrusion
- Clamping force in the fastening during mounting tends to remain stable
- Flange products are more economic than large washers under normal screws and nuts (fewer fastening elements and quicker assembly).
- Flange screws and nuts allow greater hole tolerances and so are more economically efficient
- Flange nuts have a better stability against shaking than normal screws and nuts
For more information, or if you have any more questions, contact us at ProvenProductivity@bossard.com.
Surface Pressure Under the Screw Head by Bossard