#THE GUN DRILLING HANDBOOK PDF CODE#

The experimental results show that the strain at fracture measured in incremental compression is consistent with that measured in orthogonal cutting when all deformation variables are properly accounted for and that, contrary to the results obtained using other kinds of material characteristics, the resistance to cutting of workpiece material in orthogonal cutting is not affected by high strains, strain rates and temperatures occurring in the cutting process.

It is shown that the strain at fracture is the most general material behavior characteristic. Part one of this two-part paper presents a novel approach of characterizing the resistance of workpiece material to cutting. chip from the rest of the workpiece, this paper defines the metal cutting process as the purposeful fracture of workpiece material. Since metal cutting involves the physical separation of the. The greatest obstacle to develop a more basic, efficient approach is a lack of understanding of material behavior under unique deformation conditions of cutting. The developed and validated 3D FE model can be used for optimizing the cutting process in gun drilling (good surface finish and straightness) taking into account the complex gun drill geometry, cutting conditions, heat transfer and the thermo-mechanical behaviour of the workpiece material.Įveryday practice of cutting process planning requires reliable cutting force estimates, which currently can be obtained only from process-dependent machinability databases. Experimental gun drilling tests were carried out in steel AISI 4150 for the validation of the developed 3D FE model.

During gun drilling simulation, modified gun drill cutting edge rounding and friction law are performed to investigate the effect of tool wear and lubrication on feed force and torque respectively.

#THE GUN DRILLING HANDBOOK PDF CODE#

The Lagrangian formulation proposed in the FE code DEFORM 3DTM and the constitutive Johnson-Cook material model were utilized to simulate the chip formation and to predict the cutting reaction forces as well as the temperature in gun drilling process using carbide gun drills with two different diameters. The main objective of this paper is the development and validation of a three dimensional thermomechanically coupled finite element model for gun drilling AISI 4150 quenched and tempered steel. The role of the clearance in the starting bush and the design of the gundrill’s supporting area are analyzed. Part one deals with the first stage of drill entrance, which begins when the gundrill touches the face of the workpiece and ends when the gundrill’s cutting edges are fully engaged in cutting. This paper reveals the main design and technological factors affecting entrance stability and provides practical recommendations on the design of gundrills. Entrance instability is the prime cause for the so-called ‘unpredicted’ drills’ failure, which often appears as a fatigue crack(s) on the drill shank and cannot be explained when only stable drilling is considered. Entrance stability plays the chief role when the rotational speed and feed rate are high, which is the common case in the automotive industry where engine heads made of aluminum alloys are drilled. This stability is defined as a complex issue consisting of the following sub-items: entrance, static, and dynamic stabilities. The reliability of the gundrilling process in the automotive industry is greatly affected by tool stability.

The gun drilling handbook pdf