Both damage to dies and punches and their limited lifespan is caused by the omission of some simple procedures that should be intuitive. Very often, these are neglected and become major issues because of the consequences which result.
In the majority of cases an initial and periodic check is enough. By initial check we mean careful cleaning of the punch reductions, of the die holders, of the housing and machine turrets with complete removal of scraps and foreign bodies which otherwise could cause tool breakage and other problems.
Our punches are manufactured using the latest machines and cutting edge techniques, and subsequently hardened with top quality heat treatments; the raw material is chosen according to the different required characteristics and varies from M2 steel to more high-performing options based on the metallurgy of powders.
Strippers or sliding guides
Our strippers and sliding guides are manufactured with steels which are resistant to both wearing and heavy stress. They are produced with the tolerances necessary to guarantee endurance for the punches and punching machine turret. All guides are hardened and feature appropriate lubricating grooves for an unlimited life.
Full automatic production and control cycles guarantee maximum quality standards for our dies. They are manufactured with high performing steel (D2) and undergo customizable heating treatment. Great attention is paid to design and study of die geometry to obtain optimal structural tensions, longer tool life and anti-scraps pulling.
Material thickness related to hole thickness
Material thickness is an important issue both in itself and in relation to the hole diameter. This is especially true when the diameter of the punched holes is close to that of the sheet metal thickness. Traditionally the punch diameter should not be less than the sheet thickness.
However with the advent of hydraulic punching machines, punching speed is adjustable, overcoming this rule. In certain cases, sometimes with heavy stress, we punch material with thicknesses greater than the hole diameter. In these conditions, there is more stress and wearing and tool life is shorter. These same heavy stress conditions require precautions and the respect of all safety regulations such as the installation of protections and guards.
Rounding off and smoothing
The lifespan of a stamp can be influenced significantly by the shape of the hole to be punched. Geometry with sharp corners is less favorable. Wherever possible, it is necessary to smooth or round off these sharp corners. In case of square or rectangular holes, providing a 0,3÷0,5 mm minimum round off, will greatly help tool life.
The machine operator
The machine operator is probably the most important factor for a stamp life. The correct use of a punching machine requires experience: first of all, the machine operator must be familiar with the machine, he must be informed on the points detailed above and also on related operations. Punching operations develop high pressure and stresses, so that the machine and operator safety must be duly considered, following the safety regulations and all correct procedures even when not indicated in the regulations.
- Always use proper die clearances (cause of the majority of problems)
- Sharpen tools frequently
- After punch sharpening make a 0,15 mm light radius on all cutting edges and demagnetize
- Clean all machine components and tools carefully, grease or lubricate all moving parts
- Always lubricate the cutting area, or use coated punches
- Periodically check adapters, punch holders and alignment keys for correct machine centering. Correct punch press programming is necessary for the punch life
- Punching is always more convenient than nibbling
- When nibbling, use suitable tools according to the material thickness and feed with at least 70% of the tool length