Causes of burr production

Causes of burr production in hardware stamping parts(Sheet metal parts)

1.The first possible reason is that the knife edge is blunt. Burr will be produced when the cutting edge is worn, blunt or gnawed.

The factors affecting the blunt edge are:

1)It is not lubricated in time during operation, resulting in rapid wear;

2)Didn’t grind the knife edge in time;

3)The material and surface treatment of the die are poor, so the wear resistance is poor;

4)The die has poor structure and rigidity, resulting in gnawing.

2.The second possible cause is improper clearance. Burrs can be produced if the blanking clearance is too large, too small or uneven.

The factors affecting the clearance are as follows:

1)Die manufacturing error, die parts processing does not comply with the drawing, poor parallelism of the bottom plate, etc;

2)Die assembly error, large clearance of guide part, non-concentric assembly of concave and convex dies, etc;

3)The accuracy of the press is poor. For example, the clearance between the guide rail of the press is too large, the parallelism between the bottom surface of the slider and the surface of the worktable is not good, or the verticality between the stroke of the slider and the table surface of the press is not good, resulting in deflection during blanking, which can cause the change of the clearance;

4)Unreasonable die structure, insufficient rigidity of die and working part, unbalanced blanking force, etc

5) The curvature of the steel plate is large or the steel plate is uneven.

3.The third possible reason is that the performance of stamping oil does not meet the standard.

Rapeseed oil, mechanical oil, recycled oil and other non-special oil products can not meet the requirements of stamping processing, so it will cause problems such as workpiece bristling, machine rust and yellow blister, worker skin allergy and so on. The requirements should be considered from the wear resistance, corrosion resistance and cooling performance of stamping oil. The special stamping oil is prepared with sulfurized lard and sulfurized fatty acid ester as the main additives. It is suitable for stamping, punching and drawing of copper aluminum, carbon steel, stainless steel, titanium alloy and other materials for various types of equipment.

4.When the blanking state is improper, the manufacturability of the parts is poor or the materials do not meet the process regulations, it will also lead to burrs on the component.