Vacuum Pump

Vibration Isolation

System

Winter

2011PRODUCT DESIGN

SPECIFICATIONS REPORT

Sponsoring Company: Edwards Vacuum Ltd.

Contact Engineers: Mark RomeoBree Edwards

Academic Advisor:Dr. Dave Turcic

Team Members:Ron PahleKhoa T. TranDuc M. LeThanh Q. Nguyen

Table of Contents1. Project Background.....................................................................................................32. Purpose of the Product Design Specification Document.............................43. Mission Statement.......................................................................................................54. Project Plan.....................................................................................................................55. Customer Identification.............................................................................................56. Customer Interview and Feedback Summary..................................................67. Product Design Specification..................................................................................68. House of Quality...........................................................................................................99. Risk Mitigation............................................................................................................1010. Conclusion.................................................................................................................1111. Appendices................................................................................................................11

1. Project Background

Undesired noise and vibrations are major problems in many engineering activities and domains. At Edwards Vacuum Ltd., vibrations from vacuum pumps present an issue to their customers at Intel Corporation. Fabrication of microchips at Intel involves precise operation at the nano-scale. This leads to a very strict tolerance to vibratory noise in Intel’s fabrications. At Intel, multiple vacuum pumps (from Edwards) are used for atmospheric control in sensitive microchip fabrication processes. Rotating equipment is a potential source of vibration and can transmit vibration from the vacuum pumps to the building structure and to the processing tools. These vacuum pumps are seated on a rigid steel frame on a concrete floor within a limited space as shown in Figure 1. These pumps propagate vibration waves through the rigid frame to the floor and other piping fixtures attached to the frame.

Figure 1: Frame pump system from Edwards Vacuum Ltd.

Edwards wants to remain a top supplier of vacuum pumps and are anticipating Intel’s demand of further vibration reduction. As a vacuum pumps supplier, Edwards has achieved a great amount of vibration reduction without looking into the dynamics of the supporting frame. The vacuum pumps are designed with vibration isolators as shown in Figure 2. In fact, Edwards has legitimately satisfied all terms of their contract with Intel concerning vibrations. The capstone team at Portland State University expects to provide Edwards with another competing technique to reduce the overall vibration in their system.

Figure 2: Edward’s typical vacuum pump system (side-view).

2. Purpose of the Product Design Specification Document

The Product Design Specification document must clearly define the design criteria, metrics, targets, priorities and customer needs. Some prominent criteria include: cost; percent reduction in vibration; size and service life. A detailed list of criteria is provided in the Product Design Specification section. The team and our customers are to agree on this document as a principal guideline for product delivery. This document will be referred to in case of a dispute over the product’s performance or related issues.

3. Mission Statement

Devise a solution to minimize the vibration propagated from the pump system through the steel frame and to the surrounding workplace. This is meant to reduce any interference the pumps vibrations have on the sensitive manufacturing equipment on the manufacturing floor located above the pump floor. There are a variety of constraints that will be addressed including seismic regulations, environmental cleanliness, and space limitations. This solution will consist of a working prototype, supporting data, detailed drawings and a final report. Our customers for this solution will be Edwards Vacuum Ltd. and their correspondents at Intel Corporation. The solution will be needed for full scale testing by April 11th, 2011 and a finalized design due on June 8th, 2011.

4. Project Plan

The details of the project’s timeline are detailed in a Gantt Chart in Appendix A. This timeline was constructed based on deadlines provided by ME492 and by Mark Romeo of Edwards Vacuum Ltd. The main features of this plan include the Product Design Specifications, External and Internal Research, Concept Evaluation and Selection, Detail Design, Prototype Construction and Testing, and Documentation.

5. Customer Identification

The main external customer of this project is Edwards Vacuum Ltd. in Hillsboro, OR. Other external customers are Edwards’ direct customer Intel Corporation. Intel uses the pump system on its manufacturing floor and machine technicians are responsible for operation and maintenance of the pump system.

The main internal customers of the project are the capstone courses, ME 491/492/493. Other internal customers are PSU faculty

advisors, who help keep track of the project’s progress and all team members.

6. Customer Interview and Feedback Summary

The initial meeting with the sponsor took place during the ME 491 course. Other meetings and tours at Edwards Vacuum’s facility were held later, when the problem was further clarified and general design specifications were discussed. Some technical and functional requirements were determined in the interview with engineers from Edwards Vacuum Ltd. as followed:

The system must reduce vibration from the pump to the ground

The vibration isolation system needs to be compact enough to fit

the size of the existing frames.

The system should work for a variety of pump speeds (frequencies

from 30 – 105 Hz).

Also, weekly meetings were held with Dr. Turcic, PSU faculty advisor. Internal customers’ feedback from these meetings helped the team with communication and design decisions.

7. Product Design Specification

The Product Design Specification (PDS) is the most important part of this report. In this section, all the criteria related to the product are listed with their corresponding priority level. These criteria have been discussed and developed by the team based on requirements from our customers as well as advice from experts. The PDS is outlined in Table 1.

Table 1: Applicable PDS criteria and page

Criteria Priority Page

Performance High 6Environment High 6Life in service Low 6Cost of production per part Medium 7Size Medium 7Weight Low 7Maintenance Low 7Installation High 7Ergonomics (Ease of operation) Low 7Materials High 7Quality and Reliability High 7Documentation High 7Competition products Medium 7Timelines High 7

Legend: High priority Medium priorityLow priority

PERFORMANCEPriority

Requirement Customer

Metrics Target Target basis

Verification

Vibration reduction

Edwards

% in acceleration

25> Edwards required

Prototyping

Power consumption

Edwards

Watt 0 Edwards required

Prototyping

Ease of use Edwards

N/A Totally passive operation

Edwards required

Prototyping

Life in service Edwards

Years 10 Edwards required

Design

ENVIRONMENTPriority

Requirement Customer

Metrics

Target Target basis

Verification

Clean room compatible

End user

yes/no

Clean room qualified

End user required

Design

Eco friendly product

Self yes/no

Green material

Group interest

Design

SIZE, SHAPE AND WEIGHTPriority

Requirement Customer

Metrics

Target Target basis

Verification

Size Edwards

yes/no

Fitting within the frame

Ergonomic

Prototype

Weight Edwards/Self

lbs < 100 Product portability

Prototype

INSTALLATION AND MAINTENANCEPriority

Requirement Customer

Metrics

Target Target basis

Verification

Time to assemble/disassemble

Edwards

Minutes

< 15 Product complexity/Edwards required

Prototype

Tool requirement

Edwards

Number of special tool

0 Product complexity/Edwards required

Prototype

Mechanical compatibility

Edwards

Yes/No

Yes Edwards required

Prototype

Maintenance frequency

Edwards

Years 10 Edwards required

Testing

MATERIAL Prior Requirement Custo Metri Target Target Verificat

ity mer cs basis ionClean room compatible materials

End user

Yes/No

Clean room qualified

End user required

Design

Reasonable price

Self N/A Inexpensive

Budget Design

Easy to machine

Self N/A Can be machined in the machine shop

Self/Expert

Prototype

DOCUMENTATIONPriority

Requirement Customer

Metrics

Target Target basis

Verification

PDS PSU Deadline

PSU Report

Progress report

PSU Deadline

PSU Report

Final report PSU/Edwards

Deadline

PSU/Edwards

Report

Timeline Self/Edwards

Deadline

Self/Edwards

Report

8. House of Quality

The House of Quality is a strong tool for exploring the relationship between requirements and engineering criteria. It can also be used as a tool for comparing similar products from different competitors. From that we can set the target for our own product. In the left column, the most

COSTPriority

Requirement Customer

Metrics

Target Target basis

Verification

Price per pump

Edwards

$ < 1000

Edwards required

Design

Testing equipment

Self $ < 3000

Budget/Expert

Testing

important requirements obtained from the PDS are listed. Those requirements are related to some engineering criteria on the right. The * symbol represents the level of influence.

Highest influence: *****

Lowest influence: *

The competitor evaluation part of the House of Quality is neglected due to the unique characteristic of this project. The product that we will deliver in June will not compete in the market, but will be internally used by Edwards. An effort will be made to keep an open mind to any approach that could possibly solve the problem.

Table 2- House of Quality

Requirement Customer

Imp Engineering Criteria

WeightLb

StiffnessLb/inch

Size

inch

Cost$

Damper

Lb-s/inch

Component

No. of unit

PERFORMANCE

End user

4Vibration reduction 1.5 ** **** *** *****

Frequency range 1.5 *** *** *****Ease of use 1 * * ** **

QUALITY/ RELIABILITY

Edwards

3

Maintenance 1.5 ** ** ** ****Life in service 1.5 ** *** ** *

INSTALLATION

Edwards

3Assemble/

disassemble time 2 *** ** ** ****

Human power 1 *** *** **

9. Risk Mitigation

Some of the risks associated with the project are identified in the Table 3.

Table 3- Risk Assessment Table

Risks Consequence Likelihood Level of risk

Product is not delivered on time Marginal Unlikely Medium

Product does not achieve the desired level of damping

Critical Possible Medium

Project budget overspent Marginal Rare Low

Machine breakdown during testing Critical Rare Low

The project is determined to be a medium risk one, mostly due to the complexity of the system and the project time constraints. Budget and machine breakdown are also considered, but their rare occurrence indicates a low level of risk.

10. Conclusion

The PDS document will serve as a reference throughout the design process for the Isolating Vacuum Pump System Vibration project. . The requirements in the PDS section of the report will be a valuable tool in the design process that will help deliver a solution that can satisfy Edwards Vacuum Ltd. as well as the projects other customers. The projects mission to deliver a solution that minimizes the vibration from the pump to the process floor will be challenging. The detailed design plan outlined in this document will alleviate some of the challenges that come with such a difficult project.

11. Appendices

Appendix A- Project Timeline