April 25, 2013

Benefit Assessment of High Productivity Ultrasonic-Assisted Drilling for Shipbuilding

Matt Short

Engineering Team Leader

Ultrasonics

614.688.5137

mshort@ewi.org

Harvey Castner

EWI

614-688-5063

hcastner@ewi.org

Outline

� Background and Advantages of Ultrasonic Machining

� Project Objectives and Approach

� Shipyard Survey

� Applications Development

� Future Work

UM – Part of Field of High Power Ultrasonics (HPU)

• HPU … application of intense, high-frequency acoustic energy to changematerials, processes.

Ultrasonic energy causes change in Material or Process

Ultrasonic

Transducer

Transmission

Material/Process

Power supply

60 ~

What is Ultrasonic Machining?

� The application of ultrasonic vibrations to “traditional” machining processes (drilling, turning, milling …) to improve performance (e.g. faster drilling, drilling of hard materials, better tool life, increased accuracy, …)

Concepts of adding US vibrations to various machining processes

AcousTech Machining

� Ultrasonic machining was investigated with limited applications in the 1960’s and 1970’s

� Prior work relied on heavily modified systems using one off tooling─ Specialty machines requires additional capital

investment

─ Unique tooling increases operation costs and training requirements

� AcousTechTM Vision─ Develop modular device that can be attached to

existing machine tools, and use conventional metalworking tools to significantly reduce operating costs while improving productivity

Technology Overview

� AcousTechTM

Machining─ Application of intense

acoustical vibrations to conventional cutting tools

─ HP Transducer

─ 5kW total power

─ 20kHz frequency

─ Adjustable displacement

─ Longitudinal wave

� Benefits ─ Reduced forces/torque

─ Lower tool temperatures

─ Increased feeds

─ Improved chip evacuation

─ Improved surface finish

Video of Drill Bit Excitation

Portable Application Example

� Integration of US power to portable equipment for field repairs

─ Portable equipment

─ Drill diameter of 1.875-in.

Technology Demonstration

Results

� Capable of performing operation in 36-sec. Not desirable due to surface finish.

� Successfully met surface requirements at ~5-min operation time.

� Improved true position of hole� Maintained ability to revert to

Morse taper tooling� Completely isolated vibrations

from drill head� Capable of performing several

operations with same drill bit� Reduced total cycle time from 2.3-

hrs per hole to 20-min per hole

Machine Tool Applications

� Develop modular system to be fitted with new or existing machine tools

� System to work with industry standard spindle designs (CAT-, HSK-, BT-, Morse Taper, etc.)

� Design of system must isolate vibrates from spindle bearings, machine structure, and machined part

Haas 5-axis MC

Machining Module Test Results

Static, Case Mounted

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0.00% 20.00% 40.00% 60.00% 80.00% 100.00% 120.00%

Long. Node Amp Displacement

Radial Amp at Nodal Position

Bore Face Amp Displacement

Tool Tip Displacement

Back Mass Long. Amp Displacement

Radial Amp at Back Mass

Long. Amp. @ Tool Holder Interface

Rad. Amp. @ Back End of Case

Rad. Amp. @ Node Position w ith Case

Critical measurement

is longitudinal displacement

at tool holder interface.

Laser vibrometer data

proves that all vibrations

are isolated out of the

tool holder, therefore, spindle.

Project Summary

Objective: This project will assess the potential of shipbuilding applications that can benefit from the use of ultrasonic assisted drilling to shorten build time and reduce the cost of ship construction.

Scope of Work:

� Task 1 Shipyard Survey

� Task 2 Application Development

� Task 3 Business Case Analysis and Reporting

� Task 4 Industry Workshop

Shipyard Survey

� EWI identified high-volume or high-cost drilling applications that can benefit from improved drilling methods at the participating shipyards.

� Twenty-six potential ship-board drilling applications were identified at one shipyard. Data gathered included: ─ Current drilling practices

─ Type of drilling tools and machines

─ Material types and thicknesses

─ Sizes and number of holes drilled

� Selected applications for development and demonstration.

Application Development

� Portable drilling of steel selected as technology demonstration

� Portable magnetic drill similar to systems used by shipyards.

� Two new modules were designed, built, and tuned to operate at 20 kHz. to allow for the demonstration of a two-step drilling operation:─ Module #1 will be fitted with a small diameter bit (e.g. a 7/8-in.

twist bit) and used to drill a new hole in the base material

─ Module #2 will be fitted with a larger diameter bit (e.g. a 1-1/2-in. spade tip bit) and used to drill out the original hole.

� Drilling feeds and speeds will be developed and the improved capabilities of UD demonstrated.

Shipyard Applications

� First prototype fabricated around design of Morse Taper attachment method─ Confirmed isolation of vibrations

─ Utilized external slip ring assembly for power transmission

─ Performed drilling studies to measure level of impact

─ Integrated various tool attachment methods

� Next steps:─ Complete business case analysis of shipyard

applications

─ Hold workshop to demonstrate technology

─ Compete final report

Questions