DEFORM

Developed by SFTC, DEFORM has been specifically designed for the accurate, fast and convenient simulation of cold, warm & hot manufacturing operations for preform optimisation, process troubleshooting & die stress analysis. The suite of 2D and 3D programs are used by manufacturers serving the aeropace, nuclear, automotive and industrial equipment industries, as well as leading research institutes involved in metallurgy and advanced manufacturing.

A highly cost effective application of FEA technology, DEFORM is known to generate significant benefits including:

• Development of new innovative production methods
• Reduced shop trials and lead time
• Improved process control and quality
• More robust tooling
• Superior product microstructure and strength

“DEFORM has enabled us to reduce the development time of a typical fastener project by up to 150 days… and a saving of £300,000 by implementing upfront analysis.” Avdel (UK) Ltd.

The automatic remeshing capabilies and robust non-linear solvers are optimised to predict extremely large deformation material flow and coupled thermal behaviour – simulations which are beyond the capabilities of general purpose FEA programs. Forming equipment models enable the energy losses of hammer and screw presses and the power limits of hydraulic presses to be incorporated in the analysis. DEFORM also includes advanced capabilities for predicting phase transformation, ductile fracture, microstructural evolution, machining distortion & chip morphology. Extensive user subroutines allow advanced researchers to incorporate their own constitutive, fracture and microstructural models, press specifications & non-metallic materials.

Ultimately, DEFORM is able to study the entire manufacturing chain from ingot conversion, through forming, machining and heat treatment, to final product installation. At the same time, the modern user interface has been designed to be accessible to both production engineers and research scientists.

DEFORM Integrated Manufacturing Simulation System

DEFORM was initially applied to hot forging applications in the 1980s. Applications cover the entire range of forged products, including:

• Turbine disks
• Flanges
• Upset tubes and shafts
• Gears
• Crankshafts, connecting rods and pistons
• Control arms, tracks and yokes
• Medical implants

DEFORM has also been used in cold forming applications, such as fasteners, bearing components, spark plug bodies, since the early 1990s.

This lever forging with flash is shown in the DEFORM-3D postprocessor, which features OpenGL graphics. Note the transparent dies, with an opaque workpiece and punch.

In the case of this lever, the dies form the handle of the lever, with the bottom die in a stationary position and the top die moving down. As the part flashes and closure is obtained, the load increases. At a critical value, the bottom die is pushed down to allow the mounting cylinder to be reverse extruded over the punch. During this process, the workpiece material is always finding the path of least resistance to determine die fill and the final shape. DEFORM has very powerful die movement controls to support a wide range of presses, hammers and sliding (spring loaded) tools. Unlike many oversimplified simulation programs, DEFORM supports multiple moving dies throughout the entire range of product offerings.

This warm formed gear carrier was the subject of a German simulation benchmark. DEFORM-3D results matched the production process with excellent accuracy.

During the development of new forging designs, DEFORM can be used to study die fill, load, energy, strain, adiabatic heating and tool stress analysis. Small defects can be observed prior to committing to production tooling. Multiple sequential trials can be run in days rather than weeks – at a much lower cost.

Simulated models cost less than shop trials, as no tooling is required. In cases with occasional failures, the results can be used to assess the probability of an improvement for a given design. DEFORM simulations of this type of process can be run faster than shop trials requiring new tooling (one day vs. days or weeks). More importantly, DEFORM provides more information than any shop trial.

This flange bolt is cold formed from round steel wire using a four-blow progression on a high speed cold header. This process was optimized using DEFORM-3D.

An earlier version of the design experienced issues with occassional ductile fracture before DEFORM was available.

Tool failures resulting from high forming pressure can be analyzed and eliminated using the powerful die stress analysis capability.

Die Stress Analysis

The fracture modelling capability in DEFORM has now been used for a number of years to study the localisation deformation of material around the failure zone. Since shear-type forming processes develop high gradients of stress through the thickness, the solid elements of a bulk forming code are required. By simulating the effect of process parameters on burr formation during fine blanking in sheets, this capability can be used to aid the optimisation of the punch-die clearance for minimum roll-over and burr formation. Furthermore, by predicting punching loads, simulation studies can also be used when investigating tool wear problems.

Simulation of a fine blanking process. Simulation clearly shows rollover, shear zone, and rupture zone.

Standard rolling applications include cross wedge rolling, shape rolling, orbital forming and thread rolling. Cross wedge rolling has proven to be an economical and reproducible means of producing preforms for forging operations as the process control is far superior to traditional manual drawing operations. DEFORM can be used to optimize the rolled shape in the blocker or finished forging dies, typically resulting in a much higher material yield than traditional preforms. Once the target shape is developed, DEFORM-3D can be used to simulate the cross wedge rolling process. The finite element solver includes special modeling techniques to enhance speed, accuracy and robustness of this process. As companies move into new manufacturing methods, such as cross wedge rolling, DEFORM plays a strong role in minimising the learning curve.

This multi-pass rolling operation demonstrates the capabilities of DEFORM to simulate multi-pass rolling operations. In this case, the contours of temperature are shown throughout the process.

A multiple operation template provides the ability to set up all of the operations prior to the initial simulation and manage all operations sequentially.

A specialized system has been developed with the mesh design, updating, finite element solver, contact and simulation control optimized for ring rolling. Unlike most solutions for ring rolling, the ‘artificial’ assumptions are kept to an absolute minimum. As with other DEFORM Systems, ring rolling is fast, produces accurate results, easy to use and designed to run on a desktop PC or workstation.

Ring Rolling Application

DEFORM is leading solution for heat treatment and microstructure simulation. SFTC has been used by leading manufacturers in aerospace, automotive, energy and other fields for joint advanced research projects.

DEFORM-2D with the Microstructure Module was used to predict the microstructure in this turbine disk. Microstructure predictions are available with both JMAK and CA (cellular automata) models.

The models can account for dynamic recrystallization, static recrystallization, metadynamic recrystallization and grain growth.

In this scanning induction hardening simulation, the steel shaft is heated by eddy currents, provided by a moving, two-turn copper coil. The surface of this 1055 steel shaft is austenitized to a predetermined depth. Closely following the heating coil, a water quench jacket (omitted for clarity) moves along the shaft, quenching the austenite material and providing a hard, martensitic case. The martensitic case depth is shown in the cutaway view of the shaft. With DEFORM, analysis of coil design, applied power and induction frequency may be carried out to determine the optimum processing conditions for a given steel shaft application. In addition, the distortion or dilatation of the shaft can be predicted, and design modifications made, prior to production runs.

Induction Hardening

During cogging, the workpiece is typically rotated between or during passes. The ingot cross section is reduced as it changes shape to a round, hexagon or octagon. This thermo-mechanical processing refines the coarse ingot grain structure to homogenized, fine grained, recrystallized billet microstructure. Cogging simulation provides critical process information, which is used to determine optimum process parameters. This leads to improved material yield and fewer quality problems.

DEFORM Cogging Simulation

Complex forming operations such as rivets and staked fasteners are possible in both 2D and 3D simulations. Mechanical joining requires a robust FEA solver and mesh generator. Over the years, a wide range of 3D mechanical joining simulations have been presented and published.

The installation of staked and self-clinching fasteners are other frequent applications of DEFORM. While the analysis of multiple bodies during small deflection is possible with some general purpose codes, large deformation of multiple plastic bodies requires a very powerful analysis capability with a sophisticated contact algorithm to generate accurate results. This simulation is indicative of advanced DEFORM capabilities that are frequently used by fastener manufacturers and their customers.

This rivet installation is an example of the multiple deforming body capability of DEFORM, which was first published in 1994.

Machining simulation was first shown at a DEFORM Users Group Meeting in the late 1980s by a well-known tooling manufacturer. Today, DEFORM-3D can to simulate milling, drilling and even tapping, as well as predicting product distortion due to material removal.

MachiningTap Simulation

This tap simulation demonstrates the capability to model extremely fine details required in machining processes, including efficient contact and mesh generation to resolve the chip shape.