ERC NSM Development of Forming Processes for Copper Components for The Stanford Linear Accelerator Master’s Thesis Project for Dan Hannan Graduate Research

ERCNSM

Development of Forming Processes for Copper Components for The Stanford Linear Accelerator

Master’s Thesis Project

for

Dan HannanGraduate Research Associate

In Cooperation with the Stanford Linear Accelerator Center (SLAC)

Title

Precision Forging Technology

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Outline

• Introduction – What is an accelerator cell?

• Objectives

• Approach

• Flow stress measurement

• Lubricant contamination tests

• Future work

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What is an Accelerator Cell?

• An accelerator cell allows subatomic particles to achieve high energy and then collide with targets within an accelerator structure

• Out of this interaction come many other subatomic particles that pass into detectors

• From the information gathered in the detectors, physicists can determine properties of the particles and their interactions.

• The higher the energy of the accelerated particles, the more closely one can probe the structure of matter.

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Accelerator Cell

Tolerances as low as .5 Microns

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Accelerator Cell

*Cost estimate for cell

fabrication without forging

Rough Machining $23.38 24%Annealing $4.07 4%

Precision Machine $20.70 21%Daimond Turn $47.13 48%

QC $1.27 1%Cleaning $1.74 2%

Total $98.29

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Accelerator Cell

*Cost estimate for cell

fabrication with forging

Forge $0.54 4%Annealing $0.50 3%

Precision Machine $8.21 56%Daimond Turn $4.02 28%

QC $0.31 2%Cleaning $0.44 3%Shipping $0.35 2%

Total $14.37

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Accelerator CellSLAC’s Perspective

• With the following assumptions:– 980,000 accelerator cells– Shop rate = $200.00/Hr = .06 cents/sec

• Then every second saved during manufacturing of a single cell will result in savings of $54,000 for the entire lot of cells

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Accelerator Structure

980,000 Total Cells

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Objectives

• Investigation of surface contamination during forming of copper

• Reduce the machining cost by forming to near net shape dimensions– Develop forming sequence– Tool design– Compensation for elastic deflection

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Approach

• Measurement of flow stress for copper

• Lubricant contamination tests

• Process design for copper accelerator cell

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Flow Stress Measurement

• Compression Test w/ Rastageav’s Specimens

• Specimens coated with wax• Dies lubricated with Teflon sheets

and Teflon spray• Load and displacement recorded

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Flow Stress Measurement

• Specimens to be manufactured by SLAC– 10 from sheet, as received– 10 from billet, as received– 10 from billet, stress relieved

• No barreling can occur

• Must correct for press deflection and temperature

• Purpose:– To obtain accurate flow stress data for FEM simulations

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Lubricant Contamination Tests

• Contamination of formed surfaces is a major concern in the manufacturing of the SLAC particle accelerator cell

• If the contamination is too deep into the surface of the part it will not be removed during the finish machining stage

• Two different tests will be used to investigate contamination from the lubrication and the tool surface:– Single cup backward extrusion test– Ring test

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• Specimens will be manufactured by SLAC

• Candidate lubricants will be chosen by ERC/NSM and approved by SLAC

• Common lubricants used in the forging of copper are:– Emulsions of fatty oils – mineral oils– Fatty oils – graphite– Graphite – grease

• From the ring test, the coefficient of friction will be approximated

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• The single cup backward extrusion test will produce higher pressures than the ring test

• The single cup backward extrusion test will provide insight on the ability to deliver formed parts to the tolerances required

• After the experiments are finished, specimens from both tests will be shipped to SLAC for inspection (lubricant contamination)


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Future WorkProcess Design

• Design of the as-formed geometry

– ERC/NSM will find the geometry that limits that amount of machining required, but allows the part to be formed to the required tolerances

– Elastic deflection of the tools and metal flow will be investigated

• Development of preliminary forming sequence

– ERC/NSM will design a forming sequence that produces the part to the required tolerances at minimal cost.

– High forming pressures will be avoided to limit deflection of the tools

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Future WorkProcess Design

• Development of preliminary forming sequence (cont.)

– The help of forging companies will be used to evaluate the feasibility of suggested forming sequences

– FEM simulations will be used to test the forming sequence to see if the part can be formed without defects under reasonable loads.

• Compensation for tool deflection

• Investigate other copper components that could be formed to near net shape dimensions

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Deliverables

• Know how on forming processes to produce the accelerator cell

• Cost reduction in the production of the accelerator cell

• Tool drawings for the manufacture of forming tooling

• Progress Reports, Final Report

Documents

ERC NSM Development of Forming Processes for Copper Components for The Stanford Linear Accelerator Master’s Thesis Project for Dan Hannan Graduate Research