Autocad Drafting

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Die clearance is the amount of clearance between a punch and a die. The optimal clearance can be determined by two factors: material thickness and material type. For thinner material, the clearance should be as tight as possible to prevent ragged edges. However, for thicker material the clearance should be larger to allow the perforating process to be successful without damaging the punch and the die and to give a good edge quality.

According to Machinery’s handbook 27th edition, page 1329, there are two definitions of clearance among top die makers. The first and the most commonly used one is that a clearance is the space between the punch and the die on one side. If we take a round punch tool as an illustration, according to this definition, the clearance will be the die radius minus the punch radius. On the other hand, the second definition says that the clearance is the total difference between the die and the punch. For example, if the die is 12.8mm round and the punch is 12.7mm round, the clearance according to the second definition will be 0.1mm. But, according to the first definition, the clearance will be 0.05mm.

In order to avoid any misconception about the clearance, I recommend consulting the sales team where you have purchased your tool and die (e.g. Wilson tooling or Mate tooling).

On this page, I would like to share some useful articles and information regarding die clearance.