How high can you bend?
For 90-degree bending, the bending height shall not be less than 2 times of the thickness of sheet; for example, a 1mm-thick sheet is to be bent into 90 degrees, and the bending height shall be less than 3mm (including sheet thickness).
How small the bending radius is on the outside of bending?
Take a 90-degree bend for example. The outside radius of bending is approximately 1.2 times of the sheet thickness. For example, a piece of 1mm-thick sheet is to be bent into 90 degrees. The inside radius can reach almost 0 whereas the outside radius will be close to 1.2R.
Why is there punching cross section?
Punching works by shearing a part of material off with brutal force, and that’s why there is a punching cross section. In general, the thicker the sheet is, the obvious the cross section will be.
Why punching generates burrs?
Burrs are what is left behind after materials being sheared off. Once sheared off by punching, any material, regardless of thickness, will have burrs at the sheared edge. In principle, it all comes down to how thick the material is. The thicker the sheet is, the more burrs it generates. Burrs are removed with dies, vibration grinding, electroplating or bake-painting. The choice depends on customers’ needs and considerations.
Why is the hole distorted after punching?
If the hole to be punched is close to a bent, the material within the hole is pulled and the edge of hole will be easily distorted. If the distortion compromises the functionality, it is better to bend before punching.
What are the materials commonly used and what is the thickness?
- Steel sheet
- SPCC: 0.5mm,0.6mm,0.7mm,0.8mm,0.9mm,1.0mm,1.2mm,1.4mm,1.5mm,1.6mm,2.0mm,2.3mm,2.5mm,3.0mm,3.2mm
- SECC: 0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,1.6mm,2.0mm
- SGCC: 0.6mm,0.8mm,1.0mm,1.2mm,1.5mm
- SGLC: 0.2mm,0.3mm,0.5mm,0.6mm,0.8mm,1.0mm
- SPTE: 0.15mm,0.2mm,0.25mm,0.3mm,.0.4mm,0.5mm,0.6mm,0.8mm
- SK7: 0.3mm,0.35mm,0.4mm,0.45mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,1.6mm,1.8mm,2.0mm,2.5mm,3.5mm
- SK5: 0.1mm,0.2mm,0.3mm,0.35mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.4mm,1.5mm,1.6mm,1.8mm,2.0mm,2.3mm,2.5mm,2.8mm,3.0mm,3.2mm,3.5mm,4.0mm,4.5mm
- Aluminum sheet
- AL1050: 0.3mm,0.4mm,0.5mm,0.6mm,0.8mm,1.0mm,1.2mm,1.5mm,1.6mm,2.0mm,2.3mm,1.5mm,3.0mm,4.0mm,5.0mm,6.0mm
- AL5052: 0.3mm,0.4mm,0.5mm,0.6mm,0.8mm,1.0mm,1.2mm,1.5mm,1.6mm,2.0mm,2.3mm,1.5mm,3.0mm,4.0mm,5.0mm,6.0mm
- AL6061: 0.6mm,0.8mm,1.0mm,1.2mm,1.6mm,2.0mm,2.3mm,2.5mm,3.0mm,3.2mm,4.0mm,5.0mm,6.0mm,6.35mm
- Stainless steel sheet
- SUS430: 0.2mm,0.25mm,0.3mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,2.0mm
- SUS304: 0.2mm,0.25mm,0.3mm,0.35mm,0.4mm,0.45mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,2.0mm,2.5mm,3.0mm
- SUS301: 0.05mm,0.08mm,0.1mm,0.12mm,0.15mm,0.2mm,0.25mm,0.3mm,0.35mm,0.4mm,0.45mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,2.0mm
- Copper sheet
- C1100: 0.1mm,0.125mm,0.15mm,0.2mm,0.25mm,0.3mm,0.4mm,0.5mm,0.6mm,0.7mm,0.8mm,1.0mm,1.2mm,1.5mm,1.6mm,2.0mm,2.3mm,2.5mm,3.0mm,3.2mm,4.0mm,4.8mm,5.0mm,6.0mm
- C5191: 0.1mm,0.15mm,0.2mm,0.25mm,0.3mm,0.4mm,0.5mm,0.6mm,0.8mm,1.0mm,1.2mm,1.5mm,2.0mm
- C2680: 0.2mm,0.25mm,0.3mm,0.4mm,0.5mm,0.6mm,1.7mm,0.8mm0.9mm,1.0mm,1.2mm,1.4mm,1.5mm,1.6mm,1.8mm,2.0mm,2.3mm,2.5mm,3.0mm,3.2mm,4.0mm
- C 7701: 0.1mm,0.15mm,0.2mm,0.3mm,0.4mm,0.5mm
What are the materials commonly used for dies?
- SS41: general steel sheet used for die seats, shim plates and base plate.
- YK30: a.k.a. red plate, it is a steel material used for stripper plate, stopper plate, shim plate and other low-end dies.
The problem is it is not hard enough to play a major role in die structures.
- SKD11: a.k.a. purple plate, this steel is used commonly for upper and lower die, stripper plate and punch.
It is a common steel material used in punching metal die. With heat treatment, it can be as hard as HRC 58~59.
- SLD: this die steel is commonly used in upper and lower die, stripper plate and punch. It is one level higher than SKD11 and commonly used in punching thick stainless steel sheets. It is more ductile than SKD11 and as hard as HRC 58~60 with heat treatment.
- DC 53: this die steel is commonly used in upper and lower die, stripper plate and punch. It is at the same level as SLD and perfect for cutting thick stainless steel sheets. With heat treatment, the hardness can reach HRC 58~60. However, a good control of heat treatment is required to allow the material to perform its best.
- SKH: this die steel is commonly used in upper die, lower die and punch. It is a high-end model material featuring high hardness but weak in ductility and brittle. It is appropriate for punching thin stainless steel sheets (<0.5mm).
The downside is that it is expensive and therefore used only when needed. The hardness can reach HRC 61~62 with heat treatment.
- ASP23: this die steel is often used for upper die, lower die and punch. It is a high-end material with hardness greater than that of ASP60 but not as ductile. The downside is that it is expensive and therefore used only when needed. The hardness can reach HRC 64~66 with heat treatment.
- T15: this die steel is often used for upper die, lower die and punch. This is a high-end material with hardness and ductility falling between ASP23 and ASP60. The downside is that it is expensive and therefore used only when needed. The hardness can reach HRC 66~67 with heat treatment.
- ASP60: this die steel is often used for upper die, lower die and punch. This high-end material features hardness greater than that of ASP23 but it is less ductile. It is perfect for punching thin sheets, but the downside is that it is expensive and therefore used only when needed. The hardness can reach HRC 67~69 with heat treatment.
- Tungsten steel: this die steel is often used in upper die, lower die and punch. This high-end material is usually made by MIM (Metal Injection Dieing). It features great hardness but low ductility, and is perfect for high-speed punching of thin sheets and drawing. The downside is that it is expensive and therefore used only when needed. The hardness can reach as high as HRC 70~80 with heat treatment.