En rubrik om SMC
Sinter Steel vs.
• Cutting machining
• Stamping
• Cold forming
• Forging
• Precision casting
• Die Casting Al and Zn
Sinter Steel vs. Cutting Machining
No or modest tool costs i.e. low start-up costs
Plenty of freedom to make changes.
Labour-intensive
Poor use of material
Sinter Steel vs. Forging
Good material characteristics
More limited geometry
Poorer tolerances +-0,3 calibrated
Often requires finishing
Sinter Steel vs. Precision Casting
Copes with transverse grooves and channels
Tolerances and material characteristics
Sinter Steel vs. Cold Forming
Fast process, comparable to sinter
Copes with thin-walled geometries
More limited geometry
Phosphatising of workpiece
Sinter Steel vs. Die Casting Al and Zn
Fast process
Good tolerances
Weak material
Costly tools
Design
When you design sinter it’s very important to have your target image clear as soon as possible, because in sinter steel you material wise do just above die casted Zn to almost as good as forged but if want the best material characteristics you may have to lose some on complex design. Here follows some tips, facts and examples and if you need more help please contact us and we will help you to design your sinter steel part.
Making the target image
Re design
- What are your present elastic limit, hardness etc.?
- Do you want any new functions?
- Can the design be changed?
- Does it break today? If so, where?
New design
- What do you think about material characteristics, e.g. take a steel quality which you use today
- Where do you think it is going to be under greatest load?
- Describe the function clearly
- What degree of freedom is there in regard to other details?
Density/ Material characteristics
Density-dependent
- Flexural strength & elastic limit
- E-module
- Endurance limit
- Impact resistance & crack growth
- Elongation
- Apparent hardness
- Electrical and thermal characteristics
- Surface smoothness
- Expansion coefficient
- Fluid permeability
- Magnetic characteristics
- Poisson constant
NON-density-dependent
- True hardness
- Fusion temperature
- Phase change temperature
- Curie temperature
High density limits complexity in design.
Tolerances
Tool-related
- IT 9 after sintering
- Can be improved with different types of finishing e.g. repressing cutting-machining and roll polishing
In direction of pressing
- IT 13
- Large shallow cavities make it easier and vice versa
Contour and levels
Contour like this odd shape does not cost extra on part, just on tooling.
Contour like this odd shape does not cost extra on part, just on tooling.
Levels cost extra and limits density
1 level (easiest)
2 levels
3 levels
Gears
Gear are a very good sinter product but you have limitations on small modules like 0,5 and lower.
Remember
- Hold down projected surface in direction of pressure.
- When you save weight, do it straight away so you save surface and don´t create another level.
- Avoid thin sections less than 1.5 mm produce thin stamps and fill problems.
- Bit must come out of the tool can be biggest in the middle.