ERC
NSM
Title
Development of Forming Processes for Copper
Components for The Stanford Linear Accelerator
Master’s Thesis Project
for
Dan Hannan
Graduate Research Associate
In Cooperation with the Stanford Linear Accelerator Center (SLAC)
Precision Forging Technology
Outline
• Introduction – What is an accelerator cell?
• Objectives
• Approach
• Flow stress measurement
• Lubricant contamination tests
• Future work
Precision Forging Technology
ERC
NSM
What is an Accelerator Cell?
ERC
NSM
• 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.
Precision Forging Technology
Accelerator Cell
Tolerances as low as .5 Microns
Precision Forging Technology
ERC
NSM
ERC
Accelerator Cell
*Cost estimate for cell
fabrication without forging
NSM
Rough Machining
Annealing
Precision Machine
Daimond Turn
QC
Cleaning
Total
Precision Forging Technology
$23.38
$4.07
$20.70
$47.13
$1.27
$1.74
$98.29
24%
4%
21%
48%
1%
2%
ERC
Accelerator Cell
NSM
*Cost estimate for cell
fabrication with forging
Forge
Annealing
Precision Machine
Daimond Turn
QC
Cleaning
Shipping
Total
Precision Forging Technology
$0.54
$0.50
$8.21
$4.02
$0.31
$0.44
$0.35
$14.37
4%
3%
56%
28%
2%
3%
2%
Accelerator Cell
SLAC’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
Precision Forging Technology
ERC
NSM
Accelerator Structure
980,000 Total Cells
Precision Forging Technology
ERC
NSM
ERC
NSM
Precision Forging Technology
Objectives
ERC
NSM
• 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
Precision Forging Technology
Approach
• Measurement of flow stress for copper
• Lubricant contamination tests
• Process design for copper accelerator cell
Precision Forging Technology
ERC
NSM
Flow Stress Measurement
ERC
NSM
• Compression Test w/ Rastageav’s
Specimens
• Specimens coated with wax
• Dies lubricated with Teflon sheets
and Teflon spray
• Load and displacement recorded
Precision Forging Technology
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
Precision Forging Technology
ERC
NSM
Lubricant Contamination Tests
ERC
NSM
• 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
Precision Forging Technology
Lubricant Contamination Tests
ERC
NSM
• 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
Precision Forging Technology
Lubricant Contamination Tests
ERC
NSM
• 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)
Precision Forging Technology
Future Work
Process Design
ERC
NSM
• 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
Precision Forging Technology
Future Work
Process Design
ERC
NSM
• 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
Precision Forging Technology
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
Precision Forging Technology
ERC
NSM